Achillea

SPECIALTY CUT FLOWERS

SPECIALTY CUT FLOWERS 

The Production of Annuals, Perennials, Bulbs, and 

Woody Plants for Fresh and Dried Cut Flowers 

Second Edition, Revised and Enlarged 

Allan M. Armitage and Judy M. Laushman 

Illustrations by Patti Dugan 

Timber Press 

Portland • Cambridge

Photographs by Allan M. Armitage unless otherwise noted. 

Frontispiece (Gypsophila paniculata ‘Bristol Fairy’) and all other illustrations by 

Patti Dugan 

2235 Azalea Drive 

Roswell, GA 30075 

770.643.8986 

email Kdugan3000@aol.com 

Copyright © Allan M. Armitage 2003. All rights reserved. 

First edition published 1993. 

Published in 2003 by 

Timber Press, Inc. 

The Haseltine Building 2 Station Road 

133 S.W. Second Avenue, Suite 450 Swavesey 

Portland, Oregon 97204 U.S.A. Cambridge CB4 5QJ, U.K. 

Printed in China by Imago 

Library of Congress Cataloging-in-Publication Data 

Armitage, A. M. (Allan M.) 

Specialty cut flowers : the production of annuals, perennials, bulbs, and 

woody plants for fresh and dried cut flowers / Allan M. Armitage and Judy 

M. Laushman; illustrations by Patti Dugan. 

p. cm. 

Includes bibliographical references (p. ). 

ISBN 0-88192-579-9 

1. Floriculture. 2. Cut flower industry. 3. Cut flowers. 4. Cut flowers— 

Postharvest technology. 5. Floriculture—United States. 6. Cut flower 

industry—United States. I. Laushman, Judy M. II. Title. 

SB405 .A68 2003 

635.9'66—dc21 

2002073256

To my wife, Susan, who constantly strives for perfection in 

everything she attempts. She is my role model. 

—A.M.A. 

In memory of my mom, Catherine Brennan Marriott; and 

with gratitude and love to Roger, Dan, and Katie for their 

support, patience, and unique humor. 

—J.M.L.

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CONTENTS 

Preface 9 

Acknowledgments 12 

Introduction 15 

Postharvest Care 20 

Drying and Preserving 30 

Cut Flowers: Achillea to Zinnia 35 

References 553 

Appendix I. Stage of Harvest 559 

Appendix II. Additional Plants Suitable for Cut Flower Production 565 

Appendix III. Useful Conversions 571 

U.S. Department of Agriculture Hardiness Zone Map 572 

Index of Botanical Names 573 

Index of Common Names 581 

Color photographs follow page 64 

7


PREFACE 

The first edition of Specialty Cut Flowers arrived on book stands in 1993 and 

immediately became a highly popular book on the subject. A good deal has 

changed since the first edition, including the emergence of additional crops in 

the cut flower market and the decline of others. The world has seen new leaders, 

breakthroughs in medicine and science, boom and bust of economic indicators, 

conflicts, peace, and unimagined visions of terrorism. Through all these events, 

people went about their business. Companies emerged and others failed, money 

was made and life savings were lost. The cut flower business was no exception. 

Florida and California are home to major flower farms, and a scattering of 

farms greater than 50 acres can be found in various other states; but large growing 

facilities are mainly found overseas. The dominance of the overseas grower 

has had an interesting effect on the cut flower market in America. Certainly, 

American growers cannot compete in the rose, carnation, and mum markets, 

nor are staples like baby’s breath easy to grow profitably. These flowers are such 

commodity items, it is difficult to be profitable, regardless of where or how these 

plants are grown. But while the bulk of flowers still arrives from overseas, American 

growers have filled in many of the gaps because they are able to serve small 

markets and to capitalize on the issues of freshness and diversity of material. 

Markets are always changing, but as long as the consumer wants the product, 

there are enough outlets for everyone. 

The marketing of flowers has changed. The traditional route of grower to 

wholesaler to retailer continues to be the highway for large numbers of cut 

stems; however, smaller and equally efficient avenues have reemerged. The small 

grower has made a huge comeback, supporting farmers’ markets in many small 

towns and large cities. 

When the first edition was written, specialty cut flowers were just beginning 

to be recognized as “real” crops, not just flunkies of the Big 3—roses, carnations, 

and mums. Today, the trend toward specialty crops is even stronger because of 

the willingness of the market to try unusual material and the willingness of 

growers to provide it. For example, marginal crops like verbena and cardoon are 

found as cut stems; florists are offering dodecatheon, Chinese forget-me-nots, 

and weed-like plants like chenopodium, atriplex, and even Johnson grass. And 

who would have thought that vegetables like okra, artichoke, ornamental kale, 

9

10 PREFACE 

and eggplant would be considered useful crops for cut stems? But growers are 

producing them, and they are being sold. One thing is certain about the cut 

flower market: the only limitation to what can be used as a cut stem is the imagination 

of the user. 

The consumer remains the key. The cut flower market is like a burlap bag full 

of puppies: the edges are always moving, it constantly changes position, and it is 

not made up of a single predictable element but rather of many elements, moving 

randomly. Nobody can predict what the strength of the market will be, 

nobody can predict the next great flower or the next great color. The question 

remains, how do we keep the consumer interested in our product? It really 

doesn’t matter if the stems come from Bogota, Quito, or Omaha, what matters 

is that someone wants to buy flowers. Promotional campaigns, television ads, 

Grandmother’s Day all help—but what keeps everyday consumers and professional 

floral arrangers coming back is the perception of value. Most producers 

don’t have the funds to create ad campaigns, and to be honest, who pays attention 

to ads anymore? No amount of advertising is going to talk anyone into a 

bouquet or some stems if they don’t believe that those flowers push an emotional 

button, such as love, beauty, sympathy, or gratitude. These buttons are 

genetically programmed in the human race; the only difference is what pushes 

them. Fine food, fine wine, and good movies all compete for these spots in a person’s 

soul, so what is a cut flower farmer in Dubuque to do? The answer is 

uncomplicated: grow fine flowers—not just flowers, but fine flowers. Provide the 

best freshness, the best stems, the best bouquets, and the best service you know 

how, and service those buttons. That is all you can do, but if that is done well, the 

rest takes care of itself. 

The answer might be simple, but the techniques needed to grow fine flowers 

and provide fine service are constantly changing. Production methods, cultivar 

selection, postharvest procedures, transportation, floral displays, and running 

the day-to-day aspects of a business are challenging and tiring. To be successful, 

one must be a horticulturist, agronomist, and pathologist, mixed with the skills 

of a salesperson and truck driver, and topped off with the enthusiasm of a cheerleader. 

Larger operations can delegate these activities; smaller ones find a few 

people balancing them all. 

This edition serves the same function as the first—to help growers produce the 

fine flowers needed to be profitable. But some changes are obvious. Two authors 

are better than one, and the addition of Judy Laushman as co-author has elevated 

the quality of the book significantly. The format has been changed for easier 

reference (bulb or woody, plants now appear in single, straightforward A-to- 

Z order), crops have been added, and research findings and readings have been 

updated (so you know we didn’t just make all this stuff up). We debated long and 

hard over the addition of several flowers. We know they’re being grown, sold, 

and accepted by the market; however, unless we could find current research as 

well as sufficient production information, we decided that crop would have to 

wait until the next edition. 

But the most important change has been the input of the cut flower growers 

themselves, the vast majority of whom are members of the Association of Spe-

PREFACE 11 

cialty Cut Flower Growers. They not only reviewed the sections, they gave us permission 

to use their candid comments about their experiences in growing the 

crops. These personal, “real world” comments provide invaluable insights and 

are a refreshing contrast to the many impersonal words and numbers in the 

book. To everyone who helped, you have the thanks of every reader, in every state 

and country. 

Allan M. Armitage 

Judy M. Laushman

ACKNOWLEDGMENTS 

The information contained in a book of this magnitude is only as good as the 

people who helped generate it. We were extraordinarily fortunate to have had the 

help of several talented reviewers. They read, corrected, critiqued, and suggested 

changes to various sections; their comments and suggestions were invaluable. 

Many of the people below assisted in the first edition (1993), and affiliations 

and locations may have changed since that time. 

Carolyne Anderson, Anderson Farms, Clark, Mo. 

Bob Anderson, Dept. of Horticulture, University of Kentucky, Lexington 

Kelly Anderson, WildThang Farms, Ashland, Mo. 

Frank Arnosky, Texas Specialty Cut Flowers, Blanco, Tex. 

Linda Baranowski-Smith, Blue Clay Plantation, Oregon, Ohio. 

J. B. Barzo-Reinke, Small Pleasures Farm, Bandon, Ore. 

Bill Borchard, PanAmerican Seed Company, Santa Paula, Calif. 

Pat Bowman, Cape May Cut Flowers, Cape May, N.J. 

Jo Brownold, California Everlastings, Dunnigan, Calif. 

Lynn Byczynski, Growing for Market, Lawrence, Kans. 

Maureen Charde, High Meadow Flower Farm, Warwick, N.Y. 

Phillip Clark, Endless Summer Flower Farm, Camden, Maine 

Ken and Suzy Cook, Atlanta, Ga. 

Douglas Cox, Dept. of Horticulture, University of Massachusetts, Amherst 

Ralph Cramer, Cramers’ Posie Patch, Elizabethtown, Pa. 

Mimo Davis, WildThang Farms, Ashland, Mo. 

Elizabeth Dean, Wilkerson Mill Gardens, Palmetto, Ga. 

August De Hertogh, Raleigh, N.C. 

John Dole, Dept. of Horticultural Science, North Carolina State University, 

Raleigh 

Dave Dowling, Farmhouse Flowers, Brookeville, Md. 

Fran Foley, Aptos, Calif. 

Janet Foss, J. Foss Garden Flowers, Everett, Wash. 

Keith Funnell, Dept. of Horticulture, Massey University, Palmerston North, 

New Zealand 

Jim Garner, Atlanta, Ga. 

12

ACKNOWLEDGMENTS 13 

Karen Gast, Kansas State University, Manhattan 

Chas Gill, Kennebec Flower Farm, Bowdoinham, Maine 

Ken Goldsberry, Dept. of Horticulture, Colorado State University, Fort 

Collins 

Jack Graham, Dramm and Echter, Watsonville, Calif. 

Bernadette Hammelman, Hammelman’s Dried Floral, Mt. Angel, Ore. 

Jeff Hartenfeld, Hart Farm, Solsberry, Ind. 

Will Healy, Ball Seed Company, West Chicago, Ill. 

Brent Heath, The Daffodil Mart, Gloucester, Va. 

Mel Heath, Bridge Farm Nursery, Cockeysville, Md. 

Peter Hicklenton, Agriculture Canada, Kentville, Nova Scotia 

Christy Holstead-Klink, Floral Communication and Technical Services, 

Nazareth, Pa. 

Mark Hommes, Bulbmark, Inc., Wilmington, N.C. 

Steve Houck, Accent Gardens, Boulder, Colo. 

Cathy Itz, McCall Creek Farms, Blanco, Tex. 

Jennifer Judson-Harms, Cricket Park Gardens, New Hampton, Iowa 

Corky Kane, Germania Seed Company, Chicago, Ill. 

Philip Katz, PanAmerican Seed Company, Santa Paula, Calif. 

John Kelley, Dept. of Horticulture, Clemson University, Clemson, S.C. 

Huey Kinzie, Stoney Point Flowers, Gays Mills, Wis. 

Roy Klehm, Klehm Nursery, South Barrington, Ill. 

Mark Koch, Robert Koch Industries, Bennett, Colo. 

Bob Koenders, The Backyard Bouquet, Armada, Mich. 

Ginny Kristl, Johnny’s Selected Seeds, Albion, Maine 

John LaSalle, LaSalle Florists, Whately, Mass. 

Dave Lines, Dave Lines’ Cut Flowers, La Plata, Md. 

Dale Lovejoy, Anderson Levitch/Lovejoy Farms, Eltopia, Wash. 

Howard Lubbers, Ottawa Glad Growers, Holland, Mich. 

Tom Lukens, Golden State Bulb Growers, Watsonville, Calif. 

Robert Lyons, Dept. of Horticultural Science, North Carolina State 

University, Raleigh 

Roxanne McCoy, Lilies of the Field, West Falls, N.Y. 

Shelley McGeathy, McGeathy Farms, Hemlock, Mich. 

Jeff McGrew, Jeff McGrew Horticultural Products, Mt. Vernon, Wa. 

Mike Mellano Sr., Mellano & Company, San Luis Rey, Calif. 

Ruth Merrett, Merrett Farm, Upper Kingsclear, N.B. 

Kent Miles, Botanicals by K&V, Seymour, Ill. 

Susan Minnich, Coles Brook Farm, Becket, Mass. 

Don Mitchell, Flora Pacifica, Brookings, Ore. 

Brian Myrland, Floral Program Management, Middleton, Wis. 

Sally Nakasawa, Nakasawa Everlastings, Yuma, Ariz. 

Jim Nau, Ball Seed Company, West Chicago, Ill. 

Knud Nielsen III, Knud Nielsen Company, Evergreen, Ala. 

Peter Nissen, Sunshine State Carnations, Hobe Sound, Fla. 

Leonard Perry, Dept. of Horticulture, University of Vermont, Burlington

14 ACKNOWLEDGMENTS 

Ed Pincus, Third Branch Flower, Roxbury, Vt. 

Bob Pollioni, Ventura, Calif. 

Bill Preston, Bill Preston Cut Flowers, Glenn Dale, Md. 

Whiting Preston, Manatee Fruit Company, Palmetto, Fla. 

Jeroen Ravensbergen, PanAmerican Seed Company, The Netherlands 

Jim Rider, Jim Rider Flowers, Watsonville, Calif. 

Jan Roozen, Choice Bulb Farm, Mount Vernon, Wash. 

Roy Sachs, Flowers and Greens, Davis, Calif. 

Paul Sansone, Here and Now Garden, Gales Creek, Ore. 

Craig Schaafsma, Kankakee Valley Flowers, St. Anne, Ill. 

Bev Schaeffer, Schaeffer Flowers, Conestoga, Pa. 

Ray Schreiner, Schreiner’s Iris Gardens, Salem, Ore. 

Mary Ellen Schultz, Northbloom Farm, Belgrade, Mont. 

Gay Smith, Pokon & Chrysal, Portland, Ore. 

Ron Smith, R. Smith Farm, Renfrew, Pa. 

Roy Snow, United Flower Growers, Burnaby, B.C. 

George Staby, Perishables Research Organization, Grafton, Calif. 

Vicki Stamback, Bear Creek Farm, Stillwater, Okla. 

Rudolf Sterkel, Ernst Benary of America, Sycamore, Ill. 

Dennis Stimart, Dept. of Horticulture, University of Wisconsin, Madison 

Mindy Storm, Blairsville, Ga. 

Joan Thorndike, Le Mera Gardens, Ashland, Ore. 

Ralph Thurston, Bindweed Farm, Blackfoot, Idaho 

Ann Trimble, Trimble Field Flowers, Princeton, Ky. 

Bernie Van Essendelft, Dual Venture Farm, Pantego, N.C. 

Kate van Ummersen, Sterling Flowers, Brooks, Ore. 

Alice Vigliani, Maple Ridge Peony Farm, Conway, Mass. 

Mike Wallace, Wood Creek Farm, Cygnet, Ohio 

Ian Warrington, HortResearch, Palmerston North, New Zealand 

Van Weldon, Wood Duck Farm, Cleveland, Tex. 

Eddie Welsh, Palmerston North, New Zealand 

Linda White-Mays, Sundance Nursery and Flowers, Irvine, Ky. 

Roxana Whitt, Wise Acres, Huntingtown, Md. 

Tom Wikstrom, Happy Trowels Farm, Ogden, Utah 

Blair Winner, PanAmerican Seed Company, Santa Paula, Calif. 

Bob Wollam, Wollam Gardens, Jeffersonton, Va. 

Jack Zonneveld, M. van Waveren Co., Mt. Airy, N.C. 

Patrick Zweifel, Oregon Coastal Flowers & Bulbs, Tillamook, Ore.

INTRODUCTION 

In the first edition of this book, the term “specialty cut flower” was defined as any 

crop other than roses, carnations, and chrysanthemums. In the years since, the 

market has changed so much, and the diversity of flowers in the market has 

become so great, that the term “specialty” really means very little any more. Bob 

Wollam, president of the Association of Specialty Cut Flower Growers, Inc. 

(2002–03), defines a specialty cut as “something that isn’t on the market on a regular 

basis or is there only for an exceptionally short time period. It can’t be used 

in a numbered bouquet, like FTD #46, which requires flowers you can get all 

year round.” John Dole of North Carolina State University adds that the definition 

is continuously evolving: “Soon . . . we will simply refer to ‘cut flower’ production 

in the U.S., not ‘specialty’ cut flower [production].” 

However, the Big 3 traditional crops have historically comprised the largest 

portion of cut flower production and sales in the world market and, in all likelihood, 

will continue to do so. The unwieldy number of specialty species, the 

difficulty in controlling field conditions, the lack of standards for specialty cuts, 

and the popularity of greenhouse-grown flowers made traditional crops easier to 

fund, and information flowed readily. The business of growing specialty cut 

flower crops, however, has been practiced for hundreds of years. European and 

Asian growers produced a vast variety of cut flowers in fields and conservatories. 

The American grower joined in with large acreages of peonies, tuberose, 

larkspur, gypsophila, and gladiolus, especially during the 1940s and 1950s. 

Growers come and go, the world market rises and falls, and while consumption 

of cut flowers has been stagnant in recent years, there is still significant room for 

expansion. 

The type of floral product purchased and the amount of money spent is more 

dependent on the use for which it is intended than on the product itself. In America, 

the most important reason is to celebrate special occasions: anniversaries, 

birthdays, Valentine’s Day, funerals, weddings. Competition for the special-occasion 

dollar is fierce. Flowers must go neck-and-neck against restaurants, movies, 

theaters, chocolates, and gifts. A second reason is to express emotions, such as 

love, thanks, condolence, apology, and congratulations. The third and still 

untapped reason for purchasing cut flowers is to create a pleasant atmosphere at 

home and work; promoting the use of flowers in these everyday ways must 

15

16 INTRODUCTION 

increase if they are to become a mainstream item. Whatever the consumer’s 

impulse to buy, enhanced sales can be accomplished only through production of 

high-quality flowers, aggressive promotion, and an increased number of outlets. 

The Role of Imports 

In some overseas countries, cut flowers have been politically expedient, and their 

development has been aggressively supported. Standard flowers—roses, carnations, 

mums, gypsophila, gladiolus—arrive from offshore suppliers daily, and, 

although many may disagree, their presence has had a positive influence on the 

American grower. The marketing skills of the Dutch, the inexpensive stems from 

Colombia and Ecuador, and the acceptance of these crops by the American florist 

have resulted in more crops and a significantly higher volume of cut flowers 

sold in this country than ever before. Competition from abroad will no doubt 

increase for all species of cut flowers, yet American growers will adjust and use 

that competition to their advantage. Some buyers will always base their purchases 

solely on price, but what else is new? 

The question, then, begs to be asked. How can the American grower compete? 

He can best compete by growing the highest quality product possible, providing 

the best service available, and ensuring proper handling and harvesting 

methods at a reasonable price. Local growers can supply specific products that 

ship poorly or that can be produced efficiently in their area. In fact, growers must 

always look for local niches for flowers that are poor shippers and otherwise 

difficult to find. Quality, freshness, and consistency are the keys to competitiveness, 

whether one is competing with Holland or California. Domestic growers 

must provide fresh-dated flowers and guarantee on-time delivery of all flowers 

on the contract. If flowers are going to be supplied by overseas growers, make 

those growers earn every dollar. The American grower can waste his time looking 

over his shoulder, or spend it doing a better job providing a consistently 

high-quality fresh-dated crop, on time and for a realistic price. 

Product Mix 

Many species are useful as cut flowers, but the decision of what to grow must be 

based on climatic conditions, availability of seed and plants, and, most important, 

what will sell in a given area. Diversity of product is important; growers 

should always be on the lookout for something new, and the importance of staying 

up-to-date cannot be overstated. But just remember: it is impossible to grow 

everything, and it is easy to turn around and suddenly find oneself producing 

100 different species and cultivars. 

More than ever before, the consumer reacts to and is willing to pay for the 

unusual. It used to be that the buying public was unaware of many lesser-grown 

plants, but times have changed, and the lesser-known specialty crops are in high 

demand. With the emergence of better cultivars and aggressive marketing, 

obscure species may turn out to be major winners. Growers of specialty flowers 

should not believe their products will replace the rose, or even the carnation; to

INTRODUCTION 17 

believe so is unrealistic and self-defeating. Growers, wholesalers, and retailers 

should be striving, instead, to complement the rose, enhance the carnation, 

show off the mum, and liven up the gladiolus. 

Plant Diversity 

The diversity of available plants and seeds includes annuals, perennials, bulbs, 

and woody species. Each class of cut flowers (or berries, foliage, stems) includes 

a wealth of plant species and cultivars, which may be used throughout the growing 

season. All these stems are now seen in wholesale coolers, florist outlets, and 

garden shops. Such species may end up routed through auctions or local flower 

or farmers’ markets, or sold directly to florists. Personal contacts between growers 

and salespersons can be made and sustained if there is a will to do so. Nowhere 

is it written that all produce must go through a distributor, ending up as 

generic product in a generic market for faceless people. 

A movement toward cut flowers grown for the local market has taken place, 

and consumers shopping at local florists and farmers’ markets are benefitting 

the most from this return to hometown roots. No longer is it necessary to ship 

a majority of flowers long distances before selling them. Growing areas near 

small towns and large cities have been established to provide material for distribution 

to those areas. There is no reason why growers near New York or Chicago 

or Denver should not be efficient enough to supply their own areas with 

product first, supplemented with materials from distant fields and lands. 

Volume and Price 

The volume of material in the market directly affects its price, creating a trap 

that many growers fall into. A new grower, for example, may find the demand for 

his crop is higher than expected, so immediately doubles production. More than 

likely, such a decision will prove unprofitable. Simply because 2000 bunches of 

flowers sold for $5 a bunch does not mean that 4000 bunches will sell for the 

same price. Not only does the unit price for his product fall, so do prices for 

other growers of the same product. The classic grower thinking that more is better 

must be changed. Similarly, the price a grower demands for a crop should not 

automatically fall in times of market glut. If the quality is consistent throughout 

the year, the grower need not acquiesce to claims of cheaper sources by the buyer. 

If trust and consistency of quality have been cultivated with the buyer, discounting 

the product to the point where profit has disappeared is poor business. 

Sometimes it is better not to harvest the excess than to sell it for a loss. No 

one wants to throw away potential earnings; however, once prices are lowered, it 

is difficult to raise them once again. 

Grading 

Most specialty cut flowers in America are not graded. The lack of standards 

reflects the inability to adequately enforce them in a country with such diverse

18 INTRODUCTION 

market outlets. Specific crops may call for specific standards, and it would seem 

to make sense to establish minimum baseline standards for appearance and 

quality of all American crops. Until such time as standards are agreed upon, 

grading will continue to be the domain of the producer—which is not all bad. 

Good businesses will become known not only for the quality of their product but 

for the consistency of their grading. Strict grading enhances trust: the buyer will 

soon realize that bunch after bunch, box after box, week after week, the product 

is consistent and true to grade. 

One’s grading system should be based on a combination of flower quality, 

stem strength, and stem length—standards that once established must be 

adhered to throughout the growing season. The numbers of flowers in a bunch 

should be established and maintained. For most flowers, a minimum of 10 stems 

per bunch is the standard. Let’s keep it simple: people know how to count by 

10s, while 8, 12, or 15 stems per bunch simply confuses the issue. Obviously, 

some larger flowers will not be bunched in 10s, and filler-type products are often 

sold by weight. Simply because stems are fatter or flowers a little larger does not 

excuse bunches with fewer stems. Similarly, if stems are thin, adding more flowers 

to the bunch does not raise the quality of the flowers—they still have thin 

stems! Placing poor-quality stems in the middle of a bunch or at the bottom of 

the box fools no one. Such tactics eventually fail, and someone gets hurt. Flowers 

must be graded as if the grower were the buyer, not the seller. 

Consignment 

Let the system of consignment die; it is wasteful and unproductive, benefiting no 

one in the long run. The product should be bought, not rented from the grower, 

and the responsibility for final sale and distribution of the fresh product must 

rest with the florist, distributor, or wholesaler, not the producer. Consignment 

systems inevitably result in ill will between producer and distributor and tend to 

weigh down a distribution system already burdened with lingering mistrust. 

Trust 

Trust between wholesaler and producer is a necessity in any business transaction. 

This will never change. In a good working relationship, problems on either 

the producer’s or wholesaler’s part can be discussed and corrected in professional 

terms. An open and frank communication makes the business of cut flowers 

far more enjoyable for all concerned. Similarly, discussion between growers 

is essential if the cut flower industry is to blossom and succeed in this country. 

People who put on cloaks of secrecy and refuse to share experiences and methods 

with others do themselves a great disservice. We have enough problems— 

seasonality, imports, hail, rain, freezing temperatures, drought, heat, and rodents—without 

tripping over each other to keep “secrets” secure. A free-flowing 

exchange of ideas is essential in any business, and this one is no exception. 

To that end, membership in trade associations, such as those that follow, is 

highly recommended for anyone dealing with specialty cut flowers.

Association of Specialty Cut Flower Growers, Inc. 

MPO Box 268 

Oberlin, OH 44074-0268 

phone 440.774.2887 

fax 440.774.2435 

www.ascfg.org 

International Cut Flower Growers 

P.O. Box 99 

Haslett, MI 48840 

phone 517.655.3726 

fax 517.655.3727 

ICFG@voyager.net 

Preserved Floral Products Association 

2287 Ash Point Road 

White Cloud, KS 66094 

phone 785.595.3327 

fax 785.595.3283 

Society of American Florists 

1601 Duke Street 

Alexandria, VA 22314 

phone 800.336.4743 

www.safnow.org 

INTRODUCTION 19 

The Association of Specialty Cut Flower Growers (ASCFG) is the only group 

devoted solely to the business of specialty cut flowers; their electronic bulletin 

board, on which members air problems and discuss solutions, is particularly 

effective.

POSTHARVEST CARE 

Whether flowers are delivered in a Volkswagen bus to the farmers’ market down 

the road or shipped thousands of miles across the world, comprehensive postharvest 

care and handling are essential. It may be argued that no one step in the 

chain of marketing flowers to the consumer is more important than any other. 

That is, if even one step is poorly accomplished, the whole chain is weakened: if 

water quality is poor, the fertility program is out of balance; if the incorrect cultivar 

is grown, the quality and potential sales of the crop suffer. These comments 

are true; however, once the stem is cut, proper harvesting, handling, and postharvest 

treatments are essential for maintaining the quality of the flowers. Without 

a suitable postharvest program, the wholesaler, florist, or consumer is being 

sold a defective item. 

The grower is responsible for the first stage of postharvest treatment, but 

others who handle the flowers (wholesaler, trucker, florist) have equal responsibility. 

It is easy to understand the importance of postharvest techniques when 

flowers must be shipped a long distance, but perhaps not so easy to justify the 

expense and trouble when they are only going across town. That thinking gets 

everyone in trouble. A lack of a consistent postharvest program can limit the 

sale of fresh flowers and greens. Consumers feel cheated when the flowers they 

purchase decline prematurely. The perception of “not getting one’s money’s 

worth” is extremely dangerous to this industry and must be eliminated. 

Carnations and chrysanthemums are popular because, in addition to shipping 

well, florists and the public perceive they are a good value for the money. 

That perception is the key to success in the fresh cut flower industry. Message to American 

growers: if your flowers are not fresher, of better quality, and longer lasting than 

those from overseas, then you should think seriously about another line of work. 

We need to sell more flowers, period. Better postharvest care translates into 

more flowers being sold, regardless of origin. More flowers sold translates to 

higher public visibility and a perceived necessity of the product. Purchasing 

flowers should be as commonplace as renting a video or dining out, but this 

won’t happen until the value for the money spent is perceived to be at least equal 

to that movie or meal. The industry must not only believe in the importance of 

correct postharvest treatments but practice them as well, for if flowers are not 

well handled, the future of the cut flower grower is questionable. 

20

Considerations of the Crop in the Field 

POSTHARVEST CARE 21 

Steps to enhance postharvest longevity of the flower may be taken before any 

flowers are cut. These practices begin with the selection of the cultivar to be 

grown and extend to maintaining the health of the plant in the field. 

Species and cultivar selection: Proper cultivar selection can mean the difference 

between profitability and economic struggle. Choose cultivars not only for 

flower color but for their potential vase life; simple tabletop tests of old favorites 

and new introductions will provide valuable data to help with plant selection. 

Test new products in vases and in foam; the more information the buyer receives, 

the more he will rely on the grower. Relying on information from the breeder is 

useful but should not be the final criterion for selection. Do it yourself. 

The environments under which plants will be grown must be considered. If a 

crop is grown in an unsuitable area, plants will never be as vigorous and active as 

they would be under more hospitable conditions. In general, plants grown in 

marginal environments are stunted and produce fewer flowers (each of which 

has a shorter vase life) compared to plants grown in a favorable environment. 

Why try to grow delphiniums in Phoenix in June? Attempting to grow a crop 

unsuitable to the area invariably results in a low-quality product and a decline in 

postharvest life. 

Health of the plants in the field: Integrating good postharvest methods with a 

growing regime that produces reasonable yields and high-quality stems is a goal 

to which all growers should aspire. Research has shown that anything that 

results in prolonged stress (improper fertility, over- or underabundance of water, 

cold, or heat) reduces postharvest life. Healthy plants produce long-lasting flowers, 

but it does not necessarily follow that the lushest, most vigorous plants bear 

flowers with the best postharvest life. In fact, flowers from plants that have been 

heavily fertilized or grown under warm temperatures often exhibit shorter shelf 

life than those that are grown a little “leaner” and cooler. In the greenhouse, 

plants are often hardened off by reducing temperature, fertilizer, or water prior 

to harvest to increase the life of the flower. 

Harvesting: The best time to harvest flowers is always a compromise, reached 

by weighing various factors. Flowers harvested in the heat of the day can be 

stressed by high temperatures. Dark-colored flowers can be as much as 10F (6C) 

warmer than white flowers on a bright, hot day. It may be argued that harvesting 

should be accomplished in late afternoon because the buildup of food (for 

subsequent flower development) from photosynthesis is greater than it is in 

the morning, but in the morning, water content of the stem is high and temperatures 

are low. These beneficial factors, combined with the practical considerations 

of packing, grading, and shipping of the same stems, mean that 

stems are generally cut early in the day. Harvesting should be delayed, however, 

until plants are dry of dew, rain, or other moisture. Cutting at high temperatures 

(above 80F, 27C) and high light intensity should be avoided whenever 

possible. 

After harvest, transfer all stems immediately to a hydrating solution and then 

to a cool storage facility to prevent water loss. Ethylene-sensitive flowers (see list

22 POSTHARVEST CARE 

later in this section) should also be placed in a hydrating solution in the field 

until treated with silver compounds in the grading area. 

Stage of development of the flower: In general, harvesting in the bud stage or as 

flowers begin to show color results in better postharvest life for many crops. One 

reason for cutting flowers in a tight stage is to reduce space during shipping. 

Tight flowers are not as susceptible to mechanical damage or ethylene, and more 

stems may be shipped in the box than stems with open flowers. Another is that 

tight-cut flowers, if handled well, provide more vase life to the consumer. But the 

tight flower stage is not optimum for all flowers; spike-like flowers, such as 

aconitum, delphiniums, and physostegia, should have 1 or 2 basal flowers open, 

while yarrow and other members of the daisy family require that flowers be fully 

open prior to harvest. If one is not shipping long distances, harvesting during the 

tight stage is not necessary; if you’re displaying your flowers at a farmers’ market, 

give your customers some color to view. In general, if flowers are cut tight, placing 

stems in a bud-opening solution is useful for the secondary user (wholesaler, 

florist, consumer). Research has not been conducted for every specialty cut 

flower, but the optimum harvest stage is provided at each entry for all crops discussed 

in the book. The optimum stage has been determined by research, observation, 

or discussion with growers and wholesalers. Appendix I is a brief summation 

of the recommendations. 

Considerations of the Cut Stem 

Air temperature: No factor affects the life of cut flowers as much as temperature. 

At every stage along the cut flower system—after harvest, boxing, shipping, 

at the wholesaler and the florist—the cut stems should be wrapped in cold. The 

importance of cold is directly related to the length of the journey. Michael Reid, 

perhaps the nation’s leading researcher in cut flower postharvest, states emphatically 

that the life of most flowers is 3–4 times longer when they’re held at 32F 

(0C) than at 50F (10C); some short-lived flowers, such as daffodils, persist 8 

times longer (Reid 2000). Even if flowers are hydrated and held and shipped in 

water, warm temperatures still result in loss of postharvest quality. 

For the producer, growing cut flowers without a cooler is like having a restaurant 

without a kitchen. Warm temperatures cause increased water loss, loss of 

stored food, and rapid reduction of vase life. Most cut stems should be cooled to 

33–35F (1–2C). It is imperative to rapidly reduce field heat and to maintain cool 

temperatures throughout the marketing chain of the flowers. If possible, stems 

should be graded and packed in the cooler; though this is not particularly popular 

with employees, the quality of the flowers is greatly enhanced. If field heat 

is not removed, or if loose flowers or flower boxes are simply stacked in a refrigerated 

room, rapid deterioration takes place. In rooms without proper air movement, 

it can take 2–4 days to cool a stack of packed boxes of warm flowers, and 

this same stack will never reach recommended temperatures, even after 3 days in 

a refrigerated truck (Holstead-Klink 1992). Proper box design and forced-air 

cooling of boxes to quickly remove heat significantly enhance the postharvest 

life of flowers.


Having said all that, not all cut flowers should be cooled at 33–35F (1–2C); 

tropicals such as anthuriums and celosia prefer temperatures above 50F (10C). 

Forced-air cooling: Boxes with holes or closeable flaps are necessary for forcedair 

cooling, in which air is sucked out of (or blown into) the boxes with an inexpensive 

fan. In general, cooling times are calculated as the time to reach 7/8 of 

the recommended cool temperature for a particular species; often that temperature 

is 40F (4C). Half-cooling time (the time required to reduce the temperature 

by 50%) ranges from 10 to 40 minutes (Nell and Reid 2000), depending on product 

and packaging. Flowers should be cooled until they are 7/8 cool or about 3 

half-cooling times. Work by Rij et al. (1979), an excellent early synopsis of precooling, 

provided methods of setting up small forced-air systems and information 

for calculating cooling times. Proper packing of the boxes is necessary to 

reduce temperature quickly. A minimum of 3" (8 cm) between the ends of the 

flowers and the ends of the boxes will prevent petal damage and enhance cold 

temperature distribution inside the boxes (Reid 2000). 

Initial and final box temperature at the packing shed should be measured 

and entered on data sheets. Actual temperatures should be appraised with a 

long-probed thermometer; the final temperature of the flowers can be estimated 

by using a temperature probe to measure the air being exhausted from the box. 

The air coming out of the box will always be cooler than the flowers, and an experienced 

operator knows the relation between flower temperature and exhaust 

temperature. 

The retailer is responsible for maintaining proper temperature control 

through to the sale. When the boxes arrive at their final destination, the box 

temperature can be again measured with an inexpensive needle-type probe even 

before the boxes are opened. If temperature inside the box is above 37F (3C), the 

flowers have likely been exposed to improper temperatures during transportation 

and/or storage. Once unpacked, stems should be rehydrated and placed 

immediately in coolers at 33–35F (1–2C). Retailers must insist on proper cooling 

from suppliers and then consistently maintain proper temperatures at the retail 

outlet. 

Water temperature: Although water uptake is more rapid at warm temperatures 

than at cool, flower stems should not be placed in warm water unless 

needed. Some growers actually immerse stems up to the flowers in a deep bucket 

of cold water, creating a mini hydro-cooling system. Warm water is useful if 

flowers are particularly dehydrated coming out of the field or for bud opening. 

In such cases, water heated to 100–110F (38–43C) is most effective for rehydration. 

Using warm water seldom causes problems, but it is not particularly beneficial 

on a routine basis. Water at room temperature is fine for mixing floral 

preservatives unless otherwise noted by the manufacturer. 

Water quality: The water used for holding cut flowers affects the quality of the 

flower. Tap water is most commonly used; depending on the source, it may be 

high in salinity, vary in pH, or be contaminated with microorganisms. Sensitivity 

to saline conditions varies with species, but measurements of salinity must be 

treated with caution. More important is the measurement of the buffering 

capacity of the water, or its alkalinity. A salinity reading of 190 ppm appears


dangerously high at first glance; however, the reading may consist of 40 ppm 

alkalinity and 150 ppm saline components. Such water is fine. The higher the 

alkalinity, the more difficult it is to adjust the pH of the water. This can be 

important when using preservatives. Most preservatives are effective at low pH 

(3.0–5.5), and if the pH cannot be adjusted, the preservative may be useless. Some 

preservative solutions work well in high alkaline waters, others do not. Knowing 

the alkalinity of the water used to treat cut flowers allows one to choose the most 

efficient preservative. Water may be tested through state universities or private 

laboratories for a reasonable price. It is money well spent. 

Flowers persist in acidic water longer than in basic pH water. Water that is 

acidic (pH 3.0–5.5) is taken up more rapidly and deters the growth of numerous 

microorganisms. The pH of the solution also affects the efficacy of the germicide 

in the preservative. Matching the proper preservative with the available water 

should result in good water quality and enhanced postharvest life of the flowers. 

Tap water often contains fluoride, which can be injurious to some cut flowers. 

The presence of as little as 1 ppm may injure gerberas, freesias, and other flowers. 

Snapdragons and other crops are less sensitive; daffodils, lilacs, and some 

orchids are insensitive. 

Depth of water: Relatively little water is absorbed through the walls of the stem 

(the majority is absorbed through the base), therefore the water or solution in 

which stems are held need not be deep, if stems are turgid or nearly so. The only 

advantage of plunging stems into 6" (15 cm) of water rather than 1" (2.5 cm) is 

that the water flows 6" (15 cm) up the water-conducting tissues of the stem, 

reducing the height the water must be moved by capillary action. Plunging stems 

in water more than 6" (15 cm) deep reduces air circulation around the leaves and 

crowds the stems and flowers together. If stems are severely wilted (often due to 

blockage by air bubbles), plunge them in water to a depth of at least 8" (20 cm); 

they will be more likely to revive than if put in shallow water (Nell and Reid 2000). 

Shipping wet or dry: Historically, shipping flowers in water was possible only for 

short distances; dry shipping (i.e., in boxes) is the norm when shipping by air or 

by truck, or when large volumes of flowers are involved. Some firms ship more 

fragile flowers across the country in innovative wet pack systems such as Procona 

and Freshpack. Brian Myrland of Floral Program Management points 

out a few of the many advantages to setting up a program based on this fastdeveloping 

technique: “Cutting stages [can] be tighter, more product [can] be 

packed in the wet pack, and less damage to open flowers [results].” Most wet 

packing is done by truck; however, transportation costs for air shipments are 

not as affected as one might anticipate, as air bills are often based on volume 

rather than weight. Retailers can use the containers as ready-to-sell, and shippers 

find that the expense continues to decline (Anon. 2000). Wet shipping methods 

will become far more popular as techniques improve and costs decline. 

Ethylene: Ethylene is released by all flowers, although ripening fruit and damaged 

flowers result in a significant increase in concentrations of the gas. It is also 

produced during the combustion of gasoline or propane and during welding. 

Low levels (

ylene, hold flowers in a cool, well-ventilated area, away from aging flowers or 

ripening fruit. The metal silver, which reduces the effects of ethylene, has historically 

been provided by silver thiosulfate (STS). This product, however, is not 

available in many states (see next section, on STS). 

The following genera are listed by Floralife, Inc., or Pokon & Chrysal as sensitive 

to ethylene. Not all are equally responsive to ethylene; for example, Rudbeckia 

is very much less sensitive and therefore less responsive to ethylene 

inhibitors than Delphinium. 

Achillea 

Aconitum 

Agapanthus 

Alchemilla 

Allium 

Alstroemeria 

Anemone 

Anethum 

Antirrhinum 

Aquilegia 

Asclepias 

Astilbe 

Astrantia 

Bouvardia 

Callicarpa 

Campanula 

Celosia 

Centaurea 

Chamaelaucium 

Chelone 

[Clarkia] 

Consolida 

Crocosmia 

Curcuma 

Cymbidium 

Daucus 

Delphinium 

Dendrobium 

Dianthus 

Dicentra 

Digitalis 

Doronicum 

Echium 

Eremurus 

Eustoma 

Francoa 

Freesia 

Gladiolus 

Gypsophila 

Helianthus 

Ilex 

Ixia 

Juniperus 

Kniphofia 

Lathyrus 

Lavatera 


Lilium 

Lysimachia 

Matthiola 

Narcissus 

Ornithogalum 

Paeonia 

Penstemon 

Phlox 

Physostegia 

Ranunculus 

Rosa 

Rudbeckia 

Saponaria 

Scabiosa 

Silene 

Solidago 

Trachelium 

Triteleia 

Trollius 

Tulipa 

Veronica 

Veronicastrum 

STS: In the late 1990s, silver thiosulfate (STS) was banned in the United 

States. In this country and abroad, the status of STS remains in a state of flux, 

and we asked postharvest expert Gay Smith of Pokon & Chrysal to clarify the situation. 

Her summary: Floralife essentially abandoned STS and threw their 

efforts into research and distribution of EthylBloc. Pokon & Chrysal started 

the registration process to get their STS solution, called AVB, approved by the 

EPA at federal and state levels; AVB received federal registration in September 

2001, then state-by-state registration began. Florida registration was approved 

in January 2002; approval in California and other states is expected in the near 

future. But STS was never banned in South or Central America, and flowers can 

still be treated at the grower level in South and Central American countries. In 

fact, some California growers moved production of ethylene-sensitive crops (e.g., 

delphinium, satin flower) to Mexico so they could continue to treat them.


Aquilegia hybrid 

Pulsing: Placing freshly harvested flowers for a short time (a few seconds to 

several hours) in a solution to extend vase life is referred to as pulsing. Hydration 

solutions, sugar, and STS are common pulsing ingredients; short pulses (10 seconds) 

of silver nitrate (100–200 ppm) have also been successful with a few species. 

Silver nitrate, however, is seldom used commercially. 

Removal of leaves: As a rule, ⅓ of the leaves are removed from the base of the 

stem, and in some cases all leaves are removed, especially if flowers will be dried. 

Foliage immersed in water leads to bacterial growth and toxin buildup, reducing 

the postharvest life of the flower. 

Clean buckets: At every conference, at every meeting, and at every farm, the 

importance of clean buckets is discussed. This is not arguable—it is as basic as a 

surgeon scrubbing up before an operation. Buckets must be cleaned with soap, 

and a protocol to wash them must be established. Why go to all the trouble and 

expense of growing a crop only to lose it in the bucket?

Dicentra spectabilis 


Availability of food: Since few or no leaves are cut along with flowers, little food 

is available to the stem and flower. The quality and longevity of cut flowers are 

improved when stems are pulsed in a solution containing sucrose or table sugar. 

In general, concentrations of 1.5–2% sugar are used, although higher concentrations 

are effective for certain species. Most commercial preservatives contain 

approximately 1% sugar, which is sufficient for most flowers. Sugar solutions 

can be made up, if necessary, by the grower. Add 13 oz of sucrose to 10 gallons of 

water per percentage required. That is, for a 1% solution, dissolve 13 oz (370 g) 

of sucrose in 10 gallons (38 l) of water; for a 4% solution, add 52 oz (1482 g) to 10 

gallons (38 l) of water. 

Air bubbles: Air bubbles, which restrict the upward flow of water, occur after 

harvesting with many types of flower stems. Recutting stems (approximately 1", 

2.5 cm) under water reduces the blockages. Nell and Reid (2000) suggest a creative 

home remedy for rehydration. Fill a soft plastic container, like a 1 gallon 

(4 l) milk jug, to the top with hot water (150–160F, 65–71C). Cap it and place it 

in the refrigerator or cooler. As the water cools, the container shrinks, air is 

excluded, and the remaining water is air-free. When stems with trapped air in 

their stems are placed in this water, the water acts as a scavenger for the trapped 

air and removes it from the stems. Flowers placed into degassed water will 

hydrate quickly. Placing stems in citric acid (pH 3.5) also reduces air emboli. 

Cutting stems under water: Staby (2000) reinvestigated the benefit of cutting 

stems under water. After all, it is an inconvenient practice, and if there really is no 

difference between cutting in air or under water, then it need not be done. He 

found that if plants rehydrate properly when put in water, it does not matter 

how they are recut, but that most do rehydrate faster when recut under water. 

His most important finding was that if the water under which the stems are cut 

is contaminated (excessive levels of microorganisms, dirt, debris, sap from stems 

being cut), it is better to cut the stems in air. Of course, cutting under clean water


extends vase life anyway, so keep the water fresh. Add household bleach to the 

water, and rinse the bottom half of the flower stems before cutting under water. 

Bacteria can also block the ends of stems. Clean containers and acidified 

water greatly reduce this problem, as do commercial floral preservatives, which 

contain antibacterial and antifungal agents, such as 8-hydroxyquinoline citrate 

or sulfate (8-HQC, 8-HQS). Additional agents should not be necessary. 

Conditioning: Conditioning or hardening of cut stems restores the turgor of 

wilted flowers. In general, demineralized water should be used when conditioning 

solutions are prepared. When stems are placed in solutions, they should be 

held at room temperature initially (a few hours to overnight) then placed in cold 

storage for several hours. Warm water (110F, 43C) is highly recommended for 

restoring turgor only in badly wilted stems. Badly wilted stems, especially those 

with woody stems, may benefit from being placed in hot water (180–200F, 82– 

93C) prior to being placed in room temperature solutions. 

Postharvest Solutions 

Rehydration solutions: This is an essential step after harvest. Freshly harvested 

flower stems are placed in water to restore turgidity, a process called rehydration. 

Rehydration solutions contain no sugar and are essentially used to jumpstart 

the flow of water through the plant’s plumbing system. They include a germicide 

and wetting agent and have a pH around 3.5. If possible, rehydration 

should take place immediately after cutting. 

Pulsing solutions: Generally, pulsing solutions are used to provide sugars 

(sucrose or glucose, 2–20% added to flower food) and silver compounds (STS), 

and occasionally to reduce leaf yellowing (cytokinins) and as a germicide (5- to 

10-second silver nitrate dip on specific crops). The uptake of all solutions is 

affected by both the temperature of the solution and the temperature of the air. 

Colder temperatures require a longer pulsing period than warmer temperatures. 

Bud-opening solutions: Flowers that are cut bud-tight respond to bud-opening 

solutions prior to sale to the final consumer. These consist mainly of a fresh 

flower food and additional sugar. Nell and Reid (2000) suggest that bud-opening 

solutions be used at 70–75F (21–24C), 60–80% relative humidity, and relatively 

high light. 

Fresh flower food: These solutions are known and sold as flower preservatives, 

but the term “fresh flower food” is kinder and gentler, and that is a good thing. 

Most consist of sugar (the food), a biocide to reduce bacterial growth, and an 

acid to reduce the pH; sometimes they contain a growth regulator to reduce leaf 

yellowing or an anti-ethylene substance. Fresh flower food can increase vase life 

up to 75% (Nell and Reid 2000), and while not all flowers will respond dramatically, 

few will be harmed by the products. 

In-house mixing: Flower preservatives, silver solutions, bactericides, bud openers, 

conditioners, and sugar solutions are all part of the postharvest jargon. 

While these various components can be mixed in the back room, what is the 

point? It is doubtful that homemade solutions will significantly differ from commercial 

mixes, and often mistakes are made in the process, resulting in solu-


tions that are either ineffective or phytotoxic. A grower is a busy enough, already 

functioning as farmer, market analyst, and information gatherer combined. 

Why add chemist, waste disposal technician, and preservative manufacturer to 

the list? Preservative companies provide information, effective chemicals, and 

good service. Growers don’t manufacture insecticides, why should they concoct 

preservatives? Last but not least, it is illegal to manufacture preservatives “inhouse” 

without necessary Materials Safety Data Sheets. 

Some mixing is always necessary. That is why we learn to read, so routine 

flower preservatives can be mixed properly. Almost always, when flower foods are 

mixed improperly, they are used at weaker-than-recommended levels (Staby 

2000). When insufficient amounts of floral food are used, the sugar in the food 

actually promotes the growth of microorganisms because there is insufficient 

biocide to control them. Better to use no flower food at all than one that is mixed 

improperly. Do some simple tests on your own to determine which flower food 

or other chemical is best for your flowers. 

Reading 

Anon. 2000. Fill ’em up, ship ’em out. Florists’ Review (Nov.):88–90. 

Holstead-Klink, C. 1992. Postharvest handling of fresh flowers. In Proc. 4th Natl. 

Conf. on Specialty Cut Flowers. Cleveland, Ohio. 

Nell, T. A., and M. S. Reid. 2000. Flower and Plant Care. Society of American Florists, 

Alexandria, Va. 

Reid, M. S. 2000. Some like it cold. Florists’ Review (Nov.):82–84. 

Rij, R. E., J. F. Thompson, and D. Farnham. 1979. Handling, precooling, and 

temperature management of cut flowers for truck transportation. In Advances 

in Agricultural Technology AAT-W-5 (June). USDA, Sci. and Edu. Admin. 

Staby, G. 2000. The latest on cut flower processing. Florists’ Review (Nov.):86. 

Many thanks to George Staby, Christy Holstead-Klink, Gay Smith, and Brian 

Myrland for reviewing this section.

DRYING AND PRESERVING 

Dried flowers are an important segment of the specialty market. Growers of 

dried flowers must be efficient because their products may be shipped from anywhere 

at any time. Quality, however, is still a significant marketing advantage. 

Producers who provide dried material should do so as a primary focus, not as 

means of using up unsold fresh production. Cultural methods, harvest stage, 

and postharvest techniques differ for dried production. Two ways to go out of 

business: thinking that “material that could not be sold fresh can always be 

dried” and that “material of inferior quality for fresh can always be dried.” Garbage 

in equals garbage out. “Fresh” dried material—harvested at the optimum 

stage, treated correctly, and smartly displayed—can compete with flowers anywhere 

and is far more appealing than leftovers dried as an afterthought. 

Dried materials are not “dead sticks and twigs,” but include colorful flowers, 

preserved fruits, and soft, supple stems whose postharvest life is far superior to 

that of fresh material. Significant gains in methods for rapid drying have been 

made in recent years, methods that maintain the color, shape, and size of the 

plant material. But methods are often poorly excecuted, and materials useful 

for drying misunderstood. It is wrong to believe that dried flowers are easier to 

produce than fresh; in fact, dried flower producers must produce a high-quality 

fresh product before the process of drying even begins. The highest-quality 

dried material begins with the highest-quality fresh material, and the trend in 

the marketplace is to grow for the fresh market or the dried market, but not 

both. 

Dried flower producers face a great deal of competition from plastics, silks, 

and other faux products. According to Shelley McGeathy of Hemlock, Mich., 

who has been producing dried material for many years, “It is more important 

than ever to produce top-quality, incredibly colored dried materials. Only outstanding 

preserved products will keep the market strong for dried materials.” So 

the questions beg to be asked. What should one expect from dried materials? 

And how is that elusive excellent quality attained? 

In answer to the first question, Mark Koch of Robert Koch Industries suggests 

that dried floral products should have a minimum useful life of one year. 

As to the second, he has produced an excellent series of technical bulletins on the 

many aspects of drying floral product; the information contained therein is easy 

30

DRYING AND PRESERVING 31 

to comprehend, and they should be read by anyone involved in the cut flower 

business. They are available through Robert Koch Industries, Bennett, Colo. 

Much of the information in this section is based on Mark’s work. 

Drying 

Air drying: Air drying is the most widely used method for preserving material: 

it’s simple, it allows a large volume of material to be processed, and it requires 

low capital investment. In passive air drying, the most common process, plant 

materials are dried in an uncontrolled environment, like a barn or converted 

shed. Active air drying is a controlled process that directs heated air across the 

plant surfaces; it requires a furnace or other heat source and fans and blowers to 

direct the heat. The advantages of active air drying are more rapid drying and the 

ability to control humidity and eradicate insects. 

Plants for drying: In general, plant material with a high water content (e.g., 

peonies) do not dry as well as those with a moderate or low moisture volume. 

Delicate flowers (iris, carnations) are more difficult to air dry than tougher flowers 

(sinuata statice). Tropical flowers do not air dry well. Essentially, materials 

with a higher lignin content tend to be easier to dry than those with a high water 

content. Unfortunately, flowers that do not dry well are equally difficult to preserve 

with glycerine treatments. Some flowers with high water content are more 

easily dried using freeze-dry techniques. Roses, calla lilies, and peonies can all be 

freeze-dried and preserved for many years. 

Facilities for air drying: Drying sheds range from basements to elaborate greenhouses 

or storage areas with sophisticated equipment. Whether flowers are dried 

in the attic or in converted warehouse space, all sheds must have a few characteristics 

in common. Protection from excessive sunlight, wind, water, and dust 

is important. Concrete floors are expensive but highly recommended. Not only 

do they act as excellent heat sinks, warming up during the day and slowly releasing 

heat at night, they also reduce dust. Dust particles become permanently 

attached to stems that have been treated with sealers or flame retardants. Dirt 

floors are never recommended; however, gravel floors have been used successfully. 

Lining floors with straw or wood shavings is done, but these materials can 

be a haven for insects. Protection from insects and rodents can be accomplished 

through screens. 

Ventilation is another important consideration. During the drying process, 

materials release moisture to the air. Without adequate air movement, drying 

rates are considerably prolonged. Sheds should be constructed to take advantage 

of natural ventilation (e.g., prevailing winds), but fans are often incorporated to 

aid air circulation. Poor air movement also encourages the buildup of molds 

and disease organisms. If fumigation is necessary to kill insects, the shed must 

be airtight. Some drying sheds are constructed so that all or a portion of space 

may be sealed for fumigant application and then properly vented in keeping 

with regulatory statutes. 

The rate of drying increases with increasing temperature and decreasing 

humidity. Plant materials with waxy cuticles and large stem diameters take

32 DRYING AND PRESERVING 

longer to dry; so do those with high moisture content. Temperatures in the drying 

shed vary widely, averaging 70–120F (21–49C). Humidity levels are seldom 

controlled by smaller producers and generally reflect the outside humidity. Airdrying 

equipment with humidity and temperature control is popular with larger 

processors and those whose natural environment is humid. Optimum humidity 

levels of 20–60% should be monitored by all processors. 

Some materials are best dried in darkness, others in sunlight. Drying sheds 

with the ability to adjust the amount of light will allow the grower to dry a range 

of materials. Most plant materials, when exposed to sunlight, fade to pale yellow, 

which is advantageous when material is to be dyed—a pastel shade is easier to 

color than green. This sun bleaching is used by many processors in preparation 

for drying; grasses, for example, must be bleached if light color shades are to be 

produced. Sun bleaching also provides an autumnal look for grasses, grains, 

and thin-stemmed flowers. If the natural plant color is to be retained, drying in 

the absence of light is recommended. 

Required drying times: Drying times vary considerably, depending on species, 

location, drying shed design, and season. Drying times also depend on the 

amount of water in the fresh material and the desired water content of the dried 

product. This is known as the dry fraction. Dry fractions for all crops are best 

obtained by doing simple weighing experiments at the beginning and end of the 

drying cycle. This can be done by occasionally weighing individual bunches; to 

obtain the dry fraction, divide the dry weight of the plant by the fresh weight. For 

example, sinuata statice is approximately 70% water, therefore the dry fraction is 

30% (or 0.3). If 100 pounds (46 kg) of fresh sinuata statice is to be dried, drying 

is complete when the weight is 30 pounds (13.6 kg). In general, drying times 

range from 3 days to 2 weeks in a passive system. In an active system, plant materials 

typically dry in 24 hours or less. Failure to adequately dry a plant can lead 

to serious mold problems if material is sleeved and boxed too early. 

Bunch size and handling: Stems are generally grouped in bunches for resale. 

Bunch size is determined by the desired weight of the dried product and the dry 

weight fraction of that product. If the final weight of a dried bunch of sinuata 

statice (dry weight fraction = 0.3) is to be 4 ounces (114 g), then the initial fresh 

bunch weight should be 4/0.3 or 13.3 ounces (379 g). Bunches with too many 

stems may reduce air circulation within the bunch, and bunches should not be 

placed so close together as to reduce air movement between them. They are normally 

hung on strings or wires from the roof, and it is common to date each line 

as stems are hung, to ensure proper drying times. In active systems, plants are 

often placed on drying racks that can be rolled into the drying chamber. 

Mold and insect problems: Poor air circulation, prolonged periods of high 

humidity, excessively large bunch size, and overcrowding in the drying facility 

are common causes of mold formation. Low humidity and adequate air flow 

greatly reduce mold problems. Insects can be treated with chemicals, but these 

are highly restricted and require licensing. Heat is an effective way to reduce 

insect problems but is usually only possible in active systems or in passive systems 

where a heat source is available. Mark Koch (1996a) suggests the following 

exposures to control insects:

Drying temperature Exposure time 

110F (43C) 24 hours 

120F (49C) 3 hours 

150F (66C) 20 minutes 

DRYING AND PRESERVING 33 

Storage after drying: Material is usually boxed and stored after drying. Boxes 

should be stored in a pest-free area with low humidity. Air temperatures should 

be low but are not as important as low humidity. 

Glycerine 

The replacement of water with glycerine results in soft, pliable plants that behave 

as if they have been preserved. Material to be preserved should be treated as soon 

after harvest as possible. For most plants, incorporation of glycerine is accomplished 

through systemic uptake through the base of the stem. In general, 1 part 

of glycerine, mixed with 3 parts hot water (by volume), and a surfactant, to 

reduce the surface tension of water, is recommended. Avoid using tall buckets, 

which reduce air circulation around the leaves; place stems in approximately 3" 

(8 cm) of solution in a well-ventilated area indoors at 70–85F (21–29C). After 

treatment, the portion of the stems immersed in glycerine/dye should be 

removed; the solution bleeds from the treated area otherwise. In general, the 

smaller the diameter of the stem, the less glycerine is used. Normal preserving 

time is 3–7 days. Water-soluble dyes may be added at the same time. 

If stems are allowed to remain in glycerine too long, the glycerine will move 

through the plants and be pumped out through the flowers and foliage, resulting 

in stems that may be wet, oily, and essentially unusable. After treating, the 

stems should be rinsed with clear water and hung to dry. If stems are still not sufficiently 

soft 4–5 days after removal from the glycerine, a misting of the glycerine 

solution over the foliage helps to make them more supple. A drying time of 

about 1–2 weeks is necessary. Most plants are preserved in the dark; however, 

eucalyptus is light-treated, and baby’s breath is preserved in the light to give an 

amber glow to the stems and flowers. The glycerine solution may be reused up to 

3 times; simply pour through a fine screen to remove leaves and other debris. If 

the solution is to be stored for more than a week or used over a long period of 

time, antimicrobial agents, such as potassium sorbate and citric acid, should be 

added (Koch 1996b). 

Some plants do not absorb glycerine well and must be immersed in the glycerine 

solution, for 1–2 days if the solution is unheated, for 6–12 hours if heated 

to 180F (82C). As with the absorption method, material is removed, rinsed, and 

hung to dry for 1–2 weeks. 

Freeze-drying 

Freeze-drying allows the water in plants to pass from the solid state (frozen) to 

the vapor state (steam) without passing through the liquid phase. Advances in

34 DRYING AND PRESERVING 

freeze-drying equipment and polymer chemistry have resulted in more and more 

flowers being freeze-dried, particularly stems and flowers with high water content. 

Small equipment designed for the florist industry is available, as well as 

high-volume dryers for wholesalers and wholesale growers. Freeze-drying provides 

flowers with a natural shape and color and extended longevity. Freezedrying 

is highly technical and requires a significant capital investment; however, 

it creates a marvelous product and is a viable method for delicate flowers. 

Silica Gel 

For many dried products, the water in the plant is transferred to a desiccant, 

such as silica gel. Plants are completely embedded in the gel and remain there 

until all the water has been removed. The main benefits of silica gel are excellent 

retention of color and shape. Useful flowers to treat with gel are those with 

high moisture content and little fiber, such as zinnias and sunflowers. Stems 

seldom dry well with silica gel, and flowers dried by this method are cut with 

very little stem remaining. Silica gel can be reactivated after use by heating in an 

oven at 250–300F (120–150C) for 2–3 hours. Drying time will vary with the product 

but is usually accomplished in 1–3 days (Koch 1995). 

Dying Flowers 

Many stems and flowers are colored for the marketplace, and the systemic watersoluble 

dyes developed for the floral industry will provide almost any color 

desired. Choice of container, solution temperature, dye concentration and handling, 

wetting agents, the necessity of avoiding contamination—all are considerations 

when using dyes. We recommend reading Mark Koch’s product sheet 

on dying fresh flowers (Koch 1999) for more detailed information. 

Reading 

Koch, M. 1995. Drying flowers and foliage with silica gel. Robert Koch Industries 

Tech. Bul. 460:1–8. 

———. 1996a. Air drying flowers, foliage and ornamental plant materials. Robert 

Koch Industries Tech. Bul. 430:1–15. 

———. 1996b. Overview of current technology for drying and preserving flowers 

and foliage. Robert Koch Industries Product Sheet. 

———. 1999. Systemically dying fresh cut flowers and foliage with absorption 

(systemic) floral dyes before air drying. Robert Koch Industries Product Sheet 

102:1–4. 

Many thanks to Mark Koch and Shelley McGeathy for reviewing this section.

CUT FLOWERS: 

ACHILLEA TO ZINNIA


Achillea yarrow Asteraceae 

perennial 

Four of the approximately 100 species are useful as commercial cut flowers. The 

best yellow-flowered forms are Achillea ‘Coronation Gold’ (coronation gold yarrow) 

and A. filipendulina (fern leaf yarrow). Achillea millefolium (common yarrow) 

is available in numerous colors; A. ptarmica (sneezewort) is white-flowered. 

Hybrid selections of yarrow with flower stems 1½–2½' (45–75 cm) long have 

potential for cut flower production. Yarrows may be used fresh or dried. For 

Armitage, sneezing and yarrow are synonymous: they go together like popcorn 

and a movie, but not nearly as pleasant. 

Achillea ‘Coronation Gold’ coronation gold yarrow Asteraceae 

perennial, Zones 3–9 hybrid origin yellow 3–3½'/3' (0.9–1.1 m/0.9 m) 

Coronation gold yarrow is a hybrid between Achillea filipendulina and A. clypeolata. 

No seed is available (the seed occasionally offered is most likely A. filipendulina). 

The gray-green foliage is fragrant (some say smelly), and flower heads are approximately 

3" (8 cm) wide, although 4–4½" (10–11 cm) wide inflorescences are not 

uncommon. 

Propagation 

Division: Plants may be divided any time after flowering. From a mature 

3-year-old plant, up to 100 divisions may be made. Divisions should be sorted to 

size, with large crowns planted in the production bed, smaller ones planted in 

pots for growing-on or in a separate production area. Water divisions well. 

Environmental Factors 

Temperature: Cold is not necessary for the flower development of cultivars 

with Achillea filipendulina in their parentage. Plants are perennials and flower as 

far south as south Florida, indicating that cold temperatures are not critical. 

Temperatures below 40F (4C), however, are beneficial by increasing uniformity 

and plant vigor. The optimum duration of cold is likely less than 4 weeks. Plants 

have a wide range of temperature adaptability and are useful as cut flowers from 

Minnesota to Florida. 

37

38 ACHILLEA ‘CORONATION GOLD’ 

Photoperiod: No photoperiod control is necessary in the field, although plants 

respond to lengthening days. Plant maturity is more important for flowering 

than photoperiod is. 

Soil pH: Yield and stem length are better with a soil pH of 6.4 than a soil pH of 

3.7 (Escher and Ladebusch 1980). 

Field Performance 

Longevity: ‘Coronation Gold’ produced consistent quality and yield for 5 years 

in the Georgia trials. The following results were recorded on a 1 × 1' (30 × 30 

cm) spacing. 

Longevity of Achillea ‘Coronation Gold’. 

Stems/ Stems/ Stem Stem 

Year plant ft 2z length (in) y width (mm) x 

1 7 7 23 4.9 

2 41 41 25 4.6 

3 46 47 28 5.1 

4 45 45 29 4.8 

5 45 45 25 5.3 

z = multiply (stems/ft 2 ) by 10.8 to obtain (stems/m 2 ) 

y = multiply (in) by 2.54 to obtain (cm) 

x = divide (mm) by 25.4 to obtain (in) 

Similar results were obtained in second-year in trials in Burlington, Vt. Twoyear-old 

plants yielded 54 stems/plant, approximately 19" (48 cm) tall. In that 

trial, 2 × 2' (60 × 60 cm) spacing was used (Perry 1989). 

Stem length: Distribution of stem lengths over a 5-year period is presented in 

the following table; plants were on a 1 × 1' (30 × 30 cm) spacing. 

Stem length distribution of Achillea ‘Coronation Gold’ over time. 

Stem length (%) 

Year 20" 

1 3 96 1 

2 9 53 38 

3 3 36 61 

4 0 13 87 

5 0 5 95 

z = multiply (in) by 2.54 to obtain (cm)

In the sixth and last year of testing of ‘Coronation Gold’ at Athens, Ga., plants 

originally spaced 2 × 2' (60 × 60 cm) yielded 58 stems/plant and 16 stems/ft 2 

(173 stems/m 2 ) with an average stem length of 22" (55 cm). Plants originally 

spaced 3–4' (0.9–1.2 m) apart yielded 97 stems/plant with an average stem length 

of 24" (60 cm). 

Spacing: ‘Coronation Gold’ does not spread as aggressively as many other 

yarrows, and high-density planting is not detrimental. The yield per plant 

increases as spacing distance increases but yield/ft 2 declines. Stem length also 

increases as spacing distance becomes smaller (Armitage 1987). Spacing closer 

than 1' (30 cm) apart is feasible if plants remain in production no more than 3 

years. Close spacing results in additional root rot and foliar disease problems. 

Greenhouse Performance 

The financial return on yarrow may make it economically questionable to force 

in heated greenhouses, however, off-season production will provide better prices 

and justify added expenses. 

For ‘Coronation Gold’, treatment of the plugs with cold is not required or 

recommended. Plants should be potted up, placed under short days (winter conditions), 

and grown on until plants fill the containers. This will require several 

weeks, depending on greenhouse temperatures. It may be more feasible financially 

to grow them at 50F (10C) for 5–6 weeks rather than 65F (18C) for 4 weeks; 

avoid temperatures above 70F (21C). Long days (either 16-hour or 4-hour night 

interruption) after bulking up in SD is highly recommended; continue LD until 

flowers appear (Nausieda et al. 2000). At Michigan State University, ‘Coronation 

Gold’ required 9 weeks to flower at 68F (20C), ‘Gold Plate’ required 7.5 

weeks (Nausieda et al. 2000). 

Botrytis and powdery mildew can be problems, particularly if plants are overwatered 

or overfertilized. Do not mother these plants to death. 

Guideline for Foliar Analyses 

At field trials in Athens, Ga., foliage was sampled from vigorously growing 

healthy plants when flower buds were visible but prior to flower opening. These 

are guidelines only and should not be considered absolute standards. Based on 

dry weight analysis. 

‘Coronation Gold’ 

ACHILLEA ‘CORONATION GOLD’ 39 

(%) 

N P K Ca Mg 

2.9 

(ppm) 

0.24 3.15 0.70 0.18 

Fe Mn B Al Zn 

210 33 35 156 30

40 ACHILLEA FILIPENDULINA 

Stage of Harvest 

Flowers should not be harvested until pollen is visible on the inflorescence. 

Stems harvested prior to pollen shed have unsatisfactory shelf life. 

Postharvest 

Fresh: Flowers persist 7–12 days in water if harvested at the proper stage 

(Blomme and Dambre 1981). 

Dried: Yarrow can be hung upside down to air dry, but flowers will shrivel if 

picked too early. Good results with small numbers of stems are obtained by placing 

the stems in 1–2" (2.5–5 cm) of water and allowing the water to evaporate in 

the drying area (Vaughan 1988). 

Grower Comments 

“With ‘Coronation Gold’ and Colorado Mix you must cut them as mentioned 

and wait until the pollen is out on the flower, otherwise they will droop. I have 

cut mine and simply placed in tepid water with preservative and have had no 

problem getting 2-plus weeks from them in the vase.” Shari Keefe, Shari’s Berries 

& Garden, Hiram, Ohio. 

Achillea filipendulina fern leaf yarrow Asteraceae 

perennial, Zones 3–9 Caucasus yellow 3–4'/2' (0.9–1.2 m/0.6 m) 

Fern leaf yarrow is the common “yellow yarrow” of florists and outdoor markets. 

The bright yellow inflorescences are up to 4" (10 cm) across and held on 

longer stems than ‘Coronation Gold’. Plants differ from ‘Coronation Gold’ by 

having green rather than gray-green foliage, brighter yellow flowers, and fewer 

breaks. It is popular for its strong tall stems, ease of culture, and availability 

from seed or crowns. 

Propagation 

Seed: Seed germinates in 7–14 days at 65–70F (18–21C) and high humidity. 

Cover the seed lightly. Approximately 1/64 oz (0.4 g) of seed yields 1000 seedlings 

(Nau 1999). Direct sowing is not recommended. 

Division: Plants should be divided in the early spring or early fall (or any time 

after flowering). 

Growing-on 

Transplant to 4" (10 cm) pots or large cell packs about 3 weeks after sowing. 

Temperatures of 55–60F (13–15C) are optimum for growing-on. Fertilize with 

100 ppm N until ready to transplant to the field.


Temperature: As with ‘Coronation Gold’, cool temperatures are useful only 

for quality and uniformity. Plants are tolerant of warm temperatures and may be 

grown as far south as central Florida. They also do well in cool climates and are 

the leading yellow yarrow in northern European countries. With its longer stem 

lengths, fern leaf yarrow may be a better choice than ‘Coronation Gold’ in northern 

states. 

Photoperiod: Photoperiod does not significantly affect flowering. 


Spacing: 1 × 1' (30 × 30 cm) or 12 × 18" (30 × 45 cm) between plants and 2–3' 

(60–90 cm) between rows. 

Yield: Fewer stems are produced compared with ‘Coronation Gold’, but stem 

lengths are generally longer with Achillea filipendulina ‘Parker’s Variety’. 

Longevity: Plants are productive 3–5 years. 


See Achillea ‘Coronation Gold’. 



Postharvest 


ACHILLEA FILIPENDULINA 41 

Cultivars 

Few differences between these cultivars occur in the field; all are suitable. 

‘Altgold’ is only about 2' (60 cm) tall and bears deep yellow flowers. Plants 

often bloom twice a year; the spring bloom is far heavier. 

‘Cloth of Gold’ is a popular gold-flowered cutting form. Stems are 2–3' (60– 

90 cm) long and flowers are 3–4" (8–10 cm) wide. 

‘Gold Plate’ has large, golden-yellow flowers and long stems. 

‘Moonwalker’ has 4–5" (10–13 cm) wide yellow blooms on 2–3' (60–90 cm) 

stems. 

‘Parker’s Variety’ has long stems, 2–3' (60–90 cm), and deep yellow flowers, 3– 

4" (8–10 cm) wide.

42 ACHILLEA MILLEFOLIUM AND HYBRIDS 

Achillea millefolium and hybrids common yarrow Asteraceae 

perennial, Zones 2–9 Europe many colors 2–2½'/3' (60–75 cm/90 cm) 

Large color selection makes this one of the most popular yarrows for cut flowers, 

although attention to post production is important. Common yarrow is a matforming 

species with deeply cut, dark green foliage. The flower heads are small 

and arranged in flattened inflorescences (corymbs). The species itself is predominantly 

creamy white, but nobody grows it: selections and hybrids abound in 

pink, rose, mauve, and bicolors. Plants spread rapidly, and beds fill in within 2 

years after planting. They are highly productive and may be propagated readily. 

Propagation 

Seed: Seed germinates in 10–15 days at 70–72F (21–22C) under humid (sweat 

tent or mist bed) conditions. The small seed should be covered lightly with vermiculite 

or clean sand. Approximately 1/64 oz (0.4 g) of seed yields 1000 seedlings 

(Nau 1999). 

Division: Plants may be divided at any time but preferably in early spring or 

immediately after flowering. Even root pieces (essentially root cuttings) reproduce 

a new plant. A 2- to 3-year-old plant yields hundreds of single crown divisions. 

Place divisions in a propagation bed for growing-on. 

Growing-on 

If seedlings are planted in plugs, grow for 3–5 weeks at 55–62F (13–17C) in full 

light. Fertilize with 50–100 ppm N to maintain green foliage. Do not over-fertilize, 

or plants become spindly. Transplant to field when plants are large enough 

to handle. 

If seeds are sown in a seed flat, transplant seedlings to cell packs after the first 

true leaves have formed. Grow on as with plugs. 

Sort divisions by size. Transplant large divisions directly to the field; place 

the smallest ones in pots or cell packs and grow on in the greenhouse or cold 

frame. 


Cold is not necessary for optimum flower development, although 3–4 weeks of 

40F (4C) temperatures may contribute to uniformity and stem quality. Cool 

temperatures delay flowering time, however. Plants are particularly cold hardy 

and are common from the prairies of Canada to the Piedmont of Georgia. Stem 

strength and flower color is enhanced by cool night temperatures, and stems 

are of higher quality in the North than in the South. 

Work with ‘Summer Pastels’ showed that long days were necessary for flowering. 

Zhang et al. (1996) determined that plants grown under 8-hour photoperiods 

remained vegetative and that the critical photoperiod was between 12 

and 16 hours. Photoperiod is an important consideration when considering 

forcing for winter production.


Longevity: Plants are tenacious and spread rapidly. Long-lived perennials, they 

are productive 3–5 years. Divide every 2–3 years to rejuvenate the planting, otherwise 

plants become less vigorous and yield declines. 

Longevity of Achillea millefolium ‘Rose Beauty’ at Athens, Ga. 

Spacing 1' (30 cm). 

Stems/ Stems/ Stem Stem 

Year plant ft 2z length (in) y width (mm) x 

1 14 14 27.0 3.3 

2 42 42 31.5 3.4 

3 36 36 38.1 4.4 

z = multiply stems/ft 2 by 10.8 to obtain stems/m 2 



ACHILLEA MILLEFOLIUM AND HYBRIDS 43 

Achillea millefolium ‘Paprika’


Stem length: Stem lengths are short the first year of planting, but as plants 

mature, the percentage of saleable stems greater than 20" (50 cm) increases as 

shown in the following table. 

Stem length distribution of Achillea millefolium ‘Rose Beauty’ over 

time. Spacing 1' (30 cm). 


Year 20" 

1 7 17 76 

2 4 9 87 

3 0 0 100 

z = multiply (in) by 2.54 to obtain (cm) 

Spacing: Common yarrow spreads aggressively and forms a dense mat. Any 

semblance of spacing in our trials disappeared by the third year; even those 

spaced 3' (90 cm) apart were a solid mat at that time. As the following table 

shows, flowering stems/plant increased as spacing distance increased, but 

stems/ft 2 declined. A 1' (30 cm) spacing is recommended. 

The effect of spacing on yield and stem quality of Achillea 

millefolium. Second-year data. 

Spacing (in) z Stems/plant Stems/ft 2y Stems >20" (%) 

‘Rose Beauty’ 

12 42 42 90 

24 91 23 83 

36 107 12 91 

‘Cerise Queen’ 

12 94 94 68 

24 143 36 42 

36 185 21 58 


y = multiply (stems/ft 2 ) by 10.8 to obtain (stems/m 2 ) 

Work in Italy also found up to 12 stems/ft 2 (130 stems/m 2 ) in the second year 

when planted at a little less than 1' (30 cm) spacing (Zizzo et al. 1994). 

Fertilization: Plants need little additional fertilizer if planted in organic soils. 

High rates of nitrogen result in rapid vegetative growth at the expense of flower


development. If planted in pots, however, higher rates of nitrogen and potassium 

should be supplied compared to that required with field production (El- 

Kholy 1984). 


Common yarrow is seldom forced for winter production, but it could be, if financially 

feasible. 

For cultivars and hybrids of common yarrow, treatment of the plugs with 

cold is not required. Some benefits occur (additional stems, faster and more uniform 

flowering) but perhaps not enough to warrant the use of coolers. At the 

University of Georgia, Zhang et al. (1996) grew plants under normal photoperiods 

(i.e., short days) until plants reached approximately 10 nodes. Long days 

(>14 hours) were used to force flowering. Nightbreak lighting (4 hours with 

incandescent lamps) may be used, but beware of potential stretch of flower 

stems. Supplemental lighting (e.g., high-intensity lamps) is recommended when 

winter light is low. We recommend low forcing temperatures for stronger stems, 

around 55F (13C) with bright light; however, warmer temperatures result in 

faster cropping time. Researchers at Michigan State University bulked plants 

up under SD, then forced flowers under LD until flowering, but they grew plants 

at 68F (20C); the number of weeks to flower varied with cultivars (Nausieda et al. 

2000). 

Anthea 7 weeks 

Apple Blossom 6 weeks 

Fireland 9 weeks 

Hope 6.5 weeks 

Moonshine 3.5 weeks 

Paprika 7 weeks 

Terra Cotta 7 weeks 

Botrytis and powdery mildew can be problems, particularly if plants are overwatered 

or overfertilized. 





dry weight analysis.


‘Lilac Beauty’ 

(%) 

N P K Ca Mg 

2.76 

(ppm) 

0.34 5.04 0.85 0.19 

Fe Mn B Al Zn 

127 62 32 49 47 

‘Paprika’ 

(%) 

N P K Ca Mg 

3.08 

(ppm) 

0.43 5.56 0.75 0.19 

Fe Mn B Al Zn 

135 60 29 54 48 


Flowers should not be harvested until pollen is visible on the inflorescence. 

Stems should be harvested in the coolest part of the day, such as the morning. 

Postharvest 

Fresh: Shelf life in water or appropriate preservative is only 3–4 days at room 

temperature. If necessary, place stems in warm water, to aid water uptake. The 

use of silver thiosulfate (STS) increases postharvest life only slightly. Stems 

placed directly in a cooler (40F, 4C) may be held for about one week. 

Dried: See Achillea ‘Coronation Gold’. 

Cultivars 

Many cultivars and hybrids are available to the American grower. A few were 

subjects in 2-year production in trials in Athens, Ga., and Watsonville, Calif.; 

results are shown in the following table.

Yield and stem length of yarrow cultivars. 

Stems/ Stem 

plant length (in) z 

Cultivar Flower color Year Ga. Calif. Ga. Calif. 

Heidi dark violet 1 15 21.0 11.8 21.0 

2 46 * 20.6 * 

Kelwayi dark red 1 26 25.0 14.5 38.0 

2 56 * 17.8 * 

Kelwayi y dark red 1 20 16.2 

2 60 21.0 

Lilac Beauty lilac 1 6 17.0 15.5 33.0 

2 51 * 18.0 * 

Lilac Beauty y lilac 1 7 18.3 

2 43 18.2 

Paprika red with 1 12 13.0 14.4 33.0 

yellow center 2 46 * 18.7 * 

Weserandstein light rose 1 11 21.0 14.4 33.0 

2 31 * 23.3 * 

White Beauty creamy white 1 10 26.0 13.3 27.0 

2 28 * 19.2 * 


y = grown under 55% shade, Georgia only 

* = no data available 


First-year production in coastal California conditions saw higher yield and significantly 

longer stems than Georgia did; but unfortunately, stem lengths were 

so short in the second year in California that no data were taken. Second-year 

yield and stem lengths in Georgia improved dramatically over first-year data. 

Many cultivars are available from seed, but variability from seed is great. Some 

of the more useful cultivars are also vegetatively produced. Many offerings are 

hybrids, which have longer, stronger, and straighter stems; their uniformity 

makes it easier to sell a 10-stem bunch. 

‘Anthea’ has 3–4" (8–10 cm) wide sulphur-yellow flowers on 2½' (75 cm) stems. 

A terrific hybrid introduction and increasingly useful to cut flower growers. 

‘Borealis’ bears dense clusters of rose-pink flowers. 

‘Cassis’ is about 2' (60 cm) tall with deep cherry-red blooms. Blooms first year 

from seed. 

‘Cerise Queen’ is an old-fashioned red-flowered cultivar that performs well 

throughout the country. It grows about 18" (45 cm) tall and provides bright 

drifts of color. Losing favor as a cut flower as newer hybrids are introduced. 

‘Citronella’ bears butter-yellow flowers on an erect habit. 

‘Colorado’ has wonderful rosy terra-cotta color and fine foliage. A popular 

color. A series of colors is also available.


‘Creamy’ bears large heads of creamy yellow flowers. Plants fill in quickly. 

‘Credo’ is a 3–4' (0.9–1.2 m) cultivar with light yellow flowers that tend to 

fade to creamy white. Excellent for cut flowers. 

‘Debutante’ is a mixture of plants bearing rose to creamy white flowers. ‘Pink 

Debutante’ is an excellent selection. 

‘Fire King’ and ‘Fire Beauty’ have dark red flowers; there is little difference 

between them. 

‘Fireland’, bred in Germany, opens red then fades to pink and finally to a 

tawny gold. Plants grow about 3' (90 cm) tall, but the stems are reasonably stout. 

A popular form for cuts. 

‘Jambo’ bears mid-yellow flowers on 15–18" (38–45 cm) stems. 

‘Kelwayi’ bears magenta-red flowers on 18" (45 cm) stems. 

‘Lilac Beauty’ produces lilac flowers on strong, upright stems. 

‘Lilac Queen’ has flat heads of pastel lilac flowers and is offered occasionally 

by mail-order nurseries. 

‘Lusaka’ is a vigorous grower with white flowers. 

‘Martina’ has large, flat yellow flower heads on 2–2½' (60–75 cm) stems. 

Foliage is ferny and green. 

‘Maskarade’ bears interesting pale yellow flower heads with red flecks along 

the edges as they mature. Quite a different look. 

‘Nakuru’ produces purple and white bicolor flowers. 

‘Orange Queen’ has unusual orange-gold flowers. Plants are about 30" (75 

cm) tall and 18" (45 cm) wide. 

‘Ortel’s Rose’ blooms heavily with rosy pink and white flowers. A terrific selection 

for southern gardeners, introduced by Goodness Grows Nursery of Lexington, 

Ga. 

‘Paprika’ produces red and yellow flowers on a flattened inflorescence. One of 

the most handsome cultivars available. 

‘Pink Island Form’ is about 2' (60 cm) tall and produces pastel pink flowers. 

‘Red Beauty’ bears 2' (60 cm) tall cerise-red flowers in mid summer. 

‘Rose Beauty’ has rather nondescript rose-pink flowers on 2' (60 cm) stems. 

‘Sawa Sawa’ bears lavender-purple flowers on 20" (50 cm) stems. 

‘Schneetaler’ (‘Snowtaler’) is a hybrid with pure white flowers. Plants are good 

for cut flowers and may rebloom if cut back hard after the initial bloom. 

‘Snow Sport’ is a vigorous grower with dark green foliage and dozens of clean 

white flowers on 18" (45 cm) stems. 

‘Summer Pastels’ is a seed-propagated hybrid that includes various pastel colors 

(pink, rose, lavender, salmon to orange) on 2' (60 cm) tall plants. Plants 

flower the first year from seed. The yellow hues are particularly good. 

‘Terra Cotta’ has wonderful terra-cotta flowers with strong stems. Outstanding 

color. 

‘Weser River Sandstone’ (‘Weserandstein’) has deep rose-pink flowers on 2–3' 

(60–90 cm) tall plants. 

‘White Beauty’ produces creamy white flowers. 

Galaxy series, a cross of Achillea millefolium × A. taygetea, has resulted in numerous 

selections. They are similar in leaf shape and texture to A. millefolium but are

ACHILLEA PTARMICA 49 

not quite as rampant. The flower heads, however, are much larger and more colorful. 

Available cultivars include ‘Appleblossom’ (‘Apfelblute’; mauve), ‘Beacon’ 

(‘Fanal’; red), ‘Great Expectations’ (‘Hoffnung’; pale yellow) and ‘Salmon Beauty’ 

(‘Lachsschonheit’; salmon-peach). Unfortunately, all fade badly, at least in the 

heat of Georgia summers—a serious drawback to the series becoming a major cut 

flower. Flower stems arise from lateral breaks, resulting in many short stems, 

another problem more prevalent in the South than the North. Cultivars were 

originally selected as garden plants, and their relative lack of height and propensity 

to fade may limit their usefulness as cut flowers in the United States. 


“I am astonished by how happy folks are with yarrow, which I think is lovely but 

nothing exotic in my book. Colorado’s colors seem to mix nicely with lots of 

things.” Eliza Lindsay, Puzzle Creek Gardens, Portland, Ore. 

“I have learned with ‘Summer Pastels’ to wait until the florets are totally open, 

flat (or a little beyond) before cutting, to strip off the side shoots that aren’t 

completely open, and to put the stems immediately into water when cut. Then 

I clean the remaining dirt off and put into Floralife solution. Drooping, for me, 

has mainly been the result of cutting it too soon.” Julie Marlette, Blue Heron 

Gardens, Fall Creek, Wis. 

Achillea ptarmica sneezewort Asteraceae 

perennial, Zones 3–7 Europe white 2–3'/3' (60–90 cm/90 cm) 

Obviously someone with allergies bestowed the common name upon this species, 

although the flowers are less allergenic than those of common yarrow. Few 

common names in the plant kingdom are as ugly, and hearing the name for the 

first time certainly doesn’t endear this species to anyone. The common name is 

derived from the fact that the “floures make one sneese exceedingly.” In Victorian 

England the leaves and roots, dried and reduced to powder, were used as an 

inexpensive substitute for snuff. 

The creamy white flowers are held in terminal corymbs. Achillea ptarmica is 

less important commercially than A. filipendulina and A. millefolium, but interest 

in it is increasing. We think it is a poor cut flower crop compared with other 

available yarrows; however, yield is good, the crop continues into the fall, and 

shelf life is better than the colored types. 

Propagation 

See Achillea millefolium for seed techniques. About 0.03 oz (0.9 g) yields 1000 

plants (Nau 1999). For vegetative propagation, tip cuttings are best for rapid 

growth (Geertsen and Bredmose 1986).

50 ACHILLEA PTARMICA 


Production under greenhouse conditions is best for cuttings taken in early February 

and grown at 60F (15C) (Geertsen and Bredmose 1986). 


Yield: First-year harvests for Georgia and California and second-year harvest 

for Vermont are shown in the following table (Perry 1989). 

Yield and stem length of Achillea ptarmica in Georgia, Vermont, 

and California. 

Location Stems/plant Stem length (in) z 

Athens, Ga. 13 12.2 

Burlington, Vt. 25 17.0 

Watsonville, Calif. 19 27.0 


Second-year harvest at Georgia was significantly higher, with over 100 

stems/plant. Flowers were harvested until mid November with an average stem 

length of 20" (50 cm). Work in Italy found up to 10 stems/ft 2 (108 stems/m 2 ) in 

the first year when planted at approximately 1' (30 cm) spacing (Zizzo et al. 

1994). 


Sneezewort is greenhouse-grown in some European countries, but it is seldom 

produced this way in the United States. In Finland, with supplemental lighting, 

flowers were harvested for 3–5 weeks 12 weeks after planting (Sarkka 1991). The 

second harvest was also faster with supplemental lighting. Work at Michigan 

State University (Nausieda et al. 2000) found ‘The Pearl’ could be forced (see 

‘Coronation Gold’) in 4.5 weeks under LD and 68F (20C) temperatures. Mildew, 

however, is a serious problem under greenhouse forcing conditions. 


Harvest when flowers are fully open. 

Postharvest 

Fresh: Flowers last 5–8 days in water. 

Dried: Flowers may be air-dried. 

Storage: Flowers may be stored wet for 2–3 days at 40F (4C).

Cultivars 

‘Angels’ Breath’ bears many ½" (13 mm) wide clean white flowers on 15–18" 

(38–45 cm) tall plants. Good filler for bouquets. 

‘Ballerina’ is a relatively new cultivar with clean white flowers. Good as a dried 

cut flower. 

‘Globe’ has small button-like blossoms on 12–18" (30–45 cm) stems. 

‘Perry’s White’ is tall (up to 30", 75 cm), with flowers similar to the species but 

opening about a week earlier. 

‘The Pearl’ (‘Boule de Neige’, ‘Schneeball’) is the most popular cultivar and 

bears a profusion of double, creamy white flowers on 2' (60 cm) stems. In warm 

climates, plants sprawl and are weedy looking. All double-flowered cultivars produce 

some single flowers as well—up to 30% singles, depending on weather and 

cultivar. 

Additional Species 

Achillea ageratum (sweet yarrow) has for centuries been used as a fragrant and 

medicinal herb. The flower head is similar to that of A. filipendulina ‘Parker’s Variety’ 

but about ⅓ the size. The species itself is not particularly useful as a cut 

flower, although ‘Moonwalker’ has been selected for its cut flower habit. Plants 

grow 2½–3' (75–90 cm) tall; the flowers are useful as fillers in a fresh bouquet and 

also dry well. Approximately 1/256 oz (110 mg) of seed yields 1000 seedlings. 

No cold treatment is needed, and if sown sufficiently early, plants flower the first 

year. ‘Golden Princess’ bears flat, golden inflorescences on 3–4' (0.9–1.2 m) 

stems. 

Achillea sibirica is probably too short for cut flowers, but a few growers are trying 

it. The dark green leathery leaves are sessile, more compact than other 

yarrows and quite handsome. The ray flowers are yellow; the disk is brown. ‘Love 

Parade’ (var. camtschatica) grows to 20" (50 cm) tall and bears soft pink flowers; 

sometimes sold as ‘Kamschaticum’. ‘Kiku-San’, about 18" (45 cm) tall with 

creamy white ray flowers and brown center, has been an exceptional performer 

in the Georgia trial garden. 

Pests and Diseases 

ACHILLEA PTARMICA 51 

Most yarrows are relatively pest and disease free, although downy and powdery 

mildew can be a problem. Aphids and spittlebugs are also common. 

Downy mildew results in small, yellow spots on the upperside of the leaves 

and white mold on the underside. 

Powdery mildew results in white spots on both sides on the leaves. 

Stem rot (Rhizoctonia solani) may result in decay of the stem base. Application 

of fungicides and crop rotation alleviate the problem.

52 ACONITUM 

Reading 

Armitage, A. M. 1987. The influence of spacing on field-grown perennial crops. 

HortScience 22:904–907. 

Blomme, R., and P. Dambre. 1981. (The use of outdoor flowers for cutting) Het 

gebruik van bloemen in openlucht als snijbloem. Verbondsnieuws voor de Belgische 

Sierteelt 25(15):681–685. 

El-Kholy, S. A. 1984. Soil moisture and macronutrient effects on yield and quality 

of Achillea millefolium L. Minufiya J. of Agr. Res. 8:331–348. 

Escher, F., and H. Ladebusch. 1980. (Cut flower plants: the influence of soil acidity 

on their growth) Schnitt-Stauden: Der Einfluss der Bodenversauerung auf 

ihre Entwicklung. Gb + Gw. 80(51/52):1135–1136. 

Geertsen, V., and N. Bredmose. 1986. (Three new cut flowers for growing in early 

spring) Tre nye snitblomster til dyrkning i det tidlige forar. Gertner Tidende 

102(18):574–575. 

Nau, J. 1999. Ball Culture Guide. 3rd ed. Ball Publishing, Batavia, Ill. 

Nausieda, E., L. Smith, T. Hayahsi, B. Fausey, A. Cameron, R. Heins, and W. Carlson. 

2000. Forcing perennials, Achillea. In Firing Up Perennials: the 2000 Edition. 

Greenhouse Grower, Willoughby, Ohio. 

Perry, L. 1989. Perennial cut flowers. In Proc. 2nd Natl. Conf. on Specialty Cut Flowers. 

Athens, Ga. 

Sarkka, L. 1991. Wintertime production of Achillea and Physostegia with supplementary 

lighting and CO2 enrichment. Abstr. presented at 2nd International 

Symposium on Development of New Floricultural Crops. 17–21 Sept. 1991, Baltimore, 

Md. 

Vaughan, M. J. 1988. The Complete Book of Cut Flower Care. Timber Press, Portland, 

Ore. 

Zhang, D., A. M. Armitage, J. M. Affolter, and M. A. Dirr. 1996. Environmental 

control of flowering and growth of Achillea millefolium L. ‘Summer Pastels’. 

HortScience 31(3):364–365. 

Zizzo, G. V., U. A. Roxas, and S. Agnello. 1994. Response of three Achillea species 

to two planting densities. Colture Protette 23(6):71–76. 

Many thanks to Ron Smith for reviewing this section. 

Aconitum monkshood Ranunculaceae 

perennial, Zones 2–6 central China blue 2–3'/3' (60–90 cm/90 cm) 

Flowers of monkshood provide some of the finest blue cut flowers available; 

however, production in the United States is limited to areas with cool nights 

and warm (but not hot) days. Although we have seen successful plantings as far 

south as St. Louis, only the coastal areas of California, the Northwest, and the 

Northeast are producing significant numbers of monkshood. Monkshood is 

well established in several European markets but is only sporadically shipped 

to the United States. The most popular species for cut flowers is Aconitum napel-

lus (common monkshood). In all species, one of the sepals is enlarged, covering 

the floral parts like a hood, thus accounting for the common name. The flowers 

are held in terminal racemes and open in mid to late summer. Aconitum grows 

from tubers (enlarged roots); the number and size of these tubers directly influence 

the success of the crop. The tubers are extremely poisonous, containing 

significant amounts of aconite, and the foliage is only slightly less toxic. No taste 

tests need be conducted with this crop. 

Propagation 

ACONITUM 53 

Seed: Although many companies offer seed of monkshood, the seed is notoriously 

difficult to germinate. Seed develops a deep dormancy upon ripening; 

12-month germination times are not uncommon (Armitage 1997). To speed up 

the process, sow seed for all Aconitum species in moist, well-drained medium and 

place at 65–70F (18–21C) for 2–4 weeks. Transfer seed flat to 20–25F ( − 7– − 4C) for 

6–8 weeks. Avoid soil temperatures below 16F ( − 9C). Place in cool temperatures 

around 45–55F (7–13C) even if germination has occurred. Grow at cool temperatures 

until ready to transplant. Sowing in the fall and placing the flats where 

they will be snow-covered during the winter is a cost-effective way to provide 

these conditions. Winter provides the cold, the melting snow in the spring 

reduces inhibitors, and germination occurs in early spring. Germination is 

erratic; it may take 2 years for 50–70% germination rates. However, recent work 

has shown that soaking seed in 50 ppm GA3 enhances germination (Lurie et al. 

1997). 

Division: The tubers may be carefully divided in early spring. The larger the 

tuber, the faster the plant will flower. Small tubers can be planted in a holding 

area; handle them as gently as possible when moving to the final field site. Do not 

divide for at least 2 years after planting; waiting 3 years is even better. 


Tuber size: Flower quality—as measured by stem and raceme lengths, stem 

diameter, and flowers per stem—is directly related to the mother tuber size (Lurie 

et al. 1992). Daughter tubers are formed from the mother tuber; they reach final 

size and weight approximately 4–6 weeks after flowering (Watad et al. 1999). 

Flowering is highly dependent on tuber weight: 30–40 g tubers provide flowers 

of optimal quality, whereas plants from tubers 5 g or less will not flower (Watad 

et al. 1999). Anything that enhances tuber weight enhances flower yield and 

quality. 

Temperature: Aconitum is a cool crop and performs poorly south of Zone 6. 

Plants require moist, cool conditions for adequate establishment, and summer 

temperatures in much of the country preclude high yields and quality. If plants 

are subjected to temperatures greater than 70F (21C) for any length of time, 

stems weaken, making support necessary (Lurie et al. 1992), and basal leaves 

quickly turn yellow. Performance is best in the Pacific Northwest and the 

Northeast.

54 ACONITUM 

A cold period of 32–35F (0–2C) provided during winter (or for 10–12 weeks 

during the forcing period in a cooler) is necessary for flowering. Tubers may be 

stored at 28F ( − 2C) to delay flowering. Frozen tubers may be planted as late as 

early July for late fall flowering. Attempts to force Aconitum napellus to flower 

earlier in the field using plastic tunnels advanced flowering only 4–5 days; quality 

was unaffected (Loeser 1986). 

Gibberellic acid: Preplant application of 200 ppm GA3 to the tubers eliminated 

the need for cold and enhanced sprouting. Also, a single application of 100 ppm 

GA3 as the plants start to bolt increased stem length significantly (Lurie et al. 

1992). Use caution when applying GA; experiment on a small portion of the 

crop to determine if unwanted side effects occur. 

Light and photoperiod: Grow in full sun or afternoon shade. Long days increase 

stem and raceme length as well as the number of flowers per stem (Lurie et al. 

1992). 

Soil pH: Yield and stem length are better with a soil pH of 6.4 than a soil pH of 

3.7 (Escher and Ladebusch 1980). 


Longevity: Plants are long-lived perennials and are productive for at least 5 

years. Replanting 20% of the area every year allows for a constant supply of flowers. 

Spacing: For first-time planting, purchased tubers can be planted as wide as 12 

× 32" (30 × 80 cm). Although yield will be low the first year, by the third year, 

yield will be as high as if planted far more densely. Spacing at 18 × 18" (45 × 45 

cm) or 2 × 2' (60 × 60 cm) also works just fine. If tubers are plentiful, plant as 

close as 8 × 12" (20 × 30 cm) (Sprau 1991). 

Tubers should not be planted deeply. Although research has shown that 

tubers will emerge even if planted up to 2' (60 cm) deep, increased planting 

depth delayed emergence and reduced the number of shoots and the percentage 

that flowered. The number and size of tubers were also negatively correlated 

with depth of planting. Interestingly, new tubers were formed much closer to the 

surface no matter how deep they were planted (Hagiladi et al. 1992). In general, 

plant no deeper than 6" (15 cm). 

Light: The further north the plants are grown, the higher the light intensity 

the plants can tolerate. Afternoon shade does not appear to diminish yield or 

quality. 

Yield: Eight to 12 flowers per mature plant is not uncommon. 


Precooled tubers may be planted in ground beds or in 8–10" (20–25 cm) pots. 

Temperatures should be approximately 45–50F (7–10C) for 6–8 weeks then 

raised to 55–60F (12–15C) during crop growth. Crops planted in late February 

flower in late May. High light is important; blind shoots result from low winter 

light and restricted root systems (Lurie et al. 1997). Long days are not essential

ACONITUM 55 

but are beneficial; begin LD when plants are about 4" (10 cm) high and continue 

at least until bud color. Heating greenhouses to 40F (4C) for the entire duration 

can be successful, although flowering will be slower. Plants must be supported 

with netting. Monkshood, with its low energy requirements, has excellent 

potential for winter cropping. 


Inflorescences (racemes) should be harvested when 3 basal flowers are open. If 

cut too early, flower buds will not open. Plunge immediately into flower preservative. 

‘Spark’s Variety’ (a cultivar of Aconitum henryi) should be cut with more 

open flowers than A. napellus. The question of how much stem to leave behind 

arises with all species of Aconitum, because the leaf area affects the tuber formation 

for the next year. Leave as much behind as possible; there is no magical node 

number at which to cut. Work in Israel (Watad et al. 1991) showed that more 

tubers were formed when cutting height was raised. 

Postharvest 

Fresh: Monkshood persists 7–10 days in preservative, fewer in plain water. 

Flowers are susceptible to chilling injury, and blackening of flowers is said to 

occur if they are stored below 45F (7C) (Vaughan 1988); however, Ed Pincus of 

Roxbury, Vt., has been storing flowers at 33F (1C) for years with no problems. Do 

avoid storage temperatures above 70F (21C). Flowers are sensitive to ethylene. 

Silver thiosulfate (0.75 mM for 12 hours) together with 2% sucrose and a bactericide 

improves vase life (Kalkman 1983, Lurie et al. 1997). Products containing 

STS are recommended as long as they remain available. 

Dried: Aconitum may be air-dried and will persist many months. Strip the 

foliage prior to hanging stems upside down. It may not be a good idea to preserve 

poison on a stem, however, regardless of how well it dries. 

Species and Cultivars 

The following species of Aconitum are useful as cut flowers. Nomenclature may 

change on some of these, but the plants are still the same. 

Aconitum ×cammarum is the class of hybrids between A. napellus and A. variegatum. 

‘Bicolor’ (blue and white), ‘Blue Sceptre’ (deep blue), ‘Bressingham Spire’ 

(violet-blue), and ‘Newry Blue’ (dark blue) are excellent cultivars with stiff, 

upright racemes. ‘Bicolor’ and ‘Newry Blue’ are sometimes sold as selections of 

A. napellus. 

Aconitum carmichaelii is a common garden species whose cultivars are sometimes 

used as cut flowers. Forms include ‘Arendsii’ (Arend’s aconite), which bears 

some of the largest flowers and stoutest stems in the genus; it is sometimes listed 

as A. ×arendsii. The rich, dark blue flowers and strong, upright stems are excellent 

for flower production. If obtainable, it is the cultivar of choice for the cut flower 

grower. Unfortunately, it is more difficult to find than many others. ‘Barker’s

56 ACONITUM 

Variety’ and ‘Kelmscott’ have light blue and violet-blue flowers, respectively. 

Some authorities claim that these cultivars are derived from var. wilsonii, which 

is 5–6' (1.5–1.8 m) tall and bears dark blue flowers. Support is required. 

Aconitum henryi has indigo-blue flowers and is best known for its 3–5' (0.9–1.5 

m) tall ‘Spark’s Variety’, with dark blue flowers and strong stems. 

Aconitum orientale (Oriental monkshood) and A. lamarckii (yellow wolfsbane) 

have sulphur-yellow flowers but do not have the strong, upright stems or the 

market potential of blue-flowered species. 


Crown rot (Sclerotinium delphinii) produces symptoms of leaf yellowing, plant 

wilt, and rot at the crown where the stems emerge. It causes black streaks in the 

water-conducting vessels of the stems and roots. 

Mosaic virus causes yellow mottling and stripes on leaves. Plants should be 

culled. 

Verticillium wilt (Verticillium albo-atrum, Cephalosporium spp.) results in leaves 

that fade to green-yellow, often on one side of the plant only. Leaves die, flowers 

are of poor quality, and black to brown discoloration in the cut stem is apparent. 

Can also be caused by bacterial infections, mainly from Pseudomonas spp. 


“I trialed small amounts of aconitum and the only ones to do well are napellus 

and ‘Bressingham Spire’.” Ron Smith, R. Smith Flowers, Renfew, Pa. 

“We plant in 4' wide beds, 10–12" apart on centers. We do minor harvests 

the first year and then heavy harvests for the next 2–4 years, and then divide. We 

mulch with wood chips 3-plus inches deep. We use no supports except for 

‘Sparks’, which can grow 7–8' with somewhat weak stems. Though napellus 

does okay in sun, it does much better with some shade, but too much shade 

causes the flower head to be elongated increasing the space between florets.” Ed 

Pincus, Third Branch Flower, Roxbury, Vt. 

Reading 

Armitage, A. M. 1997. Herbaceous Perennial Plants. 2nd ed. Stipes Publishing, 

Champaign, Ill. 

Escher, F., and H. Ladebusch. 1980. (Cut flower plants: the influence of soil acidity 

on their growth) Schnitt-Stauden: Der Einfluss der Bodenversauerung auf 

ihre Entwicklung. Gb + Gw. 80(51/52):1135–1136. 

Hagiladi, A., N. Umiel, Y. Ozeri, R. Elyasi, S. Abramsky, A. Levy, O. Lobovsky, 

and E. Matan. 1992. The effect of planting depth on emergence and development 

of some geophytic plants. Acta Hortic. 325:131–137. 

Kalkman, E. C. 1983. Pretreatment improves the quality of summer flowers. Vakblad 

voor de Bloemisterij 38:26–29.

Loeser, H. 1986. (Forcing of cut perennials) Verfruhung von Schnittstauden. 

Zierplanzenbau 26(8):316. 

Lurie, G., H. Borochov, and A. A. Watad. 1992. Aconitum: effect of tuber size, day 

length and GA3 on growth, flowering and tuber production. Acta Hortic. 325: 

113–117. 

———. 1997. Aconitum: effects of environmental conditions on growth, flowering 

and tuber production. Acta Hortic. 430:233–240. 

Sprau, G. 1991. Dense plantings only raise the initial yield. Gartenbau 38(10):50. 


Ore. 

Watad, A. A., Y. Ozeri, A. Hagiladi, L. Afgin, R. Eliassi, and E. Adolian. 1991. Aconitum: 

effect of cutting height on formation of tubers. Hassadeh 71(1):90–91. 

Watad, A. A., G. Lurie, and A. Borochov. 1999. Aconitum: effects of environmental 

conditions on growth, flowering and tuber production. Scientia Hortic. 

81(2):135–147. 

Many thanks to Ed Pincus for reviewing this section. 

AGASTACHE 57 

Agastache Mexican hyssop, giant hyssop Lamiaceae 

annual/perennial 

Agastache, a member of the mint family, is used as a filler in mixed bouquets, providing 

attractive flowers and scented foliage. The flowers are magnets for butterflies 

and hummingbirds. All sorts of agastaches are available in the landscape 

trade, ranging from hard-to-find species to trendy salmon- and rose-colored 

hybrids, such as ‘Tutti Frutti’. Many hybrids are perennial, at least to Zone 6; 

however, they may not have sufficient “substance” to serve even as fillers. The 

blue-flowered forms, such as Agastache foeniculum, provide vigor and substance 

and are probably the first choice when agastache is tried for the market. The 

common names come from the hyssop-like fragrance, but the actual herb Hyssopus 

officinalis (hyssop) is not worth growing for cuts. 

Agastache foeniculum anise hyssop Lamiaceae 

perennial, Zones 5–8 southwestern U.S. blue 1 

20–30"/30" (50–75 cm/75 cm) 

Break off a leaf and smell the licorice fragrance of anise, to some a little too 

strong, depending on the selection. 

Propagation 

Seed: Seed sown at 70–72F (21–22C) germinates in 7–10 days. There are 

approximately 64,000 seeds/ounce (2300/g), and about 0.06 oz (2 g) of seed 

yields 1000 seedlings (Kieft 1996). Cover lightly with soil mix; seed benefits from

58 AGASTACHE FOENICULUM 

Agastache foeniculum 

‘Licorice Blue’ 

light during germination. Plants may be direct sown at a rate of 0.01 oz per 100' 

(1 g per 100 m), but germination may be erratic. Terminal cuttings may also be 

used. 

Growing-on 

Transplant into cell packs or small containers 15–20 days after sowing. Grow 

under 60F (15C) temperatures until ready to place in the field. Plants flower 12– 

16 weeks after seeding.


High light and well-drained soils are basics for all hyssops. With Agastache rupestris 

and A. cana, however, excellent drainage is imperative. Plants flower in the 

summer; cultivars of A. foeniculum have the longest flowering time. Long photoperiods 

are likely beneficial, if not necessary for continued flowering. 


Space plants 9–12" (23–30 cm) apart in the row, 1–2' (30–60 cm) between rows. 


Seldom grown in the greenhouse. We suggest 65/60F (18/15C) day/night temperatures. 

If flowers are to be forced in early winter, the use of LD through nightbreak 

lighting approximately 6 weeks before flowers may be useful. 


Harvest when the inflorescence is ½ to ⅔ open. 

AGASTACHE FOENICULUM 59 

Postharvest 

Vase life is approximately 6–10 days using a general-purpose preservative. Suzy 

Neessen of Cedar Falls, Iowa, reports that vase life is 10 days in water. 

Cultivars 

‘Alabaster’ has creamy white flowers. Plants are about 3' (90 cm) tall. 

Honey Bee series, presented as a landscape plant, is also an excellent form for 

cut flowers. Stems grow to 24–32" (60–80 cm). 

Licorice series has 36" (90 cm) flower spikes in blue and white. Likely hybrids 

involving Agastache rugosa. Zone 6(7). 

‘Snowspire’ grows up to 4' (1.2 m) with clean upright white flowers. Zone 6. 


Agastache cana has rosy-pink flowers, much darker than those of A. rupestris. A 

filler. 

Agastache rugosa (Korean mint) has purple-rose flowers; plants grow to 24" 

(60 cm). 

Agastache rupestris has wonderful airy salmon-peach flowers. Definitely a filler 

—stems are not sufficiently full to stand alone. Strong, pleasant foliage odor. 

A good deal of hybridization has also occurred. The only reason this is important 

is in the overwintering characteristics of the cultivars. Some are hardy to 

Zone 4, nearly all overwinter in Zone 7b. For most of these hybrids, consider 

Zone 7 as the winter cutoff, plus or minus a zone.

60 AGERATUM HOUSTONIANUM 

‘Apricot Sprite’, a cross between Agastache coccinea and A. auriantica hybridized 

by Richard Dufresne of North Carolina, has 2–3' (60–90 cm) stems and a marvelous 

flower color that stops people in their tracks. ‘Apricot Sunrise’ bears many 

1½" (4 cm) golden-orange tubular flowers. 

‘Blue Fortune’ is an exceptionally good hybrid, growing 2–3' (60–90 cm), 

hosting lavender-blue flowers from July to September. Zone 6. 

‘Firebird’, also from Richard Dufresne, is a hybrid of Agastache coccinea and A. 

rupestris. It bears many orange-salmon flowers on 3' (90 cm) tall plants. Plants are 

fuller than either of the parents and are cold hardy to Zone 6. Terrific plant for 

hummingbirds. 

Fragrant Delight Mix grows 2–3' (60–90 cm) with flower spikes of blue, white, 

rose, and lilac. Zone 6(7). The foliage is particularly fragrant. 

‘Pink Panther’ (Agastache coccinea × A. mexicana) grows 3–4' (0.9–1.2 m) tall 

and produces many 1½" (4 cm) long tubular rose-pink flowers held in long 

racemes, starting in mid summer. 

‘Tutti Frutti’ (Agastache barberi × A. mexicana) has tubular pink flowers from 

mid summer to frost on 2–3' (60–90 cm) stems. The foliage, to some noses, 

smells like tutti frutti. What does tutti frutti smell like, anyway? Actually, like 

bubble gum. Zone 6(7). 


The biggest problem with agastaches is poor drainage or overly wet soils, resulting 

in root rot. Many need replacement after 2 years. Botrytis, aphids, and thrips 

are also commonplace. 


“I grew agastache for cuts for the first time this year, and I absolutely love it! 

Great vase life (at least 10 days), wonderful fragrance, easy to cut, just keeps producing. 

I grew the ‘Licorice’ blue and white, as well as ‘Tutti Frutti’, which was 

slow to get started and not nearly as prolific, but smelled just like bubble gum. 

It makes a great filler for bouquets.” Suzy Neessen, The Flower Farm, Cedar 

Falls, Iowa. 

Reading 

Kieft, C. 1996. Kieft Grower’s Manual. 2nd ed. Kieft Bloemzaden, Venhuizen, The 

Netherlands. 

Ageratum houstonianum flossflower Asteraceae 

annual Mexico blue, lavender, white 2–3'/2' (60–90 cm/60 cm) 

Flossflower provides spring- and summer-blooming flowers whose color range 

has expanded from the common lavenders of the past to whites and violets. The

AGERATUM HOUSTONIANUM 61 

flowers are excellent for local markets, although they may be shipped short distances. 

Most cultivars have been bred for the bedding plant trade; however, 

recent breeding has resulted in many cut flowers forms. Flowers are persistent on 

the plant; the generic name comes from the Greek a (“not”) and geras (“old age”), 

presumably because the flowers retain their color for a long period of time. The 

species name has nothing to do with the Texas city but rather commemorates 

William Houston (1695–1733), a Scottish surgeon who collected plants in Central 

America and the West Indies. 

Propagation 

Seed: Seed germinates in 8–10 days if sown at 78–82F (26–28C), slower with 

cooler temperatures, under intermittent mist or in a sweat tent. Cover lightly or 

not at all, as seed germinates better under light. Seeds are not often direct sown, 

Ageratum houstonianum 

‘Blue Bouquet’


but if accomplished, wait for soils to rise above 55F (13C), then sow approximately 

1/100 oz (0.3 g) of seed for 100' (Kieft 1996). Approximately 1/64 oz (0.4 

g) of seed yields 1000 transplants at 80–90% germination (Nau 1999). 

Growing-on 

Grow plugs at 60–65F (15–18C) for 4–6 weeks. If sown in open flats, transplant 

to 72-cell plugs 3–4 weeks after sowing. Fertilize with 100 ppm N, using a complete 

fertilizer, until plants are ready to transplant to the field. Approximately 

7 weeks are needed between sowing and transplanting to the field. 


Plants flower slightly faster under LD, but photoperiod is of minor concern. 

Flowering is mostly influenced by temperature. Flowering occurs throughout 

the summer. Ageratum is most productive in moderate temperatures of 60–70F 

(15–21C). 


The goal of 10–20 stems/plant is easily attainable at a 9 × 12" (23 × 30 cm) spacing. 

Place in full sun in the field after the danger of frost has passed (Utami et al. 

1990). Best yields in the South occur from mid spring to mid summer; in the 

North, plants continue flowering unless summers become excessively hot. In 

general, temperatures below 50F (10C) and above 90F (32C) inhibit flowering. 

Make at least 2 separate plantings in southern locations. The first planting 

should be done in April, another in June; if the market is strong for fall material, 

consider another planting in August. A single tier of netting is useful because 

plants easily lodge (fall over) in inclement weather, and the netting minimizes 

this potential catastrophe. 

Pinching: Some breeders recommend pinching, although with newer cultivars 

and if sequential plantings are accomplished, it may not be required. If pinching 

is done, pinch to about 4 leaf nodes (around 1–2 weeks after planting out). 


Flowers may be forced any time in the greenhouse without artificial photoperiod 

control. Under 62–65F (17–18C) nights and 70F (21C) days, 12–13 weeks are 

required between sowing and flowering; 5–6 weeks are needed for finishing from 

plugs. Flowering occurs 10–14 days earlier in the South. According to Jeff Mc- 

Grew of Jeff McGrew Horticultural Products, Mt. Vernon, Wa., 3–4 harvestable 

stems will be produced 10 weeks after pinching. Additional time is needed if 

temperatures are maintained below 62F (17C). Plant in final containers or in 

ground beds at 6–10" (15–25 cm) spacing. Zizzo et al. (1998), working in unheated 

greenhouses in Sicily, Italy, showed that increased density of planting, up

AGERATUM HOUSTONIANUM 63 

to 55 plants/100 ft 2 (6 plants/m 2 ) resulted in the highest yield, 10 flowers/ft 2 

(107 flowers/m 2 ). Fertilize with 125–150 ppm N and K with potassium nitrate/ 

calcium nitrate or 20-10-20 in the winter. A complete fertilizer, such as 20-20-20, 

may be used when light levels and temperatures increase in the spring. It makes 

no sense to grow anything but cultivars bred for cut flower use, therefore a single 

tier of netting is useful. Reduce fertilization by 50% when flowers begin to 

show color. 


Harvest when the center floret is fully open and lateral florets are well colored. 

Postharvest 

Fresh: Flowers persist 7–10 days in floral preservative. Flowers do not store 

well and are best for local markets. Little or no ethylene sensitivity. 

Dried: Flowers may be air-dried, but flower color often fades. 

Cultivars 

‘Blue Bouquet’ has mid-blue flowers. Somewhat similar to but later-flowering 

than ‘Blue Horizon’. Yields in the 2000 ASCFG National Cut Flower Seed Trials 

(Dole 2001) averaged 9 stems/plant, with an average stem length of 19" (48 cm). 

‘Blue Horizon’, an F1 cultivar, was the first acceptable tall-flowered ageratum 

and is still as good as any. Plants grow 2–3' (60–90 cm) tall and provide midblue 

flowers. Yields in the 1994 ASCFG National Cut Flower Seed Trials (Dole 

1995) averaged 16 stems/plant, with an average stem length of 23" (58 cm). Its 

drawback: it is only available in a single color. 

‘Dondo Blue’ boasts 30" (75 cm) stems with deep blue flowers; ‘Dondo White’ 

is slightly shorter. 

‘Escapade’, with lavender-blue flowers, is a vegetative cultivar that should be 

pinched. 

‘Escobar’ bears bordeaux-red flowers and is later to flower than many others. 

A vegetative cultivar that should be pinched. 

‘Estafette’ produces white flowers and is early. Another vegetative cultivar— 

pinching recommended. 

‘Market Growers Blue’ is an older tall offering, growing to about 2' (60 cm). 

Superseded by newer cultivars but still seen occasionally. 

‘Red Top’ (‘Red Sea’) is closer to purple, although descriptions suggest it is 

rich burgundy. Flower stems are 24–28" (60–70 cm) and branch strongly when 

pinched (though not as strongly as ‘Blue Horizon’). Yields in the 1997 ASCFG 

National Cut Flower Seed Trials (Dole 1998) averaged 15 stems/plant, with an 

average stem length of 17" (44 cm). 

‘White Bouquet’ carries clear white flowers on 20–28" (50–70 cm) stems. They 

seem to have a narrower stem diameter and are therefore more susceptible to 

lodging.



No diseases peculiar to Ageratum occur, although leaf rust (Puccinia conoclinii) 

has been a problem in outdoor plantings. The worst pests are whiteflies, which 

seem to be able to detect the presence of Ageratum from miles away. Once they’ve 

detected it, they tell all their friends and the banquet begins. Aphids can also be 

a problem, often resulting in curling of leaves and distortion of new growth. 

Plants tend to “melt out” in areas of hot humid summers (e.g., southern United 

States), particularly if summer rain is heavy. In staggered plantings, this problem 

is of little concern. If plants lodge in the field, fungal diseases can occur more 

readily. Nematodes don’t appear to be a significant problem, as shown by experiments 

in which Ageratum ‘Blue Mink’ was nearly free of galling even after inoculation 

with root-knot nematodes (McSorley 1994). 


“In my perennial border ‘Blue Horizon’ does self-seed; it behaves like a hardy 

annual where young plants would overwinter, and it did seem as though they 

bloomed taller and stronger than the year before.” Janet Foss, J. Foss Garden 

Flowers, Everett, Wash. 

Reading 

Dole, J. 1995. 1994 ASCFG National Cut Flower Trials. The Cut Flower Quarterly 

7(1):7–12. 

———. 1998. 1997 ASCFG National Cut Flower Trials. The Cut Flower Quarterly 

10(1):1–16. 

———. 2001. 2000 ASCFG National Cut Flower Seed Trials. The Cut Flower 

Quarterly 13(1):1–10, 12–19. 


Netherlands. 

McSorley, R. 1994. Susceptibility of common bedding plants to root-knot nematodes. 

Proc. Fla. State Hort. Soc. 107:430–432. 


Utami, L., R. G. Anderson, R. L. Geneve, and S. Kester. 1990. Quality and yield of 

Ageratum, Aster, Celosia, and Godetia grown as field grown cut flowers. Hort- 

Science 25:851 (abstr.). 

Zizzo, G. V., U. A. Roxas, and G. Donzella. 1998. Ageratum F1 Blue Horizon in 

cool greenhouses in Sicily. Colture Protette 27(3):61–64. 

Many thanks to Janet Foss for reviewing this section.

AGROSTEMMA GITHAGO 65 

Agrostemma githago corn cockle Caryophyllaceae 

annual western Europe purple 3–4'/2' (0.9–1.2 m/0.6 m) 

Corn cockle, native to the meadows and fields of western Europe, is considered 

little more than a weed in its native habitat. Flowers are generally 1½–2" (3–5 cm) 

wide, but in cooler areas, flowers 3" (8 cm) wide have been reported. The purplemauve 

flowers have dark veins and are borne singly or in groups of 3–5 on thin, 

branched stems. Plants perform best in cool summers and cannot be recommended 

as a summer crop in the South. However, if planted in mid March to 

mid April, southern growers can succeed with this crop. Nothing spectacular, 

but a useful filler for bouquets. 

Propagation 

Seed: Seed may be direct sown 0.62 oz per 100' (58 g per 100 m) in early spring 

(Kieft 1996). Indoors, seed may be germinated at 65–70F (18–21C) under mist or 

a sweat tent. Germination under controlled temperatures occurs in 6–10 days. 

Approximately 0.03 oz (0.9 g) should be sown in the greenhouse for 1000 plants 

at 65–75% germination (Nau 1999). 

Studies from the Czech Republic showed that approximately 85% of corn 

cockle seeds still germinated even after 3 years of storage (Novakova 1996). The 

seed of Agrostemma is poisonous; it contains saponin, which can account for 5– 

7% of the dry weight of the seed (Kingsbury 1964). In 1997, a pair of Holstein cattle 

died in Kentucky after ingesting seeds and calyx tubes of corn cockle in the 

hay used for feed (Smith et al. 1997), so be careful! Seed may be stored dry at 

32F (0C) for up to 20 years (Zeevaart 1989). 

Cuttings: Take 1–3" (2.5–8 cm) long vegetative cuttings. Rooting hormone is 

not necessary. Cuttings root in 10–12 days if placed in 70F (21C) root-zone propagation 

beds. 

Growing-on 

Most plants are direct sown to the field. They may also be grown in the greenhouse 

at 65/55F (18/13C) day/night temperatures. Grow on in cell packs (18–32 

cells/tray) or 4" (10 cm) pots. Fertilize with 50–75 ppm N in the form of potassium 

or calcium nitrate at each irrigation. Plants are ready to transplant to the 

field in 4–5 weeks. Warmer temperatures and high nitrogen nutrition result in 

internode elongation and soft transplants that are prone to injury in the field. 


Photoperiod: Agrostemma is a long day rosette plant (Zeevaart 1989). That is, 

plants remain vegetative (in a rosette) and stems do not elongate under short 

days. Transfer of plants to LD results in rapid stem elongation and subsequent 

flowering. Flowering occurs approximately 40 days after transfer to LD. The critical 

photoperiod (i.e., the length of the long day) is not known, but probably a

66 AGROSTEMMA GITHAGO 

12-hour day minimum is necessary. Long days are needed for initiation and subsequent 

flower development (Jones and Zeevaart 1980). 

Temperature: Plants are cool-season crops. Linda Baranowski-Smith reports 

that in northwest Ohio (Zone 5b), field transplants in April or early May are finished 

by mid to late July, with as little as 3 weeks to as much as 6 weeks harvest 

time. Yield and stem length decline as temperatures rise. Plants are short-lived in 

hot humid summers. Plants planted in early April in north Georgia (Zone 7b) 

also declined by mid July. 


Spacing: Plants are normally spaced 9" (23 cm) apart or on 6–9" (15–23 cm) 

centers, but may be planted as close as 6 × 6" (15 × 15 cm) or as wide as 18" (45 

cm) apart. 

Yield: Plants were trialed in north Georgia at different spacings to evaluate 

yield and stem quality. Stems were harvested June–July. 

The effect of spacing on yield and stem quality of Agrostemma 

‘Purple Queen’. 

Spacing (in) z Stems/plant Stems/ft 2y Stem length (in) z 

12 2.3 2.3 24.0 

15 2.5 1.1 22.6 

24 2.9 0.7 22.9 



Each stem carries 4–6 flowers. Although stems/plant and stem length slightly 

increase with greater spacing, the differences are not dramatic. The yield/ft 2 

declines rapidly as spacing increases, therefore close spacing is recommended. In 

northern Ohio, in poor years (drought, weeds), yields were as low as 0.5 stems/ 

plant, and in favorable years, much higher yields were noted (see comments 

by Baranowski-Smith). Flowers, particularly white varieties, are prone to rain 

spotting. 

Direct sowing: Seed broadcast over 150 ft 2 (14 m 2 ) on 15 February in Athens, 

Ga., resulted in 806 stems (5.4 stems/ft 2 , 58 stems/m 2 ) with an average stem 

length of 26" (66 cm). This is a significantly higher yield than from plants spaced 

on 12" (30 cm) centers (see previous table); flowering time and stem length were 

similar. Direct sowing is useful in climates where seed may be sown early. 

Successive sowings/transplanting: Two to 3 successive sowings, 2 weeks apart, 

early in the season are most useful. This is particularly true for southern growers, 

who can put plants out early in the year. The further north, the shorter the 

season, and the less the benefit of successive plantings for Agrostemma.


AGROSTEMMA GITHAGO 67 

Plants can be produced in the greenhouse, although stem prices are seldom high 

enough to justify greenhouse production. To force flowers, space transplants 

6–12" (15–30 cm) apart and maintain under short days (

68 ALLIUM 


“Spacing on 6" centers, in black plastic mulch in northwest Ohio produced 3.7 

stems per plant with stem length of 24–30". Maybe this was just the right combination 

of factors—mild temperatures, regular rainfall, weed suppression, care, 

and long daylength. . . . It needs to be picked when cool [and immediately] placed 

into floral preservative. The few florists we sell to love it and market customers 

like it also.” Linda Baranowski-Smith, Blue Clay Plantation, Oregon, Ohio. 

“We plant several plantings, and pick entire plants, and bunch and sell it at 

the market. It is easy to pick 30 bunches in no time at all when you pick the 

entire plant. . . . Many customers equate the flowers with cosmos for beauty and 

longevity. . . . We have had the best luck with ‘Purple Queen’. ‘Ocean Pearls’ has 

not performed well due to tarnished plant bug issues.” Chas Gill, Kennebec 

Flower Farm, Bowdoinham, Maine. 

Related Genera 

Various species of Lychnis, a short-lived perennial, are similar. Lychnis coronaria 

(rose campion), L. chalcedonica (Maltese cross), and L. coeli-rosa (rose of heaven) 

have potential as cut flowers. 

Reading 

Jones, M. G., and J. A. D. Zeevaart. 1980. Gibberellins and the photoperiodic 

control of stem elongation in the long day plant Agrostemma githago L. Planta 

149:274–279. 


Netherlands. 

Kingsbury, J. A. 1964. Poisonous Plants of the United States and Canada. Prentice Hall, 

Englewood Cliffs, N.J. 


Novakova, J. 1996. Seed production and germination in Agrostemma githago. Preslia 

68(3):265–272. 

Smith, R. A., R. E. Miller, and D. G. Lang. 1997. Presumptive intoxication of cattle 

by corn cockle, Agrostemma githago L. Vet and Human Tox. 39(4):250. 

Zeevaart, J. A. D. 1989. Agrostemma githago. In The Handbook of Flowering. Vol. 6. 

A. H. Halevy, ed. CRC Press, Boca Raton, Fla. 

Many thanks to Chas Gill and Linda Baranowski-Smith for reviewing this 

section. 

Allium ornamental onion Liliaceae 

bulb 

The genus consists of approximately 750 species widely distributed over the 

northern hemisphere, many of which are useful for cut flowers. The pungent

smell of onion, present in all species to varying degrees, is noticeable on most 

species only when stems are cut, damaged, or crushed. Seldom is any smell 

detectable after they have been placed in a vase. The principal cut flower species 

are Allium giganteum and A. sphaerocephalon, although A. aflatunense, A. caeruleum, 

A. christophii, A. moly, A. triquetrum, and numerous hybrids are also grown. The 

genus has it all: plants are easy to grow, have handsome flowers, bear long stems, 

and are relatively insect and disease resistant (Davis 1992). 

Know and trust your bulb dealer, and once trusting, be ready to pay a little 

more for high-quality bulbs. This is true for all bulbous material, but confusion 

seems to be particularly rampant in this genus. In general, cut all flowers on the 

ripe side; resist the pressure to cut and ship green. They will not do well if you do. 

All we need now is a decent name. “Ornamental onions” conjures up no warm 

feelings of beauty and romance—more like purple-skinned circles on display in 

the salad bar. “Chives” is no better. For better marketing, a better name has been 

needed for years. We’re still waiting. 

Bulb size: In most species, size does make a difference. In general, the biggest, 

healthiest bulbs make the biggest, healthiest stems and flowers. Here are some of 

the choices and the size of the bulb commonly available. Smaller (and cheaper) 

bulb sizes can be obtained but should be avoided; they will be of inferior quality. 

Bulb circumference is always given in centimeters. 

Species Bulb circumference Flower color 

Allium aflatunense 12/+ purple 

Allium aflatunense 

‘Purple Sensation’ 12/+ violet 

Allium caeruleum 4/+ blue 

Allium christophii 12/+ purple 

Allium cowanii 4/+ white 

Allium ‘Firmament’ 10/+ dark purple 

Allium giganteum 20/+ purple 

Allium ‘Gladiator’ 18/20 lilac-purple 

Allium ‘Globemaster’ 18/20 purple 

Allium jesdianum 10 rosy pink 

Allium ‘Mars’ 16/+ dark purple 

Allium ‘Mt. Everest’ 20/+ white 

Allium nigrum 10/12 creamy white 

Allium roseum 4/+ pink 

Allium schubertii 14/16 pink 

Allium sphaerocephalon 6/+ burgundy 

Allium triquetrum 6/+ white 

ALLIUM 69 

Mulching: Most species are naturally cold hardy to Zones 3 or 4, and mulching 

of the bulbs is not necessary, although many growers recommend mulching for 

the addition of organic matter as well as to slow the freezing–thawing cycle. Bob

Allium christophii

ALLIUM GIGANTEUM 71 

Koenders of The Backyard Bouquet in Armada, Mich., always grows a companion 

cover crop, such as annual rye grass. 

Cold storage prior to planting: Bulbs of all onions are stored (in Holland or wherever 

the source) until shipped. Studies have shown that most species do not 

require cold storage if fall planted, as any cold needed for initiation and development 

is provided during the winter. For forcing in the greenhouse, 4–8 weeks 

of storage (preplanted in the crate or pot) at 40F (4C) improves flower percentage 

and stem length for some species, such as Allium giganteum and A. aflatunense 

(Dubouzet et al. 1994). 

Staggered planting times: Staggered planting times for spring-flowering species 

provide only a small expansion of the season, because as soil temperatures warm 

up, flowers develop more rapidly and often on shorter scapes. Also, staggered 

plantings usually involve longer periods of cold storage, and this can have a negative 

effect on flower quality. Instead of staggered plantings, select species and 

cultivars that flower at different times, thereby expanding the season. 

Allium giganteum giant onion Liliaceae 

bulb, Zones 4–8 Himalayas purple 3–4'/3' (0.9–1.2 m/0.9 m) 

Still among the most common onions for cut flowers, stems may be found in 

most major markets in the spring and early summer. The globe-shaped bulb is 

2–3" (5–8 cm) across and up to 12" (30 cm) in circumference, making it among 

the largest bulbs in the genus. Small flowers are clustered close together in a 

lilac-purple ball (umbel), 4–5" (10–13 cm) wide, on top of a naked 3–4' (0.9–1.2 

m) stem. Well-grown flowers are particularly eye-catching and command excellent 

prices. The bulbs are prone to virus, however, and clean stock is expensive 

relative to other Allium species. Flowers must realize high prices to be profitable. 

Propagation 

Seed: Seeds require 3–5 years to reach flowering size. Seeds should be sown 

lightly in a cold frame or other cool semi-protected area. Germination is erratic, 

and seeds may require up to one year for complete germination. Don’t mess with 

seed unless you are a hobbyist, or a masochist. 

Division: Bulbs split about every 2 years and may be divided and replanted in 

the field immediately. Flowering occurs the second year from a split bulb, although 

flowers are smaller. 


Temperature: Experimental evidence suggests cold is not necessary for flowering 

(Rees 1985), but it appears to be beneficial. Storing bulbs for 8 weeks at 40F 

(4C) improved the flowering percentage (Dubouzet et al. 1994) and is a useful 

practice in areas where little or no cooling occurs.

72 ALLIUM GIGANTEUM 


Bulb size: Use 8" (20+ cm) circumference bulbs. 

Spacing: Space bulbs 9–12" (23–30 cm) apart and 4" (10 cm) below the surface 

for best yields. 

Planting time: In most climatic zones, bulbs may be planted in the fall, although 

early spring planting may be practiced. Planting from October through 

January did not affect yield in Zone 7b. 

In general, each bulb yields a single stem and occasionally a shorter second 

stem. Foliage may be damaged by spring frosts, but flowers are unaffected. 

Foliage declines before the flowers are harvested. General performance is shown 

in the following table (De Hertogh 1996). 

First Harvest Stem 

Location (Zone) harvest duration (days) length (in) z 

Ottawa (4) 18 Jun 30 46 

East Lansing, Mich. (5) 27 Jun 23 44 

Washington, D.C. (7) 10 May 18 44 

Raleigh, N.C. (8) 26 May 9 44 

San Francisco (9) 5 Jul 30 28 


Many growers find harvest duration is shorter than this table shows. In fact, 

depending on methods used, many alliums are harvested in a 4- to 7-day period. 

If left in the field too long, damage may occur. Harvest times are generally earlier 

and shorter as plants are grown in areas of warmer summers. The consistently 

cool climate in San Francisco resulted in delay of flower harvest. 

Longevity: Commercial production is possible for years. Some growers, such as 

Bob Koenders of Michigan, cut from the same bulbs for 10 years, whereas others 

replace after 2–3 years. In trials in north Georgia, flowering declined after 2 years 

and was dismal the third. Most parts of North America lack the proper combination 

of cold winters, warm summers, and good soils necessary for longevity. 

Shading: Not necessary. Full sun is best. 


Flowers should be harvested when ½ the flowers are open. The remainder open 

naturally in any normal postharvest solution. Place flowers in a 36–42F (3–6C) 

cooler after harvesting. Storage has a negative effect on vase life, reducing marketable 

time after stems emerge from coolers (Kalkman 1984). 

Postharvest 

Fresh: Flowers have a vase life of approximately 14 days (Sacalis 1989). Shipping 

of fully open flowers results in visible damage and decreases postharvest life.

Storage: Stems may be stored for up to 6 weeks (Sacalis 1989). Recut stems 

after flowering and place in a preservative solution of pH 4.0. 

Allium sphaerocephalon drumstick chives Liliaceae 

bulb, Zones 4–8 western Europe to Iran purple 1 

2–3'/2' (60–90 cm/60 cm) 

In early summer, the oval flower heads, 2" (5 cm) in diameter, are green and purple, 

but they mature to a deep purple. The inflorescence consists of many bellshaped 

flowers. The oval bulbs may be planted in the fall. Each bulb produces 

many offsets in the summer and can become almost weedy in some areas. 

Propagation 

Seed: Seeds require 2–4 years to reach flowering size. Seed should be sown 

lightly in a cold frame or other cool semi-protected area. Seeds may require up to 

one year for germination. Buy bulbs. 

Division: Offsets are routinely formed and may be divided after 1–2 years. Separate 

bulbs by diameter and replace larger ones in the production area. 


Cold does not appear to be necessary for flowering. Bulbs, once dug, may be 

stored at room temperature prior to planting. Dormancy occurs approximately 

4 weeks after flowering. 


Bulb size: Optimum size is 2–3" (5/6 or 6/7 cm) circumference (De Hertogh 

1996). 

Spacing: Space 1" (2.5 cm) apart and 4" (10 cm) below the soil surface. 

Planting time: Yield, harvest times, and stem length do not seem to be affected 

by planting date; stem width was only slightly affected by a later planting, as 

shown in the following table (Armitage and Laushman 1990). 

The effect of planting date on Allium sphaerocephalon. 

Harvest Stem Stem 

Month Flowers/ First duration length width 

planted bulb harvest (days) (in) z (mm) y 

Nov 1.1 4 Jun 10 27.4 7.2 

Dec 1.2 31 May 13 26.6 6.4 


y = divide (mm) by 25.4 to obtain (in) 

ALLIUM SPHAEROCEPHALON 73

Allium sphaerocephalon

ALLIUM SPHAEROCEPHALON 75 

Harvest times and stem lengths in Nova Scotia (Zone 5), East Lansing, Mich. 

(Zone 5), and Fayetteville, Ark. (Zone 7) were 22 June/26", 1 July/24", and 15 

May/12", respectively (De Hertogh 1996). 

Longevity: Allium sphaerocephalon is productive for 2–3 years before problems 

with diseases and offset production reduce yield. 

Spacing: Space bulbs 2–4" (5–10 cm) apart. De Hertogh (1996) recommended 

1" (2.5 cm) apart, and we have had success with bulbs spaced as far as 8" (20 cm) 

apart. 

Shading: Not necessary. 


Harvest when the bottom 3 or 4 whorls of flowers are open (when ¼ to ½ of the 

inflorescence is open). Flowers continue to open if placed in clean water. Place 

stems in cooler at 40F (4C) only if necessary, as cold storage may reduce shelf life. 

Postharvest 

Fresh: Stems have a vase life of approximately 10–14 days in water. 

Storage: Flowers may be stored in water up to 4 weeks at 32–35F (0–2C) (De 

Hertogh 1996). 

Dried: Wait until nearly all flowers are open; some seed may be formed from 

the basal flowers (Bullivant 1989). Stems may be hung upside down but that is 

not necessary. 


Many species and their hybrids are useful for cut flowers, and not much distinguishes 

one tall form from another. The main limitation is availability. The 

other concern is that labeling on alliums is terribly confused and often incorrect. 

The problem is far less severe when dealing with reputable sources. Be suspicious 

when prices are too good to be true. 

Allium aflatunense (Persian onion; Zones 4–8) has ball-shaped flowers similar 

to A. giganteum but plants are significantly shorter, about 2–3' (60–90 cm) tall. 

Space bulbs 2–3" (5–8 cm) apart and 4" (10 cm) below the surface. Longevity 

and performance are poor south of Zone 7. Bulbs must be precooled at 41F (5C) 

for 8–10 weeks prior to planting south of Zone 7. Average stem length in Zones 

4–7 is approximately 26" (66 cm) (De Hertogh 1996); south of Zone 7, stems 

are shorter. Bulbs are readily available and relatively inexpensive. Some outstanding 

cultivars are available, the most common and best being ‘Purple Sensation’, 

whose flowers always seems to be in high demand and low supply. ‘Blue 

Powderpuff’ is similar to ‘Purple Sensation’ but with shorter stems, larger heads, 

and lilac-blue flowers. Hybrids in which A. aflatunense is a dominant parent 

include ‘Gladiator’, ‘Mars’, and ‘Mt. Everest’. These produce some excellent flowers 

in lilac-purple, dark purple, and white. All have starburst-like flowers on 4–5' 

(1.2–1.5 m) stems. Hardy in Zones 4–8.

76 ALLIUM SPHAEROCEPHALON 

Allium atropurpureum (Zones 5–8) has dark purple flower heads, so purple as 

to be almost black. Stems are about 2½' (75 cm). Sometimes sold as A. nigrum 

var. atropurpureum. Stems should not be harvested until neck has “hardened” 

and about ½ the flowers are open. 

Allium caeruleum (syn. A. azureum; blue globe onion; Zones 2–7) has grass-like 

foliage and deep blue flowers. Stem length averages 18" (45 cm) and inflorescences 

are 1–2" (2.5–5 cm) in diameter. Plant 2–3" (5–8 cm) apart and 4" (10 

cm) below soil surface. One of the most finicky of bulbs; treat as an annual in 

most of the country. 

Allium christophii (Zones 4–8) has metallic-blue, many-flowered umbels on 6– 

8" (15–20 cm) tall plants. The flowers are handsome and dry well; however, the 

stem length may be too short for wholesale markets. Flowers do not ship well 

and are best grown for local sales. ‘Firmament’, a hybrid between A. christophii 

and A. atropurpureum, bears heads similar to the former but taller (approximately 

2', 60 cm) and with darker flowers. 

Allium ‘Globemaster’ (Zones 4–8) is a hybrid between A. christophii and A. macleanii. 

Plants are 3–4' (0.9–1.2 m) tall and have large, round, light purple heads 

consisting of hundreds of small flowers. An exceptional performer but still relatively 

expensive. 

Allium hirtifolium (Zones 4–8) has rosy red flowers in a drumstick head, similar 

to A. stipitatum. A more common form bears pure white flowers on 3–4' (0.9– 

1.2 m) stems. 

Allium jesdianum (Zones 5–8) is another “tall” (2½–3', 75–90 cm) drumstick 

onion, with purple-lilac flowers. Interesting flowers have white stamens. 

Allium nigrum (syn. A. multibulbosum; Zones 5–8) is an excellent hardy onion, 

with many star-shaped white to pale pink flowers, each with a green center. Ballshaped 

head is formed on 3–4' (0.9–1.2 m) stems. 

Allium schubertii (tumbleweed onion; Zones 6/7–9) is one of the weirdest 

onions, with 2–3 rows of pink flowers arranged loosely on a circular inflorescence 

6" (15 cm) wide. Stems are only 12–18" (30–45 cm) tall, but it is unique 

among the onions and may do well in local markets. Pick with only a few flowers 

open. Gaining popularity. 

Allium siculum (Zones 5/6–8) is actually Nectaroscordum siculum var. bulgaricum 

but is still sold under alliums. Stems are up to 4' (1.2 m) tall; inflorescence consists 

of multicolored tubular flowers that hang down. After fertilization, seed 

pods stand erect and can be dried. Cut with 4 or 5 flowers open; remove any leaves 

that are cut with the stem. Stems become curly as they grow and are difficult to 

harvest and bunch. Caution: this can be quite smelly (garlicy) and very invasive. 

Allium stipitatum (pink and white giant onion; Zones 4–8) is similar to A. giganteum 

but less available in this country. Variety album is a white form. 

Allium thunbergii (Zones 5–8) produces rose-lilac flowers in the fall that persist 

on the plant until frost. If the flowers are not harvested, they literally dry on the 

plant. Although plants are only 12–15" (30–38 cm) tall, the late-flowering habit 

and drying ability make this a potential species for cut flowers. 

Allium triquetrum (three-cornered onion; Zones 5–9) is grown in the field and 

occasionally forced in the greenhouse. The pendulous white flowers have a green

ALLIUM SPHAEROCEPHALON 77 

central stripe and are held on a three-cornered scape, thus the common name. 

Scapes are usually less than 18" (45 cm) long and are reasonably fragrant. 


Bulb rot (Sclerotinia cepivorum) causes abortion and destruction of the flowering 

stem and eventual death of the bulb. Tips of the leaves turn yellow and finally 

brown. The bulbs are covered in a mat of white mycelia, on which appear small 

black sclerotia. Destroy infected bulbs. Excellent drainage is key to reducing this 

serious disease. 


“We grew Allium caeruleum this year along with A. sphaerocephalon, nigrum, christophii, 

and schubertii. The caeruleums had quite a strong oniony smell—true, only 

when you cut the stems—but enough to scare even our most adventurous florists 

away. Nigrum and christophii were borderline on odor but sold ok. Sphaerocephalon 

and schubertii were by far our best allium sellers.” Michelle Smith, 

Blossoms, Inc., Fletcher, N.C. 

“I love [Allium aflatunense] ‘Purple Sensation’. Three-foot stems, heads that 

are big and showy, but not so big as to be difficult to design with, and always very 

reasonably priced.” Susan O’Connell, Fertile Crescent Farm, Hardwick, Vt. 

“I grew Allium nigrum for the first time this year, and I think it was perhaps my 

favorite allium—the large white heads were quite impressive and made great 

cuts.” Cynthia M. Holloway, “The Wild Bunch” Flower Farm, Bradyville, Tenn. 

Reading 

Armitage, A. M., and J. M. Laushman. 1990. Planting date, in-ground time affect 

cut flowers of Acidanthera, Anemone, Allium, Brodiaea, and Crocosmia. Hort- 

Science 25:1236–1238. 

Bullivant, E. 1989. Dried Fresh Flowers from Your Garden. Pelham Books/Stephen 

Greene Press, London. 

Davis, D. 1992. Alliums: the Ornamental Onion. Timber Press, Portland, Ore. 

De Hertogh, A. A. 1996. Holland Bulb Forcer’s Guide. 5th ed. International Flower 

Bulb Center, Hillegom, The Netherlands. 

Dubouzet, M. M., J. G. Arisumi, T. Etoh, and Y. Sakata. 1994. Effects of storage 

and staggered planting in forcing culture of spring-flowering Allium species. 

J. Jap. Soc. Hort. Sci. 63(3):629–638. 

Kalkman, E. C. 1984. Storage has a negative influence on the vase life of Allium 

and Eremurus. Vakblad voor de Bloemisterij 39:33. 

Rees, A. R. 1985. Miscellaneous bulbs. In The Handbook of Flowering. Vol. 1. A. H. 

Halevy, ed. CRC Press, Boca Raton, Fla. 

Sacalis, J. N. 1989. Fresh (Cut) Flowers for Designs. D. C. Kiplinger Chair, Ohio State 

Univ., Columbus. 

Many thanks to Bob Koenders and Jan Roozen for reviewing this section.

78 ALSTROEMERIA 

Alstroemeria Peruvian lily Amaryllidaceae 

annual South America many colors 2–4'/2' (0.6–1.2 m/0.6 m) 

The popularity of Alstroemeria continues unabated in florists shops worldwide. 

Most flowers are greenhouse-grown in Europe, South America, and England, 

but greenhouse production occurs in the northern United States, and field production 

is popular in coastal California. All commercial cultivars are hybrids 

whose parentage is not well known; however, Alstroemeria aurea, A. ligtu, A. pelegrina, 

A. pulchra, and A. violacea are key to their makeup. The environmental responses 

of the parents greatly affect the responses of the hybrids, therefore, cultivars 

do not always react to the environment similarly. Few cut flower cultivars 

are produced from seed; the great majority are obtained from commercial propagators. 

Most breeding has taken place in Holland and England, although American 

hybridizers have also turned out some fine cultivars. 

Shoots arise from a rhizome that has fibrous and fleshy storage roots. Depending 

on the cultivar, Alstroemeria can be flowered year-round, but flowering 

is heaviest in spring and early summer. Outdoor production in California occurs 

in fall and early spring, with some flowering in the winter. 

Propagation 

Seed: Approximately 1.5 oz (42 g) of seed per 1000 seedlings is required, and 

after sowing, the seed flats are generally cooled 2–4 weeks at 45–50F (7–10C). 

Germination is 50–70% (Nau 1999). 

Tissue culture: New cultivars are routinely propagated by tissue culture for 

rapid buildup of numbers. 

Rhizome division: Commercially, rhizomes with 3 or more vegetative shoots 

are commonly available. 


Temperature: Flowering is controlled by the temperature of the rhizome, 

which can perceive the temperature of the soil surrounding it. Soil temperature 

of 41F (5C) for 6 weeks is most effective; however, initiation still occurs at 55F 

(13C), although slower (Healy and Wilkins 1981, 1985). Newer cultivars are not 

as sensitive to low temperatures as older cultivars are. Soil temperatures are more 

important than air temperature for Alstroemeria; if soil temperature is maintained 

below 60F (15C), plants continue to flower, regardless of air temperature 

(Healy and Wilkins 1981, Doi et al. 1999). Dry-stored rhizomes do not respond 

to cool temperature treatments (Vonk Noordegraff 1975), thus they must be 

planted and watered in for temperature to be effective. Soil temperatures above 

70F (21C) inhibit flower initiation by devernalizing the rhizomes. If plants have 

been subjected to inductive temperatures, flowering is reduced if they are given 

subsequent temperatures above 62F (17C) (Healy and Wilkins 1982). For continuous 

production of flowers, maintain greenhouse temperatures at 50–55/ 

60–65F (10–13/16–18C) night/day (Dole and Wilkins 1999).

Alstroemeria 

‘Rebecca’


Photoperiod: Long days result in faster flowering than short days. The optimum 

photoperiod appears to be 14–16 hours and can be provided from late 

September to late March (Dole and Wilkins 1999). The LD treatment is not 

effective unless rhizomes have been subjected to cool temperatures. 

Supplementary light and CO2: Supplementary lighting is useful, particularly in 

the winter, and results in increased flower stem production and quality. Supplementing 

carbon dioxide to 900 ppm CO2 had even more positive results (Labeke 

and Dambre 1998). In cold climates, such as Norway, where cool soil temperatures 

can be maintained all year, supplemental lighting of 18–36 W/m 2 can 

be effective all year (Bakken and Baevre 1995). Supplemental lighting seems to 

be more cost-effective when less light per unit time is spread out over a 20-hour 

photoperiod rather than higher light over a 16- or 12-hour photoperiod (Bakken 

and Baevre 1999). 


Soil: Soil should be well drained with a pH of 6.0–6.5. 

Covering: Many growers provide a saran or low-density shade cloth covering 

over the top and on the side toward the prevailing winds. Plants are expensive, 

and some protection from wind and rain is good insurance. 

Spacing: Space plants on 12–18" (30–45 cm) centers or 18 × 20" (45 × 50 cm) 

in 2 rows in a 3' (90 cm) wide bed. Correct spacing depends on cultivar. 

Planting: Bury rhizomes at the same depth as in the pot (or in the liner). Plant 

so that the growing point is headed into the center of the bed. Carefully spread 

roots out when planting. The fat storage roots are necessary for continuous 

flowering and should be handled with respect. 

Support: Provide at least 2 tiers of support mesh. They may be raised as the 

shoots grow. Place the bottom layer approximately 1' (30 cm) above the soil. 

Harvesting: Stems are usually pulled, not cut. Remove with a rapid upward 

pulling motion. Not all stems should be pulled; many butterfly types do not 

produce sufficiently strong stems and should be cut. Similarly, when young 

plants start to flower, stems should be cut to reduce chances of removing the 

rhizome. Some people report skin rashes when handling Alstroemeria. Use of 

gloves and long-sleeved shirts is recommended. 

Thinning: For longer flowering, thin vegetative shoots as often as possible. No 

more than 30% of the shoots should be removed at one time. 

Scheduling: In many cases, rhizomes arrive in November, are potted and placed 

in a greenhouse until April, and are then planted to the field. Flowering begins 

in June, but the early flowers are removed to strengthen the plant; yield from 

April planting peaks in August. In warm climates, rhizomes planted in August 

start to flower in October; peak flowering occurs in March and April, when soil 

temperatures are cool. 

Yield: Fifty to 100 stems per plant per year are reasonable for field-grown 

Alstroemeria, depending on latitude, cultivar, and spacing. Plants spaced in rows 

3' (90 cm) wide produce higher yield per plant than those on 2' (60 cm) rows.


ALSTROEMERIA 81 

The great majority of flowers worldwide are grown under protection. Use ground 

beds for best production. Rhizomes should be immediately planted 3–4" (8–10 

cm) deep and at 16 × 20" (40 × 50 cm) or 20 × 24" (50 × 60 cm) spacing (De Hertogh 

1996). Use 2 rows per 3' (90 cm) wide planting bed. Provide cool soil temperatures 

(


Cultivars 

Most of the many available cultivars evolved from European sources. ‘Rebecca’ 

is among the most popular; other useful cultivars for cut flowers include ‘Amazone’, 

‘Ballet’, ‘Cinderella’, ‘Diamond’, ‘Dusty Rose’, ‘Irena’, ‘Jubilee’, ‘Lorena’, 

‘Pacific Sunset’, ‘Sacha’, ‘Sunny Rebecca’, ‘Victoria’, ‘Virginia’, and ‘Yellow 

Dream’. Most stems are sold as mixed bunches, not as individual colors (e.g., 

whitish, lavender). Consult your sales representative for current availability. 


Alstroemeria aurea (syn. A. aurantiaca) has bright orange and yellow florets. A 

parent of several hybrids. 

Alstroemeria ligtu (St. Martin’s flower) bears large numbers of small red to pink 

flowers; sometimes the perianth segments are streaked with white. One of the 

dominant parents of the Ligtu hybrids. 

Alstroemeria magnifica provides light bluish to purple flowers. 

Alstroemeria pelegrina has lilac and white flowers spotted with red-purple; the 

perianth segments are streaked with white. 

Alstroemeria pulchella and A. psittacina are probably the same thing. The dark 

red flowers are long and narrow, with dark red perianth segments. Hardy to Zone 

7. ‘Parrot’ is a hybrid with A. pulchella. 


Normal pathogens such as Botrytis, Pythium, and Rhizoctonia affect plants, but 

no diseases specific to Alstroemeria occur. It is essential to provide adequate ventilation 

and spacing for plants. Aphids, spider mites, and whiteflies can be a 

problem. 

Reading 

Bakken, A. K., and O. A. Baevre. 1995. Supplementary lighting and soil cooling 

for year-round production of Alstroemeria. Gartenbauwissenschaft 60(5):224– 

228. 

———. 1999. Optimizing the lighting regime for Alstroemeria with respect to 

photoperiod and fluence rates. Sci. Hortic. 80(3/4):225–233. 

Bik, R. A., and Th. J. M. van den Berg. 1981. Nitrogen and potassium fertilization 

of the Alstroemeria cultivars ‘Orchid’ and ‘Carmen’ grown on peat. Acta Hortic. 

126:287–191. 



Doi, M., Z. Cheng, K. Saito, E. Sumitomo, K. Inamoto, and H. Imanishi. 1999. 

Improving the yield and cut flower quality of autumn flowering Alstroemeria 

by a soil cooling system. J. Jap. Soc. Hort. Sci. 68(1):160–167. 

Dole, J. M., and H. F. Wilkins. 1999. Floriculture: Principles and Species. Prentice 

Hall, Upper Saddle River, N.J.

AMARANTHUS CAUDATUS 83 

Healy, W. E., and H. F. Wilkins. 1981. Interaction of soil temperature, air temperature 

and photoperiod on growth and flowering of Alstroemeria ‘Regina’. 

HortScience 16:459. 

———. 1982. The interaction of temperature on flowering of Alstroemeria ‘Regina’. 

J. Amer. Soc. Hort. Sci. 107:248–251. 

———. 1985. Alstroemeria. In The Handbook of Flowering. Vol. 1. A. H. Halevy, ed. 

CRC Press, Boca Raton, Fla. 

Labeke, M. C. van, and P. Dambre. 1998. Effect of supplementary lighting and 

CO2 enrichment on yield and flower stem quality of Alstroemeria cultivars. Sci. 

Hortic. 74(4):269–278. 

Menguc, A., and M. Zencirkrian. 1996. A research on cold storage of Alstroemeria 

‘Ostara’ cut flowers. Acta Hortic. 429:591–596. 




Nowak, J., and R. M. Rudnicki. 1990. Postharvest Handling and Storage of Cut Flowers, 

Florist Greens, and Potted Plants. Timber Press, Portland, Ore. 



Vonk Noordegraff, C. 1975. Temperature and daylength requirements of Alstroemeria. 

Acta Hortic. 51:267–274. 

Many thanks to Fran Foley and Will Healy (first edition) and Roy Sachs and Roy 

Snow (second edition) for reviewing this section. 

Amaranthus caudatus love-lies-bleeding Amaranthaceae 

annual tropics red, green 4–6'/2' (1.2–1.8 m/0.6 m) 

Amaranthus comes from the Greek amarantos (“unfading”), a reference to the 

flowers on some species, which act much like everlastings. As the name implies, 

flowers can be persistent. All amaranths are showy; some are grown for the flowers, 

others are harvested for the colorful foliage. 

Plants of love-lies-bleeding bear drooping, deep red flowers on 12–15" (30–38 

cm) long racemes. In the first edition of this book, Armitage said he found the 

plants in this genus “rather gaudy” and related how his friend Jo Brownold had 

tried to set him straight: “Not every cut or dried flower needs the grace of lilies or 

the charm of larkspur. Amaranths have long histories as food, religious, and ceremonial 

plants; their use as ornamentals is just the latest chapter.” Jo’s perceptive 

comments notwithstanding, Armitage still finds them gaudy but must 

admit: they capture the eye as well as the imagination. Flowers may be used fresh 

or dried, and their ease of cultivation makes them attractive to growers looking 

for gaudy additions to their crop palette.

84 AMARANTHUS CAUDATUS 

Propagation 

Amaranthus caudatus 

var. atropurpureus 

Seed: In the greenhouse, lightly cover seed in a peat/perlite medium and place 

under mist at 70–75F (21–24C). Germination occurs in 7–10 days. Approximately 

0.03 oz (0.9 g) of seed yields 1000 plants (Nau 1999). Most amaranth 

seed is direct sown. Seed may be direct sown in the field after potential for frost 

has passed. Rates of 0.13 oz per 100' (12 g per 100 m) are common; Ralph 

Cramer in Elizabethtown, Pa., uses a higher rate, up to 0.4 oz per 100' (38 g per 

100 m). Higher rates yield smaller flower heads, which may be more useful for 

certain purposes.

Growing-on 


Seedlings should be transplanted to final containers about 3 weeks from sowing. 

Grow at 62–65F (17–18C) or as warm as 68F (20C) if needed, until ready to transplant 

to the field. Fertilize sparingly with 50–75 ppm N once a week. Green 

plants (plants not in flower) are generally ready for field planting 6–7 weeks from 

sowing. If purchased or produced from plugs, the plugs may be directly transplanted 

once a strong root ball has developed. 


Photoperiod: Amaranthus is a short day plant, although critical daylengths may 

be as high as 16 hours (Kohdi and Sawhney 1979). Plants provided with 8-hour 

photoperiods flower 1½–2 times faster than those provided with 16-hour photoperiods 

(Kigel and Rubin 1985). Plants become sensitive to short days after a 4week 

juvenile period (i.e., as young plants) (Zabda 1961). 

Light intensity: Full sun is best; flowering time is delayed and plants become significantly 

taller under shade, regardless of daylengths (Koller et al. 1975). 

Temperature: No cold treatment (vernalization) is necessary for Amaranthus. 

Temperatures above 70F (21C) result in faster flowering than cool temperatures 

(


of 8–10 hours when plants are approximately 2' (60 cm) tall. Fertilize with 75– 

100 ppm N using a complete nitrogen fertilizer (e.g., 20-20-20, 15-16-17). Maintain 

temperatures of 68–70F (20–21C) during long days, and reduce to 60–65F 

(15–18C) during short days. Reduce further to 55F (13C) 5–7 days prior to harvesting 

to enhance color. Support is necessary. 


For fresh flowers, cut when at least ¾ of the flowers on the inflorescence are open. 

If producing dried flowers, allow the flowers to grow until seed has begun to set 

and the flowers feel firm to the touch. If picked too early, they shrivel to thin 

strings. Harvest the main flowers and allow side flowers to develop. 

Postharvest 

Fresh: Flowers persist 7–10 days in water. If flowers must be stored, keep at 36– 

41F (2–5C) but no longer than 7 days. 

Dried: Flowers may be air-dried. Hang upside down to dry for approximately 

10 days. If you can accelerate the process with heat, it locks in a much better 

color. This is actually true of most plants, but amaranthus particularly benefits. 

Cultivars 

var. atropurpureus has blood-red leaves and is usually more dwarf than the 

species. 

‘Pony Tails’ grows 3–5' (0.9–1.5 m) long, with bead-like flowers on the trailing 

spike. 

‘Red Tails’ has multiple, brilliant red cascading flower spikes, about 12" (30 

cm) long. ‘Green Tails’ bears similar spikes in green and yellow. 

var. roseus bears rose-pink tassels on 4–5' (1.2–1.5 m) tall plants. One of the 

more handsome choices in the species. 

var. viridis has hanging, yellow-green spikes that are not even remotely appealing. 


Stage of harvest for all species grown for their flowers is ½ to ¾ open for fresh, 

open for dried. All are native to tropical climes, and all grow rapidly but can collapse 

at maturity equally fast. If you’re lucky, you will find plants listed under 

cultivar names (don’t expect any accuracy in listing of botanical names), but 

glowing descriptions can be found with nothing more than Amaranthus. We need 

to be more professional than that; let’s at least get the cultivars right. 

Amaranthus cruentus (purple amaranth, red amaranth, red cathedral) has 

leaves that are smooth above, coarsely hairy beneath; the sharp apex usually terminates 

in a soft “spine.” Flowers are greenish red and droop from the leaf axils. 

Plants are 3–6' (0.9–1.8 m) tall. This species is terribly mixed up taxonomically


speaking (the plant has been called A. paniculatus, A. hybridus, and a few others), 

but it has given rise to some really neat cultivars. 

‘Aurora’ is excellent for hot growing areas, with an eye-popping combination 

of yellow and dark green foliage. Top leaves are creamy yellow and lower are dark 

green. Height is about 3½' (1.1 m). 

‘Bronze Standard’ bears bronze flower spikes and deep green foliage. 

‘Foxtail’ has long deep red spike-like racemes of flowers over bronze foliage. 

Plants grow 2–3' tall (0.6–0.9 m). Often sold as ‘Red Cathedral’. 

‘Giant Copperhead’ from Cramers’ Posie Patch has greenish yellow leaves 

and beautiful copper stems and flowers. Grows to 4' (1.2 m). Yield from the 

ASCFG’s national trials was 6 stems/plant with 3' (90 cm) stems (Dole 1999). 

‘Hopi Red Dye’ will dye your fingers, but the red stem and red flower are outstanding 

fresh. Better transplanted than direct seeded. Available from heirloom 

catalogs. 

‘Hot Biscuits’ is really cool. Plants grow 5–6' (1.5–1.8 m) tall, with 2' (60 cm) 

feathery plumes of earthy cinnamon flowers. Difficult to obtain, unfortunately. 

‘Komo’ is completely burgundy-colored, growing 5–6' (1.5–1.8 m) tall. Outstanding! 

‘Oeschberg’ grows to 6' (1.8 m) in height and bears dark scarlet flower spikes. 

‘Red Cathedral’ is probably the most diverse of all cultivars in the amaranth 

trade. Tall, 4–5' (1.2–1.5 m), with bronze-red leaves and large flower heads of 

shocking burgundy. If you are growing ‘Red Cathedral’, you are probably growing 

the species itself or ‘Foxtail’. 

‘Split Personality’ is 3–4' (0.9–1.2 m) tall, with irregularly patterned red and 

golden-green inflorescences that can be up to 18" (45 cm) long. 

Twin Towers series grows 28–40" (70–100 cm). Both the green and red forms 

provide good height and attractive, long-lasting flowers (Dole 2002). 

Amaranthus hypochondriacus (prince’s feather) can be a spectacular plant that 

shows off both foliage and flowers during the summer and, under cool summer 

conditions, remains colorful until frost. In general, they are upright plants, 3–6' 

(0.9–1.8 m) tall, with leaves dark green or deeply flushed with purple. The deep 

crimson axillary flower spikes stand erect above the foliage, like popping fireworks. 

As garish as these plants are, we think they are more graceful than lovelies-bleeding. 

Plants are sometimes sold as A. erythrostachys. Only a few cultivars 

sold belong to this species, among them ‘Prince’s Feather’, a 3–5' (0.9–1.5 m) 

tall blood-red selection, and ‘Pygmy Torch’, 2–3' (60–90 cm) tall with deep 

maroon flowers and purple foliage. 

Amaranthus tricolor (joseph’s coat, tampala, Chinese spinach) is shorter, only 

1–2' (30–60 cm) tall. The 1" (2.5 cm) long flower spikes, found in most of the leaf 

axils, are insignificant compared to the colorful upper leaves. Not the best cut 

flower (actually cut stems), and leaves are best used for local markets only. They 

do not ship well, nor do they persist more than a few days. Keep cool as long as 

possible after cutting. Many cultivars are available through garden sources; the 

following are most useful for the cut trade. 

‘Early Splendor’ bears bright crimson uppermost leaves and bronze bottom 

foliage.


‘Flaming Fountain’ has thin, willow-like leaves of carmine, crimson, and 

bronze. 

‘Illumination’ almost looks like a poinsettia, with large orange to scarlet 

leaves with golden centers. Lower leaves are green to bronze. 

‘Intense Purple’ is just that, with red-veined, deep purple leaves and intense 

red-purple tassels. 

‘Molten Fire’ has a scarlet growing center over green to bronze leaves. 

‘Opopeo’ from Mexico bears striking bronze foliage. It grows to 6' (1.8 m) 

tall. 

‘Splendens’ is probably one of the most colorful varieties, if not the showiest. 

The leaves are deep red, the uppermost ones a brilliant light red. An even more 

exotic blend, particularly useful for shock value, is ‘Splendens Tricolor’ (‘Splendens 

Perfecta’) whose uppermost leaves combine red and gold in a gaudy but 

not uninteresting combination. 

The many new Amaranthus cultivars of unknown parentage that have appeared 

like magic on the market may be worth a try as cut flowers and stems. 

One, Cascade series, produces 3–5' (0.9–1.5 m) ropy stems. 


Few serious pests or diseases affect ornamental amaranths. They may be scared 

of them. 


“It’s a good money maker for us; 90% of what we sell is direct seeded.” Ralph 

Cramer, Cramers’ Posie Patch, Elizabethtown, Pa. 

Reading 

Dole, J. 1999. 1998 ASCFG National Seed Trials. The Cut Flower Quarterly 11(1):1– 

16. 

———. 2002. ASCFG National Trials Report. The Cut Flower Quarterly 14(1). 

Kigel, J., and B. Rubin. 1985. Amaranthus. In The Handbook of Flowering. Vol. 1. 


Kohdi, R. K., and S. Sawhney. 1979. Promotory effect of GA on flowering of Amaranthus, 

a short day plant. Biol. Plant. 21:206–213. 

Koller, D., J. Kigel, I. Nir, and M. Ofir. 1975. Environmental control of weed physiology. 

Final report. Project A10-CR27. USDA Washington, D.C. 


Zabda, J. J. 1961. Photoperiodism in Amaranthus caudatus. Amer. J. Bot. 48:21–28. 

Many thanks to Jo Brownold (first edition) and Ralph Cramer (second edition) 

for reviewing this section.

AMMI MAJUS 89 

Ammi majus false queen anne’s lace Apiaceae 

annual Europe, Asia, N. Africa white 2–3'/2' (60–90 cm/60 cm) 

No longer new to the cut flower market, Ammi is now produced throughout the 

United States, Europe, and South America. Approximately 6 species occur, but 

only Ammi majus and a closely related species, A. visnaga, are grown commercially. 

The white flowers of A. majus are similar to the common roadside weed, queen 

anne’s lace, thus its common name. Although native to the Old World, the species 

appears to be as adaptable to Alabama as it is to Arizona. 

Ammi majus

90 AMMI MAJUS 

Harvesting of Ammi majus requires the use of gloves and protective clothing. 

The sap of the cut stems may result in severe contact dermatitis in sensitive individuals. 

Serious cases may cause permanent scars. 

Propagation 

Seed: In the greenhouse, chill seed at 40–45F (4–7C) for 1–2 weeks prior to 

sowing. Sow in plugs or directly to the field. In controlled environments, cover 

seed lightly and place at alternating night/day temperatures of 68/86F (20/30C). 

Germination of prechilled seed placed at alternating temperatures is approximately 

75–80%; without alternating temperatures, germination may be well 

below 50%. Germination occurs in 7–14 days. Approximately 0.06 oz (2 g) of 

seed yields 1000 seedlings (Nau 1999). 

Seed may be sown directly in the field in the fall (this is a must in southern 

areas) or early spring. Temperatures may fall to as low as 18F ( −8C) during the 

winter without significant damage to seedlings if hardened off. Night temperatures 

should be consistently below 50F (10C) for best germination. Sow 0.03 oz 

per 100' (2.8 g per 100 m) in the field. There are 40,000 tiny seeds/oz (1400 seeds/ 

g), and spacing is often dictated by available equipment. Germination is often 

better in the field than in the greenhouse because of natural alternating temperatures. 

If sown in the field in the summer, chill the seed prior to planting. Two to 

3 successive sowings, 2 weeks apart, are often used. Some growers have found 

that they had better success waiting to plant until the ground was a little warmer, 

but no later than mid May in the Midwest. Even then, successive plantings can be 

accomplished, often with longer stems produced from the last planting. 

Growing-on 

If not direct sown, transplant seedlings to 2–3" (5–8 cm) containers approximately 

3 weeks after sowing or maintain in 200-cell plugs for 4–5 weeks. Fertilize 

with 50–75 ppm N after transplanting. Temperatures of 58–62F (14–17C) are 

recommended to establish the seedlings. Place in the field when plants are large 

enough to handle (about 3 weeks after transplanting) at approximately 6 × 8" 

(15 × 20 cm) spacing. 


No photoperiodic response is known. Plants do not perform well at temperatures 

above 85F (29C) and are best handled as a winter crop in Zones 8–10. In 

areas where summer temperatures are not excessive (Zones 3–7), it is a useful 

summer crop. Total crop time from greenhouse sowing to flowering in the field 

is approximately 15 weeks (White-Mays 1992). 


Yield: Plants transplanted to 12" (30 cm) centers yielded 4–6 stems/plant at 

Maryland (Healy and Aker 1989). Spring planting is important because plants

AMMI MAJUS 91 

should be 3–4' (0.9–1.2 m) tall prior to budding up. If they flower before 3' (90 

cm), they have probably been planted too late. Plants transplanted on 2 April in 

Kentucky flowered in late May. Eight to 12 stems/plant with stem lengths of 

18–24" (45–60 cm) occurred over a 4- to 5-week harvest period (White-Mays 

1992). 

Spacing: Direct sow in fall (South), after danger of heavy frost in the North (see 

“Propagation” for rates) or transplant 9–12" (23–30 cm) apart. A spacing of 6 × 

8" (15 × 20 cm) is sometimes recommended, but disease pressure is increased at 

high-density plantings. If spring planting, transplant no later than 20 April in 

the South, 15 May in the Midwest, 21 May in the North. Late frosts, after warm 

spring temperatures, may result in significant losses. 

Support: Plants can grow 5–6' (1.5–1.8 m) tall and should be supported with 

at least one tier of mesh, 2 layers if spring rains are common. Without fail, torrential 

rainstorms will occur the day before harvest. Each small, perfect blossom 

collects water, and without support, plants wind up in the mud. The lateral 

stems do not always grow straight, and although the twists and curves cause 

problems with bunching, they are handsome and should still be marketable. 


Transplant to ground beds at a 12–15" (30–38 cm) spacing in January and February 

for flowering plants in May and June. Start plants under night temperatures 

of 60–63F (15–17C) to establish the crop. After 2–4 weeks, reduce night 

temperatures to 55–60F (13–15C) until flowering. Expect about 3 months from 

transplanting to flower in the winter, at least 2 weeks earlier in the summer. 


Harvest when approximately 80% of the flowers in the inflorescence are open. 

Flowers cut too early (50% open) do not take up water and tend to wilt. The flowers 

should be a crisp white with only the slightest green tint and no hint of pollen 

shed. Once pollen sheds, flowers decline rapidly. This is an excellent local 

item because it is difficult to cut at the proper stage if plants are to be shipped 

long distances. Some growers cut the initial center flower with only a 6–12" (15– 

30 cm) stem length, allowing the secondary flowers to bloom on 20–24" (50–60 

cm) stems. 

Postharvest 

Fresh: Flowers persist 5–8 days in preservative. They may be stored at 37–40F 

(3–4C) for approximately one week. 

Dried: Flowers may be air-dried for 2–3 weeks in a dark, dry place. Darkness is 

necessary to maintain green stems and keep the white flowers from browning.

92 AMMI MAJUS 

Cultivars 

‘Queen of Africa’ is recommended for greenhouse production. This generally 

indicates that plants are not as weather tolerant as field-grown forms, which 

is certainly not a criticism. Sow in mid June for flowering in mid September. In 

national field trials, plants yielded 9 stems/plant with 2' (60 cm) stems (Dole 

1997). 

‘Snowflake’ has 2–3" (5–8 cm) wide flower heads and grows 3' (90 cm) tall. 

‘White Dill’ bears flowers that are slightly whiter than the species; otherwise, 

plants are the same. 


Ammi visnaga, known and sold as green mist (‘Green Mist’), is a coarser, and, 

in our opinion, larger and more beautiful form than false queen anne’s lace. The 

chartreuse flowers open slowly and can be outstanding cuts as well. A little more 

difficult to locate, but well worth the search. Some people find the odor of the 

flowers mildly unpleasant; Lynn Byczynski of Lawrence, Kans., compares it to a 

turpentine-like smell. 

The genus has been studied extensively in pharmaceutical circles. Numerous 

flavonols, alkaloids (some poisonous to livestock), and cumarins have been isolated 

from leaves and fruits of Ammi species. Ammi visnaga contains visnadine, 

extracted from the fruit, which exhibits peripheral and coronary vasodilator 

activities and has been used in the treatment of angina pectoris (Duarte et al. 

1997). Off the subject but interesting information nevertheless. 


Daucus carota (queen anne’s lace) is a popular filler for eastern and southern 

growers. It can usually be distinguished by the small black center flower (“Queen 

Anne”) in the inflorescence. The species is biennial; 2 years are necessary for efficient 

flowering. Many growers simply cut from roadside populations which, if 

done too aggressively, may result in significant decline in plant numbers. Since 

this plant is not native to North America, this may not be a concern. Plants may 

be easily grown from seed and planted in the field. Populations can be continued 

through self-seeding. Some wholesalers accept queen anne’s lace as readily as 

Ammi. 

Reading 


9(1):31–37. 

Duarte, J., I. Vallejo, F. Perez-Vizcaino, R. Jimenez, A. Zarzuelo, and J. Tamargo. 

1997. Effects of visnadine on rat isolated vascular smooth muscles. Planta 

Medica 63(3):233–236.

ANEMONE CORONARIA 93 

Healy, W., and S. Aker. 1989. Cut flower field studies, 1989. Univ. of Maryland 

Hort. Production Co-op Ext. Serv. HE 141-89. 


White-Mays, L. 1992. Ammi majus, false queen anne’s lace. In Proc. 4th Natl. Conf. 

on Specialty Cut Flowers. Cleveland, Ohio. 

Many thanks to Knud Nielsen III and Linda White-Mays (first edition) and Lynn 

Byczynski (second edition) for reviewing this section. 

Anemone coronaria poppy anemone Ranunculaceae 

bulb, Zones 6–8 Mediterranean many colors 8–15"/8" (20–38 cm/20 cm) 

Anemones have been produced as cut flowers for years. Plants are not tolerant of 

warm weather, and cut flowers are produced in the cool season: spring in the 

field or winter in the greenhouse. Most production must be accomplished under 

some sort of protection to minimize wind and rain damage. Active selection and 

breeding of anemones have resulted in numerous hybrids from controlled 

crosses in many colors. The market is strongest prior to Mother’s Day; demand 

decreases after that date. 

Propagation 

Tubers: Anemones are not usually propagated by the grower but can be 

divided if clumps are large. With low growth rates, this is seldom feasible. Tubers 

are usually soaked in water overnight prior to other treatments such as cold storage. 

Tubers may be soaked in running water at room temperature water for up 

to 48 hours, with a fungicide added for the last half hour or so (water turned 

off). After soaking, and allowing them to drip dry, they should be packed into 

perforated or ventilated plastic bags with moist (but not wet) perlite, peat moss, 

or vermiculite for subsequent cold treatment (Gloeckner 2001). 

Cold treatment of tubers: Research in Japan (Ohkawa 1987) suggested that 100% 

of tubers stored 4 weeks at 41F (5C) initiated flowers after planting, but that 

50F (10C) was optimal for flower quality and yield. Other work in Florida suggested 

that 7 weeks at 43F (6C) was best. If planting tubers, we suggest 4–5 weeks 

at 45–50F (7–10C) prior to planting. 

Seed: Sow seeds on top of soil and place at 55–60F (13–15C). Germination 

occurs in 10–14 days. Plugs are available for most cultivars through plug 

specialists. 

Growing-on 

Seedlings should be fertilized lightly (50–75 ppm N) and placed in high light 

and cool temperatures around 45–55F (7–13C). Soak tubers for 12–48 hours in 

water prior to planting.

Anemone ‘De Caen White’ and ‘Saint Brigid (Saint Bridgid) Blue’


Temperature: Cold treatment (vernalization) of the tubers is discussed earlier. 

Natural vernalization occurs in the field if tubers are planted in the fall in mildwinter 

climates or in early spring elsewhere. Poppy anemones are winter hardy 

only to Zone 6, perhaps to Zone 5 if sufficient mulch is applied. Warm temperatures 

during production inhibit flowering and result in poor-quality flower 

stems, therefore field production is practiced mainly in Mediterranean climates, 

or in areas with mild winters and cool springs in the United States. Weather protection 

is highly recommended. High temperatures signal the onset of tuber 

dormancy. 

Research in the greenhouse has provided guidelines for day/night temperatures 

that optimize flower yield and quality (Albrecht 1987, Ohkawa 1987). In 

general, day temperatures of 54–60F (12–15C) and night temperatures of 45– 

48F (7–9C) will provide excellent yield and quality. Temperatures as high as 61F 

(16C) were optimal when combined with 16-hour daylengths in Alaska (Karlsson 

1997). 

Photoperiod: Photoperiod studies are not definitive, but it appears that SD 

accelerate flowering and LD result in early termination of flowering and hastening 

of dormancy (Kadman-Zahavi and Horovitz 1980, Kadman-Zahavi et al. 

1984). Under normal flowering times, natural SD occur during flowering and 

need not be changed. Supplemental light, however, during the SD of winter, is 

recommended if economically feasible. 



Tuber size: Use tubers 4/5 cm in circumference (De Hertogh 1996). Since 

tubers cannot be easily measured, use at least one-year-old tubers to be confident 

of tubers of sufficient size. Tubers above 5 cm should be avoided; they become 

quite woody and can be a problem. Some English gardeners learned the hard 

way: “Such monsters should be put straight on the fire, they are worth neither 

time nor space for their planting” (Genders 1960). 

Spacing: Plant tubers 1–2" (2.5–5 cm) apart. Research in Israel showed that 

tubers can emerge from as deep as 12" (30 cm) below the surface (Hagiladi et al. 

1992). We suggest planting about 1" (2.5 cm) deep, but it is nice to know that 

tubers are so adaptable. 

Planting time: The best planting time for tubers is in the fall in Zones 7–9 and 

in early spring further north. Late planting results in significant decrease in yield 

and quality. The effect of different planting times in Zone 7b, Athens, Ga., is 

shown in the following table (Armitage and Laushman 1990).

96 ANEMONE CORONARIA 

The effect of planting date on Anemone coronaria De Caen Group. 

Tuber Harvest Stem 

Month survival First duration length 

planted (%) Flw/tuber harvest (days) (in) z 

Nov 96 10.2 27 Feb 65 9.5 

Dec 89 4.8 30 Mar 33 7.4 

Jan 25 1.1 15 Apr 17 5.4 

Feb 20 0.2 30 Apr 5 5.5 


Obviously, early planting is essential, at least in Zone 7. With late planting and 

subsequent delay of first harvest date, flowers emerged as weather became 

warmer, but warm weather shortens duration of harvest and decreases stem 

length, stem diameter, and flower diameter. 

Planting zones: In other locations, flowering time and stem lengths of De Caen 

were 20 May/10" in Glencoe, Ill. (Zone 5); 2 May/12" in Washington, D.C. (Zone 

7); and 27 January/6" in Baton Rouge, La. (Zone 9) (De Hertogh 1996). Data 

based on planting from October to December. 

Longevity: Anemones should be treated as annuals for commercial production. 

Research on tubers that remained in place for 3 years showed that productivity 

declined after the first year (Armitage and Laushman 1990). 

Longevity of Anemone tubers for cut flower production in the field. 

Year Tuber survival (%) Stems/tuber Stem length (in) z 

1 90 6.5 10.0 

2 30 7.0 9.3 

3 20 5.4 8.5 


Although the number of stems per tuber and stem length were only slightly 

affected, the survival of tubers was dramatically reduced each year. Survival was 

affected by warm summer soil temperatures, pests, and diseases. This work was 

done in Georgia, but most growers in the United States find that yearly renewal 

of tubers is necessary for best production and quality (De Hertogh 1996). 

Shading: Shading results in longer stem lengths. In research at Georgia, stems 

of De Caen Group hybrids were approximately 9" (23 cm) and 12" (30 cm) long 

under full sun or 67% shade, respectively (Armitage 1991). Yield was unaffected. 

This may not be the case in areas of cooler temperatures and less light intensity. 

Tubers vs. plugs: Tubers often do not germinate as well as growers would like, 

even when they are soaked and cooled, and field planting of seedlings (plugs) is


often practiced. The use of plugs results in better stands of plants, but the yield 

and quality of cut stems are not affected. 


Greenhouse production in northern states occurs October through December in 

cool greenhouses. Commercial production in the South is also possible, but harvesting 

must be finished before 1 April because of warm day temperatures in the 

winter. Most growers plant plugs in ground beds or 4–6" (10–15 cm) pots. Space 

approximately 6" (15 cm) apart and maintain temperatures below 55F (13C). 

In general, crop time in the greenhouse from vernalized tubers can be as fast 

as 16 weeks or as slow as 32 weeks, depending on latitude. With purchased plugs, 

12–13 weeks are needed (De Hertogh 1996). 


Some recommendations suggest that flowers should be harvested after they have 

opened and closed once or twice. This is difficult to monitor, however, and most 

growers harvest flowers when the petals (actually sepals) have started to separate 

from the center but are not fully open. 

Postharvest 

Fresh: Bud-cut flowers open well in water alone and persist 4–6 days. Exposure 

to ethylene causes petal shatter and reduces vase life. Additional vase life occurs 

if pulsed with silver thiosulfate (STS) for 15–30 minutes. Transfer stems to a 

solution containing 2–4% sugar (Nowak and Rudnicki 1990). Recut the base of 

the stems with each transfer. Stems should be shipped in an upright position if 

possible. 

Storage: Flowers may be stored dry at 38–44F (3–8C) for 1–2 days, after conditioning 

with 100 ppm hydroxyquinoline sulphate plus 1.4 oz/gallon of sugar 

(Nowak and Rudnicki 1990). 

Dried: Flowers may be dried in a microwave (Vaughan 1988). Place the flowers 

on approximately 2" (5 cm) of warm silica gel and cover the flower with additional 

gel. Heat for 1–3½ minutes, depending on the fleshiness of the flower. 

Cultivars 

Cleopatra series is only recommended for the greenhouse. Available as seeds, 

plants bear 18–24" (45–60 cm) long scapes. Flowers are available in single colors 

and a mix. 

De Caen Group hybrids, the most popular field-grown anemones, consist of 

single, saucer-shaped flowers. They are available as a mix or as single colors. 

La Beau is a tetraploid series of anemones, with strong thick stems and large 

early-season flowers.

98 ANEMONE CORONARIA 

Mona Lisa Group is mainly used in the greenhouse trade. The stems are 

longer than De Caen hybrids, and the vase life is better. In the field, they flower 

a little later than De Caen. 

Saint Brigid (Saint Bridgid) hybrids have semi-double to double flowers. They 

are also available as a mix and as single colors. 

St. Piran Mix has long stems of single and semi-double flowers. 


Anemone ×fulgens also grows from a tuber and should be treated similarly to A. 

coronaria (De Hertogh 1996). The most popular cultivars are members of the 

Saint Bavo Group. 

Anemone hupehensis, a Japanese species, and the hybrids of A. ×hybrida are effective 

cut flowers, but vase life is short. However, their flowers occur in late summer 

and fall, an important time for field flowers. White cultivars like A. ×hybrida 

‘Honorine Jobert’ are particularly effective for fall weddings. 


Leaf spots and tuber rots are caused by various fungi. Apply appropriate fungicides 

after the foliage has emerged. Anthracnose (Colletotrichum acutatum) can be 

a problem, but hot water treatment (118F, 48C) of the corms for one minute 

killed 99% of the spores (Doornik 1990). 


“I sold some white Japanese anemones this fall for a wedding, and then got an 

additional request for some for another wedding. They have nice long stems, 

and the unopened buds are interesting, even though there aren’t too many flowers 

open on a stem at once. In this climate, they can be rampant spreaders.” Carol 

Paschal, Island Flowers, Anderson Island, Wash. 

Reading 

Albrecht, M. L. 1987. Growth retardant use with potted anemone and ranunculus. 


Armitage, A. M. 1991. Shade affects yield and stem length of field-grown cut 

flower species. HortScience 26:1174–1176. 



Science 25:1236–1238. 



Doornik, A. W. 1990. Hot-water treatment to control Colletotrichum acutatum on 

corms of Anemone coronaria. Acta Hortic. 266:491–494. 

Genders, R. 1960. Bulbs All the Year Round. Faber and Faber, London.

ANTIRRHINUM MAJUS 99 

Gloeckner, Fred C. 2001. www.fredgloeckner.com 



of some geophytic plants. Acta Hortic. 325:131–137. 

Kadman-Zahavi, A., and A. Horovitz. 1980. Acceleration of dormancy in the 

poppy anemone by long days. Hassedah 51:434–435 (in Hebrew). 

Kadman-Zahavi, A., A. Horovitz, and Y. Ozeri. 1984. Long-day induced dormancy 

in Anemone coronaria L. Ann. Bot. 53:213–217. 

Karlsson, M. 1997. Flowering response of Anemone coronaria to photoperiod and 

temperature. HortScience 32:466 (Abst). 



Ohkawa, K. 1987. Growth and flowering of Anemone coronaria L. ‘De Caen’. Acta 

Hortic. 205:159–168. 


Ore. 

Antirrhinum majus snapdragon Scrophulariaceae 

annual Mediterranean many colors 3–4'/2' (0.9–1.2 m/0.6 m) 

The market for snapdragons continues to fluctuate, and always will, primarily 

due to over- and underproduction. When prices are poor, production is decreased, 

and, in time, prices become sufficiently strong to warrant additional 

volume, resulting in another cycle. The length of time the highs persist is directly 

related to the number of growers producing snapdragons. While this is true of 

all crops, snaps seem to have been buffeted around more than most. In the early 

2000s, the market for snapdragons is strong and getting stronger. 

There will always be a market for spike flowers, and few other species can provide 

the range of colors and strength of stem commonplace in today’s snap cultivars. 

Most of the breeding is directed toward cultivars for the greenhouse, and 

greenhouse production is common in all areas of the country. Snaps may also be 

field-produced in the spring in southern and far western states, and in the summer 

further north. Snapdragons have cultural requirements similar to other 

cool-loving plants, such as larkspur, lupines, and delphiniums. In areas where 

winters are sufficiently cold for flower production, but not so cold as to damage 

or destroy the plants (Zones 7–10), early spring production in the field is 

feasible. 

Propagation 

All plants are raised from seed, generally in plug trays. For optimum germination, 

seed should be sown, watered in, and cooled at 40F (4C) for 2 weeks (Nau 

1999). After cooling, germinate at 72F (22C) under mist or sweat tent. Although 

cooling is beneficial, it is not a requirement; if it is not possible to provide cooling, 

commence germination temperatures immediately. Seedlings should

Antirrhinum majus 

‘Potomac Yellow’


emerge in 7–14 days. Thomas McElroy of Newton Greenhouses suggests placing 

sown plugs in chambers in the dark for 3 days, then for 2 days under fluorescent 

lights for 24 hours a day (McElroy 1998). Approximately 1/128 oz (221 mg) of 

seed yields 1000 seedlings, depending on cultivar (Nau 1999). 

Growing-on 

After plants have 3–5 true leaves, grow at 50–55F (10–13C) night temperature. 

Maintain day temperatures as close to 60F (15C) as possible. Warm temperatures 

cause stem elongation, resulting in lanky transplants. Fertilize at approximately 

200 ppm N when grown in warm temperatures; reduce by 50% when 

growing at 50–55F (10–13C). Transplant to field or greenhouse as soon as plants 

can be handled without damage (usually 5–6 weeks). In spring (late March 

through early May, depending on frost dates), transplant to the field. In areas 

where fall transplanting may be accomplished, transplant from mid September 

through early November. In the greenhouse, transplanting may take place yearround. 


Photoperiod: The snapdragon is essentially a quantitative long day plant, 

meaning that it is capable of flowering under short days but flowers earlier and 

at a lower leaf number in LD (Laurie and Poesch 1932, Maginnes and Langhans 

1961). Although this is a typical response, many current greenhouse cultivars 

have been bred to be virtually unaffected by daylength, particularly the late-flowering 

ones. Plants grown under SD produce more vegetative growth, while LD 

mainly affects the initiation of flowers. Once initiated, the subsequent development 

is relatively unaffected by daylength (Maginnes and Langhans 1961). Photoperiod 

also affects the juvenile stage, that is, the number of leaves that must 

form before flowers occur. The minimum number of leaves is higher under SD 

than LD (Cockshull 1985). Greenhouse (forcing) cultivars have been bred to 

flower at virtually any time of year under natural daylengths; photoperiod is less 

important than it was for older cultivars. However, HID lamps are often used for 

both additional light and long days (adding 2–5 hours to the natural day) in the 

winter, particularly in northern houses. 

Light intensity: Snapdragons flower with stronger stems, more rapidly, and 

with higher yields under high light. Low light results in more blind shoots and 

reduces yield and stem quality. Light intensity is more of a concern for winter 

greenhouse production than field production. Some winter cultivars have been 

bred for low light response and may be used for winter production, however to 

assure high-quality stems, the use of HID lamps is recommended. 

Temperature: Snapdragons have no vernalization requirement, but those 

grown cool (50F, 10C or below) initiate and open flowers later than those grown 

warmer (Maginnes and Langhans 1960, 1961). Although warm temperature hastens 

flowering, it reduces spike length and stem strength (Post 1955). During 

summer, stem strength is poor in the field in the Southeast.

102 ANTIRRHINUM MAJUS 


Planting time: In general, successive plantings are practiced, often 3 per season. 

In the Midwest and North, plant as soon as the ground can be worked in the 

spring. Harden transplants by putting greenhouse plantlets outside during the 

day or placing them in cold frames day and night for about 2 weeks prior to 

planting out. If properly hardened off, plants can survive 25–28F ( − 4– − 2C) frosts; 

if not hardened, they will produce snapper soup. In the South, plant in September 

through early November. In north Georgia, 5F ( − 15C) temperatures were 

recorded in late December, and plants flowered well the next spring; plants had, 

however, gone through a cool fall. 

Fall planting is always a difficult decision, because of freezing problems. In 

Zone 7 and warmer, fall planting is common; however, when freezes come, some 

protection is recommended. Frost protection fabrics must be secured against 

gusty winds. Some growers use an inexpensive line of incandescent bulbs under 

plastic tunnels during freezing nights (see comments by Landwer). From the 

plant’s perspective, if fall temperatures cool down well and plants harden off, 

winter temperatures are far less devastating. The major cultivars for field production 

are the Rockets and Potomacs, but others are also used (see “Cultivars” 

and “Grower Comments”). 

Spacing: Plant on approximately 9–12" (23–30 cm) centers. Two to 3 rows in 

a 3' (90 cm) wide bed are often used. If plants are to be pinched, place on 12–15" 

(30–38 cm) centers. 

Yield: In Maryland, yields of crops planted out on 15 April produced averages 

of 7 and 10 stems/plant for Potomac and Rocket strains, respectively (Healy and 

Aker 1989). 

Fertilization: Side dress with a complete fertilizer as soon as temperatures 

warm up. The fertilization of outdoor snaps has been the subject of much discussion. 

In general, phosphorus is not absorbed well when temperatures are low; 

after fall growth has occurred (fall planting), nitrogen is generally reduced and 

P-levels are increased. In spring-planted materials, do the opposite, that is, 

increase the N as temperatures increase. Nutrient deficiencies of snapdragons are 

well discussed in the article by Ray Campbell and his colleagues (2000). 

Shade: Shade is not necessary, but growing under cloth tents (such as cheesecloth) 

results in longer stems and better-quality flowers. In snapdragons, petal 

shatter follows pollination; the absence of bees under the tent will assure more 

persistent flowers. 


Cultivar selection is very important in greenhouse production. Winter cultivars 

should be selected for winter forcing, summer varieties for summer (see “Cultivars”). 

Talk with a seed supplier for the best cultivars for a particular area and 

season. A great deal of information is available in manuals and books. 

Successive plantings every week (or every 10 days) is common for greenhouse 

forcing. Transplant to ground beds as close as 9" apart or as wide as 15" (38 cm) 

apart. Place transplants at 3 × 5" to 4 × 5" (8 × 13 cm to 10 × 13 cm) for winter


production and approximately 3 × 5" (8 × 13 cm) for summer production (Stefanis 

and Langhans 1982). After transplanting, provide as much light as possible. 

If cultivars are properly selected, manipulation of photoperiod is not particularly 

important; but it is often practiced nevertheless, and providing LD (12– 

16 hours) ensures flowering. Set temperatures to 50–55F (10–13C) throughout 

the crop cycle. Higher temperatures during the day are unavoidable in most 

areas, and occasional 70F (21C) temperatures are not detrimental, if not too persistent. 

Larger plants with heavier stems can be obtained if held at warm temperatures 

in the early stages and lower temperatures at later stages. 

Growers supplement the greenhouse with 900–1200 ppm CO2 in the winter, 

particularly in the North, where greenhouses are seldom vented. Fertilize with a 

complete liquid fertilizer (150–200 ppm N and K) that is low in ammonium at 

each irrigation; double the concentration if feeding only once a week. Fertilize 

only until flower buds begin to swell. At least 2 tiers of support are needed, the 

bottom one about 12" (30 cm) from the soil. A cheesecloth cover inhibits pollination 

by bees. 


For local markets, harvest flowers when ⅓ to ½ of the flowers are open. This would 

consist of 8 or more open flowers on the stem. For long-distance shipping, stems 

may be harvested when ⅓ of the flowers are open (5–7 open flowers) (Sacalis 

1989). For long-term storage or if preservatives are to be used, flowers can be cut 

as early as when 2 or 3 buds are showing color (Nowak and Rudnicki 1990). 

Postharvest 

Fresh: Fresh flowers persist 5–8 days in water; they will persist a little longer if 

treated with STS, if available. Treatment with a one-hour STS pulse is common, 

although it does not always provide additional vase life. Differences in STS efficacy 

may be due to cultivar differences or treatment variability. A 1–2% sugar 

solution (combined with a biocide) improves the color of unopened flowers and 

increases vase life from 8 to 21 days. Nell and Reid (2000) suggest an overnight 

pulse of flower food with 7% sugar enhances vase life. The gas 1-MCP, marketed 

under names such as EthylBloc, has been used effectively with snaps as a substitute 

for STS (Serek et al. 1995). EthylBloc may be commonplace in the 

future in small operations, but distribution methods and techniques must be 

simplified before use becomes widespread. A natural lipid, lysophosphatidylethanolamine 

(LPE), has also been shown to enhance vase life (Kaur and Palta 

1997), but that material is difficult to obtain. 

Storage: Stems may be stored at 40F (4C) for 3–4 days either dry or wet. If 

wrapped in plastic film to reduce desiccation, they may be stored up to 10 days. 

Preservatives and temperature have been shown to affect wet storage. At 32–35F 

(0–2C), storage can occur for 1–2 weeks in water, 4–8 weeks in a preservative. 

Use a fungicide to inhibit Botrytis spp. if storing for more than 4 days. A budopening 

solution should be used after long-term storage. Place stems in a solution 

at 70F (21C), 75–85% relative humidity, under 16-hour daylengths and high


light intensity (approximately 200 fc) (Nowak and Rudnicki 1990). Long-term 

storage can result in poor flower development and faded color (Post 1955). 

Gravity: If not stored upright, snapdragon stems bend upward. This may be 

an ethylene-induced or a calcium-mediated response; work with calcium inhibitors, 

such as lanthanum chloride (LaCl3) showed inhibition of the stem curvature 

(Friedman et al. 1998), as did the use of ethylene inhibitors, such as STS 

and 1-MCP (Philosoph-Hadas et al. 1999). Much more work is needed. It is best 

to always store and ship stems upright. Ship stems in refrigerated trucks, even if 

traveling a short distance. Warm temperatures, such as those found in airport 

loading docks, are disastrous. Maintaining cool temperatures is essential. 

Dried: Flowers may be dried in warm air, but the use of silica gel improves 

color retention (Vaughan 1988). 

Grading 

The Society of American Florists (SAF) has developed grading standards for 

snapdragons. All bunches consist of 12 stems. 

Cultivars 

Weight per stem (oz) z Min. 

open flowers Min. stem 

Grade Min. Max. per stem length (in) y 

Blue (special) 2.5 4.0 15 36 

Red (fancy) 1.5 2.4 12 30 

Green (extra) 1.0 1.4 9 24 

Yellow (first) 0.5 0.9 6 18 

z = multiply (oz) by 28 to obtain (g) 


Outdoor 

Rocket, Maryland, and Potomac strains are the 3 main forms used for outdoor 

production. Potomac appears to be more rust resistant than Rocket (Healy and 

Aker 1989). In north Georgia, the Liberty Strain, a greenhouse (forcing) variety, 

was also successful. The Ribbon series was designed for landscapers, but colors 

are strong enough to use if stem length is not an issue. Animation series is available 

in several colors, and although it is used in greenhouse forcing, the series has 

potential for field production; early flowering was frequent in national trials. 

For additional cultivars, contact seed suppliers in your area. 

National field trials 

Snapdragons have been evaluated since 1994, the inception of national trials 

conducted by the ASCFG. The following table (Dole 1995–1999, 2001) is a summary 

of the average stem lengths and yields of snaps submitted for trialing.

These data are averages over a wide geographical range and must be viewed as 

guidelines only; individual experience may differ significantly. 

Year Stem Stems/ 

Cultivar of trial length (in) z plant 

Animation Crimson 1997 16 5 

Animation Deep Rose 1997 15 14 

Animation Red 1997 15 7 

Animation Yellow 1997 18 6 

Apollo Ivory 1998 17 7 

Apollo Purple 1998 18 7 

Potomac Plum Blossom 1994 22 6 

Sonnet Mix 1995 15 5 

Sonnet White 1995 11 7 

Sunshine Deep Purple Eye 2001 18 5 

Sunshine Lemon Eye 2001 18 6 



Greenhouse 

Four main groups of snaps for forcing are offered, based on the environment 

under which they are grown. These groupings are guidelines only, not written in 

stone. Groups 1 and 2 are recommended for winter and early spring harvest, 

groups 2 and 3 for autumn and spring harvest, and groups 3 and 4 for late 

spring, summer, and autumn harvest. Growers in the North may use all cultivars 

from all groups, while those in the South should use groups 3 and 4 only. A few 

are listed here, but many more are available from a reputable seed supplier. Some 

cultivars perform equally well in more than one group, and not all colors in a 

series fit the same group (for example, ‘Monaco Yellow’ fits in 2, 3, while ‘Monaco 

Pink’ fits better into 3, 4). Similar groupings for European greenhouse production 

are also available. Check with your salesperson. 

Group Harvest Temp. range Examples of series 

1, 2 winter, 45–50F (7–10C) to Admiral, Alaska, Bismarck, 

early spring 50–55F (10–13C) Chicago, Cheyenne, 

Maryland, Oakland, 

Overture, Winter 

2, 3 autumn, 50–55F (10–13C) to Apache, Apollo, Flamenco, 

spring 55–60F (13–15C) Glorious, Monaco, Spires 

3, 4 late spring, 55–60F (13–15C) to Bali, Orlando, Navaho, 

summer, >65F (18C) Opus, Potomac, Tropicana, 

autumn Winchester



High humidity, overhead watering, and debris around the plants increases the 

incidence of botrytis. Spray with proper fungicide, and keep area clear of plant 

trash. 

Rust is among the most serious diseases of snapdragons. Brown pustules 

break out in large numbers surrounded by yellowish areas of leaf tissue. Selecting 

rust-resistant cultivars is important; increasing spacing density is helpful. 

Avoid overhead watering and apply a preventative fungicide. Once rust begins, 

it is very difficult to eradicate. 

Aphids, spider mites, and caterpillars are the most troublesome pests on 

snapdragon. Given consumer concern about postharvest chemical fumigation, 

much research has focused on nonchemical insect control, including the use of 

elevated levels of CO2 in the postharvest area or in transit. Preliminary work 

showed that 80% CO2 killed thrips and aphids with no detrimental effect to vase 

life (Reid et al. 1995). Such modified atmosphere work appears to have merit, but 

a good deal more research is needed. 


“Last winter I successfully grew Potomac in an open field with no protection. 

We had a spell of cold weather that took nighttime temps down to the low teens, 

but we had snow cover. More typical nighttime lows are in the 20s, but I know 

that we had many nights lower than 27. I had them in the ground by mid October, 

so they hardened gradually. They were spectacular last spring. Around July 

4, I cut them back, and I got a second flush in September–October. I was so 

pleased with Potomac that I am trying it again this year.” Rachel Frantz Jones, 

Bunn, N.C. 

“We use row covers in Florida to protect from freezes, and . . . to assure safe 

passage [we] string 100-watt bulbs down our rows under the cover (we just use 

agfabric, 1 or 1½ oz hooped over pvc and purlined with saran tape). The bulbs lie 

on the ground and are protected by plastic cages, . . . spaced about 10' apart. I use 

somewhere around 10 of these in 20 100' beds. The cost is for wire (black and 

white #12 stranded), the receptacles, and the cages. All the electrical stuff you can 

get at a professional electrical supply store. It has worked well for us, giving us a 

big margin of security. I couldn’t tell you how many sleepless nights we spent trying 

to protect our crops. When we are successful, we make money—when we lose 

to the freeze, we lose money. Sometimes big money.” Jon Landwer, Dragonfly 

Farm, Eustis, Fla. 

“Once my snaps have suitable growth, I let off on the nitrogen and start with 

a high phosphate feed. I fertigate with 100 ppm N, 500 ppm P, and 300 K. If 

your soils are low in organic matter (less than 2.5%) continuous light doses of 

humic acid may be beneficial. . . . Uniformly high soil moisture is important. It 

seems, for us, that once a plant becomes hardened (checked, stressed) it seldom 

seems to make satisfactory growth again.” Paul Shumaker, Never Should Have 

Started Farm, Bangor, Pa.


“We’re fertilizing with our irrigation water at 200 ppm N, 50 ppm P, 100 ppm 

K, 350 ppm calcium. We add a small amount of minors, but our soil is adequately 

supplied. The calcium may be a bit high, but our water has about 150 

ppm calcium before we add any fertilizer. We adjust the pH of our feed water to 

about 6.5.” Laurie Constable, Avalon Flowers, Santa Barbara, Calif. 

Reading 

Campbell, R. C., C. Dharmalingam, S. Pitchay, P. V. Nelson, J. L. Gibson, and B. 

E. Whipker. 2000. Nutrient deficiencies of snapdragon. GMPRO 20(11):36–39 

Cockshull, K. E. 1985. Antirrhinum majus. In The Handbook of Flowering. Vol. 1. 


Dole, J. 1995–1999, 2001. ASCFG National Cut Flower Trials. The Cut Flower 

Quarterly. 

Friedman, H., S. Meir, I. Rosenberger, A. H. Halevy, P. B. Kaufman, and S. Philopaph-Hadas. 

1998. Inhibition of the gravitropic response of snapdragon 

spikes by the calcium-channel blocker lanthanum chloride. Plant Physiology 

118(2):483–492. 

Healy, W., and S. Aker. 1989. Production techniques for fresh cut annuals. In 

Proc. Commercial Field Production of Cut and Dried Flowers. Univ. of Minnesota, 

The Center for Alternative Crops and Products, St. Paul. 

Kaur, N., and J. P. Palta. 1997. Postharvest dip in a natural lipid, lysophosphatidylethanolamine, 

may prolong vase life of snapdragon flowers. HortScience 

32(5):888–890. 

Laurie, A., and G. H. Poesch. 1932. Photoperiodism: the value of supplementary 

illumination and reduction of light on flowering plants in the greenhouse. 

Ohio Agr. Exp. Sta. Bul. 512:1–42. 

Maginnes, E. A., and R. W. Langhans. 1960. Daylength and temperature affect 

flower initiation and flowering of snapdragons. N.Y. State Flower Growers Bul. 

171(1). 

———. 1961. The effect of photoperiod and temperature on initiation and flowering 

of snapdragon (Antirrhinum majus-variety Jackpot). Proc. Amer. Soc. Hort. 

Sci. 77:600–607. 

McElroy, T. 1998. Producing and marketing cut snapdragons. GrowerTalks (12): 

51–52. 






Philosoph-Hadas, S., H. Friedman, R. Berkovitz-Simantov, I. Rosenberger, E. J. 

Woltering, A. H. Halevy, and S. Meir. 1999. Involvement of ethylene biosynthesis 

and action in regulation of the gravitropic response of cut flowers. In 

Biology and Biotechnology of the Plant Hormone Ethylene ll, Proc. EU-TMR-Euroconference 

Symposium. Thira, Greece. 

Post, K. 1955. Florist Crop Production and Marketing. Orange Judd, New York.

108 ARTEMISIA 

Reid, M., M. Cantwell, and A. Carpenter. 1995. Postharvest IPM for cut flowers. 

Perishables Handling Newsletter 82:9–30. 



Serek, M., E. C. Sisler, and M. S. Reid. 1995. 1-Metylcyclopropene, a novel gaseous 

inhibitor of ethylene action, improves the life of fruits, cut flowers and 

potted plants. Acta Hortic. 394. 

Stefanis, J. P., and R. W. Langhans. 1982. Snapdragon production with supplemental 

irradiation from high-pressure sodium lamps. HortScience 17:601– 

603. 


Ore. 

Many thanks to Peter Nissen (first edition) and Corky Kane (second edition) for 

reviewing this section. 

Artemisia wormwood Asteraceae 


A well-known group of plants, from the medicinal gardens of the Middle Ages to 

the fine perennials in our gardens. The species most used as a cut flower, 

Artemisia annua, is no slouch when it comes to the medicinal properties this large 

genus (200 species) boasts: it contains artemisinin, which is used to treat malaria. 

Artemisia annua sweet annie Asteraceae 

annual Europe, Africa yellow 3–5'/3' (0.9–1.5 m/0.9 m) 

Sweet annie or sweet wormwood, a vigorous tall plant, is popular in the potpourri 

and wreath-making trade. Small yellow flowers are produced in loose, 

spreading panicles in the summer; plants can be cut throughout the season and 

hung to dry. As a general rule, the aroma of artemisia foliage is not particularly 

welcome in houses, but the fragrance of this species is much more pleasant, even 

sweet-smelling (as Annie would say), and remains after drying. To be fair, however, 

some people think it stinks. 

Propagation 

Seeds may be sown in the field as early as the ground can be worked; but seed is 

very small, and transplanting generally yields stronger plants. 


Plants are harvested for the foliage and stems; the flowers are not significant to 

the wholesaler or retailer. Harvest time is somewhat debatable for sweet annie.

ARTEMISIA LUDOVICIANA 109 

Shelley McGeathy of McGeathy Farms in Hemlock, Mich., harvests stems just 

before the flower appears: “Once it flowers, the stem gets brown (so does the 

flower) when it dries. The small yellow flowers are of no importance when used 

for drying. As far as cutting for fresh, the florists love it for a filler. They use it 

when there are just leaves all of the way through the beaded stage. Again, we 

have been told that once it blooms, it’s messy and not as neat of a filler.” 

Ralph Cramer of Cramers’ Posie Patch cuts “right after the pollen is mostly 

gone. We actually check pollen by kicking the bush to see if there’s a puff of 

yellow or not!” For fresh, he suggests stems be cut any time after they look 

nice and green and full. For dried stems, harvest right before they turn slightly 

yellowish. 

Postharvest 

Most product is dried, but a small percentage is sold fresh. Vase life of fresh 

stems is 5–7 days in plain water, 10 days when processed. Dry quickly with heat 

to retain good green color. McGeathy also mentions that they have “wreath people” 

who like to get the artemisia when it is first cut from the field, as it is more 

pliable at that stage. They put the unfinished wreath in an area that gets good air 

circulation to dry down, so it can then be decorated. 

Cultivars 

‘Cramers’ Yardstick’ is compact (about 3', 90 cm), and the branches are more 

full (and thus more appealing fresh) than the species. It may also be harvested 

earlier. Cramer also produces a scentless form of sweet annie for fresh or dried 

stems. 

Artemisia ludoviciana white sage Asteraceae 

perennial, Zones 4–9 North America white 1 

2–3' (60–90 cm)/2–3' (60–90 cm) 

Unlike other artemisias, Artemisia ludoviciana has entire, rather than dissected, 

leaves. This is a particularly useful species for cutting, since stems grow back 

quickly after pruning. With their efficient roots, plants spread quickly and can 

be invasive, but nothing that herbicides cannot handle. 

Propagation 

In general, propagation is accomplished by cuttings and divisions. Stem cuttings 

should be taken during late spring and summer. Cuttings root best with 

bright, indirect light and 75F (24C) media temperatures. Intermittent mist can 

be used for rooting, but be sure to avoid overwatering, which results in foliar 

diseases and rots. Cuttings take 14–20 days to root; late season or stressed cuttings 

may take up to 4 weeks (Nau 1999).

110 ARTEMISIA LUDOVICIANA 


For dried stems of ‘Silver King’, Cramer waits until the buds elongate into an egg 

shape. If cut too early (i.e., when buds are still round), the dried material is of 

poorer quality. For fresh, he suggests any time from leafing out to when the buds 

start opening, about a 6-week period. 

Cultivars 

‘Cramers’ Silver’ has silvery foliage and provides at least 8 weeks of harvest. 

Harvest is best the second year; by the fourth, it is probably best to start over. 

Plants are about 4' (1.2 m) tall. 

‘Silver King’ is an old standby that (if properly labeled) is more compact than 

the species. Hardy to Zone 3 and offers excellent foliage. The flower plumes sport 

red fall color not found in the species. Very invasive where comfortable. The 

ASCFG’s 2001 Dried Cut Flower of the Year. 

‘Silver Queen’ produces sparse flowers and wide silvery leaves with deeply cut 

jagged margins. A little shorter than ‘Silver King’ but with slightly larger leaves. 


The foliage of nearly all the species can be dried and used wherever smelly foliage 

is needed. 

Artemisia abrotanum is used in potpourris. 

Artemisia dracunculus (tarragon) is popular; some producers offer several useful 

selections for cut stems. 

Artemisia lactiflora (mugwort) and the darker selection ‘Guizhou’ make reasonable 

fresh cut stems and are excellent dried. Large white flowers set this species 

apart from other artemisias. Excellent filler and much more tolerant of wet soils, 

which most artemisias abhor. Harvest stems for drying when plants are full but 

before the yellowing begins; harvest stems for fresh use when plants are green. 


Aphids are usually the predominant pest; root-knot nematode is also possible. 

Diseases include white rust, downy and powdery mildews, botrytis, rust, and 

dodder (Perry 1998). 


“I grow only Artemisia ‘Guizhou’, which is a really nice fresh cut and a great 

dried.” Joan Thorndike, Le Mera Gardens, Ashland, Ore. 

“Wormwood wilts if cut too early. It is hard to tell when it is in bloom, since 

the blooms are so small and ugly. But experiment with it once it starts setting 

those balls, to find out how early you can pick it. A consideration when using 

wormwood: lots of people are allergic to the artemisias. I used to use a lot of

ASCLEPIAS TUBEROSA 111 

wormwood and sweet annie. Then one year after making far too many wreaths, 

I developed allergies to the wormwood. The next year it was sweet annie, and 

now I can’t get near the stuff. I miss them terribly in the fall, and most of my 

customers do too, but some really appreciate not being subjected to the stuff!” 

Susan O’Connell, Fertile Crescent Farm, Hardwick, Vt. 

Reading 


Perry, L. 1998. Herbaceous Perennials Production. Northeast Regional Agricultural 

Engineering Service, Ithaca, N.Y. 

Many thanks to Ralph Cramer and Shelley McGeathy for reviewing this section. 

Asclepias tuberosa butterfly weed Asclepiadaceae 

perennial, Zones 3–8 eastern North America orange 1 

1½–2½'/2' (45–75 cm/60 cm) 

Butterfly weed is native from Maine to Florida and as far west as Arizona. The 

bright orange flowers are held in inflorescences above the leaves. Although 

orange is most common, flower color ranges from red to yellow. The subsequent 

fruits are long and narrow and are considered ornamental by some designers. 

Both flowers and fruits may be used fresh or as dried ornaments to augment 

bouquets of grasses and potpourri. It is one of the few members of the milkweed 

family that does not produce abundant quantities of milky sap and, therefore, 

is not as difficult to handle as other species of the family. Another benefit 

of butterfly weed is that it lacks the invasive qualities typical of many of its more 

obnoxious milkweed relatives. 

Propagation 

Seed: Fresh seed germinates readily. Remove seed as a mass from the fruit (follicles) 

when they turn yellowish brown and begin to split, but before the down is 

fluffy and visible. Check the follicles occasionally and allow to ripen naturally; 

seeds are ripe when they turn brown. Do not allow follicles to split completely or 

seed will be lost. Immediately after collection, clean the seed by grasping the 

mass with one hand and gently sliding the clasped fingers of the other hand 

downward. A good firm tug separates the seed from the compacted down and 

eliminates the laborious job of cleaning individual seed (Phillips 1985). Of 

course, this is easier said than done. 

Purchasing seed is a lot simpler than the job just described; 0.5–0.75 oz (14–21 

g) of seed yields 1000 seedlings (Nau 1999). Sow the seed immediately or, if not 

possible, store the seed in moistened peat at 40F (4C) for several weeks. Sow at 

70–72F (21–22C) under high humidity; germination usually occurs within 15 

days.

112 ASCLEPIAS TUBEROSA 

Asclepias tuberosa 

‘Gay Butterflies’ 

Cuttings: Terminal stem cuttings approximately 3–4" (8–10 cm) in length can 

be taken in spring prior to flowering and stuck under a sweat tent or mist system. 

Rooting hormone is not necessary; rooting requires 4–6 weeks. 

Root cuttings are an easier means of propagation. Cut the taproot into 2–3" 

(5–8 cm) long sections. For best uniformity and most rapid growth and flowering, 

use only the sections of roots closest to the plant. Upper segments emerge 

and flower faster than the middle or lower segments; the middle segments 

emerge last of all (Ecker and Barzilay 1993). The orientation of the root segments 

does not appear important, but try to place the segments vertically, maintaining 

polarity, in a well-drained, sterilized medium. Keep medium warm and 

moist.

Bare root plants can be stored up to 6 months at 28F ( − 2C) without damage. 

If necessary, roots may be stored and regrowth occurs normally, but this is not 

a recommendation and should be avoided (Maqbool and Cameron 1994). 

Digging from the wild: Plants have a long taproot, and survival percentage is 

very low when gathered from the wild. Don’t even think about it! 

Growing-on 

Butterfly weed immediately begins taproot growth upon germination; should it 

at any time become potbound, plantlets rapidly deteriorate. If seedlings are sown 

in a seed flat, transplant to 4" (10 cm) pots by the time the second set of true 

leaves appears. Provide bright light and temperatures near 65F (18C), and feed 

with 200 ppm N once a week using a complete fertilizer. Always hold under LD: 

plants will simply sit on the bench under natural winter conditions. This can be 

done with night interruption or extended daylength. Do not overwater; plants 

are more tolerant of drought than overwatering. Regardless of propagation technique, 

hold in pots only until vigorous growth occurs. Plants resent transplanting, 

particularly by “mean” hands. Think about growing-on in peat pots, so as 

little trauma as possible occurs. Regardless of container, avoid damaging the 

taproot when transplanting. If the taproot is broken, the plant requires 2 years 

to recover—if it survives. 



Temperature: Asclepias goes through a winter dormancy period and benefits 

from a chilling period (

114 ASCLEPIAS TUBEROSA 


Longevity: Once established, plants are long-lived perennials and may be kept in 

the same bed for many years. Clump diameter increases with age, as does the number 

of flowering stems. Three- to 5-year production cycles are not uncommon. 

Spacing: Space plants 18–24" (45–60 cm) apart. A 12 × 18" (30 × 45 cm) grid 

has also been used successfully. Plants commonly grow 2–2½' (60–75 cm) tall by 

the second year; spacing closer than 18" (45 cm) results in additional insect and 

disease pressure. In our trial, average stem length of 22.1" (55 cm) occurred on 

our first harvest at 18" (45 cm) spacing. 


Plant established seedlings or rooted cuttings in deep ground beds on 6–9" (15– 

23 cm) centers. Temperatures should be 50–55F (10–13C) in late spring and 60– 

65F (15–18C) as temperatures rise. Cuttings planted January through March 

flower from May to June and continue until early fall. Plants may be started 

under short daylengths in the winter or spring, but daylength must be lengthened 

when plants have approximately 2 leaves, and LD are an absolute requirement 

to force flowering. For heaviest yield, best shoot length, and earliest flowering, 

use incandescent lights to provide 14- to 16-hour LD or nightbreak 

lighting (4–6 hours during the middle of the dark period). Cropping time in the 

greenhouse is 15–20 weeks from seed, depending on season. If crowns are purchased, 

plant in sufficiently large containers and store at 38F (3C) for approximately 

14 weeks. Remove cooled crowns to a 60–65F (15–18C) greenhouse. 

Emergence occurs in 5–7 weeks. Provide LD (14–16 hours) as above. Flowering 

occurs 60–80 days after cooling crowns. 


Harvest when at least ½ to ⅔ of the flowers are open; flowers do not open well 

once stems are cut. If fruits are to be harvested, harvest when green before they 

start to split. 

Postharvest 

Stems do not exude a great deal of milky sap (unlike other members of the family), 

thus no special heat treatments or dipping solutions are necessary for cut 

stems. Stems should be immediately placed in water. After a few minutes, the 

water should be discarded and stems replaced in fresh warm water, then put 

into the cooler at 40–45F (4–7C). The water can be changed again a few hours 

after initial cutting to eliminate all vestiges of the latex. Store stems in water 

containing a citric-acid preservative and store in the cooler. Stems should be 

recut under water by the florist and consumer to provide additional shelf life. 

Silver thiosulfate has a beneficial effect on vase life. Average shelf life in water at 

room temperature is 8–10 days.

Cultivars 


Few cultivars are available; however, seed propagation yields sufficient variation 

in flower color for selections to be made. 

‘Gay Butterflies’ is a seed-propagated mix of flowers in several colors, with 

orange-red predominating. Plants grow about 2' (60 cm) tall. 


Asclepias curassavica (blood flower) should be used more often as a cut flower 

and is best treated as an annual in most parts of the country. Seed may be direct 

sown. Native to the West Indies, plants should be grown in full sun; however, 

in the South, partial shade may provide better height and performance. ‘Red 

Butterfly’ has deep red flowers and grows 2–2½' (60–75 cm) tall. Silky series has 

flowers in deep red, gold, or scarlet (seed is also available as a mix); plants grow 

to about 3' (90 cm) tall. 

Asclepias incarnata (swamp milkweed) is a perennial with lovely pink and white 

flowers on 2–3' (60–90 cm) stems. Plants perform best in moist soils but also 

tolerate “normal” soils. Like butterfly weed, A. incarnata requires approximately 

16 hours of daylight for flower initiation and flower development. ‘Cinderella’ 

has rose-red flowers and grows 3–3½' (0.9–1.1 m) tall, ‘Soulmate’ has rose-pink 

flowers and grows 2–3' (60–90 cm) tall. ‘Ice Ballet’ has been used as a cut flower, 

with 3' (90 cm) stems and pure white flowers. ‘Milkmaid’ is 3–4' (0.9–1.2 m) tall 

with white flowers. 

Asclepias physocarpa (swan plant) may be worth a try for the ornamental fruit. 

The plants, which can reach 6' (2 m) tall, bear small cream to green-white flowers. 

The inflated fruit, 2½" (6 cm) in diameter, is a translucent pale green, softly 

spiny, and with its wide “body” and sigmoid “neck,” it does sort of resemble a 

swan. Might be useful for drying. Probably best treated as an annual. 

Asclepias syriaca (common milkweed) is a perennial weed occasionally used 

for its pods. It is better known for its ability to colonize entire pastures in the 

northern states and Canada. If anyone feels that this weed is useful as a cut 

flower, simply ask your local farmer if you can cut them from his field; you will 

have a friend for life. 


Aphids are ever-present if plants are not treated. It is almost as if all Asclepias species 

have a built-in dinner bell for aphids. Spider mites can also be a major problem 

on butterfly weed, particularly in rich soils and where plants are grown too 

succulent through overwatering or overfertilization. Plants are less susceptible 

if neglected (i.e., do not feed or water them heavily); however, sprays should be 

readied by late May in the South and mid June in the North. Thrips can also be 

a problem. According to Bill Preston of Glenn Dale, Md., Asclepias species are a 

primary host for many butterfly larvae. Therefore, you can expect an “invasion” 

of brightly colored worms voraciously enjoying your plants. Be kind to everyone, 

and grow enough to allow some of the larvae to complete their life cycle.

116 ASTER 

Wilt is caused by Pythium intermedium and Rhizoctonia spp. The same organisms 

cause dry rot of the root system (Tsror et al. 1997). 

Viruses result in bright green or yellow-green spots and lines on the foliage. 

Cull infected plants. 


“Asclepias enjoy being cut in the early morning and taken to the cooler quickly. 

Cut into cool water, then change to solution at the cooler, since the milk will 

have run out by then. Swizzle the whole bucket of water around to rinse the milk 

off. They have a super vase life, usually 10-plus days, and the leaves persist well 

too. They seem to be able to be picked almost fully open with no decrease in vase 

life. If you attend a farmers’ market, they must remain in the shade, as, once cut, 

they seem to dislike direct sunlight.” Ruth Merrett, Merrett Farm, Upper Kingsclear, 

N.B. 

Reading 

Albrecht, M., and J. T. Lehmann. 1991. Daylength, cold storage, and plant production 

method influence growth and flowering of Asclepias tuberosa. Hort- 

Science 26(2):120–121. 

Ecker, R., and A. Barzilay. 1993. Propagation of Asclepias tuberosa from short root 

segments. Scientia Hortic. 56(2):171–174. 

Lyons, R. E. 1985. Asclepias tuberosa. In The Handbook of Flowering. Vol. 5. A. H. 


Lyons, R. E., and J. N. Booze. 1983. Effect of photoperiod on first year growth of 

2 Asclepias species. HortScience 18:575 (abstr.). 

Maqbool, M., and A. C. Cameron. 1994. Regrowth performance of field grown 

herbaceous perennials following bare-root storage between − 10 and + 5C. 

HortScience 29(9):1039–1041. 


Phillips, H. P. 1985. Growing and Propagating Wild Flowers. Univ. of North Carolina 

Press, Chapel Hill, NC. 

Tsror, L., M. Hazanovski, O. Erlich, and N. Dagityar. 1997. Wilt and root diseases 

of Asclepias tuberosa. Plant Disease 81(10):1203–1205. 

Many thanks to Robert Lyons (first edition) and Bill Preston and Paul Sansone 

(second edition) for reviewing this section. 

Aster Asteraceae 

perennial 

The name “aster” is commonly used for both annual asters, which belong to the 

genus Callistephus (see Callistephus chinensis), and the perennial species of the genus 

Aster, which contains over 600 species. A half dozen or so of these are useful as

ASTER 117 

cut flowers. Nearly all greenhouse production and most field production of 

asters is concentrated on the filler types, mainly hybrids involving Aster ericoides 

(heath aster) and A. novi-belgii (New York aster, Michaelmas daisy). Aster novaeangliae 

(New England aster) has been superseded by the hybrids but is still produced 

in significant numbers as a cut. Asters are grown around the world, with 

significant production in Holland, Israel, South America, and the United States. 

All are perennial and are generally cropped 3–4 years. Although the natural flowering 

time for most asters is the fall, many flower in late summer. Production 

occurs under protection as well as in the field. In the field, flower yield and stem 

length are less the first year than subsequent years, particularly in areas of warm 

summer temperatures. Growers in coastal California, with their cooler summer 

temperatures, enjoy better yields and stem lengths the first year compared with 

eastern growers; however, differences are fewer as plants age. In general, plants 

respond to photoperiod and can be forced to flower year-round under protection, 

one of the main advantages of growing this crop. Asters are often used as 

fillers in mixed bouquets and occasionally as primary flowers in single-species 

bouquets. 

In this section, all asters will be treated together, with any differences in production 

systems and cultivars noted as necessary. 

Aster novae-angliae ‘Purple Dome’

118 ASTER 

Propagation 

Most cultivars are propagated through meristematic culture, ensuring virusfree 

plantlets. Growers who purchase vegetative plantlets will pay more but are 

assured of clean material. This is the recommended means of producing cut 

asters. 

Most cut flower cultivars are bred by a handful of breeders and are protected. 

Cultivars that are not protected can be propagated by basal cuttings, often 

referred to as juvenile ground shoots; terminal cuttings, which are commonly 

used for pot plant production, result in shorter plants and should be avoided for 

cut flower use. Cuttings should be taken after flowering, in late fall, winter, or 

spring; summer cuttings will likely prove unsatisfactory. Place unrooted cuttings 

in peat/perlite or a comparably well-drained mix at 70–75F (21–24C) under 

a sweat tent or intermittent mist. Cuttings root in 7–14 days. Rooting hormone 

is useful but not necessary. 

The environment under which the plants are rooted and maintained makes 

a difference in subsequent growth and flowering. Some companies maintain 

vegetative cuttings under SD; plants pinched to induce branching provide significant 

yield the first year. Plants that are rooted and maintained under LD are 

particularly useful for dense plantings and single-stem production. The latter is 

more common in the United States, the former overseas. If purchasing cuttings, 

be sure to ask how the stock plants and cuttings were maintained. 

Growing-on 

Rooted cuttings may be planted immediately in the field or greenhouse or can be 

grown-on prior to planting. If growing-on for field production, place in 3–4" 

(8–10 cm) pots under long days, and immediately fertilize with 75 ppm N using 

potassium nitrate. Grow at temperatures no higher than 60F (15C). Approximately 

2 weeks later, raise fertility level to 150 ppm N with a complete fertilizer 

at every irrigation. Plant in the field 3–5 weeks after potting. If planting in the 

greenhouse, rooted cuttings may be placed in the ground bed or bench immediately 

and treated as just described. 


Asters appear to be highly regulated in their flowering behavior. Cooling (vernalization) 

was once widely used, followed by long days for stem elongation, 

shortening days for flower initiation, and finally short days to induce dormancy. 

In nature, this sequence is satisfied by the chill of winter, the long days of spring 

and summer, the shortening days of late summer, and finally the short days of 

late fall. If you are planting in the field and waiting for natural flowering, get 

them in the ground and get out of the way. However, an understanding of the 

processes involved may help make forcing a little easier. 

Many aster cultivars used for cut flowers do not need vernalization, and nonvernalized 

cuttings can produce quality cut stems for several years, with no vernalization 

between flowering periods.

ASTER 119 

Photoperiod: In general, asters must go through a long day/short day sequence. 

Long days result in shoot elongation and are necessary for flowering. Even without 

chilling, LD promote flowering, although the number of flowers is significantly 

fewer than if chilling has been given (Schwabe 1985). Approximately 4 

weeks of LD of at least 16 hours are promotive, but continuous lighting (24 

hours) can be used. The number of LD cycles differs with cultivar; some may 

require up to 8 weeks of LD. 

For most aster cultivars, short days are provided after LD, but they are not 

particularly short. A SD of 12–14 hours is normal for many cultivars, although 

some cultivars will flower even with 16-hour photoperiods. Avoid daylengths of 

less than 12 hours; they result in flower abortion and onset of dormancy. With 

hybrids such as ‘Painted Lady’, 13-hour photoperiod gave far superior results 

than either 14.5- or 16-hour photoperiods (Farina et al. 1994). 

Research in southern Europe under greenhouse conditions showed that 

plants of ‘Monte Casino’, ‘White Star’, and ‘Blue Star’ were maintained in 16hour 

photoperiods until they reached a height of approximately 2' (60 cm), 

after which time, natural short days resulted in flowering. Cyclic lighting (2 

minutes of lighting out of 10) could be used to provide the LD period (Farina et 

al. 2000). 

Since Aster ericoides flowers later in the fall than A. novi-belgii, this species either 

requires additional numbers of short days, or more likely, the SD photoperiod 

(i.e., number of hours of light per day) necessary for flowering is shorter than 

that needed by A. novi-belgii. 

Temperature: During the SD period, temperatures of 86F (30C) and 72F (22C) 

resulted in more flowers than 60F (15C) did. Increasing temperatures result in 

the greatest flower number. However, in comparing day temperatures of 85F 

(29C) and 62F (17C), work in Israel using cultivars from the Sun series showed 

that highest temperatures resulted in fastest flowering but also in less longevity 

and smaller flowers. Temperatures around 72/60F (23/15C) day/night temperature 

appeared to be an excellent choice for these hybrid asters (Oren-Shamir et 

al. 2000). Low temperatures (

120 ASTER 

Pinching: Plants may be pinched for more yield per plant, but plant density 

must be decreased for a pinched crop. Pinching needs to be done as soon as possible 

after the majority of plants in a block is starting to elongate (approximately 

3 weeks after planting). Leave approximately 4 leaf or bud pairs on the plant. 

Pinch a whole block at once to get uniform regrowth. A nonpinched (straight 

ups) crop is also possible; there will be less time between planting and harvest 

(approximately 3 weeks), allowing more flushes to be harvested in a year, and 

the quality of harvested flowers is generally better. 

South and North: In the South, where warm temperatures can occur in early 

spring under natural SD, late spring flowering can occur. The yield and stem 

length will be poor, and, unless flowers are needed, plants should be cut back. 

Normally, asters flower in late August through September, although some may 

flower as early as late July. First-year production data reveal that stem lengths in 

particular are significantly longer under coastal California conditions than in 

Georgia. Differences in data for the second year are not as large. Second-year 

harvest times for New England asters in Athens, Ga., ranged from 10 September 

to 10 October, but Aster ericoides flowers 3–4 weeks later, allowing for a longer 

harvest period. In general, yield and stem length of first-year harvests are less 

than subsequent years, particularly in warm climates. This can be explained by 

the relative lack of vernalization in these climates. In areas of the West Coast, 

where night temperatures in spring and early summer approach 40F (4C), some 

vernalization occurs and shoots elongate even in the first year. 

Two-year yields and stem lengths of cultivars grown in Athens, Ga., and Watsonville, 

Calif., show how yield improves over time. In the first year (fall planted), 

yield was around 12 stems/plant in Athens but improved to over 20 stems/plant 

the second season. The same cultivars in Watsonville improved from approximately 

11 stems to over 25 per plant. Although the cultivars used in that study 

are seldom grown today, the data would likely be appropriate for other cultivars. 

Stem length showed no significant improvement from one year to the next 

(Armitage 1993). 

Spacing: Plant 12 × 12" (30 × 30 cm) for smaller cultivars and 12 × 18" (30 × 45 

cm) for larger ones. In Vermont, a 2 × 2' (60 × 60 cm) spacing of Aster novi-belgii 

‘Benary’s Composition’ resulted in 44 stems/plant in the second year of production. 

The average stem length was 36" (90 cm) (Perry 1989). 

Shading: Work by Armitage (1993) showed that shade increased stem length 

only slightly and decreased yield in some cultivars. Disease was much more 

prevalent under shade in the second year compared with the first; data were not 

even taken the second year. Shade cannot be recommended due to the increased 

prevalence of mildew, root rot organisms, and various other diseases. The use of 

a low-density shade structure to reduce damage from rain is all that can be recommended. 

Longevity: Asters are true perennials, and if disease is not a problem, they 

should be productive 3–4 years. Where disease problems render their long-term 

commercial performance questionable, they can be treated as annuals.

Field Performance (Aster ericoides, hybrid asters) 

ASTER 121 

Aster hybrids usually consist of some Aster ericoides parentage but may also be 

hybrids involving other species. Plants may be planted out in the fall, early 

spring, and as late as June. Aster ericoides is a short day plant and flowers in October 

through November in the East; it flowers earlier in the West, regardless of 

planting date. Dates in Athens, Ga., ranged from 10 October to 8 November for 

second-year harvest. Planting later than mid June may result in plants with insufficient 

stem length. 

Spacing: Plant approximately 12 × 12" (30 × 30 cm) or 12 × 18" (30 × 45 cm). 

This corresponds to 1 or 0.67 plants/ft 2 (10.8 or 7.2 plants/m 2 ). 

Yield: ‘Monte Casino’ aster and other cultivars were grown in Athens, Ga., and 

Watsonville, Calif., and data were collected for 2 years (Armitage 1993). In 

Athens, yields were approximately 15 stems/plant the first year, 22 stems/plant 

the second year, depending on cultivar. In Watsonville, yields in the first and 

second year were approximately 13 and 45 stems per plant, respectively. Stem 

length was also improved the second year. The differences between California 

and Georgia trials were more dramatic the second year than the first, the trials in 

California being more productive (Armitage 1993). This is not uncommon, particularly 

when comparing the growing conditions of Watsonville, Calif., to the 

hot, humid conditions of Athens, Ga. 

Shading: Studies in Athens, Ga., showed that yield was reduced under shade 

(Armitage 1993). Disease was also more prevalent under shade in the second year 

compared with the first, and therefore shade cannot be recommended. Some of 

the worst instances of disease occurred in hybrids, such as ‘Pink Star’ and ‘Rose 

Star’. Most likely, such outbreaks were due to poor ventilation and the fact that 

shaded plants do not dry out as rapidly after rain as those in full sun. 

Greenhouse Performance (Aster novae-angliae, A. novi-belgii) 

With the advent of hybrid aster cultivars, New England and New York asters are 

seldom used for cut flowers, but they have not yet disappeared. For greenhouse 

forcing, cuttings or clumps should be vernalized. Rooted cuttings should be 

cooled to 35–40F (2–4C) for 4–6 weeks. Plant in 6–8" (15–20 cm) pots or in 

ground beds at a spacing of 9 × 12" (23 × 30 cm) by the end of July. When the natural 

daylength is too short, nightbreak lighting or day extension is necessary to 

simulate LD. The lighting can be cyclic: at least 6 minutes per half hour. 

Maintain photoperiods greater than 17 hours and temperatures of 60–65F 

(15–18C). Grow under LD until stems are 12–18" (30–45 cm) long (approximately 

3–4 weeks) and then maintain a SD of 13–14 hours. Avoid daylengths 

less than 11 hours. Photoperiods can be manipulated with incandescent lamps 

and black cloth. Temperatures during SD should average 65F (18C) for longest 

stem lengths. Flowering time is 6–10 weeks after the beginning of SD treatment, 

depending on cultivar and temperature. 

If noncooled cuttings are used, stems may be shorter and flowering delayed 

compared with cooled stems. Maintain cool temperatures during LD stage in the 

greenhouse for vernalization. Unheated greenhouses or plastic frames can be

122 ASTER 

used for late spring and early summer crops. Cuttings planted in November or 

December will be vernalized naturally after approximately 6 weeks of temperatures 

below 40F (4C). At that time, the LD-SD sequence described earlier may 

begin. 

Greenhouse Performance (Aster ericoides, hybrid asters) 

Plants can be forced for year-round production. Plants flower under short day 

conditions and grow vegetatively under long days, much like chrysanthemums. 

If forcing on a year-round schedule, it is necessary to have incandescent lamps 

and black cloth facilities for best uniformity and control of flowering time. 

Asters can be grown pinched or unpinched (straight-ups). In general, plants 

are not pinched in the greenhouse, yielding faster flowering times and additional 

flushes if grown year-round. If pinching is to be done, it should be accomplished 

3–4 weeks after planting in the field or the greenhouse. Leave at least 4–8 leaves 

on the plant. Pinch a whole block at once to get uniform regrowth. Spacing will 

increase if plants are pinched. 

Unpinched plants can be spaced as close as 5" centers, yielding 5½ plants/ft2 (13 cm centers, 60 plants/m2 ) or as wide as 6" centers, 4 plants/ft2 (15 cm centers, 

45 plants/m2 ). For pinched crops, more space is provided, approximately 10 × 

10" (25 × 25 cm) spacing, or for pinched crops, 1½ plants/ft2 (15 plants/m2 ). 

Spacing is determined by yield, air movement, and disease control measures. 

Place rooted cuttings in 6–8" (15–20 cm) pots or in ground. 

Fertilize with 50–75 ppm N from potassium nitrate. If natural daylength is 

less than 12 hours, use incandescent lights as day extension (photoperiod >14 

hours) or as cyclic lighting (see “Greenhouse Performance” for Aster novae-angliae 

and A. novi-belgii). Fertilize with 150–200 ppm N using a complete fertilizer. 

Apply long days until stems attain a height of 12–18" (30–45 cm). Short days 

may be artificially applied by black cloth from late spring through early fall, 

when natural daylength is too long to naturally trigger flowering. Jeff McGrew 

of Jeff McGrew Horticultural Products, Mt. Vernon, Wa., summarizes well: in 

general, stem length is manipulated by the number of weeks given to long day 

treatment (14-plus hours) followed by a short day treatment (black cloth to 

reduce light levels to under 12 hours daily). A stem length of 3' (90 cm) can easily 

be reached when 6–8 weeks of long days are followed by 5–7 weeks of short 

days, if average night temperature are around 60F (15C). This will vary somewhat 

with the temperature regime under which plants are grown and the time of 

year they are produced. 

Reduce fertilizer when SD begin; after 3 weeks of SD, terminate fertilizer and 

reduce watering to the point of plant wilt. Water only to keep plants from wilting; 

this “stress” results in flowers ready to be cut 4–7 weeks after the beginning 

of short days, depending on cultivar. 

After harvesting, cut plants back to the ground, remove all partially cut stems 

and stubble, and leach thoroughly with plain water. Place plants back in LD 

(>16 hours), thin to 4–6 stems/plant and start cycle again. In high-light areas 

such as California, Florida, and Colorado, or during the spring and summer

cycles, 5–7 stems may be allowed to remain. Plants may be cropped for 12–15 

months in this manner prior to discarding. 

Temperatures of 60/70F (15/21C) night/day result in excellent vegetative and 

reproductive growth. Night temperatures below 55F (13C) after SD result in 

erratic bud development and poor vase life. Terminal flowers open but the lateral 

flowers are delayed or may not open at all. The period from planting until harvest 

is approximately 13–15 weeks when the cuttings are pinched (8–10 weeks for 

the vegetative period and 6 weeks for the generative period). The whole period 

will be about 3 weeks shorter when cuttings are not pinched. 


At field trials in Athens, Ga., and Watsonville, Calif., foliage was sampled from 

vigorously growing healthy plants when flower buds were visible but prior to 

flower opening. These are guidelines only and should not be considered absolute 

standards. Based on dry weight analysis. 

‘Rosa Sieger’ (Ga.) 

(%) 

N P K Ca Mg 

3.0 

(ppm) 

0.45 3.29 1.68 0.20 

Fe Mn B Al Zn 

168 65 37 83 72 

‘Climax’ (Ga.) 

(%) 

N P K Ca Mg 

3.1 

(ppm) 

0.65 3.64 0.98 0.18 

Fe Mn B Al Zn 

162 88 39 48 121 

‘Climax’ (Calif.) 

(%) 

N P K Ca Mg 

2.2 

(ppm) 

0.24 3.67 1.39 0.35 

Fe Mn B Al Zn 

180 273 46 52 26 

ASTER 123

124 ASTER 


Cut stems when approximately ¼ of the flowers in the inflorescence have opened. 

Place immediately in water or floral preservative. Although the benefits of STS 

have not been consistent, low concentrations may result in additional vase life 

with some cultivars. Using a bactericide in the postharvest solution for 4–5 

hours increases vase life. 

Postharvest 

Fresh: New England asters (Aster novae-angliae) persist only 5–7 days. Flowers 

are relatively insensitive to ethylene. In general, vase life of New York aster (A. 

novi-belgii) cultivars is better than that of New England aster cultivars. Hybrids 

persist 8–12 days, depending on temperature and postharvest treatment. 

Storage: Flowers may be stored in preservative in the cooler at 40F (4C) for 

approximately 5 days without loss in quality. 

Dried: Flowers do not dry well. 

Cultivars 

Only a few species of asters have been bred for use as cut flowers. Cut flower 

breeders have spent significant time and money on cultivars of Aster ericoides and 

some of the hybrids listed below, whereas New England and New York asters 

and other species are seldom grown. New England asters in particular are prone 

to whiteflies and have relatively poor vase life; they can only be recommended for 

local consumption, such as farmers’ markets and local florists. New York asters 

are better, and some hybrids, such as ‘Lambada’, have a good deal of New York 

aster in their parentage. The fact that they are not used widely may be a perfect 

reason to try them for your market. There is no reason not to use any cultivar if 

it provides unique flower colors or other commercial benefits. Here are a few 

that may be of value. 

Aster novae-angliae (New England aster) 

‘Alma Pötschke’ (‘Andenken an Alma Pötschke’) is an excellent 3–4' (0.9–1.2 

m) bright rose selection. Flowers are 1–2" (2.5–5 cm) across and have slightly 

curled petals. It is more compact (but still requires support) than other selections 

and less prone to topple. 

‘Fanny’s Aster’ is covered with blue flowers and grows up to 4' (1.2 m) tall. She 

flowers in late fall and is spectacular combined with fall sunflowers. Absolutely 

terrific, particularly in the South. 

‘Harrington’s Pink’, developed by Millard Harrington of Williamsburg, Iowa, 

is one of the most popular garden asters. This 3–5' (0.9–1.5 m) tall plant bears 

1½" (4 cm) salmon-pink flowers in September through October. 

‘Mt. Everest’ is 3' (90 cm) tall with good, clear white flowers. 

‘Purple Dome’, a short but terrific introduction from Mt. Cuba Gardens in 

Delaware, offers mid summer flowering on compact 18–24" (45–60 cm) plants,

ASTER 125 

which maintain a mounded habit even while supporting hundreds of deep blue 

flowers. In high-humidity environments, leaf and stem disease can be a problem 

in mid July and August. 

‘Rosa Sieger’ has large salmon-rose flowers on 4' (1.2 m) tall plants. Very eyecatching. 

‘Rose Serenade’ is about 30" (75 cm) tall and bears soft pink flowers in early 

fall. 

‘September Ruby’ has deep ruby-red flowers on 3–5' (0.9–1.5 m) stems, especially 

if planted in rich soils or overfertilized. Although classified as a late 

bloomer, flowering begins in late May in north Georgia and continues through 

late June. If the flowers are removed, it blooms again in September. Flowering is 

3–4 weeks later in the Northeast, but seldom do flowers peak in the fall. This is 

true of many so-called fall-flowering asters. 

‘Treasure’ is 4–6' (1.2–1.8 m) tall with light purple to violet flowers. 

‘Wedding Lace’ is 3–4' (0.9–1.2 m) with clean white flowers in early fall. 

Aster novi-belgii (New York aster) 

Medium cultivars (

126 ASTER 

‘Winston Churchill’ would be proud of the handsome red daisy flowers on 2– 

3' (60–90 cm) stems. They were outstanding performers in our cut flower trials 

at Georgia. 

Tall cultivars (>4', 1.2 m): Many of these are too tall even for cut flower growers, 

require extensive support, and can become a nuisance. If grown well, however, 

they are like huge dahlias. 

‘Cardinal’ has deep rosy red flowers surrounding a yellow center. 

‘Climax’ is a 5' (1.5 m) giant with outstanding large, light blue flowers in early 

fall. Raised in the early 1920s, it is one of the few old-time michaelmas daisies 

still in cultivation. 

‘Fellowship’ bears large clear semi-double pink flowers on 4–5' (1.2–1.5 m) 

stems. 

‘Mount Everest’ has large semi-double white flowers in September and October. 

‘White Ladies’ is 5–6' (1.5–1.8 m) tall with clear white flowers and an orangeyellow 

center. 

Aster ericoides (heath aster) 

‘Blue Wonder’ has blue flowers with a tinge of pink. 

‘Esther’ has white flowers with a tinge of pink and is similar in growth habit 

to ‘Monte Casino’. Plants were less perennial in Athens, Ga., than other cultivars, 

dying after 2 years. 

‘Monte Casino’ has been the most popular cultivar, bearing clusters of small 

white flowers. Several strains of ‘Monte Casino’ have been bred and may appear 

as ‘Monte Euro’ (an improved ‘Monte Casino’), or ‘Monte Casino #1’, and so 

forth. Name recognition, higher yields, faster flowering (particularly under 

greenhouse conditions), and excellent vase life keep Monte Casino types ahead 

of the pack. 

‘San Carlos’ and ‘San Remo’, white-flowered introductions, are more floriferous 

and less light-sensitive than ‘Monte Casino’. Better adapted to greenhouse 

than to field production. 

‘White Wonder’ is similar in growth habit to ‘Blue Wonder’ but has creamy 

white flowers. 

Aster hybrids 

Hybridized from various species, these asters are finding a place in specialty cut 

flower offerings. All are best grown in the greenhouse. 

Butterfly series goes under such flighty names as ‘Lilac Blue Admiral’, ‘Purple 

Monarch’, ‘Painted Lady’ (pink), and ‘Skipper’ (dark pink). We have not tested 

these, but they are supposed to have larger flowers than ‘Monte Casino’ and stiff, 

erect stems. 

Master series includes ‘White Master’, ‘Pink Master’, and ‘Blue Master’ (lilacblue). 

They are similar in flower and habit to the Butterfly series. Both Butterfly 

and Master series appear to be excellent for greenhouse culture. 

Star series of hybrid asters includes ‘Blue Star’, ‘Pink Star’, ‘Snow Star’, and 

‘White Star’. Flowers are smaller than New England asters and New York asters

ASTER 127 

but larger than those of Aster ericoides. They are prolific but do not appear particularly 

heat tolerant and require good drainage. 

Sun series are used as filler flowers, similar to those of Aster ericoides. White 

forms consist of ‘Suncarlo’ with small white flowers, ‘Sunrio’ with medium 

flower size, ‘Sunsimon’ with 2 rows of petals, and ‘Sunspring’ with larger flowers. 

Pink flowers may be found in ‘Sunbird’, purple-blue flowers in ‘Suntop’, and 

purple flowers in ‘Sungal’. Harvest time is 5–8 weeks from beginning of SD, total 

time 10–15 weeks, depending on cultivar (Danziger 1998). 

Universum series, bred by Bartels Stek, is mainly used for fillers. All are 

hybrids with small- to medium-sized flowers. Someone in Holland enjoys the 

letter C, as shown by ‘Cassandra’ (light blue), ‘Catherine’ (blue), ‘Carola’ (purpleblue), 

‘Chelsea’ (white), ‘Claudia’ (pink), ‘Cerina White’, and ‘Cindy Special’ 

(lavender-blue). Who says creativity is dead? All flower 5–7 weeks from beginning 

of SD. 


Aster cordifolius is represented most often by the lavender-blue cultivar ‘Ideal’. 

Plants are harvested in late September and early October in the Southeast. Second-year 

yield was 22 stems/plant with an average stem length of 32" (80 cm). 

Foliage was larger and less susceptible to mildew or rust than other species 

tested. 

Aster tataricus (Tatarian aster) bears many small, lavender-blue flowers in late 

fall (September and October in the Southeast). The plants attain 4–6' (1.2–1.8 

m) in height and are among the last of the asters to flower. Most useful in southern 

states, where a long autumn is normal. 


Leaf spots are caused by Alternaria spp., Cercospora asterata, Leptothyrium doellingeriae, 

Septoria spp., and other leaf-spotting fungi. Spray at weekly or 10-day intervals 

with sulfur or copper fungicide, particularly in rainy seasons. 

Downy mildew is prevalent in the Midwest and South. 

Powdery mildew is more prevalent in the lower leaves of many asters. The disease 

usually develops in late August to mid September. 

Sclerotinia rot (Sclerotinia sclerotiorum) first appears in the center leaves and 

penetrates the stem. Black infection can be seen inside the stem of damaged 

plants. More prevalent in high-humidity conditions. 

Rust is caused by various organisms, including Coleosporium solidaginis and 

Puccinia asteris. Infected plants dehydrate, turn brown, and remain stunted. Some 

cultivars are more susceptible than others. For example, the most susceptible 

cultivars in trials in Georgia were ‘Snow Star’ and ‘Pink Star’, whereas ‘Rose Star’ 

was not affected. 

Aphids pierce the stem and leaves and secrete honeydew, the presence of 

which can result in the development of sooty mold. 

Caterpillars ruin the foliage but are seldom a problem at time of flowering.

128 ASTILBE ×ARENDSII 

Leaf nematodes cause brown or black blotches between the veins. They also 

feed in buds and young shoots, causing distortions. Sterilize the soil. 

Spittle bugs are more common on Aster ericoides than on other species. A general-purpose 

insecticide is effective. 

Thrips are increasingly a problem. Flowers are distorted or fail to open or senesce 

after only a few hours. Thrips are vectors for virus; control is important. 

Whiteflies are a major pest, particularly in the greenhouse. 

Reading 

Armitage, A. M. 1993. Specialty Cut Flowers. Timber Press, Portland, Ore. 

Danziger Flower Farm. 1998. Aster: Cultivation Practices in Israel. Danziger “Dan” 

Flower Farm, Beit Dagan, Israel. 

Farina, E., C. D. Guda, and E. Scordo. 1994. Flowering and morphogenic responses 

of new aster hybrids to photoperiod. Physiologia Plantarum 91(2):312– 

316. 

Farina, E., T. Paterniani, and M. Palagi. 2000. Timing of flowering of asters 

grown for cut flower production. Colture Protette 29(2):77–84. 

Oren-Shamir, M., L. Shaked-Sachray, A. Nissim-Levi, and D. Weiss. 2000. Effect 

of growth temperature on Aster flower development. HortScience 35(1):28–29. 


Athens, Ga. 

Schwabe, W. W. 1985. Aster novi-belgii. In The Handbook of Flowering. Vol. 5. A. H. 


Many thanks to Fran Foley, Jeff McGrew, and Jack Graham for helping with the 

data and reviewing this section. 

Astilbe ×arendsii false goat’s beard Saxifragaceae 

perennial, Zones 3–7 hybrid origin many colors 1 

2–4'/2' (0.6–1.2 m/0.6 m) 

Cut flowers of the shade-tolerant Astilbe continue to gain acceptance with florists 

and consumers every year. Flowers, ranging from white to purple to red, are 

borne in widely branched panicles. The genus was greatly enhanced by the 

hybrids raised by Georg Arends of Ronsdorf, Germany, and many subsequent 

breeders have also left their mark in recent years. Cultivars of various heights 

and flower colors abound, not to mention those with green and bronze foliage. 

Propagation 

Many commercial cultivars are available as a result of tissue culture, though 

growers may still raise additional plants from seed or division. 

Seed: Seed is not available for most cultivars; however, seed of some hybrids 

may be purchased in various shades (e.g., ‘Rose Tones’). Seed is tiny, about

ASTILBE ×ARENDSII 129 

384,000/oz (13,400/g), and should be covered lightly. Seed germinates in 3–4 

weeks if placed at 70–73F (21–23C) under mist or sweat tent. Buy plugs! 

Division: Named hybrids are best propagated by dividing the rootstock. Lift 

plants and divide into 1- or 2-eyed pieces in late fall after foliage dies back. Root 

pieces sold in the spring by commercial propagators can be stored over the winter 

in moist sphagnum at 33–35F (1–2C). Growers wishing to increase their own cultivars 

should divide in the fall or early spring every 3–5 years. A 1- or 2-eyed division 

should provide a 5- to 8-eyed crown after one growing season (Stimart 1989). 

Growing-on 

Grow seedlings at 60–65F (15–18C) for 6–8 weeks and transplant to 4" (10 cm) 

pots when seedlings can be handled without damage. Small divisions should be 

potted into 4" (10 cm) containers immediately. Fertilize propagules with 50 

ppm N from a complete fertilizer for 4 weeks and raise to 100 ppm N as plants 

grow more rapidly. Reduce temperature to 55–60F (13–15C) until plants are 

ready for the field. Green (i.e., nonflowering) plants may be put in the field 14–16 

weeks after sowing, 4–6 weeks after taking divisions. 

Partial shade (e.g., high shade from pines, or some afternoon shade) is recommended 

for growers in the South and Midwest; full sun can be used without 

problems in the cooler areas of the country (e.g., Pacific Northwest, Northeast). 

However, if planted in a moist area of the field, and if consistent moisture can be 

maintained, the need for shade becomes less critical. 


Temperature: Astilbe requires a cold treatment to flower and should be allowed 

to go dormant. The longer the duration of the cold treatment, the more uniform 

the flowering time (Iwanami 1989). In general, bare-root material from 

Holland receives approximately 10–12 weeks of 41F (5C) after digging (De Hertogh 

1996). Specific cultivars differ in their needs; research has shown that whiteflowered 

cultivars such as ‘Avalanche’ and ‘Deutschland’ require at least 9 weeks 

at 40F (4C), but only 6 weeks are necessary for the red cultivars ‘Fanal’ and ‘Red 

Sentinel’ (Beattie and Holcomb 1983). Lower temperatures of 32–35F (0–2C) 

can also used to break dormancy (Stimart 1989). 

Seed-propagated cultivars also require cooling. This may be accomplished at 

the plug stage (50–105 plug density). We found when using ‘Bella’ that 12 weeks 

of cooling at 40F (4C) was sufficient with no loss of quality. Runkle et al. (2000) 

suggest 15 weeks in a cooler (treatment with only 9–12 weeks resulted in decreased 

inflorescence count). Cooling may be accomplished in a cold greenhouse 

with natural SD or in a cooler. When cooling in a cooler, use of a 9-hour photoperiod 

at 25–50 fc is recommended (Runkle et al. 2000). 

Flowers may be forced at almost any temperature; however, temperatures of 

60–75F (15–24C) are recommended. Floral abortion may occur at high temperatures. 

Pemberton and De Hertogh (1992) showed that plants forced at day/ 

night temperatures of 78/72F (26/22C) had more aborted flowers than those


forced at 65/58F (18/14C) or 72/65F (22/18C). Forcing time is delayed with cool 

temperatures. 

Photoperiod: In general, for bare-root cultivars that have been cooled in transit 

or in storage, photoperiod has no significant effect on flowering. Some studies 

suggest that long photoperiods (14 hours) result in taller flower stems than 

short photoperiods (8 hours) (Stimart 1989), but more recent work (Runkle et 

al. 1998) found no such result. With seed-propagated cultivars, however, LD (24 

hours) can accelerate flowering by about a week, but based on overall quality 

and flowering, 12-hour photoperiods are recommended (Runkle et al. 2000). 

Avoid photoperiods of less than 12 hours. 

Water: Consistent moisture is essential for optimum yield and stem length. If 

plants dry out dramatically, plant longevity and foliar and flower quality are 

reduced. 


Longevity: Under proper conditions, plants are long lived and need not be 

replaced for 3–5 years. If placed in areas where consistent moisture cannot be 

provided, however, plants rapidly deteriorate. Longevity is also enhanced where 

cooler summer conditions prevail. Production, insignificant the first year, begins 

in earnest the second to third year. 

Longevity of Astilbe ×arendsii ‘Bridal Veil’. Spacing 12" 

(30 cm). 

Year Stems/plant Stem length (in) z 

1 2.3 15.4 

2 4.6 18.0 

3 6.4 18.5 


Spacing: Space at 10 × 12" (25 × 30 cm) or 12 × 15" (30 × 38 cm). Plants do not 

spread rapidly, and original spacings are maintained throughout the productive 

life of the planting. 


Precooled crowns may be planted in 6–10" (15–25 cm) pots or in ground beds 

with a density of approximately 1 plant/ft2 (11 plants/m2 ). Some old research 

(Latta and Doucette 1932) suggested that crowns should be given a one-hour hot 

water bath of 140–150F (60–66C) prior to forcing, resulting in more foliage and 

flowers of a higher quality; however, this is seldom done in commercial practice. 

After cooling (see “Environmental Factors”), plants should be grown at 62– 

72F (17–22C) under natural photoperiods if using bare-root material or LD if


using seed-propagated plugs. Because of differences that may occur between 

cultivars, nightbreak lighting or extended days may be used to ensure adequate 

yield and stem length. Avoid temperatures above 75F (24C) whenever possible, 

as inflorescence count may be reduced (Runkle et al. 2000). Little or no fertilization 

is necessary during the forcing stage (Wilkins 1985), but constant moisture 

is necessary. Shade plants after April. Crop time after forcing varies from 7 

to 11 weeks, depending on cultivar and forcing temperatures (Runkle et al. 

2000). 


Harvest inflorescences when ½ to ¾ of the flowers are open. The uppermost buds 

should be swollen and showing color. Flower buds harvested when the panicles 

are less than 50% open do not develop further when placed in water, and develop 

only slightly more in a preservative solution (Sacalis 1989). Roxanne McCoy of 

New York State reports that “they usually wilt and are useless if harvested when 

less than half open.” Some references suggest that at least one lower leaf per harvested 

stem should remain on the mother plant for continued development of 

the storage root (Stimart 1989); however, many growers, such as Ed Pincus from 

Vermont, have noticed no decrease in vigor when stems are harvested to the 

ground. Do a little experimentation on your own. 

Postharvest 

Fresh: Flowers require significant attention throughout the postharvest chain. 

They persist longest when pretreated by placing cut stems in 130F (54C) water, 

cooling to room temperature, sleeving in paper, and placing in floral preservative 

(Kalkman 1986). This is an important part of the harvest, and flowers so treated 

persist significantly longer compared to the 2–4 days in room temperature water. 

Fresh flowers are sensitive to ethylene and must be isolated from fresh fruit or 

other ethylene-producing tissue. If possible, ship stems in water. Pulsing with 

STS reduced ethylene damage (Sacalis 1989). 

Storage: Flowers may be stored for a few days at 33–40F (1–4C). Leaves senesce 

more rapidly than the flowers. Work using dry storage showed that when held 

for 24 hours at 68F (20C) and 60% humidity, ‘Cattleya’ did not regain turgor 

when subsequently placed in water; however, if treated with a surfactant prior to 

dry storage, plants regained turgor after dry storage (Doorn et al. 1993). 

Dried: Both flowers and seed heads can be air-dried, preferably in an upright 

position, and will last indefinitely. For drying, harvest when all the flowers are 

open or only a few buds remain at the tip of the panicle. 

Cultivars 

Many cultivars are available; the following are useful as cut flowers. All are hybrids 

and may be listed under Astilbe ×arendsii, A. ×hybrida, A. ×japonica, A. ×rosea, 

or A. ×thunbergii.


Cultivar Plant height (in) z 

Pink Bressingham Beauty 36–40 

Elizabeth Bloom 18–24 

Erica 30–36 

Europa 18–24 

Finale 16–18 

Gloria Rosea 25–30 

Granat 24–30 

Grete Pungel 30–36 

Hyazinth 30–36 

Peach Blossom 18–24 

Venus 24–30 

Magenta Amethyst 36–40 

Dusseldorf 20–24 

Gloria Purpurea 25–30 

Jo Ophurst 36–40 

Mainz 20–24 

Rose-pink Bonn 18–24 

Catherine Deneuve 18–24 

Cattleya 36–40 

Gloria 24–30 

Ostrich Plume 30–36 

Rheinland 24–30 

Red Bella* 18–20 

Etna 18–24 

Fanal 15–18 

Glow 18–20 

Glut 18–24 

Koblenz 18–24 

Montgomery 20–24 

Red Sentinel 36–40 

Spinell 30–36 

White Bridal Veil 18–24 

Bumalda 20–24 

Deutschland 24–30 

Diamond (Diamont) 24–36 

Snowdrift 24–30 

Washington 24–36 

White Gloria 15–18 

Mixed colors Bunter Zauber* 24–28 

Grande* 30–34 


* = available from seed



Astilbe chinensis bears magenta flowers and is generally too short for cut flower 

work. However, var. taquetii ‘Superba’ has magenta flowers in 3–4' (0.9–1.2 m) 

tall, narrow, erect panicles; ‘Purple Lance’ (‘Purpurlanze’) has magnificent purple-red 

blooms on 4–4½' (1.2–1.4 m) stems; and ‘Visions’ bears dense, upright 

pink-purple blooms. The seed heads too are highly ornamental and attractive. 

The use of this late-flowering species extends the cropping time of Astilbe. 

Astilbe ×japonica and A. davidii are some of the species crossed to produce the 

various hybrids. The species have limited color selection, but they are useful for 

cut flower production if they can be located in sufficient quantity. 

Astilbe simplicifolia cultivars have dark green leathery leaves and flowers ranging 

from shell-pink to rose. They are short, however, at best growing 15" (38 

cm) tall. If stem length is not an issue, they make fine cuts. ‘Sprite’, ‘Hennie 

Graafland’, and ‘Bronze Elegans’ are the most common forms. The handsome 

seed heads also have potential in a cut flower program. Dry flower stems in water. 


Few diseases affect Astilbe, however, some leaf spotting may occur. 

Powdery mildew is caused by Erysiphe polygoni. A white mold appears on the 

undersides of the foliage; defoliation occurs in serious cases. 

Wilt, generally caused by Fusarium spp., may be alleviated by placing healthy 

plants in Fusarium-free soil. 

Gray mold results when humidity is high and healthy stems become infected 

with Botrytis cinerea. If plants are well spaced and growing vigorously, little botrytis 

occurs. 

Japanese beetles are a serious insect pest of Astilbe, although in some parts of 

the country, their arrival occurs when the harvest is complete. 

Tarnished plant bugs are a major problem, disfiguring both foliage and 

flowers. 


“For raspberry and red colors, I grow ‘Granat’ and ‘Red Cattleya’. I have ‘Amethyst’, 

and it’s an interesting color, something different for the bouquet. By far 

and away, my favorite is ‘Snowdrift’. I cut flowers for a mid July wedding last 

year, and this was a real hit. The blossom timing couldn’t have been better—clear 

white, about 2' tall. Not good for tall arrangements, but excellent for the dining 

room table vase.” Karen Hanley, Stork Road Farm, North Creek, N.Y. 

“At the Flower Auction our best-selling cut varieties for 1999 and 2000 were 

‘Cattleya’, ‘Diamant’, ‘Erica’, ‘Europa’, ‘Gloria Purpurea’, ‘Granat’, ‘Spinell’, and 

‘Washington’.” Roy Snow, United Flower Growers, Burnaby, B.C. 

“We disliked ‘Amethyst’, a dark magenta pink-purple that lacks purity. Magenta 

flowers are usually prolific and not popular. ‘Gloria Rosea’ is a not-pretty 

pink, and ‘Grete Pungel’ was a loser for us.” Ed Pincus, Third Branch Flower, 

Roxbury, Vt.

134 ASTRANTIA MAJOR 

Reading 

Beattie, D. J., and E. J. Holcomb. 1983. Effects of chilling and photoperiod on 

forcing astilbes. HortScience 18(4):449–450. 



Doorn, W. G. van, R. R. Perik, and P. J. M. Belde. 1993. Effects of surfactants on 

the longevity of dry-stored cut flowering stems of rose, Bouvardia, and Astilbe. 

Postharvest Biology and Technology 3(1):69–76. 

Iwanami, K. 1989. Effects of low temperature on growth and flowering of Astilbe. 

Scientific Reports of the Miyagi Agricultural College 37:1–8. 

Kalkman, E. C. 1986. Post-harvest treatment of Astilbe hybr. Acta Hortic. 181:389– 

392. 

Latta, R., and C. F. Doucette. 1932. Insect control stimulates growth. Flor. Rev. 

70(4806):11–13. 

Pemberton, G. H., and A. A. De Hertogh. 1992. Floral development of Astilbe 

×arendsii. Acta Hortic. 325:229–234. 

Runkle, E. S., R. D. Heins, A. Cameron, and W. Carlson. 1998. Flowering of coldtreated 

field-grown Astilbe. HortTechnology 8(2):207–209. 

———. 2000. Forcing perennials: In Firing up Perennials. Greenhouse Grower Sp. 

Publ. 



Stimart, D. P. 1989. Strategies of growing fresh cut flowers of Astilbe, Liatris, and 

Paeonia. In Proc. Commercial Field Production of Cut and Dried Flowers. Univ. of 

Minnesota, The Center for Alternative Crops and Products, St. Paul. 

Wilkins, H. F. 1985. Astilbe. In The Handbook of Flowering. Vol. 1. A. H. Halevy, ed. 


Many thanks to Dennis Stimart (first edition) and Roxanne McCoy and Ed Pincus 


Astrantia major masterwort Apiaceae 

perennial, Zones 4–6 Austria white, pink 2–4'/3' (0.6–1.2 m/0.9 m) 

The unique flowers are greenish white with a pale green collar of narrow bracts, 

which gives the whole flower a starry appearance. The flowers are small but 

grouped together in a dense head. Plants are best grown in areas of cool summers 

and cool night temperatures; they are poor crops under warm growing 

temperatures. Masterwort is uncommon, even as a garden plant, in most of the 

country because of temperature extremes we experience in summers and winters. 

When offered, however, it is readily accepted by the market and may well be 

worth a try.

Propagation 

ASTRANTIA MAJOR 135 

Astrantia major ‘Lars’ 

Seed: Sow seed in moist medium and place at 60–65F (15–18C) for 2–4 weeks. 

Seed flats should then be placed at 30–35F ( − 1–2C) for a minimum of 4–6 weeks. 

After the cold treatment, put flat in cold frame or a greenhouse at 50–55F (10– 

13C). Alternating temperatures are beneficial for germination. 

Growing-on 

Grow seedlings at 55F (13C) for 4–6 weeks. Fertilize with 50–75 ppm N from 

potassium nitrate then increase to 100 ppm N of a complete fertilizer. High

136 ASTRANTIA MAJOR 

nitrogen results in poorly colored flowers. Plant in the field as soon as ground is 

workable. Spacing of 12 × 12" (30 × 30 cm) is appropriate. Plants flower more 

prolifically the second year than the first. 


Constant moisture is necessary for best growth. Yields in the Netherlands were 

reported as approximately 7 flowers/ft2 (75 flowers/m2 ) the first year and 10–12 

flowers/ft2 (107–129 flowers/m2 ) the following year. Plants may require support 

the second year. 

Longevity: Expect 3–5 years of production. 


Harvest time is critical. Harvest when the uppermost flowers are open; if harvested 

too early, plants will wilt and flowers will not open (similar to yarrow). If 

harvest is further delayed, vase life will suffer. 

Postharvest 

Fresh: Flowers persist 5–7 days in water (Vaughan 1988), but immediate 

hydration after cutting is recommended. 

Dried: Flowers may be dried with silica gel; they shrink less with desiccants 

than by air drying alone. Cover the bottom of a box with silica gel or borax. Carefully 

work the crystals between the petals and lay the stems in the box. Once 

stems are in place, cover with additional desiccant and leave for 5–6 days (Bullivant 

1989). 

Cultivars 

‘Alba’ bears white flowers. Quite uncommon. 

subsp. involucrata includes a number of cultivars with an extra long collar of 

pink bracts. One of the most impressive cultivars is ‘Margery Fish’, better known 

as ‘Shaggy’, a most apt description of the flowers. Plants may not produce sufficient 

yield to make a profitable cut flower crop. The true cultivar should be vegetatively 

reproduced from cuttings, although some seedlings with long bracts 

will occur. 

‘Lars’ is a vigorous selection with improved vigor and spectacular dark red 

flowers. 

‘Moira Reid’ is a most interesting plant with large pink flowers and salmonpeach 

collars. 

‘Primadonna’, a seed-propagated cultivar with 24–30" (60–75 cm) stems, 

bears many rose-red flowers. 

‘Rainbow’ is another seed variety with a long bloom season, large flowers, and 

a good mix of colors. Plants grow to 28" (70 cm). 

‘Rosea’ bears rose-colored flowers with deeply incised leaves.

ASTRANTIA MAJOR 137 

‘Rose Symphony’ (‘Rosensymphonie’) is a wonderfully handsome plant with 

rosy pink flowers with a silver collar of bracts. Plants are about 2' (60 cm) tall. 

‘Ruby Cloud’ is a seed-propagated cultivar with red to purple flowers, growing 

to 28" (70 cm). 

‘Sunningdale Variegated’ is most handsome in the spring, when the margins 

of the light green leaves are splashed with yellow and cream; the variegation 

fades in summer. A better landscape plant than a cut flower. 


Astrantia carniolica is available as ‘Rubra’, a purple- to maroon-flowered plant. 

Plants are a little shorter than A. major and have darker foliage. 

Astrantia maxima bears wonderfully handsome pink flowers on vigorous 

plants. Unfortunately, the supply is low and the price for plants is therefore high. 

When prices decline, more flowers should appear in the market. 


Aphids are the most common pests, although thrips and spider mites can also be 

a problem. If plants are allowed to dry out, physiological problems such as leaf 

margin die-back occur. Astrantia is considered highly susceptible to nematode 

galls caused by Meloidogyne hapla (LaMondia 1996). 


“Astrantia can be difficult to germinate. It is typically a cold germinator and needs 

a period of low temperature to induce germination. Germination will tend to be 

erratic over the last 21–30 days. For this reason, it is sometimes better to germinate 

this variety in late fall.” Corky Kane, Germania Seed Company, Chicago, Ill. 

“My favorite seed variety is Astrantia hybrid ‘Rainbow’—it has a nice mix of 

colors, very long stems, and blooms a long time, with good-sized blooms, very 

productive. The darker colors in this mix bloom earlier than other reds and 

medium pinks for me.” Janet Foss, J. Foss Garden Flowers, Everett, Wash. 

“Surface sow [Astrantia] on medium, then cold treat for 6–8 weeks. Germination 

rate is usually quite high if seed is fresh. Germinate at 68–70F, then lower 

temps to 55F once the seedlings have their first true set of leaves. Lower growingon 

temps will give you a good root system. If you’re planting for cuts, use a semishaded 

area or shade cloth in full sun for stems long enough to cut.” Jennifer 

Judson-Harms, Cricket Park Gardens, New Hampton, Iowa. 

Reading 



LaMondia, J. A. 1996. Response of additional herbaceous perennial ornamentals 

to Meloidogyne hapla. J. of Nematology 28(4):636–638.

138 BAPTISIA AUSTRALIS 


Ore. 

Many thanks to Janet Foss and Jennifer Judson-Harms for reviewing this section. 

Baptisia australis false blue indigo Papilionaceae 

perennial, Zones 3–7 North America purple 3–4'/3' (0.9–1.2 m/0.9 m) 

An underused cut flower, whose limitation appears to be a long maturity period 

and perhaps a limited availability of plants; however, seed can easily be germinated 

and flowers are well received by the consumer. The genus sports flowers in 

many colors, mainly in purple, white, and yellow, as well as a couple of hybrids 

in rather unusual colors. Although flowers are most noticeable, the foliage and 

the pods can also be harvested successfully. 

The genus, which contains about 35 species, is rife with folklore. The genus 

comes from the Greek word bapto (“to dip”), a reference to the flower extract’s 

once being used as a substitute for indigo. Baptisia australis was often used for 

blue dyes, while B. tinctoria was a source of yellow dye in the southern United 

States. Baptisia is one of the most rewarding and historically fascinating genera 

available to growers and landscapers alike. Native to large areas of the United 

States, plants afford exceptional performance and a mini-lesson in early American 

history. The common name refers to its use as a substitute, albeit not a great 

substitute, for the true indigo, Indigofera, of the West Indies. When Indigofera was 

in short supply, the English government contracted with farmers in Georgia 

and South Carolina in the mid 1700s to “farm” false blue indigo, B. australis, to 

increase the supply of the dye. 

The farming of baptisia was one of the first recorded examples of agricultural 

subsidies. The process used to extract the dye was incredibly cumbersome and 

time-consuming. A report in the Georgia State Gazette of 10 May 1788 provided 

directions “for the Cultivation and Manufacture of Indigo” by “an Indigo 

Planter.” What with planting, cutting, beating, draining, and pressing, the process 

was doomed to a short life. Today, baptisia provides growers with a living 

example of Americana and, more importantly, with useful, beautiful cut flowers. 

Propagation 

It is best to gather seeds from existing plants, although seeds may be purchased. 

The key to successful seed harvest is to gather the seed as the seed pods turn 

black and sow when fresh. Seed propagation is less erratic when seeds are given 

a scarification treatment. Piercing or scraping the seeds with sandpaper or 

another abrasive substance is helpful, but not essential. This allows moisture 

and oxygen to penetrate the seed coat. Acid scarification is used commercially 

but should be performed only by trained individuals. Once the seeds have been 

treated, place them in a peat/vermiculite mix in a moist, warm environment.

Baptisia australis

140 BAPTISIA AUSTRALIS 

Germination of over 90% occurred regardless of acid and mechanical scarification, 

cold and hot water soaking, or cold stratification (Dirr 1987). A cold treatment 

of approximately 40F (4C) is also useful and can be accomplished in a cold 

frame or in a refrigerator or incubator. Seed germinates in 10–18 days at 70F 

(21C). The fleshy roots may also be divided between October and March. 

Growing-on 

Transplant plugs or seedlings to 4–5" (10–13 cm) containers and grow on at 50– 

58F (10–14C) until they are large enough to be placed in the field. Once in the 

field, they should not be disturbed. 


Temperature: Cold is beneficial for growth and flowering of false blue indigo, 

but plants are tolerant of warm summer weather. Plants are perennials and 

flower for many years. 

Photoperiod: Plants do not appear to have a photoperiodic requirement. 


Yield: Little information on yield is available, but nothing should be harvested 

the first year, and minimal harvesting should be done the second. By the third or 

fourth year, plants are fully mature, and a dozen stems per plant can easily be 

harvested. 

Spacing: We recommend spacing of at least 2' (60 cm) between plants to allow 

them to fill in. Plants will be productive for many years, so dense spacing is counterproductive. 

Fertilization: Plants belong to the pea family, so they are able to produce their 

own nitrogen; however, this does not mean that plants do not need feeding. Side 

dress with a complete fertilizer as new shoots arise. No additional fertilizing is 

needed after early summer. 

Longevity: If plants are properly cared for, production for 10 years is not 

unusual. 


Flowers are harvested when approximately ⅓ of the flowers on the inflorescence 

are open. Janet Foss of Everett, Wash., cuts her fresh blooms when just a few 

flowers are open (not more than ⅓) but all the buds are colored. She has problems 

with shattering if they’re left too long in the field. In Vermont, Ed Pincus 

cuts 2–3' (60–90 cm) main stems and then obtains additional side branches, 

which he can cut or leave to develop the green pods. The pods eventually turn 

black. Either way, he notes, the foliage and the pods are quite attractive. 

Pods start green and eventually turn black. Pods remain green longer in the 

South and West Coast because cool weather is slower to arrive. Not all inflores-

BAPTISIA AUSTRALIS 141 

cences produce pods, so do not expect the same yield of fruit as flowers. They can 

be harvested when they are green, but better contrast between leaves and fruit 

occurs if they are brown to black. Waiting too long is not recommended, however, 

if the foliage is an important part of the “podded” stem. The foliage turns 

black in the fall and declines rapidly, at which time, put your falsies to bed. 

Postharvest 

Growers who cut into a hydrating solution report postharvest life of 7–10 days. 

Warm water in the bucket is particularly recommended for baptisia. 

Cultivars 

No cultivars of Baptisia australis are available; several hybrids have been released, 

however. 

‘Purple Smoke’ is a hybrid between Baptisia australis and B. alba, a white-flowered 

species, released by the North Carolina Botanical Garden in Chapel Hill. 

The smoky-blue flowers are held in upright inflorescences on 3' (90 cm) tall 

plants with gray stems. 


Baptisia alba (white baptisia) is an exceptional species, laden with white flowers 

on black stems. Plants are more shade tolerant than B. australis, and earlier to 

flower. ‘Pendula’ is similar in flower but with pendulous seed pods. The nomenclature 

of the genus is mixed up, other white-flowered forms include B. lactea 

and B. leucantha. 

Baptisia sphaerocarpa (yellow baptisia) has golden-yellow flowers on 2½–3' 

(75–90 cm) tall plants. Native to Arkansas and Oklahoma, plants are excellent 

choices for the western states. 


Leaf spots, powdery mildew (Ersiphe, Microsphaera), rust (Puccinia), and root rots 

are not uncommon (Perry 1998). 

Foliar nematodes (Aphelenchoides spp.) cause discolored spots on foliage that 

can worsen to leaf blight later in the season (Gill et al. 1999). 


“I have a patch of baptisia that is 6 years old. The original plugs were purchased 

and planted in our field before we had a well. I had heard it was drought tolerant 

and sure enough, it established itself and flourished without a lot of TLC.” Maureen 

Charde, High Meadow Flower Farm, Warwick, N.Y. 

“I have grown Baptisia australis for 4 years, and I think it is a real winner. Not 

only can I sell the flower, but the foliage and seed pods are wonderful too. The

142 BUDDLEIA DAVIDII 

plants ‘last forever,’ like peonies, and are natives in North America.” Pat Bowman, 

Cape May Cut Flowers, Cape May, N.J. 

“I started cutting them May 14, and the indigo blooms have opened gradually, 

lasting over a week. The foliage is gorgeous, and they make a really nice 

blue/green flower and foliage base for these early bouquets. It has taken about 5 

years for my plants to put on size enough to cut abundantly from, baptisia being 

very slow and ‘permanent,’ and I’d love to have a huge hedge of it.” Mary Ellen 

Gambutti, Springfield Cut Flower Exchange, Coopersburg, Pa. 

Reading 

Dirr, M. A. 1987. Baptisia australis. American Nurseryman 165(5):166. 

Gill, S., D. L. Clement, and E. Dutky. 1999. Pests and Diseases of Herbaceous Perennials. 

Ball Publishing, Batavia, Ill. 



Buddleia davidii butterfly-bush Loganiaceae 

woody, Zones 5–9 China many colors 5–10'/5–10' (1.5–3 m/1.5–3 m) 

Butterfly-bush bears flowers on new growth, which makes it an excellent woody: 

the plant can be cut to the ground in the spring and never get out of control. 

Plants grow rapidly, reaching 5–8' (1.5–2.4 m) tall in one season, even after being 

cut back. Flowers are available in white, pink, lavender, purple, and blue, and 

additional species also have potential. The length of the inflorescence is 6–30" 

(15–75 cm) long, depending on the vigor of the plant: the more vigorous the 

vegetative growth, the larger the inflorescence. This is an excellent plant for florists 

who are looking for unusual spikes for bouquets. 

Propagation 

Seed: Seed requires no pretreatment and germinates rapidly under intermittent 

mist or sweat tent and soil temperature of 70–75F (21–24C). 

Cuttings: Collect cuttings from June through August and provide a quick dip 

of 1000–3000 ppm IBA (Dirr 1998). Remove rooted cuttings from the bench as 

soon as possible; cuttings rot rapidly with excess moisture. 


Habit: Plants are large, multistemmed shrubs that routinely reach heights in 

warmer locations of 5–10' (1.5–3 m). In northern areas (Chicago, Ill.), plants are 

herbaceous perennials, dying back to the ground each year. North of Zone 5, 

the usefulness of plants for cut flowers is marginal. 

Transplanting: Plants transplant to the field easily; in fact, butterfly-bush is 

almost weedlike in its ability to withstand abuse. Rooted cuttings in plug trays

Buddleia davidii 

BUDDLEIA DAVIDII 143 

are the most economical means of propagating and transplanting. From plugs, 

4' (1.2 m) tall plants can be produced the first year with approximately 10 

stems/plant. Plants may also be transplanted from 1 gallon (4 l) containers into 

moist, well-drained soil. 

Spacing: Close spacing should be possible because plants can and should be 

severely cut back each season. Armitage and Dirr (1995) planted ‘Black Knight’ 

on 5½, 2½, or 1½' (165, 75, or 45 cm) centers and harvested stems for 3 years. The 

number of harvested stems per plant decreased, but the number of stems per ft 2 

(m 2 ) increased with greater plant density. Bob Wollam of Wollam Gardens in 

Jeffersonton, Va., recommends 2½' (75 cm) spacing, and even when plants are 

cut back to 1' (30 cm) in the spring, 1' (30 cm) remains between plants. A close 

spacing of 15 plants/20 linear ft (8 plants/m 2 ) may be used if plants are cut back 

to the ground in the fall, but probably would be useful for only about 3 years. 

Harvesting: Harvest stems as long as possible, remembering that a sufficient 

leaf area must remain to nourish the roots and provide next year’s growth. Allow 

at least ⅓ of the plant height to remain, or harvest alternate branches.The inflorescences 

are tender, and stems should not be harvested mechanically. 

Yield: The number of flowering stems depends on cultivar, severity of previous 

harvest, and winter conditions. On a 3-year-old plant, 60–100 stems is not uncommon. 


There seems to be little reason why Buddleia could not be forced out of season 

under greenhouse conditions. From observation of natural growing sequence, 

plants respond to long days and warm temperatures.



The proper stage of harvest is critical but debatable. Kasperski (1956) advised 

harvesting when ½ the flowers on the inflorescence are open but before the open 

flowers have started to fade, but many growers ignore this advice. Certainly, it is 

important to deadhead spent flowers on the inflorescence, so, whenever you 

choose to cut, harvest every 2–3 days in order to avoid spending time deadheading. 

Having a longer vaselife is less important than having too many flowers 

open at harvest. Regardless of when they are harvested, stems must be hydrated 

with a hydrating solution. Conditioning using warm water (80–100F, 27–38C) 

has been suggested. If panicles are not turgid by the time the water cools, place 

stems in hot water a second time. Two to 3 changes may be necessary for thorough 

conditioning (Kasperski 1956). 

Postharvest 

Fresh: Fresh flowers persist only 2–3 days if not well conditioned. This is the 

most limiting factor to the acceptance of Buddleia as a cut flower. Paul Sansone, 

a grower in Oregon, precuts under water, places the stems in a floral preservative, 

and then moves them into the cooler. Bob Wollam cuts to a minimum of 18" (45 

cm) and strips and bunches in the field, placing 10–15 stems per bunch, depending 

on flower size. Ann Trimble of western Kentucky cuts only large stems (>36", 

90 cm) shortly after daybreak and places them into water with ordinary floral 

preservative. Warm water is good if it is available. She cuts and bunches in the 

field, doing no more than 50 stems before they are put into water. Hydrating 

solution is taken to the field so that flowers can be immediately plunged. Flowers 

persist 7–10 days if properly conditioned. 

After field harvest, stems are recut, quick dipped, and placed in a preservative 

solution in warm water. Stems may be cooled at approximately 38F (3C) for 

18–24 hours. White flowers decline more rapidly than other colors. Yellow flowers 

appear to have the longest vase life. 

Dried: Large leaves should be removed and stems hung up to dry in a wellventilated 

area. Flowers retain their fragrance even after drying (Bullivant 1989). 

Storage: Stems may be stored wet for 1–2 days at 38–40F (3–4C) (Nowak and 

Rudnicki 1990). 

Cultivars 

Several dozen have been selected and named, but only a few are easily available 

and some are more suitable for cut stems than others. Contact your local nursery 

or a good woody plant distributor. Dirr (1998) has evaluated many cultivars, 

and although his comments refer to landscape use, his descriptions may be useful 

for cut flower growers as well. Bob Wollam has been growing and evaluating 

buddleia cultivars for years; his experiences are even more important to growers, 

and his favorites are marked as “Wollam favorites.” Ann Trimble notes that lavender 

and white are far better sellers than her pink cultivars. Heights given will 

differ, depending on how severely plants are harvested.

White 

BUDDLEIA DAVIDII 145 

‘Peace’ has an arching habit, with white flowers and a orange throat. Flowers 

are 6–14" (15–36 cm) long. 

‘White Bouquet’ bears 8–12" (20–30 cm) long fragrant flowers with an orange 

to yellow throat. Foliage is gray-green. 

‘White Profusion’ is a strong, upright grower with long panicles of clear white 

flowers. A Wollam favorite. 

Pink, rose, mauve 

‘Fortune’ bears long racemes of soft pink flowers, each with a yellow eye. 

‘Pink Delight’ is somewhat mixed up in the trade. Plants should be compact, 

around 6' (1.8 m), but tend to be taller. Flowers are a rich pink. A Wollam favorite. 

‘Summer Beauty’ has gray-green foliage and excellent pink-rose flowers. 

‘Summer Rose’ is 8–10' (2.4–3 m) tall, with large mauve-rose flowers. 

Lavender, blue 

‘Bonnie’ has light lavender flowers with an orange eye. Vigorous, up to 10' (3 

m) tall and equally wide. Good fragrance. 

‘Deep Lavender’ bears lilac-lavender flowers with an orange eye. 

‘Ellen’s Blue’ bears deep blue flowers with a yellow eye. Leaves are silvery. 

‘Empire Blue’ has rich violet-blue flowers, silvery foliage, and stands about 

10' (3 m) tall. Panicles are 12" (30 cm) long. 

‘Moonshadow’ is smaller than many upright cultivars, with soft lavender 

flowers on 3–4' (0.9–1.2 m) tall plants. 

‘Orchid Beauty’ has handsome mauve to lavender-blue fragrant flowers but 

appears to be less vigorous than many others. 

Purple, violet, magenta, red 

‘Black Knight’ has dark purple, highly scented flowers and grows 8–10' (2.4–3 

m) tall. A Wollam favorite. 

‘Dubonnet’ bears rich purple flowers with a light orange throat. The panicles 

may be up to 14" (36 cm) long. 

‘Potter’s Purple’, an excellent grower with upright stems, produces many deep 

purple flowers in 10" (30 cm) panicles. A Wollam favorite. 

‘Royal Red’ bears purple-red flowers on 14" (36 cm) panicles. An excellent 

“red” cultivar but not the easiest to produce. 

Yellow 

‘Honeycomb’ has Buddleia ×weyeriana parentage and produces excellent 

yellow flowers. A Wollam favorite. 

‘Sun Gold’ is a older than ‘Honeycomb’ but still popular.



Buddleia alternifolia (alternate butterfly-bush) is 10–20' (3–6 m) tall with an 

open habit and pendulous stems. The lilac flowers occur in the axils of last year’s 

growth, so they cannot be cut back until after flowering. Very interesting but 

may not be as useful for cut flowers as B. davidii. 

Buddleia globosa (orange ball tree) is a terrific useful shrub with spherical 

orange flower clusters. Flowers on previous year’s wood. Hardy only to Zone 7. 

Buddleia lindleyana bears little resemblance to normal butterfly-bushes. Plants 

can reach 12' (3.6 m) in height and produce purple-violet flowers all season. Not 

as tidy, and less mite resistant, but worth a look. Hardy only to Zone 7. 

Buddleia ×weyeriana, a hybrid between B. davidii and B. globosa, is hardy in 

Zones 7–9. The cultivars ‘Sun Gold’ and ‘Golden Glow’ bear yellow-orange and 

pale yellow-orange, fragrant flowers, respectively. If purchasing plants for yellow 

flowers, include ‘Honeycomb’ as well. 


Three-spotted spider mites can be a serious problem. Gillman et al. (1999) 

assessed spider mite resistance of Buddleia taxa. Results from bioassays and sampling 

of naturally occurring pest populations in the field identified highly resistant 

taxa (Buddleia fallowiana ‘Alba’, B. f. ‘Cornwall Blue’) and susceptible taxa (B. 

davidii ‘African Queen’, B. lindleyana ‘Gloster’). 

Few other pests bother butterfly-bush, although nematodes can be a nuisance 

in the South. Root rot (Phymatotrichum omnivorum) has resulted in serious losses 

in Texas, but it does not appear to be widespread. 


“We are in northern lower Michigan, mostly Zone 5, but sometimes Zone 4 on 

rare winters. I’ve been growing buddleia for about 8 years, and it has come back 

every year. We cut them back to about 6" in late fall with everything else, and it 

has worked just fine. At harvest time, I usually dip the stems in boiling water for 

a few seconds and that seems to help the vase life some. Even when they dry up 

in a bouquet though, the shape can still be very attractive. The lavenders and 

purples are the best for me, although I grew a bright cerise for the first time this 

year and loved it.” Phyllis Wells, Wells Family Farm, Williamsburg, Mich. 

“We have a few [Buddleia davidii] ‘Black Knight’. It needs to be picked as soon 

as it begins to open, early in the day. It will not survive a hot day at the market 

unless it is well hydrated. When picked fresh and hydrated, it will last 5 days in 

Oasis, close to a week in water. I sold some to a florist for a wedding and had 

to test it in Oasis foam for longevity; I was surprised how long it lasted. But it 

has to be picked at its peak, which, like most flowers is the minute it begins to 

bloom, not a few days later.” Dave Dowling, Farmhouse Flowers, Brookeville, 

Md.

Reading 

CALLICARPA 147 

Armitage, A. M., and M. A. Dirr. 1995. Influence of spacing on yield of Buddleia 

and Salix grown as cut flowers and stems. J. of Environ. Hort. 13(4):176–177. 



Dirr, M. A. 1998. Manual of Woody Landscape Plants. 5th ed. Stipes Publishing, 


Gillman, J. H., M. A. Dirr, and S. K. Braman. 1999. Gradients in susceptibility and 

resistance mechanisms of Buddleia L. taxa to the two-spotted spider mite 

(Tetranychus urticae Koch). J. Amer. Soc. Hort. Sci. 124(2):114–121 

Kasperski, V. R. 1956. How to Make Cut Flowers Last. M. Barrows and Co., New 

York. 



Many thanks to Paul Sansone (first edition) and Ann Trimble and Bob Wollam 


Callicarpa beautyberry Verbenaceae 

woody, Zones 5–10 tropics purple, white fruit 1 

4–8'/3–6' (1.2–2.4 m/0.9–1.8 m) 

Noted for their magnificent purple or white fruit in the fall, the beautyberries are 

easily grown and have great potential as a cut stem—and they are as frustrating 

a crop to growers as any we have discussed (see “Grower Comments”). Only a few 

of the approximately 40 species are available to American growers; Callicarpa 

americana and C. dichotoma are most useful for the colored fruits. In all species, 

the magenta or white fruits occur at the nodes in the top ⅓ to ½ of the stem. 

Callicarpa americana (American beautyberry; French mulberry), native from 

Maryland to Georgia in the East, west to Arkansas and south to Mexico, bears 

some of the largest (¼", 6 mm wide) and most ornamental fruit in the genus; its 

var. lactea is a white-flowered form whose white fruit is beautiful initially but 

discolors as it ages. Species from China and Japan with smaller but no less handsome 

fruit are also available. Callicarpa is in demand by growers because flowers 

are formed on new wood, and stems may therefore be harvested almost to the 

ground. In the northern limit of hardiness (Zone 5), plants will die all the way to 

the ground, reappearing like an herbaceous perennial. Limitations to production 

of beautyberry are the relative lack of information for the producer and the 

wholesaler/retailer, the difficulty in removing leaves, and poor shippability. 

Propagation 

Cuttings: Softwood cuttings root in 7–14 days if placed in clean sand under 

intermittent mist (Dirr 1998).

148 CALLICARPA 

Seed: Seed should be stratified for 90 days at 41F (5C) for best germination 

(Dirr 1998). 


Callicarpa dichotoma 

Habit: Plants are multistemmed shrubs. Plants reach a height of 4–6' (1.2–1.5 

m) after being cut to within 1' (30 cm) of the ground the previous winter. 

Transplanting: Plants are readily transplanted into well-drained soils in the 

spring. Irrigation is necessary for good flowering and fruit production. Plants 

tolerate full sun to partial shade, but full sun provides highest yield of useable 

stems. Plants reach fruiting stage approximately 2–3 years after transplanting. 

Spacing: Cutting back stems in the winter allows for relatively close spacing. If 

plants are cut back every year, spacing at 2–3' (60–90 cm) centers can be accomplished. 

If plants are not cut back, then wider spacing is required. 

Fertilization: Excess fertility should be avoided once plants become productive. 

High rates of nitrogen result in reduced flowering and fruit production. 

Harvesting: Harvest by cutting stems 6–12" (15–30 cm) from the ground. Fruit 

may fall off; harvest with reasonable care to retain as much fruit as possible. 

Yield: After about 2 years in the ground under proper environmental conditions, 

15–30 stems are formed. Additional shoots form as plants mature.


CALLICARPA 149 

No work has been conducted on forcing beautyberry out of season, but its 

annual growth rate and habit of fruiting on new wood suggest it could be greenhouse 

forced. It is likely that long days and warm temperatures enhance flower 

and fruit production. 


Early harvest (early October) may occur when the basal fruit clusters are fully colored 

and the terminal fruits are still green. Little additional fruit coloration 

occurs after harvest. Later harvests (mid October to November) are better because 

all fruit is colored and many leaves have fallen. Some basal fruit will fall off 

during harvest; this is to be expected. Rough handling or harvesting too late 

results in significant fruit drop. Harvest before a hard freeze, or the fruit becomes 

mushy and the stems unsaleable. 

Postharvest 

Stems should be recut and immersed in hot water. Fruit persists approximately 

2 weeks. Stems may be stored at 32–36F (0–2C) for 2–4 days (Vaughan 1988). 

Remaining foliage should be removed. Work at the University of Georgia 

showed that if stems are placed for 1–2 hours in a floral preservative, then placed 

in buckets without liquid, the foliage can be removed more easily approximately 

48 hours later. Elizabeth Dean of Wilkerson Mill Gardens in Palmetto, Ga., suggests 

rolling harvested stems in a lightly moistened paper and storing them in a 

cooler for 1–3 days to enhance leaf removal and decrease fruit loss: “It is possible 

to harvest without putting stems in water. Several days storage in a dark cooler 

makes leaf removal easier.” Once leaves are removed, place the stems back in 

water and store in a 32–36F (0–2C) cooler. 


Callicarpa bodinieri (Bodinier beautyberry) is grown in Europe but is rarely 

seen in the United States. Native to China, plants are hardy in Zones 5–7. ‘Profusion’ 

is a heavily fruited Dutch selection with large leaves and violet fruit ¹⁄₆" (4 

mm) in diameter. Where plants are happy, abundant fruit occurs even on young 

plants. A white-fruited form also exists, but it too is relatively unavailable to 

American growers. Not a particularly good plant for the Southeast. 

Callicarpa dichotoma (purple beautyberry) is arguably more ornamental than 

C. americana, but fruit is smaller, about ¼" (6 mm) in circumference, and does 

not encircle the nodes as in its American counterpart. The multistemmed species 

is relatively fast growing and persistent. Seven-year-old plants in Athens, Ga., 

produced over 30 marketable stems. Plants are more cold hardy than American 

beautyberry and grow well in Zones 5–8. The main production difficulty is the 

removal of the many small leaves, which is labor intensive and if done sloppily, 

results in a good deal of fruit loss. Postharvest tests at Georgia were disappoint-

150 CALLICARPA 

ing. The fruit falls off rapidly or dries to look like little purple raisins; however, 

even raisins are handsome to the right eyes. As Elizabeth Dean so aptly states, 

“The fruit has visual interest dried if one is not expecting perfection; if so, buy 

plastic.” Variety albifructus is a white-fruited form that discolors early. ‘Early Amethyst’ 

bears many small lilac fruits. ‘Issai’ appears to be an excellent cultivar, 

fruiting heavily, even as a young plant. 

Callicarpa japonica (Japanese beautyberry) is 4–8' (1.2–2.4 m) tall and equally 

wide at maturity. They are not as heavily fruited as C. americana or C. dichotoma, 

and some reports suggest the fruit is not as persistent. Plants have about the 

same hardiness as C. dichotoma. ‘Leucocarpa’ bears white fruit. 


Leaf spots (Atractilina callicarpae) occur as irregular, rustlike, scattered spots. 

Fungicide applications prior to fruit coloration may be necessary. 

Black mold usually signifies an insect problem. Insects such as aphids secrete 

honeydew, on which the mold grows. Controlling the insects generally controls 

the mold. 


“I have a few plants of Callicarpa dichotoma. The berries color up, but the leaves are 

still on the plants. I don’t feel like individually pulling the leaves off, so I wait— 

depending on the weather, when the leaves fall off, usually we only have a couple 

of days to harvest them. Generally, it freezes too hard, and we lose the berries 

also. In Seattle it seems the berries stay on most of the winter, looking totally 

spectacular, but the weather is just mild enough there to make the difference. 

When I actually do get to harvest them, as long as the leaves have dropped, they 

need no special conditioning. I’ve even had the berries dry, making nice winter 

decorations. But do I think this is a viable crop for us? No.” Janet Foss, J. Foss 

Garden Flowers, Everett, Wash. 

“We put in a 200' row of Callicarpa dichotoma ‘Issai’ several years ago. So far we 

have not found a way to make money on it except to dig the plants and sell them. 

The shrubs are beautiful and carefree, but the problem is that the leaves do not 

hydrate once the stem is cut. We have tried selling them with the leaves on and 

let the florist pull them off, but that didn’t fly. We have tried pulling the leaves 

off ourselves, but, besides being labor intensive, the stems get all tangled up 

without the leaves, so when you pull them apart the berries get pulled off. If you 

wait till the leaves fall off on their own, the berries are starting to rot and will 

drop. We have tried Hydraflor postharvest to no avail. We have all but given up.” 

Tammy Ford, Perennial Favorites, Leopold, Ind. 

Reading 


Champaign, Ill.


Ore. 

Many thanks to Elizabeth Dean for reviewing this section. 

CALLISTEPHUS CHINENSIS 151 

Callistephus chinensis China aster Asteraceae 

annual China many colors 1–3'/2' (0.3–0.9 m/0.6 m) 

China asters continue to be offered in various sizes and colors—including pastels, 

bright blues, and electric reds—and breeders are still bringing plants to the 

marketplace. Although popular in many circles, including Europe, the main 

drawbacks of China asters are the relatively low yields and susceptibility to disease. 

Production has moved mainly to the greenhouse, where more control of the 

environment is possible. China aster, an annual, should not be confused with 

perennial asters, which are included under Aster. 

Propagation 

Seed germinates in 3–7 days if placed under intermittent mist at 70–72F (21– 

22C). Approximately 0.12 oz (3.5 g) of seed yields 1000 plants (Nau 1999). Seed 

may also be direct sown in the field in early spring at the rate of 0.09 oz per 100' 

(10 g per 100 m) for summer production (Kieft 1996). Some cultivars are also 

propagated vegetatively, from cuttings. 

Growing-on 

Seedlings should be transplanted to cell packs or 3–4" (8–10 cm) pots at the first 

true leaf stage, then grown at 70/60–62F (21/15–17C) day/night until roots are 

well established. Do not allow plants to become root bound. Maintain plants 

under long days of approximately 15 hours with incandescent lights when natural 

short days occur. Fertilize with 100–150 ppm N with potassium or calcium 

nitrate. 


Photoperiod: Flowers develop most rapidly when a period of long days is followed 

by short days (Cockshull 1985). The term given to this plant is a “longshort 

day” plant. That is, plants are induced to flower under LD, and then 

develop more rapidly under SD after induction. If plants are provided with continuous 

LD, they flower more slowly but on longer stems than do those that are 

exposed only to SD, a useful characteristic for cut flower production. Flowering 

of laterals is also delayed when plants do not receive SD treatment (Goldsberry 

et al. 1989). Even though research has shown that only 7 LD are needed for 

flower initiation (Doorenbos 1959), approximately 4–5 weeks of LD are necessary 

to adequately “prime” the plant for SD treatment. Flowering is not acceler-

152 CALLISTEPHUS CHINENSIS 

Callistephus chinensis 

‘Meteor Purple’ 

ated with less than 4 weeks of LD followed by SD compared with plants that 

receive only SD. The critical LD photoperiod is approximately 14 hours, and 

satisfactory LD effects can be obtained by a 16-hour day extension with incandescent 

lights or with continuous light (Cockshull and Hughes 1969). In summary, 

research indicates that for pot plant use, 3–4 weeks of LD should be 

followed by SD for compact, rapidly flowering specimens. For cut flower pro-

duction, LD could be continued until desired stem length has been achieved. 

Then, SD will hasten flowering time. 

Work at Colorado State University verified much of the older research, as the 

following table shows (Goldsberry et al. 1988, 1989). 

The effect of photoperiod on growth and flowering of cut China 

asters. 

Days to Stem No. of 

Photoperiod flower length (in) z breaks 

continuous SD 49 17.5 5 

1 week LD, then SD 51 17.4 5 

2 weeks LD, then SD 53 19.5 4 






In this work, the highest-quality flowers occurred with 3–4 weeks of LD, followed 

by SD. 

Long days also promote leaf expansion, stem extension, and dry matter accumulation 

but slightly inhibit the formation of lateral breaks (see previous table). 

The promotion of flower development due to SD inhibits stem elongation. 

Temperature: A pronounced interaction between temperature and photoperiod 

occurs in China asters. Plants grown at 55F (13C) or below flower only if 

LD are provided but remain as basal rosettes if grown under SD. Raising the 

temperature to 68F (20C) resulted in 16 days earlier flowering when plants were 

grown under LD, but the effect was considerably greater when plants were grown 

under SD (Biebel 1936). In sum, keep the temperatures above 55F (13C) and 

below 86F (30C). Optimum temperatures are 77F (25C) during the day and 60F 

(15C) at night. 


Field production has been difficult because of the plant’s susceptibility to aster 

yellows virus. The phytoplasm is carried by leafhoppers, which must be controlled 

(see “Pests and Diseases”). Asters historically have been grown under 

cloth in the field to reduce the incidence of these hopping bugs. Protective 

screens must be used at least until plants are budded up; after that time, the disease 

will not have time to show up. 

Scheduling: Flowers of spray asters are generally harvested approximately 3–4 

months after transplanting to the field, depending on latitude and temperature. 

In trials in Maine, plants sown on 20 April flowered in early August (early-flowering 

cultivars) to mid to late August (later-flowering cultivars). Early flowering


in the field may be stimulated by placing seedlings under LD immediately after 

they come out of the propagation area. For example, seedlings resulting from 

February and March sowings should receive 4-hour nightbreak lighting and 

temperatures above 62F (17C) until planted in the field. Since natural photoperiod 

outside is less than 14 hours, flowering of these field transplants will 

occur on significantly longer stems than on seedlings grown under natural SD 

in the greenhouse. 

Spacing: Space plants as close as 4 × 4" (10 × 10 cm), or approximately 9 

plants/ft 2 (156 plants/m 2 ), or up to 1' (30 cm) apart, depending on cultivar and 

weed control practices. A spacing of 6 × 6" (15 × 15 cm), approximately 4 plants/ 

ft 2 (44 plants/m 2 ), is typical. 

Shading: China asters stretch appreciably if grown under shade cloth (Post 

1955). This may be useful in the South where shading is used to reduce heat in 

the field. Use of shade cloth also inhibits the entry of leafhoppers. Cloth for 

exclusion of hoppers should have approximately 22 threads per inch. 

Support: Horizontal plastic mesh or other such support structures should be 

used to prevent damage from wind or rain. 

Yield: Work at the University of Maryland (Healy and Aker 1989) showed 

yields of approximately 3 flowers per plant when only the main stems were harvested 

(all lateral shoots included with the main stem) and relatively short stem 

length, less than 20" (50 cm) long, with many cultivars of China asters. At the 

University of Kentucky, yields of approximately 3 stems/ft 2 (32 stems/m 2 ) were 

recorded with a spacing of 4 plants/ft 2 (43 plants/m 2 ). Stems averaged approximately 

18" (45 cm) long (Utami et al. 1990). Although yields are significantly 

better in coastal California, stems of Matsumoto series were only 12–18" (30–45 

cm) long. When all flowers were harvested separately (laterals and main stem) at 

Georgia, 22 stems/plant with an average stem length of 15" (38 cm) occurred 

during a 3-week period in the summer. For best-quality flowers, disbud lateral 

stems and remove some of the lower branches. 


China asters may be grown year-round, but prices are traditionally higher in fall 

and winter. Seed sown 1 August and grown under LD (nightbreak incandescent 

lights) until flowering results in flowers in late November at 42° latitude. Plant 

on 4" (high light) to 8" (low light) centers (10–20 cm). On a year-round program, 

Ken Goldsberry of Colorado State University found that at least 5 crops 

(unpinched) per square foot of bench could be realized under Colorado conditions. 

He grew single-stem plants in cell packs under LD, then moved them to 6" 

(15 cm) pots (3 plants/pot) containing pea gravel when the foliage covered the 

entire cell pack. Continuous feed and carbon dioxide were applied. China asters 

are highly sensitive to nightbreak lighting or light drift, and less than 1 fc is 

effective in stimulating stem elongation; therefore, spotlights or floodlights can 

effectively light large areas of the greenhouse. 

Daylength control is particularly important in southern Florida and southern 

Texas, where temperatures are always sufficiently warm for growth, but win-


ter daylengths are usually too short to promote stem elongation. Regardless of 

where asters are grown, LD can be applied by daylength extension (to 14 hours) 

or nightbreak lighting of at least 4 hours (e.g., 10 p.m. to 2 a.m.). 

As in the field, take steps to reduce aphid entry (to reduce aster yellows) in the 

greenhouse. Use cloths over vents and as entries through doorways. 

Temperature: See “Environmental Factors.” Temperatures above 80F (27C) 

should be avoided in the greenhouse. 

Scheduling: In Colorado, where night temperatures were 60–62F (15–17C) and 

days were 70F (21C), asters flowered approximately 4 months from sowing. 

There was a progressive increase in flowering lateral stems as planting date was 

delayed from December to March (Goldsberry et al. 1988). At night temperatures 

of 50F (10C), approximately 5 months are necessary in the fall and winter 

from seed to flower; 4 months are required in spring and summer. At warmer 

temperatures, crop time may be slightly reduced, although 14 weeks appears to 

be as fast as plants can develop (Utami et al. 1990). 

Carbon dioxide: Use of CO2 in English studies showed that 600–900 ppm CO2 

resulted in approximately one week less time on the bench and an increase in 

stem weight (Cockshull and Hughes 1969). Similar results using 1000 ppm CO2 

continuously resulted in the formation of flower buds 5 days earlier than control 

(Reekie et al. 1994). 


Harvest the terminal stem when outside ray florets begin to open. Achieving a 

minimum stem length is important. In the greenhouse, aim to produce a minimum 

stem length of 20–24" (50–60 cm); the bouquet market needs at least 20" 

(50 cm) to use in the mixes. 

Bunch size and packaging: Bunch size differs depending on where plants were 

produced. A “grower’s bunch,” which may be anything from 10 to 13 stems, is 

common in Florida. Growers in California use both “grower’s bunch” size and 

10-stem bunches. Ten-stem bunches are the norm in Holland, Ecuador, and 

Colombia. Most Dutch growers in California use 10 stems. When orders for 

mixed colors are filled, asters are usually sold in assorted color boxes with the 

mix consisting of ⅓ pink, ⅓ red, ⅓ blue. 

Postharvest 

Fresh: Vase life is 5–7 days, and generally the foliage wilts before the flower 

declines. Most growers strip the foliage ½ to ⅔ up the stem, since it turns black 

or yellow so rapidly. 

Neck droop may also occur, resulting in shortened vase life. A 10-second pulse 

in 1000 ppm solution of silver nitrate significantly extended the vase life (Evans 

and Reid 1990). Asters treated with silver nitrate may be stored up to a week at 

33–35F (1–2C). Few growers use silver nitrate because of potential problems, 

and caution must be used when working with it. 1-MCP and other ethyleneinhibiting 

products from postharvest manufacturers are more desirable. Flowers 

do not ship well, and some reduction of vase life can be expected if they are.


Dried: Harvest when flowers are fully open. Allow leaves to remain on stems 

and hang in small bunches upside down to dry. Flowers may also be dried in a 

desiccant such as silica gel. 

Cultivars 

Many cultivars are available from American and European seed companies (one 

Dutch catalogue alone offers more than 120 different cultivars suitable for cut 

flowers). The bicolor varieties have had excellent market acceptance and bring 

strong prices, while yellow and white are often poorly received (white because it 

shows damage, apricot and yellow because they are perceived as “faded” in the 

market). 

American Beauty Mix produces 3" (8 cm) wide, double flowers on 2–3' (60–90 

cm) stems in many colors. 

‘Amour Blue’ has double, 3–4" (8–10 cm) rich purple-blue blooms on a plant 

2½–3' (75–90 cm) tall. 

Andrella Super Mix produces single daisy-like blooms, 2½–4" (6–10 cm) 

across, in shades of light and dark pink and purple. Plants grow 3–3½' (0.9–1.1 

m) tall. 

Astoria series consists of 5 colors and a mix of upright single-flowered asters. 

Flowers are 2–3" (5–8 cm) in width; stems are 24–30" (60–75 cm). 

Ball Florist Mix is an old favorite consisting of 3" (8 cm) wide flowers of white, 

pink, blue, rose, and purple. 

‘Bouquet Powderpuffs’ has 2–2½" (5–6 cm) wide, fully double flowers with no 

yellow center. Plants grow 2–2½' (60–75 cm) tall. Separate colors are available, 

including azure, blue, rose, purple, scarlet, and white. 

Compliment series has been popular for many years. Flower size is 4" (10 

cm); stem length is about 30" (75 cm). Available in 6 colors and a mix. 

‘Crego’ bears a many-colored mixture of feathery, 3" (8 cm) wide flowers on 2' 

(60 cm) tall plants. 

Crestia series has flowers 2½–3" (6–8 cm) wide on plants 2–3' (60–90 cm) tall. 

The flower is a combination: quill petals in the center, ray petals on the outside. 

Daylight series consists of purple, red, rose, violet, and white. 

Duchesse series is late to flower and bears peony-like ball-shaped 3–4" (8–10 

cm) wide flowers on 24–30" (60–75 cm) stems. Available in 6 single colors, 2 

bicolors, and 2 mixes. 

Early Dawn Choice Mixed (Early Wonder) is a double-flowered series, with 

3½" (8 cm) flowers atop 18" (24 cm) stems. 

Emperor series bears 2½" (6 cm) wide flowers on 2–3' (60–90 cm) stems. ‘Emperor 

Carmine’ and ‘Emperor Red’ have carmine and deep red flowers, respectively. 

Fan series grows about 2' (60 cm) tall and bear semi-double flowers with a 

yellow center. Nine colors and a mix are available. Said to be less susceptible to 

fusarium wilt. 

Florett Strain is available in separate colors, including deep and pale pink, 

crimson, blue, and a pastel “champagne” color. The 2–3" (5–8 cm) wide flowers 

consist of fully double quill forms and are produced on 3' (90 cm) stems.


Gala series bears 3–4" (8–10 cm) double flowers on 30–36" (75–90 cm) upright 

stems. Eight colors and a mix. Four of the colors received a Fleuroselect 

Quality Mark in Europe. 

Giant Rainbow series includes ‘Crimson’, with deep crimson petals offset by 

a conspicuous yellow center, and ‘Dark Blue’, a deep violet-blue with contrasting 

golden-yellow center. Other colors are salmon, blue, pink, lilac, rose, scarlet, 

white, and a formula mix. 

Giant Ray series bears quilled double 5–5½" (12–14 cm) flowers. Good 

branching habit, about 2' (60 cm) tall. Six colors and a mix. 

Kamo series has 30" (75 cm) upright stems, with short-petaled single flowers. 

Kurenai Strain is an upright bouquet type with 1½–2" (4–5 cm) flowers. Colors 

range from cherry to dark pink to red, with ‘Peppermint Kiss’ thrown in for 

good measure. 

Matador series is similar to Matsumoto, but flowers are slightly smaller. 

Plants bear strong 2–3' (60–90 cm) stems with basal branching. Probably better 

for greenhouse than field production. Nine colors and a mix. 

Matsumoto series produces sprays of 2–2½" (5–6 cm) wide flowers with distinct 

yellow centers and has become one of the leading series of asters for cut 

flower production. Mixtures and separate colors are available. Plants have good 

resistance to fusarium wilt. 

Meteor series has large 3–4" (8–10 cm) flowers on thick stems that are up to 

28" (70 cm) long. Recommended as a greenhouse crop. Colors include carminered, 

rose-pink, purple, yellow, and a mix. 

Miss series has shown good uniformity and some tolerance to aster yellows. 

‘Miss Europe’ (medium pink), ‘Miss Nippon’ (pale pink), and ‘Miss Mexico’ 

(dark blue/lavender) have fully double 3–4" (5–8 cm) wide blooms on 28" (70 

cm) tall plants. Sometimes sold as Irresistible Mix. 

Perfection mixture produces 2–3' (60–90 cm) tall plants and 3–4" (5–8 cm) 

wide, fully double flowers with incurved petals. 

Pommax series provides 3" (8 cm) wide double flowers on upright 2–3' (60– 

90 cm) stems. Nine separate colors and a mix. Recommended for greenhouse 

culture. 

Pompon series is only about 2' (60 cm) tall but useful for a short stem program. 

Ten separate colors and a mix. 

Princess series has a well-branched habit with quilled dome-shaped double 

flowers bearing a light-colored center. Stem length is about 28" (70 cm). Late 

summer and fall flowering, available in 11 colors and 2 mixes. 

Prinette series has long, thin, curved outer petals and small, tubular center 

flowers. Flowers are available in pink and red. Plants were Fleuroselect winners. 

‘Queen of Market’ grows to 20" (50 cm) in height with medium-sized round 

flowers. Available in a mix. 

Rainbow mixes may be ordered as single- or double-flowered forms. Flowers 

generally have a prominent yellow eye and are borne on 2–3' (60–90 cm) stems. 

Serenade series is an early bloomer, with semi-double flowers and spray-type 

habit, good for filler flowers. Colors include blue, carmine, rose, rose-tipped 

white, and scarlet. ‘Serenade Light Blue’ provided excellent yield and stem length


in trials around the country and was nominated for the ASCFG’s 2001 Fresh 

Cut Flower of the Year. The entire series received high marks in the trials and was 

noted for its “rich colors and uniform growth” (Dole 2001). 

Serene series bears pompon spray flowers on 2' (60 cm) stems. Plants flower 

approximately 14 weeks after sowing. Light blue, red, and rose colors are available. 

‘Sparkler’ has double incurved flowers on 2–3' (60–90 cm) stems. Flowers are 

mainly available as a mixture. 

Standy series is touted as “the most wilt-tolerant aster with tolerance against 

Fusarium and Verticillium.” The double 3–4" (8–10 cm) wide flowers occur on 

stems approximately 30" (75 cm) tall. Nine colors and a mix. 

Starlight series produces large spider-type blooms. Colors are blue, purple, 

rose, and scarlet. 

Super Princess series is 3–3½' (0.9–1.1 m) tall with quilled petals. The “super” 

designation refers to its larger flowers and stronger stems (compared to Princess). 

Numerous cultivars in separate colors include ‘Alice’ (light blue), ‘Hilda’ 

(light yellow), ‘Scarletto’ (copper-scarlet), and ‘Victoria’ (scarlet). 

Waka series is 2–2½' (60–75 cm) tall and bears unique single 2½–3" (6–8 cm) 

wide flowers with narrow petals in scarlet or pink around a small and unobtrusive 

central disk. 


Asters have been evaluated since the inception of the ASCFG’s national trials in 

1994. The following table (Dole 1995–2002) is a summary of the average stem 

lengths and yields of asters submitted for trialing. These data are averages over 

a wide geographical range and must be viewed as guidelines only; individual 

experience may differ significantly. 

Year of Stem Stems/ 

Cultivar trial length (in) z plant 

Compliment Light Blue 1994 13 3 

Compliment Salmon Pink 1994 17 6 

Compliment White 1994 15 2 

Daylight Purple 2001 16 2 

Daylight Red 2001 12 1 

Daylight Rose 2001 15 1 

Daylight Violet 2001 19 1 

Daylight White 2001 13 1 

Gala Mix 2001 19 3 

Giant Princess Mix 2000 17 4 

Matador Mix 1994 15 2 

Matsumoto Blue/White 1995 18 4 

Matsumoto Formula Mix 1996 16 4 

Matsumoto Pink/White 1995 19 6 

Matsumoto Lavender 1995 22 5 

Meteor Carmine Red 1998 21 6

Meteor Mix 2000 14 5 

Meteor Rose 2000 17 7 

Meteor Rose Pink 2000 15 6 

Meteor Violet Blue 1998 22 6 

Serenade Blue 1998 21 8 

Serenade Blue/White 2000 17 6 

Serenade Carmine 2000 16 5 

Serenade Light Blue 2000 17 11 

Serenade Red 1998 18 5 

Serenade Rose 2000 15 6 

Serenade Rose/White 2000 17 8 

Serenade Scarlet 2000 16 12 

Serenade White 1998 18 5 




Aster yellows: This disease is caused by an unusual microbe called a phytoplasm. 

Yellowing of all or part of the plant; distorted, malformed flowers (flowers 

partly or entirely greenish and yellow); and spindly stems are indications of 

aster yellows infection. Affected plants may also exhibit considerably increased 

branching. Leafhoppers pick up the phytoplasm from weeds, and then transmit 

it to the aster. The best means of control is to reduce or eliminate the population 

of leafhoppers. Scout your area for leafhopper migrations, and, if at all 

possible, plant asters only after leafhoppers have moved through your area. Once 

plants have been infected, they must be discarded. If plants are infected early, the 

leaves turn yellow while the veins retain their green color. The use of soil sterilants 

reduces the incidence of the phytoplasm in the soil, but crop rotation 

should be routinely practiced. 

Aster wilt: Plants suddenly wilt, usually near maturity, when attacked by the 

aster wilt fungus (Fusarium conglutinans var. callistephi). The stem rots completely 

at the soil line, and often a streak of blackened tissue extends up one side. The 

wilt fungus may be carried on the seed, which should be surface sterilized. The 

advent of wilt-resistant cultivars has greatly reduced the severity of this problem. 

Verticillium wilt is similar to fusarium wilt. 

Aster spotted wilt: This disease causes streaks on the stems or circular patches 

on the foliage. Infected plants may exhibit increased branching and should be 

discarded. The wilt organism is spread by thrips, the presence of which must be 

controlled. 

Root rot and rust: Phytophthora cryptogea and Coleosporium solidaginis result in loss 

of yield and flower quality, respectively. 

Leafhoppers, leafminers, thrips, aphids, and Japanese beetles cause significant 

damage and reduce the value of the crop. They may also be responsible for 

the spread of disease. Reflective mulches are presently being trialed in Ventura 

County, California, and they appear to reduce the populations of leafminers,


whiteflies, and aphids. Thrips can wipe out greenhouse crops in the blink of 

an eye. 

Caution: Asters are highly susceptible to some pesticides. Test spray a few 

plants to determine phytotoxicity. 


“I did a big aster trial this year (52 varieties/colors) and took every precaution. 

Still we had yellows, probably due to the row cover blowing off one day. [With 

such] susceptibility, asters are a bit of a pain to grow, but their unmatched 

beauty and long vase life seem to outweigh the problems.” Ginny Kristl, Johnny’s 

Selected Seeds, Albion, Maine. 


Perennial asters such as Aster ericoides (September aster), A. novae-angliae (New 

England aster) and A. novi-belgii (New York aster) are popular cut flowers. Their 

culture is covered in the section on Aster. 

Reading 

Biebel, J. 1936. Temperature, photoperiod, flowering and morphology in Cosmos 

and China aster. Proc. Amer. Soc. Hort. Sci. 34:635–643. 

Cockshull, K. E. 1985. Callistephus chinensis. In The Handbook of Flowering. Vol. 2. 


Cockshull, K. E., and A. P. Hughes. 1969. Growth and dry-weight distribution 

in Callistephus chinensis as influenced by lighting treatment. Ann. Bot. 33:367– 

379. 

Dole, J. 1995–2002. ASCFG National Cut Flower Trials. The Cut Flower Quarterly. 

———. 2001. 2000 ASCFG National Cut Flower Seed Trials. The Cut Flower 

Quarterly 13(1):1–10, 12–19. 

Doorenbos, J. 1959. Responses of China aster to daylength and gibberellic acid. 

Euphytica 8:69–75. 

Evans, R. Y., and M. S. Reid. 1990. Postharvest care of specialty cut flowers. In 

Proc. 3rd Natl. Conf. on Specialty Cut Flowers. Ventura, Calif. 

Goldsberry, K. L., L. Kell-Gunderson, and R. Silver. 1988. Scheduling single stem 

Japanese cut asters: winter and spring responses of Japanese cut asters. Part 1. 

Colorado State Univ. Research Bul. 462. 

———. 1989. Scheduling single stem Japanese cut asters: winter and spring 

responses of Japanese cut asters. Part 2. Colorado State Univ. Research Bul. 463. 

Healy, W., and S. Aker. 1989. Cut flower field studies, 1989. Univ. of Maryland 

Hort. Production Co-op Ext. Serv. HE 141-89. 


Netherlands. 

Post, K. 1955. Florist Crop Production and Marketing. Orange Judd, New York. 

Reekie, J. Y., P. R. Hicklenton, and E. G. Reekie. 1994. Effects of elevated CO2 on

CAMPANULA 161 

time to flowering in four short-day and four long-day species. Can. J. Bot. 

72(4):533–538. 

Smith, G. 2001. Personal communication. 




Many thanks to Bob Anderson, Ken Goldsberry, and Will Healy (first edition) 

and Ginny Kristl, Gay Smith, and Rudolf Sterkel (second edition) for reviewing 

this section. 

Campanula bellflower Campanulaceae 

perennial, Zones 3–6 Europe blue 2–3'/3' (60–90 cm/90 cm) 

Only a few of the many bellflowers in the marketplace are useful as cut flowers. 

Probably the most popular are the peach-leaf bellflower (Campanula persicifolia), 

clustered bellflower (C. glomerata), Canterbury bells (C. medium), and chimney 

bellflower (C. pyramidalis), and the various hybrids that have recently appeared on 

the scene. All are more popular in European markets than in American markets. 

Flower color for all species is typically purple to blue, but cultivars in white and 

lavender are also available. 

Propagation 

Seed: Seed is small in all species and should be lightly covered with fine sand 

or a thin blanket of vermiculite. Germinate at 60–65F (15–18C) under sweat 

tents or intermittent mist. Seedlings emerge in 14–21 days. Approximately 1/56 

to 1/28 oz (0.5–1.0 g) of seed yields 1000 seedlings, depending on species (Kieft 

1996). 

Division: Divide crowns in spring or after flowering. 

Growing-on 

If planted in seed flats, seedlings should be transplanted to 3–4" (8–10 cm) pots 

or packs when the second set of true leaves emerge. If sown in plugs, sow in large 

containers (288s or less). Grow at 55–60F (13–15C) until 3–4 leaves emerge, then 

place in a cold frame or unheated greenhouse for a minimum of 6 weeks. Plant 

to the field in the fall. 


Little information is available for cut flower species, but literature concerning 

flowering of Campanula carpatica (Whitman et al. 1998, Armitage and Garner 

1999), C. fragilis (Zimmer 1985a), and C. isophylla (Moe and Heide 1985) provides 

some useful guidelines to flowering control.

162 CAMPANULA 

Temperature: All perennial campanulas benefit from a cold treatment, usually 

supplied by natural winter cold. In recent research, storage of crowns for 12 

weeks at 40F (4C) was necessary to induce flowering in Campanula persicifolia; 

cold was not necessary to break dormancy (i.e., leaves were formed) but was 

needed to induce flowering (Iversen and Weiler 1989). In C. pyramidalis, only 6 

weeks at 43F (6C) were necessary for 80% of the stems to be vernalized (Zimmer 

1985b). In C. carpatica, cold is not necessary and does little to enhance flowering 

or appearance, but it is not detrimental either (Whitman et al. 1998, Armitage 

and Garner 1999). In work with Canterbury bells (C. medium), the longer seedlings 

were exposed to 40F (4C), the higher the flowering percentage once placed 

outdoors; also, the best percentages occurred when older plants were cooled 

compared to young plants (Kim et al. 1997). In general, a cold period of 10–12 

weeks at 40F (4C) or below is recommended for most cut flower species (Bartels 

1990). 

Photoperiod: Campanula persicifolia appears to be day neutral, and, once the cold 

treatment has been satisfied, produces flowers under long or short days (Iversen 

and Weiler 1989). In other species, however, long days are necessary for flowering 

after vernalization (Wallensiek 1985, Zimmer 1985a, 1985b). Work with C. 

carpatica showed that a daylength of 15–17 hours results in the greatest flowering, 

but some cultivars may respond with critical LD of 13–14 hours. Short days 

should be avoided with with C. carpatica because plants may become devernalized 

(i.e., lose the beneficial effects of cold treatment). 

Gibberellic acid: GA does not appear to substitute for either the LD or low temperature 

requirement of Campanula. 


Location: Sufficient natural cold is not available in Zones 7b–11. Peach-leaf 

bellflower does far better in areas of cool summer nights. It performs best on 

the West Coast and north of Zone 7; production in Zone 7 and warmer results in 

tall, spindly stems whose quality cannot compete with stems grown further 

north or from Europe. 

Longevity: Plants are long-lived; production continues for at least 3 years. 

Divide ⅓ of the crop every year. 

Spacing: Space plants 12 × 12" (30 × 30 cm) or as little as 9 × 12" (23 × 30 cm). 

Subirrigation is necessary for close spacing. Provide support netting for straight 

stems. 

Forcing: After enough cooling has been provided (see “Environmental Factors”), 

portable polyethylene frames may be used to raise temperatures for earlier 

flowering. Work in Holland showed that moveable tunnels used in the winter 

greatly accelerated flowering, resulting in Campanula persicifolia and C. medium 

flowering under the tunnels before the uncovered plants had budded (Wiel 

1989). This method can lengthen the harvest time, with little monetary input.

Greenhouse Performance (Campanula persicifolia) 

CAMPANULA 163 

Cool crowns for 12 weeks at 40F (4C). The evergreen rosettes are subject to fungal 

diseases during cooling; using 20–50 fc of incandescent lights for at least 8 

hours and applying fungicides during the cold treatment alleviates the problem. 

Precooled crowns may be planted in 1 gallon (4 l) pots or in ground beds in 

January at a spacing of 10" (25 cm) apart, 6" (15 cm) between rows. Long days 

(>16 hours) are not necessary but may be applied after cold treatments are completed 

to produce taller plants (Iversen and Weiler 1989). If greenhouse temperatures 

are maintained at approximately 60F (15C), flowering occurs about 8 

weeks later. If temperatures are 50–55F (10–13C), an additional 1–2 weeks are 

required. Provide constant fertilization with 75–100 ppm N of a complete fertilizer. 

Support is necessary for stems of the best quality. Warm temperatures 

and high nitrogen levels result in tall, spindly plants. 

Greenhouse Performance (Campanula medium) 

With the advent of faster-flowering forms, greenhouse flowering is accelerated. 

Champion series is grown from seed and, since cold is not required, will flower 

first year from seed. For single-stem production (best for greenhouse production), 

plant 4–6" (10–15 cm) apart; for multiple stems (best for outdoors or cold 

frame), place 10–12" (25–30 cm) apart and expect 8–10 stems/plant. Plants 

should be lit in the winter after 8–10 leaves have emerged with mum lighting 

from 10 p.m. to 2 a.m. for 6–7 weeks. Approximately 5 months is required from 

seed to flower at 55–60F (13–15C) (Gillum 2000). 


Harvest when 1 or 2 flowers of the inflorescence are open. The best stage of harvest 

for Campanula persicifolia is when the flower buds are colored and considerably 

swollen (Vaughan 1988); for Champion series, when 2 or 3 buds are open 

(Gillum 2000). 

Postharvest 

Fresh: Most species are susceptible to ethylene. Stems persist 8 days in water 

and 16 days in Carnation Chrysal, a flower preservative (Blomme and Dambre 

1981). Flowers open from bottom to top. Leaves tend to deteriorate before flowers. 

For Champion series, stems can be stored at 36F (2C) for up to 3 weeks, but 

7–10 days is more realistic. The best vase life occurs with 2–6% sucrose solutions; 

warm water hydration is detrimental (Gillum 2000). 


Cultivars (Campanula persicifolia) 

‘Alba’ has white flowers and may be seed-propagated. 

‘Grandiflora’ has large, deep blue flowers.

164 CAMPANULA 

‘Moerheimii’ bears double, white flowers. 

‘Telham Beauty’, a popular cultivar, produces some of the largest flowers in 

the species. 


Campanula glomerata (clustered bellflower) produces clusters of bell-shaped, 

violet-blue flowers atop 1–2' (30–60 cm) stems. Approximately 1/64 to 1/128 

oz (0.4–0.2 g) of seed yields 1000 seedlings (Kieft 1996). Cold is also required for 

flowering. Spacing of 12 × 12" (30 × 30 cm) is sufficient. Vase life is approximately 

9 days in water. ‘Acaulis’ has pale blue flowers. ‘Alba’ produces white flowers. 

‘Joan Elliott’ (purple) is a dwarf, vegetatively propagated cultivar that is more 

suited to the garden than the vase. ‘Superba’, with large, blue flowers, is among 

the best cultivars for cut flowers. 

Campanula medium (Canterbury bells) has been grown for many years, and 

new hybrid cultivars, such as the Champion series, have rejuvenated interest. 

Plants take a long time to flower from seed; some estimates suggest that flowering 

may require up to a year from seed (Song et al. 1998). Available in a fine range 

of colors including lavender. Highly recommended by cut flower growers. 

Campanula pyramidalis (chimney bellflower) grows to 5' (1.5 m) tall and is an 

excellent cut flower. The bell-shaped flowers are clustered together in a pyramidal 

inflorescence. The species is a lavender-blue but a white form, var. alba, is 

also available. Approximately 1/128 oz (221 mg) of seed yields 1000 seedlings 

(Kieft 1996). Seed germinates in 3 weeks at 65–70F (18–21C). Plants forced in the 

field or greenhouse need 11 weeks of cold at 40–45F (4–7C) followed by 15-hour 

days (Zimmer 1985a). 


Aphids should be controlled to reduce problems of sooty mold. 

Botrytis and leaf spot can be problems in areas of high summer rains. 

Crown rot (Pellicularia rolfsii) results in rotting of the crown. It develops under 

moist soil conditions and warm temperatures. A grayish white discoloration of 

the base of the stems (Sclerotinia sclerotiorum) also occurs, causing plants to decay 

and fall over. 

Sclerotinia rot results in white mold followed by large dark spots on the 

foliage. The disease usually occurs in humid greenhouses with little air circulation. 

Similar results occur in dense plantings in the field under rainy weather. 

Rust (Coleosporium campanulae) can be a serious problem on the underside of 

Campanula persicifolia. The foliage is covered with orange or reddish brown pustules. 

Leaves dehydrate, and plants are stunted. Other rust-causing organisms 

are Puccinia campanulae and Aecidium campanulastri. 

Spider mites are worse on plants that are highly fertilized.


CAMPANULA 165 

“We have grown ‘Champion Blue’ for the last 2 years. Plants transplanted to the 

field in February grew to about 28–30" in height and started blooming around 

early April. We found that it was necessary to cut the flowers when they were 

just opening, as even some partially open flowers did not transport very well. 

With respect to postharvest, we placed new cuts in Floralife and found vase life 

to be approximately 8–10 days. Our Campanula is used for mixed bouquet production.” 

Van Weldon, Wood Duck Farm, Cleveland, Tex. 

“I grow Campanula persicifolia and have florist customers who love them. I get 

$7 for a 10-stem bunch. They have an excellent vase life: 10 days to 2 weeks. I 

use support net; it’s not as critical as with some crops, but it will assure nice 

long, straight stems.” Jennifer Judson-Harms, Cricket Park Gardens, New 

Hampton, Iowa. 

“I have been selling Campanula persicifolia for 6 years at $7 a bunch to my florists. 

I treat them as annuals because they don’t grow as tall the second year on. 

I replant plugs every year.” Jim Link, Sandgate Flower Farm, Sandgate, Vt. 

Reading 

Armitage, A. M., and J. M. Garner. 1999. Photoperiod and cooling duration influence 

growth and flowering of six herbaceous perennials. J. Hort. Sci. & Tech. 

74(2):170–174. 

Bartels, G. 1990. Bartels Cultural Guide. Bartels Stek, Aalsmeer, The Netherlands. 

Blomme, R., and P. Dambre. 1981. (The use of outdoor flowers for cutting) Het 

gebruik van bloemen in openlucht als snijbloem. Verbondsnieuws voor de Belgische 

Sierteelt 25(15):681–685. 

Gillum, R. 2000. Champion campanula. GrowerTalks 64 (6), supplement: 15. 

Iversen, R., and T. Weiler. 1989. Forcing the issue: a guide to forcing garden perennials 

into bloom for flower show exhibitions. American Nurseryman 169(8): 

95–103. 


Netherlands. 

Kim, W. S., K. Y. Hyh, D. M. Park, and J. S. Lee. 1997. Effect of cold storage 

according to the seedling age on flowering of Campanula medium ‘White’ for 

cut flowers. J. Korean Soc. Hort. Sci. 38(5):533–536. 

Moe, R., and O. M. Heide. 1985. Campanula isophylla. In The Handbook of Flowering. 

Vol. 2. A. H. Halevy, ed. CRC Press, Boca Raton, Fla. 

Song, J. S., B. R. Ryu, R. S. Roh, K. Y. Huh, W. S. Kim, C. S. Bang, and B. H. Kim. 

1998. Flowering time of Campanula medium ‘White’, ‘Pink’, and ‘Purple’ as 

influenced by sowing dates and the vase life of cut flowers by harvest time. J. 

Korean Soc. Hort. Sci. 39(2):189–192. 


Ore. 

Wallensiek, S. J. 1985. Campanula medium. In The Handbook of Flowering. Vol. 2. 

A. H. Halevy, ed. CRC Press, Boca Raton, Fla.

166 CARTHAMUS TINCTORIUS 

Wiel, A. van de. 1989. Use of moveable tunnels for cultivation of Campanula. Vakblad 

voor de Bloemisterij 44(7):62–63. 

Whitman, C. M., R. D. Heins, A. C. Cameron, and W. H. Carlson. 1998. Lamp 

type and irradiance level for daylength extensions influence flowering of Campanula 

carpatica ‘Blue Clips’, Coreopsis grandiflora ‘Early Sunrise’, and Coreopsis 

verticillata ‘Moonbeam’. J. Amer. Soc. Hor. Sci. 123(5):802–807. 

Zimmer, K. 1985a. Campanula fragilis. In The Handbook of Flowering. Vol. 2. A. H. 


———. 1985b. Campanula pyramidalis. In The Handbook of Flowering. Vol. 2. A. H. 


Many thanks to Leonard Perry (first edition) and Van Weldon (second edition) 

for reviewing this section. 

Carthamus tinctorius safflower Asteraceae 

annual Europe, Asia orange-red 2–3'/2' (60–90 cm/60 cm) 

Safflower has been grown in dry areas of Asia, Africa, and Europe for centuries, 

for the oil and meal derived from the seeds, and the dye from the flowers. Safflower 

oil is used in diets for hypertension and heart disease; the meal is fed to 

livestock; the dye is used in various varnishes and paints. Most published research 

deals with these economic uses (Veeranna and Rudraradhya 1980, Yazdi- 

Samadi and Zafar-Ali 1980). Compared to this long agronomic history, the use 

of safflower for cut flowers is but a blip in time. 

Obviously, given all the many safflowers sold over the years, designers and 

consumers have discerned subtle beauty in each bloom. Beauty is definitely in 

the eye of the beholder: flowers always seem to appear ragged and bedraggled 

and in need of tidying up. Not only that, but many of the older cultivars have 

short spines. And since flowers may be dried, we can be assailed with subtle safflower 

all year long. 

Propagation 

Sow seed and cover lightly to permit exposure to light. If placed under mist at 

68–72F (20–23C), seed germinates in 10–14 days. Seed are large; approximately 

3 oz (84 g) of seed are needed for 1000 transplantable plants (Nau 1999). Seed 

may be direct sown into the field or bench at the rate of 0.9 oz per 100' (100 g per 

100 m) (Kieft 1996). 

Growing-on 

Plants should be grown at 65F (18C) night temperature to establish seedlings. 

Little nutrition is needed at this stage, but fertilization with 50–75 ppm N is 

beneficial. Plants are ready to transplant to final location in 8–10 weeks. Direct 

sow seed in early spring, as soon as ground is workable.


CARTHAMUS TINCTORIUS 167 

Carthamus tinctorius 

No studies on safflower’s responses to the environment could be located. The 

plants do not appear to have significant photoperiodic responses. 


Spacing: If transplanting, space on 6–12" (15–30 cm) centers. 

Shading: In northern areas, grow in full sun. In the South, locate plants in an 

area of some afternoon shade, or provide approximately 30% shade.

168 CARTHAMUS TINCTORIUS 


Plants resulting from seed sown in January can be harvested in early spring (12– 

16 weeks later). Space transplants as close as 6 × 6" (15 × 15 cm) or as far as 10 × 

10" (25 × 25 cm). Fertilize with 100–150 ppm N once or twice a week with a 

nitrate source. Support may be necessary, particularly if a high-density planting 

is used. 


Cut stems when the majority of buds have begun to open and color is clearly 

visible. If harvested before onset of color, most buds do not open. 

Postharvest 

Fresh: Flowers persist about one week in water, but the foliage declines more 

rapidly. With its short vase life and somewhat thorny feel, foliage is often 

removed at harvest or grading. Plants do not store well, but if storage is necessary, 

they may be placed in water or preservative at 35–40F (2–4C). 

Dried: Flowers may be air-dried. 

Cultivars 

‘Early Round Leaved’ has rounded leaves and bears 1" (2.5 cm) wide orange or 

white flowers on 3–4' (0.9–1.2 m) stems. 

‘Goldtuft’ bears fuzzy golden-orange balls on 2–3' (60–90 cm) stems. One of 

the most popular cultivars for cutting. 

‘Grenada Orange’ reaches 32–40" (80–100 cm) in height and is supposedly 

uniform in germination and harvest time. 

‘Lasting Orange’, ‘Lasting Tangerine’, and ‘Lasting White’ are spineless (a 

definite advantage) and grow 2–3' (60–90 cm) tall. 

‘Orange Ball’ is similar to ‘Lasting Orange’ and also spineless. ‘White Ball’ 

and ‘Yellow Ball’ are also available. 

‘Orange Grenade’ is thornless and not very different from ‘Lasting Orange’ or 

‘Orange Ball’. ‘Yellow Grenade’ is almost thornless and can grow 2–2½' (60–75 

cm) tall. Plants produced 7 stems/plant with 19" (48 cm) stems (Dole 1995). In 

national trials (Dole 1997), plants of ‘Grenade Mix’ averaged 5 stems/plant with 

a stem length of 12" (30 cm). 

‘Shiro’ has cream-white flowers that deepen to light yellow as the flowers age. 

‘Superior Orange’ averaged 4 stems/plant with a stem length of 23" (58 cm) 

(Dole 1999). 

‘Tall Splendid Orange’ bears orange-yellow flowers on 3' (90 cm) stems. 

‘Zanzibar’ is a well-branched upright variety, with smaller flowers on 4–5' 

(1.2–1.5 m) stems.


Root rots can be a problem in warm climates and poorly drained soils. Aphids 

are a serious pest. 

Reading 



Netherlands. 


Veeranna, V. S., and M. Rudraradhya. 1980. 45 cm is the most advantageous 

spacing for safflower. Current Research 9(7):111–113. 

Yazdi-Samadi, B., and M. Zafar-Ali. 1980. Planting dates, plant densities, soil 

cultivation practices and irrigation regime as factors in non-irrigated safflower 

production. Indian J. Agr. Research 14(2):65–72. 

Many thanks to Dale Lovejoy for reviewing this section. 

Caryopteris ×clandonensis blue beard Verbenaceae 

perennial, Zones 5–9 China, Japan blue 2–4'/3' (0.6–1.2 m/0.9 m) 

Caryopteris ×clandonensis is much better known than the annual C. incana. Plants 

are hybrids between C. incana and C. mongolica and are actually woody shrubs, 

winter hardy to Zone 5. Flowers range from lavender to dark blue, and numerous 

cultivars are available. The flowers are not as long-stemmed or as full or whorled 

as those of C. incana, but growers have embraced this crop in recent years. This 

perennial has terrific potential. 

Propagation 

Propagation is always vegetative, usually from tip cuttings. Two to 3" (5–8 cm) 

cuttings of vegetative shoots may be taken during the summer. Application of 

low-strength rooting hormones (IBA, NAA) and Hormodin #1 (1000 ppm IBA 

in talc) is beneficial. Roots appear in 7–10 days if bottom heat is applied. Plants 

are also available as plugs from perennial plant nurseries. 

Growing-on 

See Caryopteris incana. 


See Caryopteris incana. 

CARYOPTERIS ×CLANDONENSIS 169

170 CARYOPTERIS ×CLANDONENSIS 


Although they are technically woody shrubs, they may be cut to the ground as 

soon as spring temperatures warm up. Wait until the sap is beginning to move; 

cutting to the ground in winter can result in severe plant damage. 

Space 15" (38 cm) apart, with 18–24" (45–60 cm) between rows. They may 

grow across each other, but that should not be a problem. 


Harvest when buds show color or when the first (lowermost) whorl of flowers is 

open. Do not allow more than ⅓ of the flowers to open prior to harvesting. Shelf 

life is similar to Caryopteris incana. 

Postharvest 

A vase life of approximately 10 days is possible; 11 days with STS for ‘Blue Mist’ 

was shown by Gast (1997). 

Cultivars 

‘Arthur Simmonds’ consists of dull green 1–2" (2.5–5 cm) long leaves and 

dark blue flowers on plants 2' (60 cm) tall. 

‘Azure’ has light blue flowers on a 2½' (75 cm) tall shrub. 

‘Blue Mist’ has gray-green foliage and light blue flowers. 

‘Dark Knight’ bears the darkest blue flowers of any cultivar. Popular as a cut 

form and in national field trials, plants averaged 16 stems/plant, with a stem 

length of 28" (70 cm) the second year of production (Dole 2000). 

‘First Choice’ has dark green foliage and wonderful dark blue flowers. 

‘Heavenly Blue’ has dark green leaves and deep blue flowers. Seed propagation 

of this cultivar has resulted in much variation, making it more difficult to distinguish. 

‘Blue Mist’ and ‘Dark Knight’ may have resulted as sports of ‘Heavenly 

Blue’. 

‘Kew Blue’ resulted from a seedling of ‘Arthur Simmonds’ and was raised in 

Kew Gardens. Flowers are a darker blue than ‘Arthur Simmonds’. 

‘Longwood Blue’ was selected at Longwood Gardens, Kennett Square, Pa. 

Plants have silvery foliage, bear sky-blue flowers in late summer, and grow 1½–2' 

(45–60 cm) tall. 

‘Worcester Gold’ is easy to distinguish. Grown mainly for its yellow-gold 

foliage, which contrasts with the average blue flowers. The foliage fades in climates 

with hot summers but looks wonderful in the spring and early summer. 


“It’s really popular, easy to sell, and very prolific. More importantly, it has excellent 

market appreciation [and] ease of cultivation. . . . The market appreciation 

for the darker blue [cultivars] is higher.” Bob Wollam, Wollam Gardens, Jeffersonton, 

Va.

CARYOPTERIS INCANA 171 

Caryopteris incana blue spirea Verbenaceae 

annual China, Japan blue 2–4'/3' (0.6–1.2 m/0.9 m) 

Plants remain little known, and although we still believe they are quite useful, 

the market will decide. Plants produce many stems of whorled, lavender-blue 

flowers and dark green foliage. Flowers are produced in late summer and fall 

and make fine cut flowers both in the field and the greenhouse. These may still 

be listed (incorrectly) as Caryopteris ×bungei. Caryopteris incana is used in traditional 

Chinese medicine to treat coughs, colds, and rheumatic pains; researchers 

aim to find the active components (Gao and Han 1997). 

Caryopteris incana

172 CARYOPTERIS INCANA 

Propagation 

Seed: Seed sown at 70–75F (21–24C) under high humidity or intermittent 

mist germinates in approximately 12 days. Transplanting seedlings is most 

common, but seed may also be direct sown. Approximately 0.03 oz (0.9 g) of 

seed yields 1000 plants (Nau 1999). 

Cuttings: Two to 3" (5–8 cm) cuttings of vegetative shoots may be taken during 

the summer. Application of low-strength rooting hormones (IBA, NAA) and 

Hormodin #1 (1000 ppm IBA in talc) is beneficial. Roots appear in 7–10 days 

if bottom heat is applied. 

Growing-on 

Grow seedlings in low-density plugs, cell packs, or 3" (8 cm) pots. Fertilize with 

50–75 ppm N using calcium nitrate for the first 2–3 weeks followed by 100–150 

ppm N of a complete fertilizer. If produced in plugs, allow 5–7 weeks before 

planting out. 


Photoperiod: Work at the University of Georgia showed that Caryopteris flowers 

under all photoperiods; however, plants flowered faster under short days (8 

hours) than long days (16 hours). Plants were intermediate in their flowering 

response when grown in 12-hour photoperiods, as the following table shows. 

The effect of photoperiod on flowering and stem length of 

greenhouse-grown Caryopteris incana. 

Photoperiod (hours) Days to flower z Stem length (in) y 

8 72 12.9 

12 92 16.6 

16 >100> *15.3* 

z = time from beginning of photoperiod treatment 


* = measurement taken on 100th day; stem had not flowered 

Although the experiment was terminated after 100 days, plants eventually flowered 

even under long days. 

Light intensity: In areas of hot summers and high light intensities, flower stems 

are longer and less brittle when grown under approximately 55% shade compared 

to full sun (Armitage and Son 1992). Flowers also have a longer vase life 

when provided with some shade (see table at “Stage of Harvest”). 

Temperature: Plants grow rapidly under temperatures of 70–85F (21–29C). 

Temperatures below 55F (13C) and above 85F (29C) reduce growth and flowering.


CARYOPTERIS INCANA 173 

Plants yield high numbers of flower stems, but as with many other annuals, subsequent 

plantings provide high-quality flowers for a longer period of time. Two to 

3 successive plantings, approximately 4 weeks apart, have been quite successful. 

Yield: On a single planting scheme, crops grown at the University of Georgia 

trials produced approximately 48 marketable stems/plant with an average stem 

length of 25.8" (65.5 cm). Plants were grown at 12 × 12" (30 × 30 cm) spacing and 

in both shade and sun. 

Shading: In warm, bright summer climates, such as Zones 7–10, the addition 

of 50–60% shade results in longer, less-brittle flower stems, although no differences 

in yield occur regardless of shade or sun. At Georgia, both shaded and sun 

plants yielded approximately 50 stems/plant, but stem lengths were 23" (58 cm) 

and 19" (48 cm), respectively. In the field, it is doubtful that return on investment 

of shade structures would be strong enough to warrant their use. Shade is 

not necessary anywhere, and certainly not in areas of cooler summer temperatures. 

The slight increase in stem length is not sufficient to overcome the potential 

for weaker stem strength. In the Deep South, however, shade may be useful. 

Lateral breaks: For growers planting a single season-long crop, the method of 

harvest can be a puzzle. Like many other crops, the main stem produces many 

lateral stems, all of which produce a flower. The dilemma for the cutter is 

whether to cut the long main stem and sacrifice the laterals, or cut a shorter 

main stem to allow some of the laterals to flower for subsequent harvest. The former 

method yields longer but fewer stems; the latter results in many more but 

shorter stems. The decision must be based on acceptability of certain standards 

for stem length and is determined by the market. The following table provides an 

example of the differences between harvesting techniques. If planting successive 

crops, this discussion is moot, as only the terminals are taken before plants 

are removed. 

The effect of harvesting methods on Caryopteris incana. Single 

planting of 40 plants used for each treatment. 

No. of Stem 

Harvesting method stems z length (in) y 

1. Whole stem cut from base 40 30.8 

2. Short terminal cut only, then one 40 16.5 

harvest of subsequent laterals 261 22.5 

z = from one harvest only (over 1000 lateral stems were harvested from 

test plants over the season) 


More labor and time are necessary to harvest by method 2, and market price 

must dictate its feasibility. In general, more full stems (method 1) are harvested

174 CARYOPTERIS INCANA 

in the “real world” for this and other crops that produce many lateral branches. 

It is simply a matter of labor. 


Little work has been attempted with this crop in the greenhouse, but preliminary 

results indicate that plantlets, plugs, or cuttings should be spaced 9–12" (23–30 

cm) apart in well-drained soils. Plants should be grown under long days (>16 

hours) until they are 2–2½' (60–75 cm) tall, then transferred to short days (


Root rot fungi (Pythium, etc.) can be a problem, but no diseases or pests are 

unique to Caryopteris. 


CELOSIA ARGENTEA 175 

“We grew Caryopteris incana . . . with mixed results. On the one hand, it is very prolific 

and easy to grow, and it blooms in late season when customers are clamoring 

for something new. It was great in bouquets but wasn’t a big seller on its 

own. Florists were lukewarm about it, and by the time they got used to using it, 

the bloom time was over. I would consider growing it again, but it is so prolific 

we don’t need a whole 100' bed of it next time.” Tammy Ford, Perennial Favorites, 

Leopold, Ind. 

“Although I still grow [Caryopteris incana] and sell it to the florists, it has limited 

appeal, and therefore I do not grow very much (only one 80' bed out of 4 

acres). . . . One point that I always found interesting about growing this plant is 

that some small percentage (maybe 5%) are pink rather than blue, and I have 

periodically seen a few with white whorls.” Bob Wollam, Wollam Gardens, Jeffersonton, 

Va. 

Reading 

Armitage, A. M., and K. C. Son, 1992. Shade and photoperiod influence Caryopteris 

incana used as cut flowers. HortScience 27(12):1275–1276. 

Dole, J. 2000. 1999 ASCFG National Seed Trials. The Cut Flower Quarterly 12(1): 

1–19. 

Gao, JianJun, and GuiQui Han. 1997. Cytotoxic abietane diterpenoids from 

Caryopteris incana. Phytochemistry 44(4):759–761. 

Gast, K. L. B. 1997. 1997 evaluation of postharvest life of perennial fresh-cut 

flowers. Kansas State Univ. Agr. Exp. Sta. and Coop. Ext. Serv. Report 805. 


Many thanks to Mindy Storm (first edition), for her help in preparing the material 

for this crop, and to Bob Wollam (second edition) for reviewing this section. 

Celosia argentea cockscomb Amaranthaceae 

annual hybrid origin many colors 2–3'/2' (60–90 cm/60 cm) 

Celosia has longed been recognized for its stunning flowers; the name comes 

from the Greek keleous (“burning”), an allusion to their brilliance. While everyone 

knows what a celosia is, taxonomists, horticulturists, and growers alike have 

been confused as to how to group the various forms of celosia. All ornamental 

forms are Celosia argentea var. cristata, which itself encompasses 4 groups. The 

most recognizable is the Cristata Group (common cockscomb), whose distorted

176 CELOSIA ARGENTEA 

flower heads make one stare in fascination or in stunned silence. Students 

remember them more easily when they’re referred to as colored brains. The second 

most common form is the Plumosa Group (prince of Wales feather), with 

feathery (plumose) spike flowers; they provide a more civilized look and are available 

in a variety of heights and flower colors. The Spicata Group (wheat celosia) 

consists of plants that are generally about 3' (90 cm) tall with long feathery flowers; 

the silvery rose flowers, borne in slender spires, have become a major flower 

in the fresh market. Sometimes marketed as flamingo flower, plants are excellent 

fresh but dry poorly. The Childsii Group is not common in horticultural circles 

but is characterized by globose heads of flowers; short in stature, they’re only 

occasionally used as cut flowers. 

Celosia argentea 

‘Kurume New Scarlet’ 

Propagation 

Seed count varies with the form, from 34,000 to 39,000 seeds/oz (1200 to 1400 

seeds/g). There is a good deal of variability in seed size and germination, even 

within the various groups. Approximately 0.03 to 0.06 oz (0.9–2 g) of seed yields 

1000 seedlings (Nau 1999). Sow seed lightly, and place at 72–80F (22–27C) 

under mist. Seed has an absolute requirement for light, although light intensity 

can be very low (Sanjay and Amritphale 1996). Germination should occur in 

2–3 days; if you don’t see seedlings by 10 days, throw seed out. Direct seeding in 

the field is not recommended for first planting; it should be done only when 

temperatures are above 70F (21C). Best accomplished for subsequent plantings.

With the Spicata Group, seeds are occasionally direct sown; 0.13 oz per 100' 

(15 g per 100 m) is recommended (Kieft 1996). 

Growing-on 


Grow seedlings at 62–68F (17–20C) night temperatures and long days (>12 

hours). Long days occur in spring, and sowing in early winter—especially if greenhouse 

temperatures are low—may result in premature flowering. If this is a problem, 

hanging incandescent lights will help. Do not allow seedlings to dry out. 

Fertilize with 100–150 ppm N once or twice a week. Plants may be transplanted 

to the bench or field 4–6 weeks after sowing; however, do not allow plants to 

become root bound. Celosias do not recover well from stress, and stressing the 

roots results in poor-quality plants. 


Photoperiod: Celosia is a quantitative short day plant, meaning that although it 

will flower at any photoperiod, it flowers faster under photoperiods of 14 hours 

or less (Armitage 1985, Porat et al. 1995). Four to 5 weeks of short days are necessary 

for most rapid flowering. After 4 weeks, plants may be placed in long days 

with no detrimental effects of rate or quality of flowering. 

Some growers have noted fasciation (deformity in the flowers, and the broadening 

and flattening of the flower stem at the base of the flower) in Celosia, particularly 

the cockscomb forms. Long days appear to have an influence on fasciation. 

In one study, 69% of the plants subjected to photoperiods 16 hours or 

longer produced fasciated stems, whereas only 3% of plants grown at 8-hour 

photoperiods developed fasciated stems. Those grown under 12-hour conditions 

were intermediate in their response (Driss-Ecole 1977, 1978). Genetics also 

plays a role, and since little can be done to change long days in the field, stay 

away from cultivars highly sensitive to fasciation (unless you like the effect). 

Unfortunately, such data are not known. 

Temperature: Temperature plays a significant role in flowering. Once plants 

are established, warm temperatures result in faster flowering than cool temperatures 

(Porat et al. 1995). Temperatures below 50F (10C) result in a significant 

delay of flowering compared with 80F (27C). 


Successive plantings are recommended for crops of the highest quality. Plant 

transplants in the field as soon as the threat of frost has passed, then plant additional 

crops 3–4 weeks apart. 

Spacing: Plants may be transplanted to a 6 × 6" (15 × 15 cm) spacing if grown 

as a single-harvest, single-stem crop. This results in the longest stem lengths, 

but plants must be planted sequentially for full-season harvesting. Plants may 

also be grown on 12" (30 cm) centers, 8 × 12" (20 × 30 cm), or as far as 18" (45 

cm) apart if plants are to be harvested continuously (single planting only).


Harvesting: Flowers are harvested from early July through late September in 

most of the United States. The highest percentage of long stems are harvested 

early in the season. 

Yield: Yield is cultivar-dependent. The yield and average stem length for several 

cultivars follow; only ‘Tall Rose Chief’ was unsatisfactory in these trials, conducted 

in Georgia. Plants were on 1' (30 cm) centers; data indicate multiple harvests 

on a single planting. 

Yield and stem length of Celosia Chief series (Cristata Group). 

Cultivar Stems/plant Stems/ft 2z Stem length (in) y 

Carmine Chief 20 14 18.9 

Fire Chief 14 11 16.7 

Gold Chief 17 12 22.6 

Tall Rose Chief 5 3 14.4 


y= multiply (in) by 2.54 to obtain (cm) 

At the University of Kentucky (Utami et al. 1990), an average of 4.5 stems/ft 2 

(48 stems/m 2 ) were harvested 8–9 weeks after transplanting when ‘Red Chief’, 

‘Gold Chief’, and ‘Fire Chief’ were grown as a single-stem crop. In the same work, 

production for the whole season averaged 12 stems/ft 2 (129 stems/m 2 ) from 

crops planted 6" (15 cm) apart. Over 60% of the stems were 18" (45 cm) or 

longer. 


Space plants 8 × 8" (20 × 20 cm) or on 12" (30 cm) centers. Use of support netting 

is desirable. Initially, place plants under 2–3 weeks of long days (>16 hours) 

and then grow under short days (






‘Red Chief’ 

(%) 

N P K Ca Mg 

3.9 

(ppm) 

0.43 5.06 2.86 1.36 

Fe Mn B Al Zn 

189 261 23 96 182 


Flowers should be fully developed on crested forms and 90–100% developed in 

the plumose form. 

Postharvest 


Fresh: Flowers of the crested form persist significantly longer than the plumose 

form. The foliage on both declines rapidly and should be removed as it 

wilts. A minimum of 7 days may be expected for flowers of Celosia. Research conducted 

in Pennsylvania suggested that flowers of ‘Red Rocket’ (a crested form) 

persisted 16 days in tap water and 23 days in distilled water. If 1% or 3% Florever, 

a floral preservative, was used, flowers persisted for approximately 

the same time; if a 0.5% solution was used, they had a vase life of only 9 days 

(Holcomb et al. 1998). If necessary, flowers may be stored for a few days at 

36–41F (2–5C). 

Dried: Flowers may be air-dried. Strip foliage and hang upside down in small 

bunches. The crested form is more popular for dried use than the plumose form. 

Some growers are doing a good job with Spicata Group cultivars, despite the 

fact that wheat celosias tends to shatter when dried. Roberts et al. (1998) 

designed a drying chamber for celosia in which hot air is passed around the 

hanging flowers and is either exhausted, partially exhausted, or recirculated, 

controlled by a humidistat. They calculated that over 36,000 bunches of 3- to 10stem 

units were dried at a cost of $0.03 per bunch for both fuel and electricity 

and that waste was reduced from 10% to 0.25%.


Cultivars 

Childsii Group (globose forms) 

The few cultivars in this group are usually listed as plumosa forms. 

Sparkler series bears strong flower stems in many colors. Space closely together 

for single-stem cut flowers. Carmine, cream, orange, red, yellow, and mixtures 

are available. 

Cristata Group (crested forms) 

Bombay series is suitable for greenhouse production, with rapid crop times 

reported. The flowers are flat, triangular combs atop 24–40" (60–100 cm) stems. 

‘Bombay Purple’ and ‘Bombay Yellow Gold’ are Fleuroselect Quality Mark winners. 

Dark red, velvet, and salmon are also available. 

Chief series gained great popularity in the 1990s and was the ASCFG’s 2002 

Dried Cut Flower of the Year. Flowers are available in red, scarlet, cherry, yellow, 

gold, and a mix. The red and scarlet strains are more vigorous than other colors. 

‘Chief Gold’ is known for its tall multiple stems; ‘Chief Persimmon’ has an excellent 

orange-salmon color and is useful for late summer and fall cropping. Plants 

grow 2–3' (60–90 cm) tall. Netting is beneficial but not necessary. 

‘Cramers’ Rose Shades’ and ‘Cramers’ Burgundy’ were highly ranked by most 

growers in the 1997 ASCFG cut flower trials. These should be pinched for longer 

stem length. Dense direct sowing can also result in tall single-stem plants. 

‘Fireglow’ is suitable for fresh or dried production, with large, deep red crests. 

Stems are 20–24" (50–60 cm). 

Kurume Strain is 2–3' (60–90 cm) tall and available in separate colors and a 

mix. ‘Kurume Red Orange’ is short but is popular for fall sales. Plants with scarlet 

flowers are available with either bronzed or green foliage. ‘Kurume New Scarlet’ 

was well liked by trialers in 2000 outdoor trials. 

‘Madras Scarlet’ bears many flowers, with the laterals and primaries forming 

almost simultaneously. Color is an intense red scarlet. 

‘Prestige Scarlet’ has green-bronze foliage and 24" (60 cm) stems. 

‘Red Velvet’ bears some of the largest flower heads we have seen. The deep 

crimson heads are at least 10" (25 cm) across on 2–3' (60–90 cm) stems. This 

could be a lethal weapon in the wrong hands. Flowers are excellent for drying. 

‘Super Crest’ was given this singular description: “true giant size cockscomb 

head but also can boast of a tall, rigid stem.” The longer the plants go uncut, 

the larger the comb size. 

Temple Belles series is about 3' (90 cm) tall, with combs 6–8" (15–20 cm) 

wide. ‘Temple Belles New Scarlet’, ‘Temple Belles Dark Rose’, and a mix are 

offered. Ann Trimble from Princeton, Ky., is pleased with the performance of 

‘Temple Belles’ and says that if a broader range of colors becomes available, they 

may replace the Chief series on her farm. 

‘Toreador Red’ carries large crimson combs on 18–20" (45–50 cm) stems.

Plumosa Group (plumose forms) 


‘Apricot Brandy’ has large plumes of apricot flowers and performs well in 

most areas of the country. Plants were developed for use as bedding plants, but 

the 1.5–2' (45–60 cm) stem length may be sufficiently long for most cut flower 

operations. 

Century is a basal-branching series with 18–24" (45–60 cm) stems and 8–12" 

(20–30 cm) flower plumes. ‘Century Red’ is outstanding. 

‘Forest Fire’ bears dense, scarlet plumes atop 2½' (75 cm) stems. ‘Forest Fire 

Improved’ has a longer flowering time and larger plumes than ‘Forest Fire’. 

Pampas Plume Mix is approximately 3' (90 cm) tall. Available in shades of 

yellow and red and gold. Better as a fresh product than a dried. 

‘Red Fox’ has 2' (60 cm) stems with brilliant carmine plumes. 

‘Toreador’ bears bright red flowers on 2' (60 cm) tall plants. 

Spicata Group (spired forms) 

Because of shattering, drying is not recommended, although stems are seen in 

the dried market. 

‘Amazon’, also from Cramers’ Posie Patch, performed well in ASCFG seed trials 

in 1997. Trialers noted less shattering than other varieties and “millions of 

blooms.” Pinching is recommended. Beautiful plants! 

‘Enterprise Dark Pink’ has a bright pink central plume surrounded by smaller 

plumes, forming a 6–8" (15–20 cm) spike. Recommended for greenhouse production 

as well as for field production in warm climates. ‘Enterprise White’ bears 

a central inflorescence of white flowers, surrounded by lateral flowers. 

‘Flamingo Feather’ (‘Pink Tassles’) has light pink flowers, which sometimes 

fade to white under high heat. In its introduction, plants grew 3–3½' (0.9–1.1 m) 

tall and received some of the highest ratings in trials held across the United 

States in 1992. 

‘Flamingo Purple’ (‘Purple Tassles’) is slightly bushier and produces dark 

foliage and flowers. However, plants don’t flower until late summer. Reseeds 

with gusto. 

‘Hi-Z’ is another introduction from Ralph Cramer of Elizabethtown, Pa. In 

the 2000 ASCFG trials, evaluators found it easy to grow and “everyone liked it.” 

‘Startrek Rose Pink’ did well in 2000 outdoor trials, providing excellent color 

on 15" (38 cm) stems. 


Celosias have been evaluated since the inception of the ASCFG’s national trials 

in 1994. The following table (Dole 1995–2001) is a summary of the average stem 

lengths and yields of celosias submitted for trialing. These data are averages over 


experience may differ significantly.


Year of Stem Stems/ 

Cultivar trial length (in) z plant 

Bombay Purple 1996 16 4 

Chief Mix 1994 18 7 

Cramers’ Amazon 1997 24 39 

Cramers’ Burgundy 1997 15 7 

Cramers’ Rose Shades 1997 17 9 

Enterprise Wine Red 2000 17 8 

Hi-Z 2000 25 12 

Kurume New Scarlet 2000 20 6 

Pink Candle 1994 17 12 

Sparkler Carmine 1994 13 7 

Sparkler Cream 1994 11 7 

Sparkler Formula Mix 1995 13 12 

Sparkler Orange 1994 13 9 

Sparkler Red 1994 13 6 

Sparkler Wine 1995 20 13 

Sparkler Yellow 1994 13 7 

Startrek Rose Pink 2000 16 7 

Super Crest Burgundy 2000 30 2 

Super Crest Mix 2000 26 3 

Temple Belles Dark Rose 2000 17 7 



Botrytis occurs on the flower head in the field during warm, humid conditions 

or after considerable rainfall. This is particularly true of the crested forms, whose 

flowers are so tightly produced that water is trapped within the inflorescence. 

Leaf spots (Cercospora, Phyllosticta, Alternaria) on the foliage occur more readily 

during wet seasons. General-purpose fungicides are useful in their control. 


“We harvest ‘Amazon’ celosia as soon as 10 stems make an acceptable bunch. 

Wait longer for drying, but don’t let it go beige.” Ralph Cramer, Cramers’ Posie 

Patch, Elizabethtown, Pa. 

“We really love celosias, so we are growing a lot of varieties. My favorite is ‘Hi- 

Z’—we have been cutting on the first planting for a while, although we have been 

replanting every couple of weeks. I took several samples of various things to a florist; 

she called back for ‘Hi-Z’—she wanted to substitute it for heather.” Lynette 

Lowrance, Broken Gate Farms, Bay City, Tex. 

“In western Kentucky, ‘Chief Gold’ is the strongest-growing celosia. Gold is

CENTAUREA 183 

capable of producing multiple stems of tremendous size at the same time.” Ann 

Trimble, Trimble Field Flowers, Princeton, Ky. 

Reading 

Armitage, A. M. 1985. Celosia. In The Handbook of Flowering. Vol. 5. A. H. Halevy, 

ed. CRC Press, Boca Raton, Fla. 


Driss-Ecole, D. 1977. Influence de la photoperiode sur de comportement du 

meristeme caulinaire du Celosia cristata. Can. J. Bot. 55:1488–1500. 

———. 1978. Influence de la photoperiode sur la fasciation et la phase reproductrice 

du Celosia cristata (Amarantaceae). Can. J. Bot. 56:166–169. 

Holcomb, E. J., W. Raffensberger, and R. Berghage. 1998. Postharvest treatments 

for Celosia. Penn Flow. Grower Bul. 450:3. 


Netherlands. 


Papenhagen, A. 1990. Yield and flower quality of Celosia ‘Togo’. Deutscher Gartenbau 

44(6):348, 374 

Porat, R., E. Shlomo, and A. H. Halevy. 1995. Horticultural techniques to improve 

Celosia plumosa growth for cut flowers. Sci. Hortic. 63:209–214. 

Roberts, W. J., R. Greenberg, and S. Kania. 1998. Design of a chamber for drying 

hanging flowers. In Proc. Northeast Agr. and Bio. Eng. Conf. Halifax, Nova Scotia. 

Sanjay, D and D. Amritphale. 1996. Very low fluence and low fluence response in 

the induction and inhibition of seed germination in Celosia argentea. Seed Science 

Research 6(2):43–48. 




Many thanks to Bob Anderson (first edition) and Ralph Cramer and Ann Trimble 


Centaurea cornflower Asteraceae 


Centaurea consists of many species with fine cut flower characteristics. Centaurea 

was named for centaurs, the half-man, half-horse creatures of Greek mythology, 

and sometimes we think a similar mixup occurs with the crop itself. The 

genus combines a mixed bag of annual and perennial species. Annuals include 

Centaurea americana (American basket flower), C. cyanus (bachelor’s buttons), 

and C. moschata (sweet sultan) (the scientific name for this last species is now 

Amberboa moschata, but it will be a good number of years before we stop thinking 

of it as a centaurea, so for now, that is where we will leave it). The perennials C.

184 CENTAUREA AMERICANA, C. CYANUS, C. MOSCHATA 

macrocephala (golden basket flower) and C. montana (mountain bluet) are also 

suitable for cut flowers. 

In the eastern half of the country, Centaurea cyanus has escaped to clothe the 

roadsides in a mantle of blue and grows more aggressively than other annuals in 

the genus. In the Northwest, northern California, and the Northeast, few production 

problems with any species should be encountered. 

All species have small, brown to black bracts at the base of the flower bud, a 

handsome characteristic that further enhances the cut flower possibilities. 

Centaurea americana, C. cyanus, C. moschata Asteraceae 

annual Europe many colors 2–4'/2' (0.6–1.2 m/0.6 m) 

Propagation 

Greenhouse: Sow in seed flats or directly to the cutting bench (for greenhouse 

production). Optimum germination occurs at 60–65F (15–18C) and when seed 

is covered by ¼ to ½" (6–13 mm) of medium. Seedlings emerge in 7–14 days 

under proper germination conditions. 

Direct sowing: Seed may be sown directly in early spring, but germination is 

delayed until temperatures rise. Seed should be covered lightly. Germination 

occurs in approximately 10 days at 65–75F (18–21C). The various species should 

be sown at the rates given in the following table (Kieft 1996, Nau 1999). 

Direct sown Transplants 

Species oz (g)/100' oz (g)/1000 plants 

Centaurea americana 0.5 (15.3) 1.0 (28.4) 

Centaurea cyanus 0.3 (9.2) 0.5 (14.2) 

Centaurea moschata 0.4 (12.2) 0.5 (14.2) 

In Florida and California, seed sown in the open field in fall flowers from February 

to June. Seed direct sown in early spring in the Midwest and Southeast 

results in flowering from June to September. 

Growing-on 

Although most seed is direct sown, many growers transplant seedlings to the 

field. Transplant seedlings to small containers or place plugs in field when danger 

of frost has passed. 

Plants respond best to short days followed by long days. Planting in early 

spring generally provides such conditions, but if plants are started in July or 

August, the lack of natural short days results in short plants, rapid flowering, 

and low yield. If possible, apply SD for 4–6 weeks prior to putting them in the 

field.


CENTAUREA AMERICANA, C. CYANUS, C. MOSCHATA 185 

Most of the research on Centaurea has been with Centaurea cyanus. It is likely, 

however, that similar results occur with C. americana and C. moschata. 

Photoperiod: Centaurea is a long day plant (Laurie and Poesch 1932). Long days 

are needed for flower induction, but, once induced, flowering continues even 

under short day conditions, although the rate of flower development is delayed. 

Approximately 3 weeks of LD are necessary (Kadman-Zahavi and Yahel 1985). 

Plants flower equally well if provided with nightbreak lighting (30 minutes of 

light in the middle of the night) or if the daylength is extended to provide a 15hour 

day. Since plants are sensitive to LD even in the seedling stage, it is important 

that they should be provided with SD at the start of production to permit 

basal branching and a larger plant. Plants grown entirely in LD elongate rapidly, 

produce few flowers, and can die (Post 1955). 

Temperature: Vernalization does not appear to have a significant effect on 

flowering; however, the literature is somewhat contradictory on this point. One 

study showed that exposing the seedlings to 10 days of temperatures at 38–50F 

(3–10C) resulted in a slight acceleration of flowering under LD, but not SD, conditions 

(Listowski and Jasmanowicz 1973). 

Gibberellic acid: GA sprays greatly increase stem elongation but have no effect 

on flowering, regardless of daylength (Kadman-Zahavi and Yahel 1985). Use 

caution when applying GA; it can cause flower distortion. 


Centaurea cyanus may be produced throughout the country; its flowers are harvested 

from June to September in the northern tier of states, as early as mid May 

in the Southeast, and in the winter and spring in California and Florida. The 

summers are too hot and winters too cold for successful year-round production 

of C. americana and C. moschata in Zones 7 and 8. 

Spacing: Space seedlings on 6–9" (15–23 cm) centers. 

Yield: Centaurea americana, grown in single-planted, multiple-harvested field 

trials in full sun at the University of Georgia, produced 11–15 stems/plant with 

an average stem length of 37.8" (94.5 cm). Stem diameter was approximately ¼" 

(6 mm). 

Centaurea cyanus produces about 5–12 flowers with an average stem length of 

15" (38 cm). Stems are strong and make excellent cut flowers. 

Centaurea moschata, also grown at the University of Georgia in full sun (single 

planting, multiple harvests), produced 5–8 stems/plant with an average stem 

length of 18" (45 cm); the cultivar tested was ‘The Bride’. Stem length was unsatisfactory 

under Georgia conditions, suggesting that field production in areas of 

hot, humid summers is likely uneconomical. Work done in India showed that 

flower and seed yields were highly suppressed by deficiencies in nitrogen and 

phosphorus (Pal and Jana 1997); side dressing with a complete fertilizer in spring 

will alleviate any problems. 

Shading: Cornflowers do best in full sun, even in hot areas of the country. With 

Centaurea cyanus, experiments showed that plants with the greatest southern

186 CENTAUREA AMERICANA, C. CYANUS, C. MOSCHATA 

exposure produced significantly more flowers than plants in rows with a more 

northerly exposure. Mutual shading results in reduced flowering (Yahel et al. 

1972). 

Work at the University of Georgia with Centaurea americana (see following 

table) also showed reduced flowering and little difference in stem length when 

plants were shaded. 

The effect of shade on yield and stem length of Centaurea 

americana. 

Shade level (%) Stems/plant Stem length (in) z 

0 13.1 38.3 

55 7.3 54.0 

68 3.0 47.1 


In more recent field trials of ‘Jolly Joker’ (Dole 1999), growers reported stem 

lengths averaging 24.9" (62.3 cm), with 6.5 stems per plant. Plants performed 

well under drought conditions, but some lygus bug damage was reported. 


Plants should be grown for 8–12 weeks under SD (winter) conditions or until 

plants are large enough to support flower development. Maintain temperatures 

of 50–55F (10–13C). Plants should be fertilized with 100–150 ppm N; do not 

overfertilize, as plants may become too leafy and lax. 

After SD, provide 15- to 16-hour LD either by extending the daylength or by 

giving a nightbreak for at least 30 minutes. Many growers use 4 hours of nightbreak 

(11 p.m. to 2 a.m.) with 10–15 fc of incandescent lighting. The following 

table (Post 1942) shows the effect of temperature and LD provided from October 

to March; plants were started in August. 

The effect of temperature and night lighting on Centaurea cyanus. 

Temperature Photoperiod Flowers/stem 

50F (10C) LD z 36.2 

50F (10C) SD 10.4 

55F (13C) LD 67.8 

55F (13C) SD 9.6 

60F (15C) LD 77.8 

60F (15C) SD 34.0 

z = all LD provided after 8–10 weeks of SD

The lowest temperature for best flowering is 55F (13C), and the use of long days 

is essential. 

Scheduling: For mid March flowering of Centaurea cyanus, sow seed in mid September. 

For May flowering, sow in early January. Other species may require more 

time in the greenhouse. If long stem length is not important, Bob Anderson’s 

work describing the fast production of short-stemmed crops, including C. 

cyanus, may be of interest. Seedlings were transferred to 4" (10 cm) pots at a spacing 

of 9 plants/ft 2 (100 plants/m 2 ) and placed under 24-hour HID lighting of 

100 µmolm −2 s- 1 . Ninety percent of the flowers were harvested 14–21 days later. 

Stem length was 14–20" (36–50 cm). The system also utilized ebb and flow 

watering and recirculated nutrient solution (Anderson 1990). 

For Centaurea moschata, research in Romania showed that yields in the greenhouse 

were greatest for early sowing or transplanting (11–15 February) compared 

to later propagation dates. Up to 29 stems/ft 2 (310 stems/m 2 ) occurred in 

this work, and time to flower for transplanted seedlings was approximately 15 

weeks (Selaru and Drǎghici 1989). 


All cornflowers should be harvested when flowers are ¼ to ½ open. In the case of 

multiple flowered stems (i.e., sprays), the uppermost flower may be ¾ open. 

Postharvest 

Fresh: Flowers persist 6–10 days. They may be stored at 35–41F (2–5C) for 2–3 

days, but long-term storage is not recommended. 

Dried: Flowers may be air-dried. The fully double forms are best for drying. 

Retain foliage and hang upside down in a warm, dark area. 

Cultivars 

CENTAUREA AMERICANA, C. CYANUS, C. MOSCHATA 187 

Centaurea americana (American basket flower) 

‘Aloha’ has 3" (8 cm) wide, lilac-rose flowers on 3–4' (0.9–1.2 m) stems. A 

white form, ‘Aloha Blanca’, is also available. 

‘Jolly Joker’ bears 3" (8 cm) wide, lavender flowers on 4' (1.2 m) stems. A popular 

cultivar—some customers appreciate the handsome buds more than the 

handsome flowers. 

‘Rose’ and ‘White’ are also listed. 

Centaurea cyanus (bachelor’s buttons) 

Single-flowered: 

‘Emperor William’ is 2–3' (60–90 cm) tall with marine-blue flowers. 

Double-flowered: 

Boy series is approximately 3' (90 cm) tall and most popular for cut flowers. 

‘Blue Boy’ bears light blue flowers, ‘Black Boy’ has blackish maroon blossoms, 

and ‘Red Boy’ produces carmine-red flowers.

188 CENTAUREA MACROCEPHALA 

Florence series is well-branched, with 18–20" (45–50 cm) plants. Colors are 

blue, lavender, pink, red, violet, white, and a mix. Plants are shorter than the Boy 

series. 

Frostie Mix (‘Frosted Queen’) bears flowers of various colors with petals 

fringed with white. Plants grow to about 30" (75 cm) in height. 

‘Jubilee Gem’ has sky-blue flowers but is only about 16" (40 cm) tall. 

‘Pinkie’ has bright pink flowers. 

‘Snowman’ has creamy white flowers. 

Centaurea moschata (sweet sultan) 

‘Antique Lace’ grows approximately 2' (60 cm) tall and bears flowers in pastel 

shades of pink, lilac, and lavender. 

Imperialis Mix offers lavender, lilac, pink, purple, rose, yellow, and white flowers 

on 2–2½' (60–75 cm) stems. 

‘Lucida’ has dark red flowers. 

var. suaveolens, whose correct name is var. flava, is often listed as a separate 

species (Centaurea suaveolens). With canary-yellow flowers and stems approximately 

2' (60 cm) tall. 

‘The Bride’ is a 18–24" (45–60 cm) tall plant with fragrant, clean white flowers. 


Aster yellows, spread by leafhoppers, causes one side of the plant to become yellow 

and flowers to become greenish. Eradicate infected plants and rotate crops. 

Botrytis results in desiccation of the tips of some stems and flower buds. 

Additional air circulation is necessary. 

Downy mildew (Bremia lactucae) results in pale green to red, irregular spots on 

the upper side of the foliage and soft, moldy growth beneath. Infected plant 

parts generally collapse and die. Young plants are particularly susceptible. 

Remove and destroy infected leaves. Control with wider spacing, better aeration, 

and appropriate spray solutions. 

Stem rots caused by Phytophthora, Sclerotinia, and Pellicularia result in significant 

losses, particularly in cold, waterlogged soils. Use clean soils and sterilized 

containers. 

Aphids and leafhoppers are the worst insect pests of most species of cornflower. 

Centaurea macrocephala golden basket flower Asteraceae 

perennial, Zones 2–6 Caucasus yellow 3–4'/3' (0.9–1.2 m/0.9 m) 

Golden basket flower, a large-leafed plant, produces abundant large, bright yellow 

flowers that are particularly useful dried. Common in European markets, 

they find their way to this country mainly as imports. Centaurea macrocephala is 

a well-known garden plant, and cut flowers have been enjoyed by the home gardener 

for many years.

Propagation 

Centaurea macrocephala 

CENTAUREA MACROCEPHALA 189 

Seed: Germinate under high humidity and 68–72F (20–22C) soil temperature. 

Research has indicated 86% germination in 5–10 days under the above conditions 

(Pinnell et al. 1985). Most plants are transplanted to the field, and about 2 

oz (56 g) of seed yield 1000 seedlings (Nau 1999). Although transplants are generally 

more successful, some growers direct sow; a volume of 0.7 oz (20 g) of seed 

per 100' (30.5 m) is recommended (Kieft 1996). 

Division: Plants may be divided in spring or fall. 

Growing-on 

Seedlings and small divisions should be transplanted to large cell packs or 4" (10 

cm) pots as soon as they can be handled. Grow at 50–65F (10–15C); avoid temperatures 

above 75F (24C). Fertilize with 100–150 ppm N from a complete fertilizer; 

do not exceed 200 ppm N.

190 CENTAUREA MACROCEPHALA 


Temperature: The need for cold in the perennial species of Centaurea is not 

well established. For Centaurea macrocephala, cold is likely beneficial if not absolutely 

necessary. 

Photoperiod: Most Centaurea species appear to be LD plants and flower more 

rapidly under daylengths of 14 hours or more; golden basket flower is likely 

similar. 


Location: Plants are more productive and flowers are of a superior quality 

when grown in areas of cool nights and bright days. Field production is best 

north of Zone 7. Research results at the University of Georgia, which sees excessive 

summer temperatures and humidity, have been disappointing. 

Longevity: Plants are long-lived perennials. Once established, 3–5 years of production 

is possible. Production of crops planted from seedlings or small divisions 

in the fall will be negligible the first season; production peaks in the second 

to third year from planting. 

Spacing: Plants are large and require sufficient space to reduce insect and disease 

pressure. Space plants 18–24" (45–60 cm) apart. 


Harvest when flowers are ½ to ¾ open. Place in warm water immediately. 

Postharvest 

Fresh: Flowers may be harvested when the yellow portion is almost entirely 

emerged. Flowers persist about one week in a preservative solution. The foliage, 

however, does not persist as long, particularly if a preservative has not been 

incorporated. 

Storage: Flowers may be stored 1–2 weeks at 38–40F (3–4C). 

Dried: Centaurea flowers may be air-dried and hung upside down. Flowers may 

also be dried in silica gel (Vaughan 1988). The handsome spherical fruit has 

shiny brown scales and may be picked immediately after the flower dies. Words 

of advice from Shelley McGeathy of Hemlock, Mich.: “You can pick the flower 

when the yellow tuft is just getting full (selling as fresh or dried cut flower). If it 

is harvested later, either after the tuft is full-blown open or after the pollen 

appears, the yellow ray flowers will fall out of the pod, and then you can hang the 

pod to dry. Time to dry for just pods is 10–14 days.” 


Centaurea crocodyllum is native to Israel and has recently been studied for potential 

as a cut flower crop (Halevy 2000). Plants have an absolute requirement 

for LD to flower and must be lit in the winter.

CENTAUREA MACROCEPHALA 191 

Centaurea dealbata, a fine perennial species with handsome lavender flowers, is 

quite popular in landscapes and gardens. Plants were evaluated in 2000; in the 

first year, flowers occurred in early May and June, and problems with weak, short 

stems and poor yield were noted (Dole 2001). 

Centaurea imperialis is sometimes listed as a separate species but is a synonym 

of C. moschata. 

Centaurea montana (mountain bluet) is a perennial species with deep blue 

flowers. Seed requires 7–14 days to germinate at 68–72F (20–22C). No vernalization 

is required, but LD (4–6 hours of nightbreak incandescent lights) can 

be used to induce flowering. Weekly spray applications of 25 ppm GA for 9 weeks 

caused flowering even under SD, although too much GA or too many applications 

resulted in weak distorted stems (Cox 1986, 1987). 

Centaurea pulchra is similar to C. macrocephala but has rosy red flowers and is 

slightly smaller. Unfortunately, plants are difficult to locate. ‘Major’ has larger 

flowers than the species. 


Stem rots are caused by Phytophthora cactorum, Sclerotinia sclerotiorum, and Pellicularia 

filimentosa. 

Wilt is caused by Fusarium spp., similar to the wilt that occurs on annual aster 

(Callistephus). 

Spider mites are a major problem in warm summers. Leaf and flower fungal 

diseases, such as botrytis, are worse if overhead irrigation is used. 

Reading 

Anderson, R. G. 1990. Use of pot plant mechanization techniques to produce 

short stemmed cut flowers for supermarket bouquets. Acta Hortic. 272:319– 

326. 

Cox, D. A. 1986. Containerized herbaceous perennial production: forcing Centaurea 

montana for early spring flowering by night-lighting. In Proc. SNA Research 

Conference 21:73–75. 

———. 1987. Gibberellic acid induced flowering of containerized Centaurea 

montana L. Acta Hortic. 205:233–235. 

Dole, J. 1999. 1998 ASCFG National Seed Trials. The Cut Flower Quarterly 11(1): 

1–16. 

———. 2001. 2000 ASCFG national cut flower seed trials. The Cut Flower Quarterly 

13(1):1–10, 12–19. 

Halevy, A. H. 2000. Introduction of native Israeli plants as new cut flowers. Acta 

Hortic. 541:79–82. 

Kadman-Zahavi, A., and H. Yahel. 1985. Centaurea cyanus. In The Handbook of 

Flowering. Vol. 2. A. H. Halevy, ed. CRC Press, Boca Raton, Fla. 


Netherlands.

192 CENTRANTHUS RUBER 

Laurie, A., and G. H. Poesch. 1932. Photoperiodism: the value of supplementary 

illumination and reduction of light on flowering plants in the greenhouse. 

Ohio Agr. Exp. Sta. Bul. 512:1–42. 

Listowski, A., and A. Jasmanowicz. 1973. Biological Data Book. P. L. Altman and 

D. S. Ditmer, eds. Federation of Amer. Soc. for Exp. Biol., Bethesda, Md. 


Pal, A. K., and B. K. Jana. 1997. Effects of nitrogen and phosphorus on growth, 

flowering and seed yield of sweet sultan. Orissa J.of Hort. 25(1):22–27. 

Pinnell, M., A. M. Armitage and D. Seaborn. 1985. Germination needs of common 

perennial species. Univ. of Georgia Research Report 331. 

Post, K. 1942. Effects of daylength and temperature on growth and flowering 

of some florist crops. Cornell Univ. Agr. Exp. Sta. Bul. 787:1–70. 

———. 1955. Florist Crop Production and Marketing. Orange Judd, New York. 

Selaru, E., and M. Drǎghici. 1989. Research in developing a technique for greenhouse 

culture of Centaurea moschata var. imperialis. Lucrǎri Stintifice, Institutal 

Agronomic ‘Nicolae Bǎlcescu’, Bucuresti, Ser. B, Horticulturǎ. 32(1):93–101. 


Ore. 

Yahel, H., A. Kadman-Zahavi, and E. Erhrat. 1972. On winter flowering of Centaurea 

cyanus for export (in Hebrew). Hassadeh 52:1514–1516. 

Many thanks to Douglas Cox (first edition) and Shelley McGeathy and Rudolf 

Sterkel (second edition) for reviewing this section. 

Centranthus ruber red valerian Valerianaceae 

perennial, Zones 5–7 Europe red, pink, white 2–3'/3' (60–90 cm/90 cm) 

This is a flower—with a certain “country” look about it—that seems to come and 

go in the marketplace. Not common in cut flower markets (and probably not a 

smart decision to grow acres of the stuff), but plants are easily grown and readily 

marketable, bearing terminal clusters of fragrant pink, red, or white flowers. 

Propagation 

Seed: Germination occurs in 2–3 weeks if seed is placed at 65–70F (18–21C). 

Approximately 0.12 oz (3.5 g) of seed yields 1000 seedlings (Kieft 1996). Seedlings 

may be transplanted to final container 4 weeks after sowing (Nau 1999). 

Cuttings: Although they are occasionally used by perennial plant growers, terminal 

stem cuttings are seldom used by commercial cut flower growers. 

Growing-on 

Grow seedlings at 60–65F (15–18C) under natural daylengths. Apply 50–100 

ppm N from a complete fertilizer. Plants may be placed in the field 8–10 weeks 

after sowing.


CENTRANTHUS RUBER 193 

Plants flower the first year from seed, indicating that a cold treatment is not 

necessary. They do not perform well where temperature fluctuates a great deal 

during the year; they are better suited for coastal areas than areas with hot summers 

or very cold winters. Yield and quality of cut stems were disappointing in 

Athens, Ga. (Zone 7b). 


Few field data are available, but since plants often occur on limestone areas in 

their native habitat (Armitage 1997), the use of lime in the beds is recommended. 

Soils rich in nutrients are not necessary and result in tall, rather spindly plants. 

Eight to 10 flowers/plant should be attainable. Plants should be spaced approximately 

12" (30 cm) apart. Flowers normally occur May through July. 


There is no reason why flowers could not be forced in a greenhouse during the 

winter. Sow in late summer to early fall, space 9–12" (23–30 cm) apart, fertilize 

lightly (100–150 ppm N), and grow at 55/65F (13/18C) night/day temperatures. 

At least one tier of support, possibly 2, is necessary. If supplemental light is available, 

plants would no doubt benefit. Flowering occurs 16–18 weeks from sowing 

(Nau 1999). 


Harvest when the first flowers in the inflorescence are fully open. The use of floral 

preservative is highly recommended. 

Postharvest 

Fresh: Flowers persist 7–10 days in preservative. 

Storage: Not recommended, but flowers may be placed wet at 40F (4C) for 3–5 

days. Maqbool and Cameron (1994) worked with storing of bare root plants and 

found that regrowth of Centranthus ruber in the spring was poor when stored at 

temperatures less than or equal to 28F ( −2C). Cultivars 

‘Albus’ (white), ‘Coccineus’ (deep red), and ‘Roseus’ (rosy red) are available as 

separate colors from seed. A mix is also offered. 

‘Pretty Betsy’ is a cut flower selection of ‘Coccineus’ that grows 2–3' (60–90 

cm) tall. 

‘Rosenrot’ has light red flowers and reaches about 3' (90 cm). Essentially the 

same as ‘Roseus’, with perhaps more uniformity of color. 

‘Snowcloud’ is a white, somewhat fragrant valerian growing 3' (90 cm) tall.

194 CIRSIUM JAPONICUM 


No pests and diseases peculiar to Centranthus have been noted. 


“I thought they (Centranthus ruber) were a nice color, vase-tested well, definitely 

for smaller bouquet work. They got to about 20". Not what you’d want for big 

arrangements, but ok for $6.50 bouquets.” Roxana Whitt, Wise Acres, Huntingtown, 

Md. 

“Centranthus is just not that special and not that profitable; it goes to seed 

very fast, it self-seeds everywhere, florists like it for a while and then they are tired 

of it.” Janet Foss, J. Foss Garden Flowers, Everett, Wash. 

Reading 

Armitage, A. M. 1997. Herbaceous Perennial Plants. 2nd ed. Stipes Publishing, 



Netherlands. 

Maqbool, M., and A. C. Cameron. 1994. Regrowth performance of field-grown 

herbaceous perennials following bare root storage between − 10 and + 5C. 

HortScience 29(9):1039–1041. 


Cirsium japonicum Japanese thistle Asteraceae 

perennial, Zones 3–7 Japan red, pink 2–3'/2' (60–90 cm/60 cm) 

It may be debatable, judging from the number sold in this country, but this 

tough plant may be one of the few useful thistles for fresh cut flowers. Growing 

any thistle for the cut flower market is an exercise in optimism, but it seems that 

everything has a market somewhere—and this is the thistle for masochistic 

consumers. Flowers can be forced most of the year if greenhouse and field production 

are practiced. The dark green foliage is prickly and will not be a favorite 

with your harvest crew. The flower heads are dark red or pink. Production is 

best in areas of cool temperatures, although production in Zone 7 is fair, if not 

spectacular. 

Propagation 

Seed: Seed sown under intermittent mist or a sweat tent at 65–68F (18–20C) 

will germinate in 7–14 days. Approximately 0.12–0.25 oz (3.6–7.2 g) of seed yields 

1000 seedlings (Nau 1999). Seed is sometimes direct sown at the rate of 3.0– 

3.5 oz/1000 ft2 , but germination is inconsistent, and direct sowing is not recommended. 

Division: Plants may be divided after 2 years’ growth.

Growing-on 

CIRSIUM JAPONICUM 195 

Cirsium 

japonicum 

Transplant from 288s to cell packs or 4" (10 cm) pots after 4 weeks, or as soon as 

seedlings can be handled. Fertilize sparingly (75 ppm N) for the first 2 weeks 

then raise to 100–150 ppm N. Grow at 55–60F (13–15C) until ready to transplant 

to the field (approximately 7 weeks from sowing). Divisions may be 

planted in 4–6" (10–15 cm) pots and grown on for 4–6 weeks in a cold frame.

196 CIRSIUM JAPONICUM 


Plants do not require a cold period for flowering. Many species of thistle are long 

day plants, but Cirsium japonicum is day neutral. 


Longevity: In general, 2–3 years of production are normal. Plants may be 

divided for rejuvenation. 

Spacing: Space plants 12 × 12" (30 × 30 cm) or 9–12" (23–30 cm) between 

plants with 6–9" (15–23 cm) rows in the bed. Denser spacings of 6–9" (15–23 cm) 

centers have also been used (Vita and Agnello 1998). 

Yield: Results from work at the University of Georgia are shown in the following 

table. 

Yield and stem length of Cirsium japonicum. 

Year Stems/plant Stems/ft 2z Stem length (in) y 

1 8 7.6 27.9 

2 13 12.6 38.4 




Plants may be forced in heated greenhouses during the fall, winter, and spring. 

Sowings in July result in flowers by December if grown in 55–65F (13–18C) 

houses. Flowers continue through April. For best quality, sow seed every 4 weeks. 

Greenhouse crops generally are used as annuals only. 


At field trials in Watsonville, Calif., foliage was sampled from vigorously growing 

healthy plants when flower buds were visible but prior to flower opening. 

These are guidelines only and should not be considered absolute standards. 

Based on dry weight analysis. 

‘Rose Beauty’ 

(%) 

N P K Ca Mg 

2.6 0.19 2.24 0.60 0.29 

(ppm) 

Fe Mn B Al Zn 

462 130 14 208 21


Harvest when the flowers are open. If cut too soon, flowers will not persist well. 

Postharvest 

CIRSIUM JAPONICUM 197 

Fresh: Flowers persist approximately one week when placed in floral preservative. 

Storage: Flowers may be held temporarily at 36–41F (3–5C), but storage is not 

recommended (Vaughan 1988). 

Dried: Flowers may be dried by cutting the flowers as soon as they come into 

full bloom and hanging upside down. Flowers may be sprayed with clear plastic 

if any sign of shattering occurs (Kasperski 1956). 

Cultivars 

‘Lilac Beauty’ bears lavender flowers on 2–3' (60–90 cm) stems. 

‘Pink Beauty’ has pink flower heads on 2–2½' (60–75 cm) stems. 

‘Rose Beauty’ has carmine-red flower heads on 2–2½' (60–75 cm) stems. 


Cirsium helenioides (syn. C. heterophyllum) grows up to 5' (1.5 m) tall and bears 

solitary purple flowers. Still spiny. 

Cirsium rivulare is about 3' (90 cm) tall and can be a useful fresh or dried cut 

flower. The lavender to purple blooms are held in clusters and measure 1–2" 

(2.5–5 cm) across. Leaves are spiny and not particularly pleasant to handle. 

‘Atropurpureum’ has deeper purple flowers than the species. 


Leaf spots (Cercospora, Phyllosticta) occur as black spots on foliage. More prevalent 

under humid, wet conditions. Aphids are also a problem. 


“We haven’t grown cirsium for a few years, but I think it’s a wonderful cut flower. 

It seems to be an aphid magnet, just like the wild thistles. The larvae of thistle 

bugs eat the seeds, and they deform the flowers of this thistle also, but even so, 

every few years when I plant it, it has good market acceptance for me.” Janet 

Foss, J. Foss Garden Flowers, Everett, Wash. 

Reading 


York.

198 CLARKIA 



Ore. 

Vita, M. de, and S. Agnello. 1998. Cirsium japonicum, effects of plant density. Colture 

Protette 27(7):81–83. 

Clarkia satin flower Onagraceae 

annual western North America many colors 1 

16–30"/15" (40–75 cm/38 cm) 

Most taxonomists have rolled everything that was Godetia into Clarkia, but seed 

packets and cut flower catalogs will use the names interchangeably; to be sure 

you get what you want, order by cultivar. We hate to muddy the already murky 

waters of plant taxonomy for cut flower growers (and most of us seldom use the 

botanical name anyway in everyday sales and production), but we might as well 

get the generic name of this plant right—although it will forever remain satin 

flower in the marketplace. Clarkia is an excellent name, after all: we need a good 

plant to commemorate one of America’s great Western explorers, Captain William 

Clark. 

The genus of about 33 species bears showy flowers arranged in racemes or 

spikes. All species are native to the West Coast of the United States, mainly California 

and Oregon, and can be greenhouse-grown most anywhere and fieldgrown 

in areas of cool summers. They are not particularly suitable for field production 

in the Midwest, East, or South. 

Propagation 

Germination occurs within 10 days at 70F (21C) in a sweat tent or under intermittent 

mist. Approximately 0.03 oz (0.9 g) of seed yields 1000 plants (Nau 

1999). Do not direct sow seed. 

Growing-on 

Seedlings should be grown at 50–60F (10–15C) night temperatures, or spindly 

growth will result. Warmer day temperatures may be tolerated but should be 

consistently below 75F (24C). Fertilize sparingly (50–75 ppm N) with a complete 

fertilizer or potassium nitrate. Supplemental high-intensity discharge 

lighting accelerates growth of seedlings considerably. 


Photoperiod: Early observations showed that Clarkia did not respond to 

daylength or temperature for flower bud formation (Post 1955). More recent 

work revealed that cultivars of the F1 Grace series are clearly long day plants, 

even though plants also flower in short days. Plants require less time to flower

when grown under long days and supplemental light, as shown in the following 

table (Anderson and Geneve 1992). 

The effect of photoperiod and supplemental light on Clarkia. 

Photoperiod Supplemental Time to flower Nodes before 

(hours) light (weeks) flowering 

8 no 21 75 

8 yes 17 70 

20 no 13 37 

20 yes 10 32 

CLARKIA 199 

In this work, the highest quality stems were produced with long days and supplemental 

light. The supplemental light level was approximately 800 fc from 

high-pressure sodium lamps (HPS). Not only do LD influence flowering time, 

they also enhance quality. Work in Italy showed that only 3–6 hours of supplemental 

light was needed for faster flowering and longer stems (Pascale and 

di Napoli 1998). Research from Israel also showed that stem lengths are significantly 

longer when LD (natural days plus 8 hours supplemental light) were 

applied. Plants grown under natural short days were about 33" (83 cm) long, 

while those under LD were over 4' (1.2 m) tall; interestingly, plants are most 

responsive to LD at low temperatures, but at 68–78F (20–26C), plants were 

day neutral (Halevy and Weiss 1991). In areas where natural daylengths are seldom 

above 12 hours, field lighting with sodium lights during the evening is recommended. 

Temperature: Clarkia is a cool-season plant and does not tolerate high temperatures. 

The best temperature for growth is 50–55F (10–13C) nights, with day temperatures 

below 75F (24C). Greenhouse production at 60–62F (15–17C) nights 

has been successful in the winter. Halevy and Weiss (1991) showed that overall 

quality of flowers and stems deteriorates rapidly at temperatures above 75F (24C). 

Warm temperature is the main reason most summer outdoor production in this 

country is limited to the West Coast; however, plants may be grown in the East or 

Midwest if planted in early spring. Cold-acclimated plants transplanted on 5 

April in Lexington, Ky., tolerated temperatures of 26F ( − 3C) a few days later and 

produced flowers in mid June (Anderson and Geneve 1992). Protective row covers 

could be used to foster earlier plant growth and development. 

Gibberellic acid: Plants respond to 100 ppm GA3 with longer stems, but they are 

often thinner and bear fewer flowers (Pascale and di Napoli 1998, 1999). GA 

may be a useful substitute for LD in field production where supplemental lights 

are not used. 


Yield: Commonly, 30 stems per plant. Work over 2 years at the University of 

Kentucky (Utami 1991) resulted in 25–75 stems per pinched plant spaced on 2'

200 CLARKIA 

(60 cm) centers, depending on cultivar. Production was highest when planted no 

later than 10 April; later plantings were much less successful. Stems were 10–15" 

(25–38 cm) long. 

In trials in Italy, plugs were planted outdoors from October to July, including 

spring plantings in March and April. Time between planting and flowering 

ranged from 180 days for the fall planting, to 75 days for the spring plantings, to 

40 days for the summer plantings. The number of flowers on the main stem was 

constant (10–12), but stem length and diameter decreased from the fall planting 

to the late summer planting (Pascale and Barbieri 1995). These data reinforce the 

fact that Clarkia should be grown at daylengths greater than 12 hours and temperatures 

of 68–77F (20–25C). 

Spacing: Spacing is dependent on whether plants will be pinched or grown 

single-stemmed. Unpinched plants should be closely spaced on 4–5" (10–13 cm) 

centers. Pinched plants should be spaced at 20–24" (50–60 cm) in rows 3' (90 

cm) apart. Although stems attain only about 18" (45 cm) in height, field support 

is necessary in the East (particularly in areas with heavy spring rains), even with 

pinched plants. Bamboo stakes (one per plant) or at least one tier of netting 

should be used. Many growers insist on at least 2 layers of support netting. 

Fertilization: Fertilize in field with 200 ppm N from calcium nitrate and 25 

ppm magnesium sulfate approximately once every 2–3 weeks to maintain and 

increase stem strength. Higher frequency of fertilization should be practiced in 

coastal California areas, lower frequency in eastern sites. Too much fertility 

results in weak stems and lanky growth; lack of fertilization causes bronzing of 

the lower foliage and stunting. If nutrition continues to be withheld, plants 

become unacceptable. 

Pinching: Although plants do not require pinching, it results in more flowers 

and more uniform flowering of axillary shoots. Bob Anderson of the University 

of Kentucky suggests 2 kinds of pinches. An early pinch is accomplished 3–5 

weeks after germination to produce 4–6 lateral (secondary) breaks. In the field, 

these secondary branches fall over, and the tertiary stems that arise may be harvested 

with 12–16" (30–40 cm) stems. A late pinch (actually a disbud), removing 

the first visible flower buds, allows the upper laterals to develop a spray of short 

stems, much like a spray mum. According to Anderson, pinching is not necessary 

under dense spacing (4–6 plants/ft 2 , 43–65 plants/m 2 ). At such a spacing, a yield 

of 35 stems/ft 2 (376 stems/m 2 ) was recorded; 75% of the stems were 22–34" (55– 

85 cm) long. 

Scheduling: Clarkia has been grown under high tunnels, planted around 1 May 

in the North and harvested 10–20 July. All the flowers are harvested within 2 

weeks. The first flush of blooms is considered the highest quality. Sequential 

planting provides season-long flowering. 

Protection: If rain during the harvest period is common, some overhead protection, 

such as shade cloth or single poly, is recommended to reduce the damage. 

Overhead irrigation or excess rain can result in significant decline in quality.


Most plants are greenhouse-grown, but successful greenhouse production must 

occur under long day conditions, high light intensity, and cool temperatures. 

These conditions may be accomplished in most greenhouses in late winter and 

early spring. In general, Clarkia should be grown at daylengths greater than 12 

hours and temperatures of 68–77F (20–25C). In Kentucky, a late January sowing 

resulted in mid May flowering (Anderson and Geneve 1992). Midwinter production 

is not possible without high-intensity discharge supplemental lighting. 

Two to 3 crops may be harvested throughout the winter season with sequential 

planting. 

Single-stem plants may be grown at 8–10 plants/ft 2 (86–107 plants/m 2 ) for 

the first 7 weeks if grown under supplemental light. Plants may be finished at 5– 

6 plants/ft 2 (54–65 plants/m 2 ) or as little as 2–3 plants/ft 2 (22–32 plants/m 2 ), 

which computes to about an 8 × 8" (20 × 20 cm) spacing. 

Flowering begins approximately 10–12 weeks from sowing and continues for 

about 2 weeks. Yields of 15–30 flowers/plant are not uncommon under such 

conditions. Plants need support throughout the duration of the crop. Subirrigation 

is essential, particularly as flower buds form. 

If plants are to be pinched, pinch once upon transplanting to the greenhouse 

bench. Use the same fertility program as for field production. 






Grace Mix 

(%) 

N P K Ca Mg 

3.2 0.26 4.18 1.03 0.34 

(ppm) 

Fe Mn B Al Zn 

189 239 23 96 36 

CLARKIA 201 


Harvest when the first flowers on the stem are open; 3–6 flowers open is optimum 

(Tesi et al. 1997). For dried flowers, allow as many flowers to open as possible. 

Flowers harvested in the tight bud stage (to reduce shipping weight and 

damage) often do not open without a floral preservative. Vase life is extended 

when stems are recut under water (Tesi et al. 1997). Relatively poor shippability 

but an excellent flower for local sales.

202 CLARKIA 

Postharvest 

Fresh: In water, vase life is approximately 5–10 days, although the fresher the 

flowers, the better the vase life. Individual flowers may last only 5–6 days, but 

flower buds continue to open without fading. Therefore, the more flowers present 

on the stem, the longer the vase life. A vase life of 2 weeks is not uncommon. 

A flower solution should be used. Chrysal AVB has been shown to be effective 

(Pascale and Viggiani 1998), but silver thiosulfate (STS) does not significantly 

improve vase life. Some work with antioxidants has been attempted, but 

little consistency was noted (Meir et al. 1994). Preservatives enhance vase life by 

an additional 1–2 days. 

Storage: Storage is not recommended, but plants may be kept in water at 36– 

41F (3–5C) if necessary. This is an excellent plant for local growers, as stems do 

not ship well dry. 

Dried: Strip foliage and hang upside down in a warm, dark, well-ventilated 

area. 

Cultivars 

All are cultivars of Clarkia amoena (syn. C. grandiflora), C. amoena subsp. whitneyi, 

or C. unguiculata (syn. C. elegans). 

Single-flowered 

‘Aurora’ has salmon-orange flowers. 

‘Flamingo’ comes in red, lavender, pink, salmon, lavender-pink, and white 

with a rose eye. 

Florist series is semi-tall and available in lavender-pink, red, rose eye, salmon, 

and white. They were trialed in the ASCFG national field trials in 2001 (Dole 

2002). 

‘Furora’ bears crimson-scarlet flowers on 2½' (75 cm) stems. 

‘Gloria’ produces clear pink flowers. 

Grace series is an F1 hybrid, and although seed is more expensive than openpollinated 

forms, uniformity and individual color selection are excellent. The 

series is particularly attractive for its upright habit and 2–3' (60–90 cm) height. 

Available in light pink, rose-pink, salmon, red, lavender, and a formula mix. 

‘Memoria’ bears clean white flowers on 2' (60 cm) stems. 

Double-flowered 

‘Azaleaflora’ mixture is available as a mix or in numerous single colors, including 

‘Brilliant’ (carmine), ‘Maidenblush’ (bright rose), ‘Orange Glory’(orange), 

‘Ruddigore’ (crimson-red), ‘Sweetheart’ (pink), and ‘White Bouquet’ (white). 

Plants generally flower on 1–2' (30–60 cm) stems. 

‘Grandiflora’ is taller than ‘Azaleaflora’ but only available as a mixture of 

colors.


CONSOLIDA 203 

Root rots (Pythium, Phytophthora, Rhizoctonia, etc.) infect seedlings in the propagation 

area or at transplant. Rhizoctonia is very pathogenic and can be lethal 3–7 

days after symptoms appear. In the field, the foliage turns pink, then red, and 

finally the whole plant declines. The pathogen may be seed-borne. Use clean soil 

and tools, and apply a fungicide as needed. 

Rusts have been reported in field plants. Remove and destroy infected plants. 

Aster yellows may also occur in field plantings. Rotate crops every 1–2 years. 

Aphids and western flower thrips are the most serious pests in the field. 

Aphids, whiteflies, mites, and thrips are significant problems in the greenhouse. 

Reading 

Anderson, R. G., and R. L. Geneve. 1992. Field production of satin flower or Godetia. 

In Proc. 4th Natl. Conf. on Specialty Cut Flowers. Cleveland, Ohio. 

Dole, J. 2002. ASCFG National Trials Report. The Cut Flower Quarterly 14 (1). 

Halevy, A. H., and D. Weiss. 1991. Flowering control of recently introduced F1 

hybrid cultivars of Godetia. Scientia Hortic. 46:295–299. 

Meir, S., Y. Reuveni, I. Rosenberger, H. Davidson, and S. Philosoph-Hades. 1994. 

Improvement of the postharvest keeping quality of cut flowers and cuttings 

by application of water-soluble antioxidants. Acta Hortic. 368:355–364. 


Pascale, S. de, and G. Barbieri. 1995. Effects of planting date on flowering in 

godetia. Colture Protette 24(4):97–100. 

Pascale, S. de, and G. di Napoli. 1998. Effects of photoperiod and GA3 on flowering 

of godetia. Colture Protette 27(10):75–79. 

———. 1999. Godetia: effects of GA3, shading and soil type. Colture Protette 28(1): 

83–86. 

Pascale, S. de, and S. Viggiani. 1998. Water relations and gas exchanges of cut 

Godetia flowers during vase life. Advances in Hort. Sci. 12(3):153–157. 


Tesi, R., C. Paoli, and A. Nencini. 1997. Vase life of cut clarkia flowers. Colture Protette 

26(1):63–66. 

Utami, L. S. 1991. Environmental factors influencing the cut flower production 

of satin flower (Clarkia amoena subsp. whitneyi). M.S. thesis, Univ. of Kentucky, 

Lexington. 

Many thanks to Bob Anderson and Jeff McGrew (first edition) and Mary Ellen 

Schultz (second edition) for reviewing this section. 

Consolida larkspur Ranunculaceae 

annual Mediterranean many colors 2–4'/1' (0.6–1.2 m/0.3 m) 

Larkspur has long been a mainstay for cut flower growers, and the market for 

larkspur continues strong (although prices fluctuate dramatically) while other

204 CONSOLIDA 

plants come and go. Cultivars offer a wide range of colors, and germination is 

relatively high, even when seed is direct sown. Historically known as annual delphinium, 

larkspur is in fact closely related to that genus and was for years 

included under Delphinium before being moved to Consolida. The species of larkspur 

used in the cut flower trade are Consolida ajacis (syn. C. ambigua), C. orientalis, 

and occasionally C. regalis. The differences between them are slight: plants of C. 

orientalis are more upright than C. ajacis, and the flowers are often in shades of 

bright pink and purple; plants of C. ajacis and C. regalis are more branched initially, 

and flowers are usually light pink or blue. Flowers are generally dried but 

may also be used in fresh bouquets and arrangements. Some varieties are recommended 

for use as bouquet fillers, similar to gypsophila. 

Propagation 

Approximately 9000 seeds/oz (300 seeds/g) is typical, and 0.25 oz (7 g) of seed 

yields 1000 seedlings (Nau 1999). Most cultivars are direct sown in the field. A 

volume of 0.3 oz per 100' (30 g per 100 m) is recommended (Kieft 1996). Seed 

does not germinate well above 65F (18C) soil temperature (Post 1955) and 

should be sown in the fall in most parts of the country. Many growers, particularly 

those in the warmer areas of the country, chill the seed for 7–14 days at 35– 

40F (2–4C) prior to planting to enhance germination. This is important! In areas 

south of Zone 5, seed may be sown in the fall without appreciable loss due to 

winter conditions; however, in very moist winters (e.g., coastal Northwest), seed 

may rot if planted in the fall. Fresh seed germinates better than old seed. 

Seeds do not appear to have an absolute requirement for darkness, but better 

germination is reported when seeds are completely covered. 

In cooler areas, seed may be sown in plugs or other containers and germinated 

in a 50–55F (10–13C) greenhouse or cold frame; or seed may be chilled at 35F 

(2C) for 2–3 weeks prior to sowing in the spring. Sow as soon as the ground can 

be worked. Plugs may be transplanted in early spring for late summer harvest. 

Growing-on 

If plants are started in the greenhouse, grow at 55F (13C) until ready to plant to 

the field. Use large plugs (no smaller than a 208-plug tray), or transplant seedlings 

to final plug container after 3–4 weeks. Fertilize lightly (50–100 ppm N 

using a nitrate-based fertilizer once a week) while growing at temperatures below 

60F (15C). 


Temperature: Plants of larkspur require a vernalization (cold) period for shoot 

elongation and flower initiation and development (Bajpal and Nerikar 1959, 

Post 1955). Vernalization is not effective on the seed. If plants remain below 55F 

(13C) for 6 weeks, then further development is enhanced: plants will rosette and 

shoot elongation will occur. Reduced rosetting or flowering occurs above 70F

Consolida ajacis 

‘Giant Imperial Pink’

206 CONSOLIDA 

(21C). The elongation of the stem and subsequent flowering occur at higher 

temperatures only if the cool treatment has been satisfied. In the experiment 

summarized in the upcoming table, seeds were greenhouse-sown in October, 

and seedlings were grown in the greenhouse at 50F (10C) until 1 January. After 

1 January, various treatments were applied. If seedlings are exposed to high temperatures 

for several days, flower initiation, development and shoot elongation 

occur rapidly with very poor stem and flower quality. 

Photoperiod: Development of the plant is best under long days, which can be 

satisfied by nightbreak lighting or day extension. Long days (>16 hours) result in 

longer stems and higher yield than short days. The effect of photoperiod and 

temperature on larkspur is shown in the following table (Post 1955). 

The effect of photoperiod and temperature on yield of larkspur. 

Seed sown in October, treatments applied after 1 January. 

50% of flowers 

Treatment cut before . . . Stems/plant 

50F (10C) + LD 17 Apr 16.2 

50F ND* 3 May 7.0 

55F (13C) + LD 8 Apr 17.0 

55F ND 16 Apr 12.0 

60F (15C) + LD 21 Mar 20.7 

60F ND 12 Mar 12.6 

* = natural days 

Gibberellic acid: GA accelerates flowering of larkspur (Bose 1965, Lindstrom et 

al. 1957); however, few growers employ the chemical. 


Planting time: Seed may be sown every 2 weeks from September to November 

in the Midwest. In New York and similar latitudes, initial sowing may be done 

from 1 to 15 September for spring production. Further south and in California, 

early to mid October through early November allows for sufficient exposure to 

the cold. In Florida and the Southwest (Arizona, Texas), planting occurs from 

mid October to mid November. 

Sowing in more northerly environments may be also be accomplished in the 

fall, but the addition of frost protection cloth such as Remay once seeds have 

germinated makes economic sense. The use of frost cloth is by no means unanimous. 

Shelley McGeathy, growing in Hemlock, Mich. (Zone 5), considers larkspur 

to be tough enough to overwinter and uses it to reduce the drying effect of 

the wind, rather than for cold production. She also recommends a cover crop of 

oats or the like, sown in fall, which eventually covers any seedlings. The cold 

kills the oats, not the larkspur seedlings. In years of below-average falls and win-

CONSOLIDA 207 

ters, however, seed may not germinate until temperatures warm up in early 

spring. If additional hard frosts are expected, put down the cloth. If sowing in the 

spring, sow early. 

Direct sowing is recommended for stronger stems; Zone 5 appears to be 

the transition area between direct sowing and transplanting (see “Grower 

Comments”). 

Spacing: Some growers do not feel spacing is necessary; they practice what 

they call solid seeding: plants are not spaced out, and because the sowing is so 

thick, there is no need for support. Additional disease has not been reported, 

and it is believed that thick rows help to protect from wind. Others do use spacing 

patterns. If sown more thickly, thin to a 4–6" (10–15 cm) spacing. Some 

growers use 3½' (1.1 m) wide rows, and direct sow 2 lines of plants in the bed 

(Nakasawa 1990). With most crops, the more dense the spacing, the higher the 

incidence of disease. 

Scheduling: Flowers occur as spring temperatures rise, but approximately 4–5 

months are required after sowing. 

Shading: Larkspur does not require shading; however, yield and stem quality 

are not adversely affected under 30% shade. 

Yield: Under 10–12" (25–30 cm) spacing, expect 6 stems/ft 2 (65 stems/m 2 ) or 

500 12-stem bunches per 1000 ft 2 (5 bunches per m 2 ). At closer spacings, expect 

higher yield per square foot but lower yield per plant. 

Support: Use 1 or 2 tiers of wire or string support (6 × 8", 15 × 20 cm), particularly 

if the site is windy. The first tier should be 12–14" (30–36 cm) off the 

ground, and the second 18" (45 cm) above the first (Nakasawa 1990). Growers 

incorporating very high density plantings use no support, allowing adjacent 

plants to support each other. 

Irrigation: Use drip irrigation if possible. 


Sow or transplant approximately 10" (25 cm) apart. Maintain 50F (10C) temperatures 

for 8–10 weeks. After plants are well established, raise temperatures to 

55–60F (13–15C) and apply long days by extending the days (>16 hours) or with 

2-hour nightbreak lighting using incandescent lamps. Sowing in September 

results in flowering in early to mid March in the Midwest; for a December sowing, 

mid April. Sowing after January is not recommended: high greenhouse temperatures 

usually occur during extension of the flower stem and development of flowers, 

and quality subsequently declines. Support is necessary for all sowing dates. 


For fresh flowers, allow 2–5 basal flowers to open, or up to ⅓ of the stem. Fresh 

stems are generally bunched in 10–12 stems (heavy) or 20 stems (light). If counting 

flowers is not feasible, harvest the entire plant at once. For dried flowers, 

harvest when the majority of flowers are open, with 4 or 5 buds unopened on terminal 

flower, but before petals drop. Some growers harvest the terminal flower

208 CONSOLIDA 

stem for fresh flowers and the laterals for dry flowers, but this practice should be 

avoided: relegating the laterals for dried material tends to make drieds “inferior,” 

looked upon as second-class stems. Either grow them for fresh or for dried, 

not both. 

Postharvest 

Fresh: The vase life of larkspur is approximately 6–8 days. Flowers are highly 

sensitive to ethylene; silver thiosulfate (STS), if available, is effective in reducing 

flower drop in larkspur and delphinium (Shillo et al. 1980). Commercial 

flower preservatives with silver in their makeup are effective treatments for cut 

stems. Six-hour pretreatment with 1-MCP (1-methylcyclopropene) prolonged 

vase life as well as did treatments with STS in an ethylene-free environment 

(Serek et al. 1995). 1-MCP appears to have promise for most ethylene-sensitive 

crops. Store fresh flowers away from fruit, vegetables, or other drying flowers. If 

flowers are stored overnight, keep upright in water at 36–41F (3–5C). Keep constantly 

hydrated; dry storage for fresh flowers is not recommended. 

Dried: Larkspurs are excellent for drying and may be air-dried in 10–14 days; 

forced-air drying requires only about 18 hours at 70–80F (21–27C). Quick drying 

is recommended for best color retention. Foliage need not be removed. Stems 

may also be dehydrated with silica gel or other desiccant. 

Cultivars 

‘Blue Cloud’ has a more airy, open flower habit than other cultivars and is 

often used as a filler. The single flowers are violet-blue. ‘White Cloud’ (‘Snow 

Cloud’) is a white form. These appear to be cultivars of Consolida regalis. 

‘Blue Picotee’ is an interesting bicolor with white flowers surrounded by a 

blue picotee edge. 

Early Bird series is earlier flowering than the Imperials and is available in blue, 

lilac, rose, white, and a mix. Stems are 3–4' (0.9–1.2 m) tall. 

‘Frosted Skies’, a selection of ‘Blue Picotee’, grows to 4' (1.2 m); it has midblue 

double flowers, tinged with white. 

Giant Florist Strain is basal branching and bears flowers with double floret on 

3' (90 cm) stems. A wide range of colors is available. 

Giant Imperial series is the standard of the industry. Plants stand approximately 

4' (1.2 m) tall and are available in numerous colors, including carmine, 

deep blue (‘Blue Spire’), deep rose, light blue, lilac, pink, salmon, white, and a 

mix. Super Giant Imperial may be as much as 2 weeks earlier than Giant Imperial, 

with longer stems and larger flower spikes; colors include carmine, white, 

dark blue, azure-blue, salmon, and a mix. 

Messenger series is approximately the same height as the Giant Imperial series 

but flowers about 2 weeks earlier. Some growers have found this good for sequential 

planting. Blue, lilac, rose, white, and a mix of colors are available. 

‘Pink Fantasies’ from Gloeckner has big, bright pink flowers. Plants performed 

well for Janet Foss of Everett, Wash.

CONSOLIDA 209 

QIS series (formerly Sunburst series) has been selected for uniformity and 

stem quality. Stem lengths are 30–36" (75–90 cm). Available colors include carmine, 

dark blue, light pink, lilac, rose, white, and a mix. The label QIS (“Quality 

in Seed”) is available in other cut flowers as well; it was developed by Kieft, whose 

seed production process includes an aggressive breeding program. Other seed 

producers have similar programs under different labels. 

Rustic series grows 36–40" (90–100 cm) with single flowers. 

Sydney series blooms in 8–12 weeks with uniform fully double flowers. Bred 

as a greenhouse crop, from Ball Seed Company. The rose color earned Fleuroselect 

Gold Medal Marks for 2000; the purple and white earned Fleuroselect 

Quality Marks. 

‘White Veil’ produces wiry stems with small white blossoms. 


Botrytis basal rot causes a soft brown basal rot; plants eventually wilt and fall 

over. Fungicides and aeration are useful preventatives. 

Black leaf spot (Pseudomonas delphinii) causes irregular, shining, tarlike spots, 

especially on the upper surface of the foliage. The lower leaves show symptoms 

first, but petioles, stems, and flowers may also be attacked by this bacterium. Remove 

infected foliage and destroy. Other leaf spots may be carried on the seed; 

seed may be treated in 125–130F (52–54C) water for 10 minutes. 

Crown rot and root rot (Sclerotinia delphinii) result in sudden wilting, stunting, 

and death of plants. The saying “here today, gone tomorrow” is particularly 

appropriate for plants afflicted with this fungus, which seems to occur in the 

weaker-growing colors (and sometimes may be most destructive on a particular 

color). The fungi live through the winter and are distributed by tools or rain. 

Crop rotation, soil sterilants, and clean tools relieve the problem. 

Cyclamen mites cause blackened buds and downward-cupped, deformed 

leaves. The “blacks” are distinguished from pseudomonas leaf spot by the 

deformities caused by the mites. Miticides are useful but not always effective. 

Aphids and leafminers can also be problems. 

Powdery mildew (Erysiphe and Sphaerotheca) is particularly prevalent during 

cool, moist seasons. Larkspur, however, is much less susceptible than delphinium. 

Avoid dense spacing and wet soils when planting. 

Slugs can mow down larkspur, especially in the Northwest. 

Stem canker (Fusarium oxysporum f. delphinii) first appears as light brown, 

water-soaked areas on the stems. Eventually the fungus reaches the crown and 

invades the vascular tissues. Plants show yellowing of the basal leaves that progresses 

upward. Fusarium-resistant strains and soil sterilization are useful. 


“We use primarily the Giant Imperial series; I also find ‘QIS Light Blue’ a very elegant 

icy color. We tried the Messenger series, which was wonderfully early but 

wasn’t quite as strong as we like to see. [The] trick is not to let [the seedlings] get

210 CONSOLIDA 

root bound, so as soon as they have a second leaf, out they go, at least to benches 

outside, and then in the ground, as quick as you can. To counteract [raising] 

soil temps, in the field, we use white plastic mulch; it keeps the roots cool and 

only causes a problem with root rot when you over irrigate.” Ruth Merrett, Merrett 

Farm, Upper Kingsclear, N.B. 

“I germinated my larkspur . . . and transferred them to a cold frame. They 

seem to be doing great, and we have had nighttime temps down into the 20s.” 

Sandy Della Villa, Patch of Paradise, West Henrietta, N.Y. 

“I plant early in the spring, after refrigerating the seed for a couple of weeks. 

It’s usually up within 10 days of 50-degree ground temperatures. I then plant 

every 2 or 3 weeks for successive crops, though here hot summers can ruin the 

later seedlings because of short stems.” Ralph Thurston, Bindweed Farm, Blackfoot, 

Idaho. 

“Larkspur will germinate poorly, if at all, when the soil is above 55F. It also 

doesn’t like to be transplanted, so you may have better luck starting them in small 

peat pots rather than plugs. If your soil temperature is still below 55F (use a thermometer) 

and weather predictions are for it to stay that way for a couple of weeks, 

you’re much better off direct seeding it. For direct seeding, I use an Earthway 

seeder and the “radish” seed plate. Cover the seed ⅛–¼" since darkness aids germination.” 

Jennifer Judson-Harms, Cricket Park Garden, New Hampton, Iowa. 

“I direct seeded larkspur the first week of November; it just sat there and didn’t 

sprout by Christmas. The larkspur may have been slow to start, but now it is 

up and looks great. Probably the best crop I’ve had, maybe the month of snow 

cover melting slowly did the trick. Last year I planted in mid May, it came up 

but was short.” Dave Dowling, Farmhouse Flowers, Brookeville, Md. 

“When we seed larkspur, we drop a seed about every inch in the row with 4 

rows 12" apart . . . and we use no support, and we don’t thin the row. What we get 

is tall plants with one flower and minimal branching, nice straight stems, and 

mostly just leaves, not too many laterals to remove. Larkspur seed is cheap, and 

direct seeding gives great stem length. We have used as much as 5 lbs of seed per 

acre, but usually about 4 lbs.” Ralph Cramer, Cramers’ Posie Patch, Elizabethtown, 

Pa. 

“Plants that have been kept in the tray too long always seem to suffer.” Susan 

O’Connell, Fertile Crescent Farm, Hardwick, Vt. 

“I’m in Zone 4, and I direct seed my larkspur in mid April; seed germinates in 

3 weeks. I can’t count on a fall sowing to come up for me; Zone 5 may be more 

favorable for that.” Julie Marlette, Blue Heron Gardens, Fall Creek, Wis. 

Reading 

Bajpal, P. N., and V. N. Nerikar. 1959. Effect of sowing at different dates on the 

growth and flowering of Cosmos, Caryopsis, and larkspur. Sci. Cul. 25:140–142. 

Bose, T. K. 1965. Effect of growth substances on growth and flowering of ornamental 

annuals. Sci. Cul. 31:34–36. 


Netherlands.

COREOPSIS, RUDBECKIA, LEUCANTHEMUM 211 

Lindstrom, R. S., S. W. Wittwer, and M. J. Bukovac. 1957. Gibberellin and higher 

plants. IV. Flowering responses of some flower crops. Quarterly Bul. Mich. Agr. 

Exp. Sta. 39:673–681. 

Nakasawa, S. 1990. How we field grow larkspur. In Proc. 3rd Natl. Conf. on Specialty 

Cut Flowers. Ventura, Calif. 



Serek, M., E. C. Sisler, and M. S. Reid. 1995. Effects of 1-MCP on the vase life 

and ethylene response of cut flowers. Plant Growth Regulation 16(1):93–97. 

Shillo, R., Y. Mor and A. H. Halevy. 1980. Prevention of flower drop in cut sweet 

peas and delphinium (in Hebrew). Hassadeh 61:274–276. 

Many thanks to Sally Nakasawa (first edition) and Bernadette Hammelman, 

Cathy Itz, and Shelley McGeathy (second edition) for reviewing this section. 

Coreopsis, Rudbeckia, Leucanthemum Asteraceae 


There are enough similarities in the production and harvest of these genera 

(commonly known as tickseed, coneflower, and shasta daisy, respectively) that 

we decided to group them together. The genus names of the first two are so well 

known that they are used as common names. Most of the commonly grown 

members of all genera are perennial; however, many annual cultivars of Rudbeckia 

and one or two of Coreopsis are also available. They all grow in full sun, tolerate 

similar environments, and bear the same type of flowers—that is, they are 

all “daisies” and sometimes are grown and sold as such. Plants are grown for the 

colorful flowers; the handsome cones of Rudbeckia are also harvested as dry floral 

items. Plants are field-produced only. In all genera, plants grow as rosettes 

until they send out a flower stem. Plants themselves remain less than 1' (30 cm) 

tall, but flower stems are significantly taller and may require some support, 

depending on winds and temperatures. 

Propagation 

Seeds and plugs are available for most daisies. All should be sown under intermittent 

mist at 70–75F (21–24C). Plants can also be divided after approximately 

3 years; division is easiest for Rudbeckia, most difficult for Coreopsis. 


Temperature: For Coreopsis grandiflora, the need for cold is cultivar specific. For 

example, ‘Sunray’ requires approximately 10 weeks of cold (40F, 4C) for flowering, 

whereas ‘Early Sunrise’ does not require any cold treatment (Yuan et al. 

2000a). For the perennial rudbeckias, cooling is not a requirement, but plants 

definitely benefit from cold in the field. The annual Rudbeckia hirta, however, nei-

212 COREOPSIS, RUDBECKIA, LEUCANTHEMUM 

Rudbeckia hirta 

‘Indian Summer’ 

ther needs nor benefits from cold. For leucanthemums, research with the garden 

shasta daisy ‘Snowcap’ showed that 6 weeks of cold of 35–45F (2–7C) were necessary 

for flower initiation and development (Runkle et al. 2000). It is likely other 

shasta daisy cultivars have similar requirements. 

Photoperiod: All these daises have a requirement for long days. For coreopsis, 

plants require approximately 3 weeks of LD for flower initiation, after which 

photoperiod is unimportant. All perennial rudbeckias flower best under LD 

greater than 13 hours (Yuan et al. 2000b); for shasta daisies, 16-hour daylength 

appears necessary (Runkle et al. 2000). This is why all these daisies flower in the 

summer, as natural photoperiods lengthen. 


Yield: Plants are productive 3–5 years. All daisies can be planted in early spring; 

perennial daisies benefit from being planted in early fall. For the perennials, yield 

is minimal the first year (although Coreopsis ‘Early Sunrise’ flowers well the first

year if spring-planted). Harvesting can occur the second year and in subsequent 

summers. 

Spacing: Spacing of 12–18" (30–45 cm) may be used for all genera. 

Longevity: All perennial daisies require division after 3–4 years, or plants 

become unproductive. Coreopsis and shasta daisies require division more often 

than rudbeckias. 

Support: Use of side supports or netting may be useful if winds are high; otherwise 

the stems are self-supporting. 


We are not aware of cut flower production in the greenhouse; however, the use 

of cold-treated plugs or field roots in combination with proper photoperiod 

manipulation will yield flowers (Yuan et al. 2000a, 2000b). In general, cool plugs 

at 40 (4C) for 8–12 weeks, then grow at 55–62F (13–17C) under winter light conditions 

(SD) until a sufficient root system and leaves fill the container. Long 

days may be applied by extending daylength through supplemental lighting or 

using nightbreak incandescent lighting for 3–4 hours per night. Turn lights off 

no later than when color first appears on the buds. High-intensity discharge 

lamps are recommended during winter months for more vigorous growth, 

although the economics of their installation may not be favorable. Greenhouse 

forcing temperatures should be around 50–55F (10–13C) for best-quality stems. 

Flowers may be forced faster at warmer temperatures, but stems will be less 

robust. 


Harvest all daisies when the flowers are starting to open (Vaughan 1988). 

Postharvest 

Vase life for most daisies is 7–10 days in a floral preservative; some species will 

persist even longer. Ethylene is not a significant problem with flowers in the 

aster family, so anti-ethylene products are not recommended. 

Cut stems can be stored at 36–41F (2–5C), but storage is not recommended. 

Cultivars 


Coreopsis grandiflora 

‘Badengold’ bears bright yellow flowers. Early to flower. 

‘Double Sunburst’ grows to 24" (60 cm) with 2" (5 cm) double flowers. 

‘Early Sunrise’ was an All-American Selection in 1989. Plants are easily raised 

from seed and bear bright yellow semi-double flowers 2" (5 cm) wide. Shortlived 

but excellent for a couple of years. 

‘Mayfield Giant’ is an old cultivar with 2–3" (5–8 cm) wide gold-yellow flowers. 

Grows 2–3' (60–90 cm) tall.

214 COREOPSIS, RUDBECKIA, LEUCANTHEMUM 

‘Ruby Throat’ bears yellow flowers with a deep claret throat. 

‘Schnittgold’ (‘Gold Cut’) produces golden-yellow flowers. 

‘Sunburst’ (sometimes called ‘Improved Mayfield Giants’) is about 2' (60 cm) 

tall with large semi-double golden-yellow flowers. 

‘Sunray’ is an exceptional selection that bears 2" (5 cm) wide double flowers 

for 8–12 weeks on 2' (60 cm) plants. 

Rudbeckia fulgida 

‘Goldsturm’, a selection of var. sullivantii and one of the most popular plants 

in the perennial trade, is occasionally used for cut flowers. It is a little short, but 

if stem length is not a problem, it should be grown for performance alone. The 

dark green foliage contrasts beautifully with the 3–4" (8–10 cm) wide deep yellow 

flowers. The center consists of a nearly black cone. The popularity of ‘Goldsturm’ 

created a demand that vegetative propagation could not meet. In 

response, growers resorted to seed propagation, and it is therefore unlikely there 

are many true ‘Goldsturm’ out there. Flowers in mid summer to fall. 


Perennials 

Coreopsis lanceolata (lance-leaf coreopsis) is similar to C. grandiflora, differing in 

vegetative characteristics but quite similar in flower. Useful cultivars for cut 

flowers include ‘Brown Eyes’, an excellent long-lived selection with single yellow 

flowers and a maroon ring near the center, and ‘Goldfink’, which produces 

many 2" (5 cm) wide single yellow flowers with an orange center. Should be 

raised from cuttings or divisions. Zones 3–8. 

Rudbeckia laciniata (cutleaf coneflower) and R. nitida are large plants, growing 

well over 5' (1.5 m) tall under favorable conditions, that flower in late summer 

and fall. They differ in minor ways, and it is best to obtain named cultivars if 

growing them as cuts. The blooms are 2–3½" (5–9 cm) wide and consist of 

drooping yellow ray flowers surrounding a green cylindrical disk. ‘Golden Glow’ 

grows 3–5' (0.9–1.5 m) tall and bears large, fully double lemon-yellow flowers; 

unfortunately, they are often covered with aphids, to which this cultivar is most 

prone. ‘Goldquelle’ (‘Gold Fountain’, ‘Gold Drop’) bears double yellow flowers 

and is a clump-former, growing 3–4' (0.9–1.2 m) tall. In full sun, stems are sufficiently 

strong to support the heavy flowers; in shady areas, they fall like cooked 

spaghetti. ‘Herbstsonne’ (‘Autumn Sun’) grows up to 7' (2.1 m) tall and is one of 

the finest coneflowers in cultivation, producing dozens of cut stems in late 

August through October. Dozens of long, drooping sulphur-yellow petals surround 

a green cylindrical disk. In the North, the stems usually don’t require 

staking; in the South, staking should be considered. Zones 3–9. 

Rudbeckia triloba (three-lobed coneflower) grows 3–5' (0.9–1.5 m) tall and produces 

dozens of flower stems with 3–6 flowers per stem. The flowers are much 

smaller than those of the perennial species just mentioned, but many more are 

produced. Plants are short-lived, persisting 2–3 years at most, but they reseed


prolifically. Zones 3–10. Purchased seed may germinate at a higher percentage if 

they are put in a seed flat or plugs and cooled at 40F (4C) for about a month. 

Annuals 

Coreopsis tinctoria (plains coreopsis) is a seed-propagated annual with multicolored 

flowers on 1–2' (30–60 cm) plants. Home Mix has 30" (75 cm) stems 

with small, brown-red flowers with yellow tips. Good for filler. 

Rudbeckia hirta (black-eyed susan), grown for years as a garden plant, is also a 

useful cut flower. Plants are true annuals and often fall apart midseason, but 

they can be resown in late spring and early summer for a second crop. Cultivars 

are many, including ‘Indian Summer’, the ASCFG’s 2000 Fresh Cut Flower of 

the Year, whose ease of production, long vase life, and high consumer ratings 

make it a favorite with growers across the country; large (6", 15 cm) flowers are 

produced on wiry stems up to 3' (90 cm) tall. ‘Gloriosa’ (‘Gloriosa Double Flowered’, 

‘Double Orange’), an All-American Selection in 1981, is an old-fashioned 

form with equally large semi-double and double flowers in orange and rust 

shades; the large plants are 3–5' (0.9–1.5 m) tall. ‘Goldilocks’ is a semi-double to 

double daisy, 18–24" (45–60 cm) tall, with 3–4" (8–10 cm) wide golden-yellow 

flowers; the doubleness is quite attractive, if you like double daisies, but flowers 

are even more susceptible to disease from summer rain and humidity. (Retailers 

look upon double rudbeckias as yellow dahlias.) ‘Irish Eyes’ is distinguished by 

the green center, surrounded by orange petals. ‘Marmalade’, another old standard, 

provides large golden-yellow flowers with a contrasting dark disk; plants 

grow 2½–3' (75–90 cm) tall. ‘Prairie Sun’ has a green center and bicolor yellow 

petals—an outstanding cultivar. ‘Rustic Colors’ are just that, a mix of bronze, 

gold, mahogany, and yellow with a contrasting black center; plants range from 

2' (60 cm; sometimes called ‘Rustic Dwarf’) to 3½' (110 cm) tall. ‘Sonora’ carries 

5" (13 cm) bicolor flowers, mahogany-red at center and golden-yellow beyond, 

on 15–20" (40–50 cm) plants. 


The normal complement of insects devours these daises, particularly aphids and 

thrips. 

Diseases include rot (Sclerotium), bacterial blights, botrytis, downy and powdery 

mildews, and verticillium wilt (Perry 1998). 

Coreopsis must be divided regularly; overcrowding results in death. Also, if 

stems are not cut and flowers go to seed, yield and longevity will suffer. Remove 

all flowers, even if they will be used as compost. 


“My favorite is Rudbeckia triloba. This is a native American flower, but reselected 

seeds producing quality cut flowers are available. This flower lasts 2 weeks plus 

in a vase; never in all the years I’ve grown it has a bunch ever ended up on the 

compost heap. This flower sells! From the time we start selling in the spring,

216 CORNUS 

people ask when it will be ready.” Janet Foss, J. Foss Garden Flowers, Everett, 

Wash. 

“Grasshoppers have been the bane of my existence since becoming a flower 

grower. They love sunflowers and rudbeckias, so be sure to cut those as soon as 

the petals start to peel away from the face of the flower. They will open nicely in 

a day or two.” Lynn Byczynski, Growing for Market, Lawrence, Kans. 

Reading 



Runkle, E., M. Yuan, M. Morrison, R. Heins, A. Cameron, and W. H. Carlson. 

2000. Forcing perennials, Leucanthemum superbum ‘Snowcap’. In Firing Up Perennials: 

the 2000 Edition. Greenhouse Grower, Willoughby, Ohio. 


Ore. 

Yuan, M., R. Heins, A. Cameron, and W. H. Carlson. 2000a. Forcing perennials, 

Coreopsis grandiflora. In Firing Up Perennials: the 2000 Edition. Greenhouse 

Grower, Willoughby, Ohio. 

Yuan, M., E. Runkle, R. Heins, A. Cameron, and W. H. Carlson. 2000b. Forcing 

perennials, Rudbeckia fulgida ‘Goldsturm’. In Firing Up Perennials: the 2000 Edition. 

Greenhouse Grower, Willoughby, Ohio. 

Cornus dogwood Cornaceae 

woody 

The diversity of dogwoods is extraordinary, from noble flowering landscape trees 

to shrubs best known for lighting up the winter landscape. The flowers are occasionally 

used for cuts (see Cornus florida), but their poor stem length and lack of 

vase life and shippability limit their popularity in the market. Dogwoods are 

most valued as cuts for the deciduous winter stems of the colored-stem forms (C. 

alba, C. sericea), harvested at the peak of color in late fall or winter. 

Cornus alba red-stem dogwood Cornaceae 

woody, Zones 2–6 Asia colored stems 8–10'/5–10' (2.4–3 m/1.5–3 m) 

Propagation 

Cuttings: Hardwood cuttings have been successfully taken in early spring, 

dipped with a rooting hormone, and rooted with bottom heat. Softwood and 

hardwood cuttings root readily any time of year, but a 1000-ppm IBA dip should 

be used on cuttings taken in June and July. Hardwood cuttings, about 8–10" 

(20–25 cm) long, can also be stuck directly into the field in late winter–early 

spring (Dirr 1998). 

Seed: Seed should be stratified for 60–90 days at 41F (5C) (Dirr 1998).


CORNUS ALBA 217 

Culture: For best stem color, plant in full sun and in areas where constant 

moisture may be maintained. Plants are normally found in the wild in wet, 

swampy areas. Neither Cornus alba nor C. sericea perform well in the South. Susceptibility 

to canker and poor stem coloration limit their usefulness south of 

Zone 6. 

Habit: Plants are multistemmed shrubs with horizontal branches. The oneyear-old 

stems are relatively unbranched, making them particularly suitable for 

cutting. Plants spread readily by underground stems. 

Transplanting: Growers may direct-stick long cuttings or transplant rooted 

cuttings in the spring or fall. 

Spacing: Plants may be grown as large masses; the only concern is to allow 

room for efficient harvesting. Stoloniferous growth eventually results in close 

spacing. 

Fertilization: Reduce nitrogen fertilization in late summer. Excess fertilization, 

particularly nitrogen, results in soft growth and retards leaf drop and the 

development of stem coloration. 

Harvesting: All stems should be cut close to the ground by late winter to allow 

new growth in the spring. New stems have the most brilliant color in the spring 

and in the winter. The best color occurs in late winter on one-year-old stems. 

Yield: A massed planting can become a thicket, particularly if mismanaged. 

Three-year-old plants should yield approximately 25 stems. 


Stems are best harvested after the foliage has fallen in the fall and can be harvested 

until foliage emerges in spring. If foliage is removed, stems may be harvested 

whenever sufficient stem color has developed. Stems can be sorted by 

height; Huey Kinzie of Stoney Point Flowers in western Wisconsin bunches in 

lengths of 1–2' (30–60 cm), 3–5' (0.9–1.5 m), and 5–6' (1.5–1.8 m), each longer 

bunch demanding a significantly higher price. 

Postharvest 

The highest demand appears to be in October to December; demand is quite 

limited the rest of the year. Stems may be stored in a humid area at 28F ( −2C). Cold storage enhances stem color. When placed in water, branch color persists 

and some flowering may also occur. 

Cultivars 

Many cultivars are available, most differing only in their foliar characteristics. 

Few have more desirable stem color than the species. ‘Bloodgood’ has excellent 

showy red stems; ‘Kesselringii’ produces purple-black stems; and ‘Sibirica’ bears 

bright coral-red stems.

218 CORNUS FLORIDA 

A few cultivars also bear handsome leaves, which may have potential as cut 

foliage. ‘Argenteo-marginata’ (also sold as ‘Elegantissima’) has gray-green leaves 

with irregular, creamy white margins; ‘Spaethii’ produces green foliage with 

strong yellow borders. 


Many fungi enjoy the delicacies of dogwood including those that cause canker, 

leaf blight, leaf spot, twig blight, and mildews. Crown canker and twig blight 

can be particularly devastating to Cornus alba. 

Crown canker is caused by Phytophthora cactorum. Leaves curl and shrivel; later, 

twigs and even large branches die. Plants grown under stress (dry conditions, 

high temperatures) are more susceptible to canker. Plants may be treated in the 

early stages of infection, but once severely infected, plants eventually die. Cull 

badly affected plants. Rotate plants regularly to reduce the incidence of canker. 

Twig blight is caused by several fungi; application of fungicides to the foliage 

and stems helps the problem. 

Scale and bagworms also debilitate plants. 

Cornus florida flowering dogwood Cornaceae 

woody, Zones 5–9 Massachusetts to Florida white 1 

10–20'/20' (3–6 m/6 m) 

This plant offers something in all seasons for the designer: in spring, lovely flowers; 

in summer, handsome foliage; in fall, red fruits and colored leaves; and in 

winter, unusual buds. Since few flowers are sold during the natural flowering 

time outdoors, flowering dogwoods are sometimes forced. Generally, they are 

cut as a budded branch, and stems are stored and then forced for winter bloom. 

Propagation 

Budding: Most cultivars are budded on seedling understock in July and August. 

Cuttings: Collect softwood cuttings immediately after flowering. Treat with a 

quick dip of 1000 ppm IBA, and root in peat/perlite medium under intermittent 

mist (Dirr 1998). 

Seed: Seed requires 100–130 days at 41F (5C) for germination (Dirr 1998). 


Culture: Plants tolerate partial shade, although full sun is acceptable, and 

many more flower buds are formed. Foliage is more handsome in partial shade 

than in full sun. Acid soils, even moisture, and a cool root run are essential for 

maximum growth. Mulch is helpful, and good drainage is an absolute necessity. 

Habit: Plants are usually grown as a low-branched tree, but when cut, they 

may become more shrubby in appearance.

Transplanting: Usually transplanted to the field as budded whips or 1- to 2year-old 

seedlings. 

Spacing: No data are available, but a 5–7' (1.5–2.1 m) spacing should allow for 

sufficient room as long as branches are pruned annually. 

Harvesting: Harvest long branches back to a node, allowing approximately ⅓ 

of the branch to remain. 


CORNUS FLORIDA 219 

Forcing: Cut when buds are swollen. This may be accomplished 4–6 weeks 

prior to normal flowering time outdoors (Kasperski 1956). Place stems in water 

at 65–70F (18–21C). Use an acid preservative and change regularly. Flowers on 

stems cut in mid March require 2–4 weeks to open (Munroe 1991). 

Cut flowers: Harvest when the bracts are beginning to open but prior to pollen 

formation in the flower. Place the stems immediately in a floral preservative to 

reduce bacterial and fungal growth. 

Buds: Buds form in late summer and early fall. As soon as they are swollen, 

budded stems may be cut and used immediately. 

Postharvest 

Kasperski (1956) suggested that fresh flowers persisted 7–10 days if branches 

were split or crushed, although little evidence on the benefit of crushing stems 

has been recorded, and few growers “hack and whack” today. Condition by immediately 

placing stems in warm water (100F, 38C). 

Cultivars 

For cut stems, usually the species, grown from seed, is used; pink-flowered forms 

are vegetatively propagated. Dozens of cultivars have been selected for the landscape 

trade, however, and while they are more expensive, they may be useful in 

broadening the offerings of the niche grower. Dirr (1998) lists 90 taxa of flowering 

dogwood; some are notable for their variegated or colorful foliage, others 

for their large flowers, double flowers, or pink to red flowers. 


Plants are susceptible to several pests and diseases, among them borer, leaf, and 

petal spots. The more stress a tree is under, the more likely damage will occur. 

Dogwood anthracnose (Discula) has been a major concern for nursery growers in 

the North and Middle Atlantic states. Symptoms include irregular, purplerimmed 

leaf spotting or tan blotches; infected leaves that stay on branches after 

normal leaf fall; die-back of twigs; water sprout formation; and infection of 

bracts under rainy conditions (Dirr 1998). Trees are killed within 3 years of 

infection.

220 COSMOS BIPINNATUS 


Cornus mas (cornelian cherry dogwood) can be grown for its flowers and fruit. 

Plants grow 15–25' (4.5–7.5 m) tall and 15–20' (4.5–6 m) wide. Bright yellow 

flowers, which occur in ¾" (2 cm) wide inflorescences, appear in late winter in the 

South and early spring in the North. Harvest when flowers are open or when 

fruit has begun to turn red, but before the fruit begins to fall. The fruit ripens 

irregularly; some may be yellow, others red. Flowers persist 7–10 days and will 

store in the cooler for up to 2 weeks. The ½" (13 mm) wide fruit, formed during 

the summer, is a bright cherry-red. Trees perform best in the North and are hardy 

in Zones 4–7. 

Cornus sanguinea (bloodtwig dogwood) has mediocre reddish stems, brighter 

on the side toward the sun, but several better cultivars are available. One, ‘Midwinter 

Fire’, is reddish at the base, changing to orange and yellow toward the 

tips during the winter; needs to be cut back for best color. 

Cornus sericea (syn. C. stolonifera) is grown for its colorful stems. Some authorities 

believe it to be a subspecies of C. alba, which it resembles; indeed, few differences 

in habit or culture exist between these species. The species is highly susceptible 

to canker, hardy in Zones 2–7. Several cultivars of C. sericea enhance the 

offerings of the grower. ‘Cardinal’ bears cherry-red stems. ‘Flaviramea’ is a marvelous 

form with bright yellow stems; if grown well, it is unbeatable for color. 

‘Silver and Gold’ is a branch sport (chimera) of ‘Flaviramea’ and bears yellow 

stems; potentially useful for its irregular, creamy-margined foliage as well. 

Reading 




York. 

Munroe, C. L. 1991. A winter extravaganza: forcing cut branches for indoor 

bloom. Penn. Hort. Soc. (Jan.):15–18. 

Many thanks to Huey Kinzie for reviewing this section. 

Cosmos bipinnatus lace cosmos Asteraceae 

annual Mexico many colors 3–5'/2' (0.9–1.5 m/0.6 m) 

Cosmos is a common bedding plant; most plants used in American landscapes are 

either the dwarf sulphur cosmos (Cosmos sulphureus) or lace cosmos (C. bipinnatus). 

Sulphur cosmos is sometimes used as a cut flower, but lace cosmos is more 

popular, being taller and available in numerous colors.

Cosmos bipinnatus 

‘Daydream’


Propagation 

Seed emerges in 7–10 days if germinated at 70–72F (21–22C) under intermittent 

mist. Seed should be lightly covered for best germination. Approximately 

0.5 oz (14 g) of seed yields 1000 seedlings (Nau 1999). Direct sowing cosmos has 

become more popular every year, particularly for a second or third sowing. Sow 

at the rate of 0.45 oz per 100' (50 g per 100 m) (Kieft 1996), but field temperatures 

must be above 60F (15C) for best results. 

Growing-on 

Plants should be grown at 60–65F (15–18C). Low nitrogen fertilization is recommended. 

Apply 50–100 ppm N during the growing-on stage; higher nutrition 

results in tall, spindly growth. Green plants may be planted out 4–6 weeks after 

sowing. 


Photoperiod: Cosmos bipinnatus is a quantitative short day plant (Molder and 

Owens 1974). This means that, although plants flower more rapidly under short 

days than under long days, they eventually flower under all photoperiods. It may 

seem to make little sense initially that cosmos is a SD plant that flowers in the 

summer; however, the optimum photoperiod for flowering is less than 14 hours. 

Only when daylengths are greater than 14 hours is flower development delayed. 

Under LD, flower buds appear sporadically. The following table (Wittwer and 

Bukovac 1959) illustrates the effect of photoperiod on ‘Sensation’. 

The effect of photoperiod on Cosmos bipinnatus ‘Sensation’. 

Plants in Days to No. of Height 

Photoperiod flower (%) visible bud nodes (in) z 

9 hours 100 47 12 37.0 

18 hours 75 56 12 39.8 


Temperature: Cosmos is a heat-loving plant and grows and flowers well at temperatures 

above 60F (15C). Temperatures below 55F (13C) inhibit growth and 

flowering. 

Plant age: As plants mature, the need for short days decreases; therefore, older 

plants are more likely to flower under long day conditions than young plants. 

Plants with 6–8 leaf pairs are sufficiently mature to flower regardless of photoperiod 

(Molder and Owens 1974). 

Gibberellic acid: GA3 substitutes for short day treatments (Molder and Owens 

1974). Approximately 100 ppm GA will substitute for the need for SD; that is, if

plants are grown under LD (>14-hour photoperiod), and given GA, they will 

flower as rapidly as if grown under SD conditions (Wittwer and Bukovac 1959). 

The effect of photoperiod and gibberellic acid on Cosmos bipinnatus 

‘Sensation’. 

Photoperiod, Plants in Days to No. of Height 

GA treatment flower (%) visible bud nodes (in) z 

9 hours + 100 ppm GA 100 46 12 45.6 

18 hours + 100 ppm GA 100 46 12 48.4 


COSMOS BIPINNATUS 223 

Care must be taken when applying GA, however, as results have shown that GA 

is not as efficient as SD treatment, nor are GA-induced flowers as large as those 

induced under SD (Molder and Owens 1974). Plants treated with GA have elongated 

internodes and generally are of inferior quality. Seldom used by commercial 

growers except perhaps those in the far North or South, where summer 

photoperiods of less than 14 hours are difficult to attain. 


Space plants 9–12" (23–30 cm) apart; support mesh is necessary, especially if 

wind is a problem. Some growers plant on 8" (20 cm) centers and find that plants 

support each other; however, excessively dense plantings can encourage disease. 

Sequential planting (planting every 2–4 weeks) results in better-quality stems 

and less disease than harvesting from the same plants throughout the season. 

This is highly recommended in the South. Cosmos are less prone to deer browsing 

than many other annuals; this is thought to be because they produce repulsive 

odors when attacked (Ball 1997). As with most crops, the degree of deer 

resistance is dependent on deer population and availability of food. 

Fertilize with a granular 10-10-10 fertilizer or an application of 200 ppm N 

using a complete soluble fertilizer in early spring, when plants are placed in the 

field. Repeat in mid summer, but do not over-fertilize, or lanky, leafy plants will 

result. 

In order to encourage long stems, some growers pinch early, near the base of 

the plant. When Chas Gill of Bowdoinham, Maine, sets out cosmos, he prefers to 

pinch the plants to the first set of nodes; alternatively, he waits until the plants 

are about 18" (45 cm) tall, then trims them with hedge shears to 10–12" (25–30 

cm). He finds that plants so treated have a better branching habit and harvest is 

easier.



Space plants 6–9" (15–23 cm) apart. Apply LD (>14 hours) until plants have 

approximately 6 leaf pairs. Apply SD for most rapid flowering at that time. 

Remember that SD only have to be less than 14 hours. If stems are too short, continue 

LD for a longer period of time. Maintain temperatures of 60–65F (15–18C) 

or higher if accelerated flowering is desired. Provide as much light as possible. 

If short stems are needed, paclobutrazol (Bonzi) at 150 ppm is effective 

(Mohd et al. 1988) and daminozide (B-Nine) is also effective. Sprays can be 

applied early, but they should be used only if necessary, as flower size is generally 

reduced as well. However, if B-Nine was applied late (just before flower stem 

elongation), the tendency of flowers to droop is reduced and little flower size 

reduction occurs (Samata et al. 1974). 

Fertilize newly transplanted plants in the bench with 50–75 ppm N using potassium 

nitrate and continue with weekly applications of 150–200 ppm N from 

a complete soluble fertilizer. Do not overapply nutrients. 


Flowers may be harvested in colored bud, particularly if flowers are to be shipped 

or used for a wedding or other event where stems are already sold. Some growers 

harvest when petals (ray flowers) on the first flower are just opening but have 

not yet flattened out. If flowers are to be dried, allow the outer row of petals to 

fully open. Stage of harvest is quite important (see “Grower Comments”). 

Postharvest 

Fresh: Vase life is only about 4–6 days in water but can be extended with floral 

preservatives. Gast (1998) looked at several cultivars of cosmos and showed that 

a vase life of approximately 7–9 days is possible. 

Storage: Store stems at 36–40F (2–4C) for 3–4 days only if necessary. Storage 

is not recommended. 

Dried: Cosmos can be dried in silica gel (2–3 days) or borax (4–6 days). 

Cultivars 

‘Bright Lights’ is a mix of 30–36" (75–90 cm) tall reds, oranges, and yellows. 

Campus series grows to 3–5' (0.9–1.5 m) and comes in apricot and lemonyellow. 

Might be useful for fall designs. 

‘Candystripe’ has white, rose, or red flowers with crimson markings on the 

petals. Plants are 2½–3' (75–90 cm) tall. 

‘Collarette’ is a mixture of different colors of semi-double flowers, although 

single flowers are also present. Plants are 2–3' (60–90 cm) tall. 

‘Daydream’ produces handsome, pale pink flowers with a deep rose center 

on 3' (90 cm) stems. 

Giant Tetra series produces flower stems 40–48" (1–1.2 m) tall. Varieties 

include ‘Elysee’ (white), ‘Louvre’ (early, pink), and ‘Opera’ (appleblossom-pink).

COSMOS BIPINNATUS 225 

‘Klondyke’ occurs in mixed colors and grows 3–5' (0.9–1.5 m) tall. 

‘Picotee’ is a mix of flowers ranging from white with red edges to red with 

faint white markings. Plants grow 3–4' (0.9–1.2 m) tall. 

Pied Piper series bears flowers with rolled petals and a yellow center. Stems are 

approximately 36" (90 cm) long. 

‘Pink Fairytales’ bears sprays of pink and white daisy-like flowers on 2–3' (60– 

90 cm) stems. 

Polidor Mix has 3' (90 cm) stems with semi-double 2" (5 cm) wide flowers in 

a mix of red, gold, and orange. 

Psyche Mix has burgundy shades of semi-double daisies on 40–48" (1–1.2 m) 

stems. Some people love it, others miss the old-time singleness of flowers. 

‘Radiance’ has rose-crimson flowers. 

‘Sea Shells’ comes in a color mix and consists of interesting flowers with tubular 

petals and fluted edges. Most decorative. 

Sensation (Early Sensation) series bears 3" (8 cm) wide flowers in many colors. 

Plants generally grow 3–5' (0.9–1.5 m) tall. ‘Dazzler’ has fiery red flowers on 3' 

(90 cm) stems; ‘Gloria’, rose flowers with a carmine zone; and ‘Purity’ bears large, 

white flowers. In national trials, ‘Sensation Purity Superior’ produced 12 stems/ 

plant with an average stem length of 30" (75 cm) (Dole 1995). A long-time favorite 

of cut flower growers. 

Sonata is an outstanding series, with many bright colors and large flowers. 

‘Summer Garden’ is a pale yellow with a touch of pink in the center. Plants 

grow about 4' (1.2 m) tall, with stiff stems of 24" (60 cm). Highly daylength sensitive 

and difficult to flower in the spring. 

‘Vega’ is said to be an early-flowering form, although it has not been tested 

widely enough to verify. Produces 3" (8 cm) flowers in shades of rose, pink, and 

white, on 3' (90 cm) stems. 

Versailles series is a particularly good cut flower selection, although not as 

tall as some of the newer offerings, with large, single flowers with crimson rings. 

Originally available only in lilac-rose, now joined by carmine, blush-pink, lilacpink 

with crimson, pink, and white forms. Cultivars evaluated in national trials 

averaged approximately 16 stems/plant with an average stem length of 17½" 

(44 cm); ‘Versailles Carmine’ was particularly well-received (Dole 1995). 

‘Yellow Garden’ bears pastel yellow flowers on 3' (90 cm) stems. Tends to fade 

in bright light. 


Cosmos atrosanguineus (chocolate cosmos) bears single, occasionally double 

flowers of purple to red, and is not as vigorous or as floriferous as other species. 

In fact, the dark color of the flowers gets lost among other more sturdy, bigger 

plants. The petals are velvet, the color is chocolate-maroon. But the real kicker is 

that as you stick your nose closer, the unmistakable smell of chocolate fills your 

head. Plants grow 2–3' (60–90 cm) tall with 2" (5 cm) wide flowers. 

Plants grow from swollen tuberous roots; they are short-lived perennials in 

some areas, but for most of the United States, they should be treated as annuals.


Greenhouse studies in England (Kanellos and Pearson 2000) provided some useful 

information on the response of chocolate cosmos to temperature and photoperiod. 

When temperatures were raised from about 54F (12C) to around 80F 

(27C), plants emerged 17 days faster and plant height doubled, but flowers were 

smaller. Increasing temperatures had only a small influence on flowering time. 

Flowering was advanced by LD; plants grown at a 17-hour photoperiod flowered 

33 days faster than those at 8 hours and were far bigger and stockier. Long 

days and temperatures of 62–70F (17–21C) seem to make sense. 

Cosmos sulphureus is a good cut flower, but stem length may be too short, 

depending on your market. Photoperiod is more critical with this species. They 

are obligate SD plants, meaning that they must see SD (

CROCOSMIA HYBRIDS 227 

tial cuts are made deep into the plant; this may cause panic at first, but be patient—long 

stems are bound to follow. We tried ‘Versailles’ but it was too short. 

. . . We mainly grew Sensation varieties and ‘Psyche’, a double variety, I love it.” 

Linda Gill, Kennebec Flower Farm, Bowdoinham, Maine. 

“I’ve grown Cosmos bipinnatus ‘Summer Garden’ a few times and I can’t get it 

to flower until fall. It seems to be very daylength sensitive.” Betsy Hitt, Peregrine 

Farm, Graham, N.C. 

Reading 

Ball, S. 1997. Something in the air. Garden 122 (11):782–785. 

Biebel, L. H., and E. Z. Bailey. 1936. Temperature, photoperiod, flowering and 

morphology in cosmos and china aster. Proc. Amer. Soc. Hort. Sci. 34: 635–643. 


7(1):7–12. 

Gast, K. L. B. 1998. 1998 evaluation of postharvest life of selected fresh-cut flowers. 

Kansas State Univ. Agr. Exp. Sta. and Coop. Ext. Serv. Report 840. 

Kanellos, E. A. G., and S. Pearson. 2000. Environmental regulation of flowering 

and growth of Cosmos atrosanguineus (Hook.) Voss. Scientia Hortic. 83(3/4):265– 

274. 


Netherlands. 

Mohd, A., S. Gauri, and A. K. Muthoo. 1988. Effect of paclobutrazol on growth 

and flowering of cosmos (C. bipinnatus Cav.). Punjab Hort. Journal 28(1–2):105– 

108. 

Molder, M., and J. N. Owens. 1974. The effects of gibberellin A3, photoperiod 

and age on vegetative growth and flowering of Cosmos bipinnatus var. ‘Sensation’. 

Can. J. Bot. 52:1249–1258. 


Samata, Y., I. Kosei, and E. Hideo. 1974. Effect of B995, succinic acid, 2,2dimethyl 

hydrazide application on double cosmos (Cosmos bipinnatus) with 

special reference to the inhibition of peduncle elongation. Bul. Fac. Agr. Univ. 

of Tamagawa. 14:51–58. 

Wittwer, S. J., and M. J. Bukovac. 1959. Effects of gibberellin on the photoperiodic 

response of some higher plants. In Photoperiodism and Related Phenomena 

in Plants and Animals. R. B. Withrow, ed. American Assoc. Advancement of Science, 

Washington, D.C. 

Many thanks to Chas Gill and Pat Bowman for reviewing this section. 

Crocosmia hybrids montbretia Iridaceae 

bulb, Zones 5–9 hybrid origin many colors 2–2½'/2' (60–75 cm/60 cm) 

This genus contains about 7 species, but the main cut flower forms are hybrids, 

sometimes referred to as Crocosmia ×crocosmiiflora (and still sold as Montbretia,

228 CROCOSMIA HYBRIDS 

although that name is no longer valid). An underused cut, crocosmias provide 

flowers on thin, spike-like inflorescences (racemes); the flowers are 1½–2" (2.5–5 

cm) long and occur in many handsome colors. The fruit too is highly ornamental, 

and plants are often left in the field so that the fruiting stem rather than the 

flowering stem may be harvested in late summer and fall. The fruit vary in color, 

although most start greenish and turn maroon and rust in September and October. 

Plants are easily cold hardy to Zone 5 and have been left in the ground in 

Zone 4 with success. 

Propagation 

Plants emerge from corms, and 1- to 2-year-old corms may be purchased from 

specialty suppliers. Seeds require approximately 2 years to reach flowering size. 

Growing-on 

Place corms or plantlets immediately to the field, at a depth of about 2" (5 cm) 

below the soil. In more northerly zones, corms may be planted as deep as 6" (15 

cm) below the soil. Emergence will be less uniform with deeper planting. 


Spacing: Space plants (corms) approximately 6" (15 cm) apart. In coastal areas, 

particularly the West Coast, corms multiply rapidly and colonize the area. Most 

cormels (new corms), however, are too small to flower. 

Planting time: South of Zone 5, corms may be planted in January. The effect of 

different planting times in Zone 7b, Athens, Ga., is shown in the following table 

(Armitage and Laushman 1990). 

The effect of planting date on Crocosmia. 

Month First Harvest Stem 

planted Flw/corm harvest duration (days) length (in) z 

Jan 1.3 2 Jul 30 25.7 

Feb 0.8 15 Jul 25 20.2 

Mar 0.8 21 Jul 21 20.0 


Later planting extends flowering time but does not significantly affect yield. 

Stem length, however, is reduced as corms are planted later in the season. North 

of Zone 5, corms may be planted as soon as field conditions warrant. 

Longevity: North of Zone 5, corms should be lifted in the fall (similar to gladiolus), 

graded, and replanted in the spring; however, Susan O’Connell of Fertile 

Crescent Farm, Hardwick, Vt., reports that she has 100% return from corms in

Crocosmia ‘Lucifer’ 

her Zone 4 farm, without any special treatment. Longevity in Zone 7b is shown 

in the following table (Armitage and Laushman 1990). 

Longevity of Crocosmia in Athens, Ga. 

Year Stems/corm Stem length (in) z Stem width (mm) y 

1 0.9 22.2 4.9 

2 1.2 16.0 4.7 

3 2.0 20.0 4.5 



CROCOSMIA HYBRIDS 229

230 CROCOSMIA HYBRIDS 

Corms did not produce well in the fourth year; therefore, treat crocosmia as a 2–3 

year crop where corms overwinter. Corms are inexpensive and are often replanted 

each year. In southern and coastal climates, crocosmia is a 2–5 year crop. 

In areas of the West Coast, plants are considered almost invasive. 


Pods: Kent Miles of Seymour, Ill., has been harvesting crocosmia for many 

years: “For our market in this area, we can get a better price per bunch as fresh 

pods than as fresh blooms. So we wait and harvest the fresh pod stems in the fall 

—10 per bunch.” He has higher success when he plants in the spring, compared 

to the fall; fall-planted material suffers with the wetness of the soil and the cold 

temperatures in Zone 5: “We now know to lift in fall, store, replant in spring.” 

Flowers: The first few flower buds at the base should be showing color but 

need not be open (Vaughan 1988). If harvesting stems with fruit, do not allow 

the fruit to open. 

Postharvest 

Fresh: Flowers and pods should be handled similarly. Fresh stems persist 7–10 

days. They are sensitive to ethylene and must be stored away from fruits and 

vegetables (Vaughan 1988). Flower buds and pods are fragile, so handle cut 

stems with care. 

Storage: Stems may be stored dry for up to 4 days at 34–37F (1–3C), although 

storage in water is recommended (Vaughan 1988). 

Dried: Flowers may be air-dried upside down in small bunches in a warm, dry 

place. The strap-like leaves are also useful and provide a fresh look to a dried 

arrangement. If bunches are hung with plenty of air circulation, they retain their 

original color (Bullivant 1989). 

Cultivars 

Only a few of the many cultivars seem to have found their way into cut flower 

markets. The parentage of many of them is not known; all are thought to be 

hybrids. Most were bred in England and may be difficult to obtain. 

‘A. E. Amos’ is a brilliant orange-red but has not performed particularly well 

in north Georgia. 

‘Bressingham Beacon’ produces many orange and yellow bicolored flower 

sprays on dark stems. Stunning. 

‘Bressingham Blaze’ has intense orange-red flowers on 2–3' (60–90 cm) tall 

plants. 

‘Citronella’ (‘Citrinum’) has small, pretty, orange-yellow flowers above light 

green foliage. 

‘Emberglow’ produces reddish burnt-orange flowers atop 2–3' (60–90 cm) 

plants.

CROCOSMIA HYBRIDS 231 

‘Emily McKenzie’, introduced in the mid 1950s, is truly impressive and still 

difficult to beat for vibrant color. The large orange petals contrast beautifully 

with the crimson throat. 

‘Firebird’ bears fiery orange-red flowers with a bright yellow throat. 

‘James Coey’ has deep red flowers with yellow centers. Not as vigorous as some 

of the new cultivars. 

‘Jenny Bloom’ is a vigorous selection with butter-yellow flowers on 2–3' (60– 

90 cm) plants. 

‘Lucifer’ is exceptional, the standard by which all other cultivars are measured. 

It has been grown in the United States for years, covered with scarlet-red 

flowers each summer, and has proven its value over and over. 

‘Météore’ bears red and yellow bicolored flowers in mid summer. About 2' 

(60 cm) tall. 

‘Norwich Canary’ is a late-flowered form with bright yellow flowers on 2' (60 

cm) plants. 

‘Plaizar’ is about 2½' (75 cm) tall with bright yellow-orange outward-facing 

flowers. 

‘Solfatare’, one of the oldest hybrids, was bred in the late 1800s by the French 

nursery Lemoine. It is 2' (60 cm) tall with apricot-yellow flowers and dark green 

leaves. 

‘Spitfire’ is a large plant with stunning orange-red flowers with a yellow 

throat. 

‘Star of the East’ is not as cold hardy as other cultivars but has handsome 

apricot flowers on 2–3' (60–90 cm) stems. 

‘Venus’ is only 18–24" (45–60 cm) tall and produces peach-yellow flowers on 

darkened stems. 

‘Vulcan’ is also relatively short, compared to ‘Lucifer’, and bears scarlet-orange 

flowers. 

‘Walburton Yellow’ has golden-yellow, upward-facing flowers. ‘Walburton 

Red’ has fire-engine-red flowers. 


“Regarding planting depth for crocosmia, in my experience 1" of soil cover is 

plenty. At deeper depths, corm sprouting is highly variable and prolonged.” Paul 

Sansone, Here & Now Garden, Gales Creek, Ore. 

“They don’t seem very prolific—I get a stem or two from each corm each year. 

They seem to ‘settle in,’ though, and I think they will continue to produce more 

and more. The open blooms are very fragile, and break off easily. Buds continue 

to open, but a rough customer in my crocosmia bucket can do a lot of damage 

very quickly. My vote for a vibrant orange that stops them dead in their tracks 

is Crocosmia ‘Lucifer’. Bright deep orange color, and when arranged with 

giant ‘Sungold’ sunflowers, customers are powerless. Their wallets jump out of 

their pockets as if under a spell.” Susan O’Connell, Fertile Crescent Farm, Hardwick, 

Vt.

232 DAHLIA HYBRIDS 

Reading 



Science 25:1236–1238. 




Ore. 

Many thanks to Kent Miles and Paul Sansone for reviewing this section. 

Dahlia hybrids Asteraceae 

bulb, Zones 7–10 hybrid origin many colors 2–5'/3' (0.6–1.5 m/0.9 m) 

Dahlias continue to be popular and are field-produced from Oregon to Minnesota 

to Florida as well as in Europe and Japan. Today’s cultivars, hybrids all, originally 

resulted from crosses of Dahlia pinnata and D. coccinea, and probably other 

species. Plants emerge from tuberous roots and bear tall, often hollow stems, 

opposite leaves, and terminal inflorescences. Although many colors and flower 

shapes occur (see “Cultivars”), most are classified as single (in which showy florets 

surround a central disk of smaller, yellow florets) or double (in which the colored 

florets predominate). Doubles are most common in cut flower use. Tubers 

must be lifted in northern states but may remain in the ground for up to 3 years 

in Zones 7–10. Flowers do not ship particularly well, making dahlias a good 

product for the local market. 

Propagation 

Most growers purchase roots from specialty suppliers, but dahlias may be propagated 

by seed, tubers, or stem cuttings. For seed germination, maintain 80–85F 

(27–29C), cover lightly, and place in an area of high humidity. Germination 

occurs in 10–12 days. Terminal cuttings can be taken from actively growing 

plants; however, the best results arise from tubers forced in the greenhouse in the 

winter. New shoots appear in about 2 weeks when greenhouse temperatures 

remain at 50–60F (10–15C). Select 2- or 3-node cuttings and place in a welldrained 

medium in a humid environment at 65–72F (18–22C). Roots should 

appear at the bottom of the pot in 3–4 weeks. Tubers may be divided, but tubers 

themselves cannot produce new buds. A piece of the old stem with a bud 

attached must be taken with each piece of tuber. Phil Clark, a small grower in 

Camden, Maine, works with dug tubers in the spring: 

Around the end of February or beginning of March, the tubers are brought 

out of storage. Up to that point they have been wintering in our cellar in 

plastic shoeboxes [filled with] vermiculite. The first thing I do is add a 

tablespoon of water to the vermiculite and introduce them to a warm area

Dahlia ‘Eveline’ 

DAHLIA HYBRIDS 233 

[because] I have consistently found that some dahlia tubers with an eye 

fail to sprout or send out feeder roots. In approximately 2 weeks, many of 

the tubers will begin to sprout (some varieties may take quite a bit longer). 

The tubers with sprouts are immediately potted up. The ones that haven’t 

are monitored weekly and potted when ready. They all have their own 

timetable. Even tubers of the same variety will send up sprouts at different 

times. After several weeks, the tubers that didn’t sprout are discarded. That 

way you don’t plant tubers that will never come up!


Growing-on 

Transplant seedlings or cuttings to 4–6" (10–15 cm) pots and grow at 60–68F 

(15–20C). Plants may be placed in the field as soon as danger of frost has passed. 

Place tubers in the ground as soon as soil temperatures remain above freezing. 


Photoperiod: Daylength has a direct influence on flowering and tuber formation. 

Long days (approximately 14 hours, depending on cultivar) cause faster flower 

initiation, but if daylengths are very short (8 hours), flowers usually fail to open. A 

large volume of research on various cultivars suggests that the percentage of flowering 

plants and the total production of flowers are optimized in daylengths of 

13–15 hours (Konishi and Inaba 1964, Durso and De Hertogh 1977). Daylengths 

below 11 hours and greater than 16 hours had a deleterious effect. Some older 

cultivars fail to flower when daylengths are greater than 16 hours (Konishi and 

Inaba 1964, 1966). Short days (12 hours or less) result in tuber formation for most 

cultivars (Moser and Hess 1968, Zimmerman and Hitchcock 1929). 

Temperature: The optimum temperature range for vegetative shoot development 

is 55–77F (13–25C), but optimum temperature for flower initiation and 

development is 50–59F (10–15C) (Dole and Wilkins 1999). Night temperatures 

between 50 and 86F (10 and 30C) do not affect flower initiation, but flower 

development proceeds more slowly at cooler temperatures (Mastalerz 1976). 

The greatest influence of cold temperatures is the breaking of tuber dormancy. 

If tubers spend at least 40 days at 32F (0C), dormancy is broken and normal 

shoot production occurs (Konishi and Inaba 1967). 


Planting: Place tubers or started plants in the field after all threat of frost. Late 

frosts check the emerging foliage and result in significantly delayed flowering. 

Unsprouted tubers may be planted earlier, but if planted when the soil is too 

cold, sprouting is delayed. The size of the tuber appears to have little to do with 

the resulting plant. 

Weed control: Research in Oregon (Maul 1999) showed that the herbicides containing 

the active ingredients oryzalin, isoxaben, or prodamine, alone or in combination 

(oryzalin and isoxaben, oryzalin and prodamine) significantly reduced 

weed populations when combined with hoeing. No phytotoxicity was noted. 

The combination of oryzalin and isoxaben (44 ml + 7 g/1000 ft2 ) resulted in best 

control. 

Spacing: Space 2' (60 cm) apart. More dense spacing results in tangled stems 

and poor air circulation—and greater disease problems. Planting up to 3' (90 

cm) apart results in more flowers and less disease but is an uneconomical use of 

space. In areas of cool temperatures and low humidity (e.g., coastal Northwest), 

closer spacing can be used without fear of disease, but don’t get greedy. 

Support: Unless excellent wind support is available, all plants used for cutting 

require some support to keep the plants from falling over, such as 4' (1.2 m)


bamboo canes (each plant is usually provided with 3 canes, forming a triangle, 

with the plants tied into the triangle), wire cages, a single stake per plant, rebar, 

or 2–3' (60–90 cm) tall wire runs. 

Mulch: Dahlias are shallow-rooted, and a root mulch should be liberally applied. 

Pine straw, bark, peat moss, manures, or lawn clippings may be used. 

Nutrition: Side dress with a complete granular fertilizer, such as 10-10-10, 

when tubers begin to sprout. Liquid fertilizer (300–600 ppm N) once every 2 

weeks is sufficient in most climates. 

Pinching: Pinching the terminal shoot encourages the development of the 

many side shoots, meaning more flowers are produced more rapidly, although 

flowering is delayed by 1–2 weeks. Pinch approximately 2" (5 cm) of growth 

when plants are about 2' (60 cm) tall. Some growers want to harvest the central 

flower, which is the largest and earliest; you must weigh the benefit of the price 

obtained for the earlier, larger flower against the cost of delay of axillary flowers. 

Disbudding: Most varieties bear flowers with small side buds beneath the center 

bud (like a chrysanthemum). Removal of the lateral flower buds yields larger 

flowers; allowing them to remain results in a spray inflorescence. Disbudding 

requires significant labor and some skill. 

Yield: Yield is highly dependent on cultivar; however, yields of 20 flowers per 

plant are not uncommon. Flowers are generally harvested in early summer and 

may continue to flower until frost. 

Longevity: In the South, where tubers are left in the ground, 3-year production 

from the same tuber is not uncommon. If tubers are lifted and stored properly, 

they may be used indefinitely. 

Lifting tubers: In northern states and Canada, tubers should be lifted after the 

first frost. Lift, clean, and store dry tubers in a well-ventilated room at 45–50F (7– 

10C). Clean the tubers well, using a brush if necessary to get rid of soil. Refer to 

Zantedeschia for additional guidelines on lifting tubers. 


With proper manipulation of photoperiod and temperature, dahlias may be 

forced year-round. When tubers arrive, plant immediately. If unable to plant, 

place tubers in cooler in the shipping containers at 45–50F (7–10C). 

Planting: Plant in ground beds or large containers around 12" (30 cm) in 

diameter. Water in well, and keep soils moist. 

Light and photoperiod: High light levels are required for best dahlia growth, and 

winter production often requires supplemental lighting. Shade may be needed 

for summer production. Provide daylengths of 11–14 hours; never allow daylengths 

to fall below 8 hours. Long days of 16 hours may delay flowering of 

newer cultivars but will not likely be detrimental otherwise (De Hertogh 1996). 

Temperature: Provide minimum night temperatures of 62–65F (17–18C); day 

temperatures of 73–77F (23–26C) are recommended. Avoid temperatures 

greater than 80F (27C), or quality will be reduced. The crop may be slowed down 

if temperature is lowered to 55F (13C). This is particularly useful when flower 

buds are in color, before the market is ready.


Pinching: As with other field-grown plants, dahlias may be pinched for additional 

flower production. Nonpinched plants may be more closely spaced than 

pinched plants. 

Scheduling: Depending on cultivar, plants flower 9–13 weeks from planting 

the tuber. The later the planting date, the more rapid the flowering. 


Dahlias should be harvested when the flowers are 75% to fully open, but before 

the outer petals begin to decline. If cut too early, dahlias fail to open, even in 

opening solutions. Flowers that do eventually open are often of poor quality. 

After harvest, immerse stems in warm water (130F, 54C) (Nowak and Rudnicki 

1990). 

Postharvest 

Fresh: Dahlias persist 3–5 days in water, 7–10 days if an opening solution is 

used (Nowak and Rudnicki 1990, Vaughan 1988). Harvest in the morning, and 

place stems immediately in hydrating solution. Some growers immediately put 

the cut stems in hot water, then allow the water to cool, before arranging. 

Dried: Dahlias are best dried in silica gel or sand; they shrink when air-dried. 

In sand, flowers take several days and up to 4 weeks to dry (Vaughan 1988). 

Storage: Flowers can be stored wet at 37–40F (3–4C) and about 80% humidity, 

but storage should be avoided whenever possible. 

Shipping: Always ship in water or preservative. 

Cultivars 

Dahlias are divided into various classes, some of which may be more useful in a 

particular market than others. Check with your supplier. 

Single dahlias Single row of ray petals. 

Anemone-flowered Usually disk flowers and ray flowers of different 

colors. 

Collarette One or more series of ray flowers. Above each 

series is a ring of florets (the collarette) only 1 ⁄2 the 

length of the rays and usually of a different color. 

May be single-, peony-, or double-flowered. 

Peony-flowered Usually 2 or 3 series of ray flowers and a single 

disk. 

Decorative Flower heads fully double, showing no central 

disk. A popular cut class. 

Pompon Similar to doubles but smaller. 

Cactus Flower heads fully double. The margins of the 

flowers are thin and elongated.



Dahlias are subject to viruses, insects, and a host of disease organisms. Slugs 

find them particularly tasty. Growing dahlias requires a preventative spray program 

for mildews, leaf spots, and Japanese beetles. Southern growers, in particular, 

must spray conscientiously, especially after afternoon thunderstorms. 


“Last year we planted dahlias in raised beds, covered with white plastic, and 2 layers 

of netting. After planting the tubers, set your posts at opposite ends of the 

bed. Run one layer of net about 6–8" above the bed. Then, run one more layer of 

net about 12" above the first layer of net. As the dahlias grow, raise the net to support 

the plant. I found that using this method rather than tomato cages (cost 

and space prohibitive), or using a fence, allowed for straighter growing stems 

and much easier access to the blooming flowers.” Joseph Caputi, Charlotte’s 

Garden, Louisa, Va. 

“I have never staked my dahlias; I cut stems that are 24–30" plus, every time I 

pick. This keeps the dahlias at a good height. If I have trouble with a dahlia that 

falls down or whatever, I quit growing it and find something else. If it doesn’t last 

in a vase for me, if I have to disbud too much, if the stem can’t hold the weight 

of the flower, if they shatter, etc., I discard it. Many reputable dahlia tuber producers 

have already done this for you, if you select tubers they recommend for 

cutting.” Janet Foss, J. Foss Garden Flowers, Everett, Wash. 

“On poppies and dahlias—dip in hot water for a few seconds when you get 

back to the packing shed, then into cool hydration solution (50% Hydraflor 100) 

and hold in cooler.” Ray Gray, Sunset Flowers of New Zealand, Oregon City, Ore. 

Reading 




Hall, Upper Saddle River, N.J. 

Durso, M., and A. A. De Hertogh. 1977. The influence of greenhouse environmental 

factors on forcing Dahlia variabilis Willd. J. Amer. Soc. Hort. Sci. 102:314– 

317. 

Konishi, K., and K. Inaba. 1964. Studies on flowering control of dahlia. Part 1: on 

optimum day-length. J. Jap. Soc. Hort. Sci. 33:171–180. 

———. 1966. Studies on flowering control of dahlia. Part 3: effects of day-length 

on initiation and development of flower buds. J. Jap. Soc. Hort. Sci. 35:73–79. 

———. 1967. Studies on flowering control of dahlia. Part 7: on dormancy of 

crown-tuber. J. Jap. Soc. Hort. Sci. 36:131–140. 

Mastalerz, J. W. 1976. Garden dahlias may have potential as a greenhouse crop. 

Daylength controls flower initiation. Penn Flow. Grower Bul. 287(1):4–6. 

Maul, J. L. 1999. Weed control in dahlias with isoxaben, oryzalin and prodamine. 

Proc. Western Soc. of Weed Sci. 52:25–29.

238 DELPHINIUM HYBRIDS 

Moser, B. C., and C. E. Hess. 1968. The physiology of tuberous root development 

in dahlia. Proc. Amer. Soc. Hort. Sci. 93:595–603. 




Ore. 

Zimmerman, P. W., and A. E. Hitchcock. 1929. Root formation and flowering of 

dahlia cuttings when subjected to different day lengths. Bot. Gaz. 87:1–13. 

Many thanks to Ken and Suzy Cook (first edition) and Phillip Clark and Howard 

Lubbers (second edition) for reviewing this section. 

Delphinium hybrids Ranunculaceae 

perennial, Zones 2–7 hybrid origin many colors 1 

3–4'/3' (0.9–1.2 m/0.9 m) 

A mainstay in the cut flower industry, delphiniums have been grown for years in 

North America, South America, and Europe. Current offerings are hybrids, 

mainly from Delphinium elatum and D. grandiflorum. They will continue to be popular, 

although the market fluctuates from year to year. In the southern states, 

delphiniums are field-planted in fall for spring flowering and treated as an 

annual; in the North, plants may be in production for up to 3 years. 

Two main forms of delphiniums are found in the trade. Elatum hybrids are 

generally double-flowered and densely flowered—the classic form of cut delphiniums. 

Belladonna (Bellamosa) hybrids are usually single to semi-double 

flowered, looser, and more open than the elatums. 

Significant differences occur between delphiniums and larkspurs (Consolida 

spp.), although the names are often used interchangeably. Consumers may be 

allowed to get them mixed up, but we, as an industry, should not. We are tired of 

reading about larkspurs being called delphiniums because someone thinks they 

sound better that way. Let’s get it right. For information about larkspurs, see 

Consolida. 

Propagation 

Seed: Lightly cover the seed and chill it (35–40F, 2–4C) for 2–4 weeks, after 

which temperatures of 65–70F (18–21C) may be used for germination (Carpenter 

and Boucher 1992). If prechilled, seeds germinate in 8–15 days. Nonprechilled 

seed will germinate erratically, continuing 2–3 weeks. Plugs are usually 

available and are recommended. 

Cuttings: Take 3–4" (8–10 cm) long terminal cuttings of new shoots arising 

from the base of the plant. The base of the cutting should be solid, not hollow. 

They will root in 3–4 weeks under mist or in a sweat tent in a sand/peat or peat/ 

perlite mixture. 

Tissue culture: Many hybrids are now produced from tissue culture and made 

available to the grower as plugs.

Growing-on 

DELPHINIUM HYBRIDS 239 

Delphinium ‘King Arthur’ 

Grow seedlings at 50–55F (10–13C) in the greenhouse or in cold frames and 

transplant when large enough to handle. Cuttings should be transplanted to 4– 

5" (10–13 cm) pots as soon as rooted and grown until ready for planting. For 

northern growers, seed sown in January will be ready for transplanting in March 

or April; for southern growers, seed should be sown in July for plants to be


moved outdoors by October. Growers in coastal, central, and northern California, 

Oregon, and Washington can plant out as late as June for flowering in September. 

Summer temperatures are too warm in other parts of the country to 

attempt such late plantings. 


Temperature: In general, cool nights, temperate days, and lots of light are recommended 

for growing delphiniums. Plants benefit from, but do not have an 

absolute requirement for, cold temperatures. That is, plants will flower the first 

year from seed without being exposed to chilling temperatures, but flower yield 

and quality will be enhanced if chilling is provided. Approximately 6 weeks at 

temperatures of 35–40F (2–4C) satisfy the vernalization requirements of most 

delphiniums (Wilkins 1985, Ogasawara et al. 1996); therefore, fall planting is 

recommended for most areas of the country. Temperatures above 70F (21C) 

reduce flower yield and size. Night temperatures of 55–60F (13–15C) are optimum 

for growth. 

Photoperiod: Long days hasten flowering, increase stem length, and improve 

quality in most delphiniums, particularly the belladonna forms (Wilkins 1985). 

Long days provided by nightbreak lighting from 10 p.m. to 2 a.m. reduced days 

to flower and increased yield in greenhouse-grown delphiniums (Garner et al. 

1997). High light levels in the winter are even more important than long days, 

especially in northern climates. 


Spacing: If used as an annual, plant at a density of as little as 9 × 9" (23 × 23 cm) 

or up to approximately 1 × 1' (30 × 30 cm); if more than one year of production 

is anticipated, plant up to 12 × 18" (30 × 45 cm). If crops are planted in the fall 

and again in the spring, harvest time is staggered over a longer period of time. 

Yield: The first year (after the first winter), 5–6 flowering stems/plant should 

be realized from Elatum hybrids. Up to 12 shorter stems may be harvested from 

belladonna types. 

Irrigation: Hollow stems remain on the plant after harvesting; overhead irrigation 

must therefore be avoided, or stem rot could become a serious problem. 

Support: Support may be necessary for the Elatum hybrids but not generally 

for the Belladonna hybrids. As temperatures rise, however, stems tend to fall 

over; support is useful for late harvests. 

Forcing: Plastic greenhouses, tunnels, or frames can be used over the outdoor 

crop in late February; flowering occurs approximately 30–40 days earlier than in 

nature. 


Seedlings or cuttings transplanted in August may be flowered in a cool greenhouse 

by January. Incandescent nightbreak lighting or daylength extension light-

ing (>14 hours) will accelerate flowering, although plants will still flower under 

natural SD if light intensity is sufficiently high. In northern latitudes, high-intensity 

discharge lamps are highly recommended. Two to 3 croppings may be cut 

from each plant. Harvesting will finish when cool greenhouse temperatures can 

no longer be maintained. Avoid temperatures above 75F (24C); long spindly 

stems result otherwise. Similarly, fertilizer concentrations greater than 100–150 

ppm N should be avoided. Use at least one layer of support netting. 

Temperature in the greenhouse is important. Trying to raise high-quality 

flowers when average day/night temperatures are consistently above 75F (24C) 

is difficult. Effective greenhouse cooling is essential to maintaining quality material. 

A study in Japan used air conditioning for a small section of a greenhouse to 

keep seedlings sown in May at around 68F (20C)—at least 18F (10C) lower than 

the control. They used the AC until temperatures cooled in the fall, when seedlings 

were transplanted to final beds. Those that were cooled produced highquality 

flowers in January; those that were not bolted earlier and were of poor 

quality (Hirai and Mori 1999). Expense was not considered. 

Elatum forms should yield a minimum of 4 stems/plant per year for a period 

of 3 years, in a good greenhouse environment, belladonnas 6–8 stems/plant per 

year. 

Pinching plants may be an effective means of lengthening harvest time 

(Armitage 1995). Garner et al. (1997) found that pinching delayed flowering, 

but yield was not significantly different under natural SD. In LD, yield was 

enhanced by pinching. 






‘Pacific Giant’ 


(%) 

N P K Ca Mg 

3.2 0.33 3.52 2.86 0.70 

(ppm) 

Fe Mn B Al Zn 

617 59 18 517 35 


Harvest stems of Elatum hybrids when ¼ to ⅓ of the flowers on the stem are 

open, Belladonna hybrids when 75–90% of the flowers are open. Immediately 

after cutting, place flowers in a clean bucket containing a solution of silver thio-


sulphate, if available, for at least 4 hours. Don’t place the bucket in a cooler during 

this time. Then put the flowers in a bucket, also containing a bactericide, 

until ready for shipment. 

Postharvest 

Fresh: Delphiniums are very sensitive to ethylene, which causes flower drop, 

incomplete flower-setting, and a short postharvest life. A good deal of research 

has been conducted in recent years on flower treatments. Flowers of delphinium 

are sensitive to ethylene and if not treated with STS, they shatter readily (Song et 

al. 1995). Various products have been tested, and although vase life in water is 6– 

8 days (Wilkins 1985), it is significantly enhanced by pulsing cut stems with a 

preservative containing silver thiosulfate (STS). 1-MCP is also effective. 

Bacteria also reduce vase life by obstructing water uptake and causing slimy 

stems, which are much less attractive to buyers. Using a bactericide in the 

postharvest mix lessens this problem; many products from America and from 

Europe are available. 

Stems may be stored upright in water for 1–2 days at 38–41F (3–6C). Plants 

exhibit a geotropic response, and stems should be stored upright whenever possible 


Dried: Most dried “delphiniums” are actually larkspur. True delphiniums may 

be dried if cut before the bottom flowers drop. If picked after that time, ⅔ of the 

flowers will end up as confetti. After leaves have been stripped, the inflorescence 

should be hung in small bunches upside down. When the flowers feel papery, 

they should be stood upright to finish drying. The closed flowers may partially 

open again, providing a more natural look (Bullivant 1989). 

Cultivars 

Dozens of cultivars, many of them European introductions, are available 

through seed producers and perennial plant growers. 

Belladonna hybrids 

Arrow series is not yet proven commercially, but it is being tested in Holland 

and should soon make its way to America. ‘Janny Arrow’, with single sky-blue 

flowers, is the latest of the 12 colors. 

Bella series has plants in blue and light blue. 

‘Belladonna’ bears light blue flowers and is very similar to the garden variety 

‘Clivendon Beauty’; ‘Bellamosum’ has deep blue flowers. Both are old-fashioned 

cultivars, yet still quite popular. 

‘Blue Shadow’ is an excellent cultivar for warm areas. Plants are 2–3' tall (60– 

90 cm), and the leaves are deep green. Recommended for areas of California, 

Florida, and others where soil temperatures are a little too warm for high-quality 

delphiniums. Plants also appear to have good resistance to powdery mildew. 

‘Casa Blanca’ produces white flowers.


‘Oriental Blue’ bears blue flowers and appears to be a good form, particularly 

for southern growers. 

‘Volkerfrieden’ (‘International Peace’) bears vibrant blue flowers on 3–4' (0.9– 

1.2 m) stems. Plants flush up to 3 times a year and may be planted as close as 9" 

(23 cm) apart or about 2 plants/ft 2 (22 plants/m 2 ) in the greenhouse. A standard 

in the industry. 

Elatum hybrids 

Aurora series is available in blue or lavender, each with a white eye. Plants 

grow about 4' (1.2 m) tall. 

‘Clear Springs’ is considered a more compact 2½–3½' (75–110 cm) series. 

Greenhouse production requires one layer of netting; field production can be 

accomplished with none. Growers in the ASCFG’s 1998 National Seed Trials 

reported good production even throughout a hot summer. Includes lavender, 

light blue, mid-blue, rose-pink, white, and a mix. An improvement over Pacific 

Giant. 

Magic Fountain series probably derived from the Pacific Giant group of delphiniums. 

They are 2–3' (60–90 cm) tall and are offered by many seed producers. 

Pacific Giant series (Giant Pacific Court hybrids) are 4–5' (1.2–1.5 m) tall with 

flowers of various colors, including ‘Astolat’ (lavender-pink), ‘Black Knight’ 

(dark purple), ‘Galahad’ (white), and ‘King Arthur’ (dark blue). All have double 

flowers, often with the center (bee) a different color than the rest of the flower, 

and most are available from seed. 

‘Princess Caroline’ provides immense flowers of salmon-pink. Almost too big. 

‘Red Caroline’, a selection of ‘Princess Caroline’, bears red flowers on 28–36" 

(70–90 cm) stems. 


Delphinium cardinale ‘Scarlet Butterfly’ has scarlet-red flowers; ‘Yellow Butterfly’ 

bears bright yellow flowers. Beverly Hills series grows 4–5' (1.2–1.5 m) tall 

and is available from seed or in plugs, in salmon, scarlet, or yellow flowers. Susceptible 

to overwatering and powdery mildew. 

Delphinium nudicaule has orange-red flowers, and D. semibarbatum (syn. D. zalil) 

has yellow blossoms. Neither has the classic style and grace of the hybrids, 

but they may find a niche in the delphinium market. They are available from 

seed. 

Delphinium yunnanense is from the Yunnan province of China. ‘Blue Bouquet’, 

with droopy inflorescences of gentian-blue flowers, may be a form of it or a hybrid 

involving it. Pretty, and a little different from other blue delphiniums. 


Black spot (Pseudomonas delphinii) results in large black spots on stems and leaves. 

Good air circulation and low humidity are helpful in reducing incidence of the 

disease. Cull infected plants.


Phoma xanthina is common and causes regular, brown-black, round or oblong 

spots on the leaves. 

Crown rot (Sclerotium rolfsii var. delphinii) causes the plant to wilt and fall over. 

Apply a general fungicide when plants are young. 

Powdery mildew can be a serious problem in the field and the greenhouse, 

especially when the weather is wet and cloudy. 

Viruses result in misshapen shoots and stunted growth. Yellow spots, which 

become necrotic, also can appear on the foliage. Control of thrips and aphids is 

essential. 

Caterpillars and slugs in the field, and thrips and aphids in both the greenhouse 

and field, can also cause significant headaches. 


“I grow a lot of delphinium. I plant them mainly in the fall and a backup lot in 

the spring. I treat them as annuals because we pick them so heavily. I grow them 

in the ground and in black cloth. If you use black cloth, they need a mulch to 

deflect the heat. Delphinium are very sensitive to slugs; in my experience, they do 

best when planted far from grassy paths that may be hosts to slugs. I use wire 

meshing about 2' from the ground to keep the stems straight, as we get a strong 

crosswind in the evening. I grow mostly Pacific Giants, as they produce wonderful 

long stems and also lots of shorter stems for the florists who prefer those. My 

choice for a bee is always white, mainly because the flower is sharper and it does 

not bleed if watered overhead. We compost heavily and feed them with chicken 

manure after every flush. I dry every stem I don’t sell fresh.” Joan Thorndike, Le 

Mera Gardens, Ashland, Ore. 

“I think ‘Oriental Blue’ is the best bellamosa type, hands down.” Frank Arnosky, 

Texas Specialty Cut Flowers, Blanco, Tex. 

Reading 

Armitage, A. M. 1995. Bringing cut flowers out of hibernation. Greenhouse Grower 

13(13):78–80. 



Carpenter, W. J., and J. F. Boucher. 1992. Temperature requirements for storage 

and germination of Delphinium ×cultorum seed. HortScience 27(5):989–992. 

Garner, J. M., S. A. Jones, and A. M. Armitage. 1997. Pinch treatment and photoperiod 

influence flowering of Delphinium cultivars. HortScience 32(1):61–63. 

Hirai, H., and G. Mori. 1999. The utilization of a spot air-conditioner in raising 

seedlings for rosetting prevention in Eustoma and Delphinium. Environmental 

Control in Biology 37(3):191–196. 



Ogasawara, N., T. Hiramasu, and H. Takagi. 1996. Effects of low temperature on 

the flowering in Delphinium ‘Blue Bird’ seedlings. J. Jap. Soc. Hort. Sci. 64(4): 

890–904.

DIANTHUS BARBATUS 245 

Song, C. Y., C. S. Bang, Y. S. Park, and S. K. Chung. 1995. Effects of pretreatment 

and cold storage on vase life and quality of hybrid delphinium (Delphinium 

×elatum). J. Korean Soc. Hort. Sci. 36(3):426–431. 

Wilkins, H. F. 1985. Delphinium. In The Handbook of Flowering. Supp. A. H. Halevy, 


Many thanks to Jack Graham (first edition) and Jeff McGrew (second edition) for 


Dianthus barbatus sweet william Caryophyllaceae 

biennial, Zones 3–7 southern Europe many colors 1 

1–2'/2' (30–60 cm/60 cm) 

Although technically a biennial (plants flower after 2 years, then die), sweet william 

may reseed itself and persist more than 2 years. Plants require a cold period 

in order to flower and are therefore often planted in the fall. New colors and cultivars 

more suited to cut flower production are constantly being introduced. 

Propagation 

Seed: Approximately 0.06 oz (2 g) of seed is needed for 1000 transplants (Nau 

1999). Plants for spring flowering are sometimes direct sown in July through 

September at 0.1 oz/100 ft (0.1 g/m) (Kieft 1996), but transplants are more common. 

Seed sown at 65–70F (18–21C) under intermittent mist or a sweat tent 

germinates in 7–10 days (Nau 1999). Cover seed very lightly or not at all. 

Cuttings: Plants may be propagated by stem cuttings, but for economic reasons, 

this is seldom practiced. 

Growing-on 

Plants raised in the greenhouse should be sown in late summer and grown at 55– 

60F (13–15C) if possible. Fertilize with 100–150 ppm N using a balanced fertilizer. 

Plants should be ready to place in the field in 4–8 weeks. 


Temperature: Most cultivars of sweet william require vernalization, and seedlings 

seldom flower well without exposure to chilling. This is not the case with 

Dianthus hybrids (‘Bouquet Purple’, for example, which see), or with bedding 

plant forms, such as Ideal or Telstar series. Flower initiation occurs only after the 

cold treatment has been fulfilled. The cold treatment consists of 40F (4C) temperatures, 

but the length of time for vernalization varies considerably among 

cultivars. Interspecific hybridization has resulted in vernalization times of 3–12 

weeks; however, seedlings must be established prior to the onset of cold: usually 

8–12 weeks are needed before they are responsive to the cold. Unrooted cuttings

246 DIANTHUS BARBATUS 

can be vernalized during the rooting process, but results are contradictory. The 

use of supplemental light to enhance the rooting of cuttings reduces the amount 

of chilling needed. If temperatures above 100F (38C) occur immediately after 

the cold treatment, the benefit of the cold treatment disappears (devernalization) 

(Cockshull 1985, Takeda 1996). 

Photoperiod: Photoperiod has little effect on flowering if plants are vernalized. 

If plants have not been vernalized sufficiently, then LD accelerates flowering 

slightly and may produce a higher percentage of flowering plants (Cockshull 

1985). If plants have received no cold, flower buds will initiate in SD during the 

winter (Takeda 1996). 


Yields of 4–10 stems/plant are not uncommon. Transplants should be placed in 

the field early enough for plants to establish themselves before cold weather 

arrives. If direct sown, seedlings should be thinned to 6–8" (15–20 cm) in the 

row (Post 1955). If planted in the spring or summer, flowering will not occur 

until the following spring. 


Because sweet william is a cool-loving plant, the greenhouse may be maintained 

at 45–50F (7–10C); it is therefore relatively inexpensive to force sweet william 

into flower. Plants (seedlings or cuttings) should be grown for 8–12 weeks at 

55–60F (13–15C) before applying the necessary cold treatment. When plants 

have sufficient roots and 6–12 leaf pairs, temperatures should be reduced to 40– 

45F (4–7C) and maintained. Plants flower as temperatures increase in the spring. 


Harvest when 10–20% of the flowers in the inflorescence are open. 

Postharvest 

Fresh: The use of STS and 1-MCP enhances vase life. The vase life of flowers 

treated with 1-MCP was up to 4 times greater than control plants (Serek et al. 

1995). Flowers persist 7–10 days. 

Storage: Flowers may be stored dry at 34–36F (1–2C) or wet at 40F (4C) for 7– 

10 days. Few differences have been seen between wet and dry storage (Bang et al. 

1996); however, treatment with an ethylene inhibitor is recommended. 

Cultivars 

Single and double forms are available, nearly all from seed. Time from sowing to 

harvest is approximately 40 weeks. Hybrid cultivars, with Dianthus barbatus as

DIANTHUS BARBATUS 247 

one of the parents, are listed separately. All cultivars are 18–24" (45–60 cm) tall 

unless otherwise noted and available in single or mixed colors. 

‘Diadem’ bears single, crimson flowers with a pale eye. 

Double Mix consists of double flowers in a wide range of colors. 

Electron Mix includes red, rose, pink, lavender, salmon, and white on 24–30" 

(60–75 cm) stems. Flower heads are about 3½" (9 cm) across. 

‘Giant White’ produces large, white flowers. 

‘Harlequin’ grows 2' (60 cm) tall and bears flowers that change from rose to 

pink as they mature. 

Messenger series is an early-flowering mixture of single flowers. 

‘Newport Pink’ is an exceptional cultivar with deep salmon-pink, single 

flowers. 

‘Nigricans’ has dark crimson, single flowers with bronze foliage. 

Parachute series consists of early single-flowered forms. Red with green leaves, 

red with bronze foliage, and white-flowered selections are available. 

‘Pride of Park Avenue’ is a mix of 18–24" (45–60 cm) tall flowers with excellent 

yields and field performance. 

‘Super Duplex’ bears double flowers in a mix of colors. 

Hybrids 

Many hybrids of Dianthus barbatus with other species have been bred as bedding 

and pot plants, including such well-known series as Telstar, Princess, and Ideal. 

They are excellent bedding and landscape plants but, because of stem length, 

have not been used for cut flower production, particularly in the field; however, 

a few excellent cultivars of Dianthus hybrids are quite useful for cut flowers. 

Although none require vernalization, growing them with cool temperatures is 

recommended. 

‘Amazon Neon’, the first color offered in the Amazon series, looks to be a 

winner. Blooms first year from seed, but treat as a short-lived perennial in subsequent 

years. 

‘Bouquet Purple’ is an excellent landscape and cut flower selection. Recommendations 

by Katz and Kreidermacher (2000) suggest a spacing of 3–4 

plants/ft2 (32 plants/m2 ). If planted in the fall, crop time in coastal California is 

14–18 weeks from sowing, for spring plantings, 12–13 weeks. Flower stems are 

taller when fall-planted. In trials at the University of Georgia, plants performed 

well when transplanted in October. Watch for more colors. 

Cinderella Mix is hardy in Zones 5–9. Stem length is 18–36" (45–90 cm). Colors 

include rose, salmon, pink, carmine, scarlet, and carmine with eye. It has a 

great deal of Dianthus barbatus in its parentage but still blooms the first year from 

seed. 

‘First Love’ produces flowers that change from white to soft pink and finally 

to rose-pink. Plants do not require cold to flower and can be forced year-round, 

although temperatures above 80F (27C) should be avoided; to produce sufficiently 

tall plants, they are generally greenhouse-grown at 55/65F (13/18C) 

night/day temperatures. Plants are spaced 9" (23 cm) apart and flower 100–110 

days from sowing.

248 DIANTHUS BARBATUS 

‘Hollandia’, a seed-propagated variety, performs best in cool summer conditions 

when grown as an annual. The mix contains single flowers in purple, red, 

pink, white, and bicolor. Flower stems are 24–30" (60–75 cm). 

Melody series blooms first year from seed but can be grown as a perennial. 

Plants come in blush-pink (flowers open white and then deepen), pink (an All- 

American Selection), and white. Plants performed well in trials in Georgia and 

have been a popular landscape and cut flower cultivar. 

Miss series is seed-propagated and generally sown in late summer or fall for 

spring flowering and planted to the field or greenhouse when plants have about 

6 leaves. Plants require cold temperatures for best performance; therefore, temperatures 

in the greenhouse should be lowered to about 40F (4C) when plants 

have produced 10–15 leaves. Maintain cool temperatures for 40–50 days, followed 

by 45/65F (7/18C) night/day conditions. In the field, plants can withstand 

− 15F ( − 26C) if properly acclimated. ‘Miss Biwako’ bears rose-red flowers on 

2' (60 cm) stems, ‘Miss Kobe’ has magenta-purple blooms, and ‘Miss Kyoto’ produces 

pink flowers. 

‘Oeschberg’ grows to 20" (50 cm) with purple-red flowers. 

‘Provencal’ is a mix that can be sown in January for June cutting. Greenhouse 

stems will reach 24" (60 cm); field plants may be shorter. 

‘Rainbow Loveliness’ is a seed variety with 18–24"(45–60 cm) stems. The 

fringed flowers are lilac, carmine, pink, white, or bicolor. 


Dianthus caryophyllus (carnation) is greenhouse-grown throughout the world 

but is not included in the context of this “specialty” book. Five spray types in the 

Gipsy series, however, are available: ‘Gipsy’ (lavender-pink), ‘Giant’ (larger but 

otherwise similar to ‘Gipsy’), ‘Pink’, ‘Bright Eye’ (white with dark pink eye), and 

‘Dark Eyes’ (large carmine eye). They may be planted outdoors in areas of moderate 

winters or grown in a cool greenhouse. 

Dianthus knappii (yellow pink—an oxymoron?) is occasionally used as a cut 

flower. Sometimes sold as ‘Yellow Beauty’. 

Dianthus plumarius (cottage pink) is also grown as a cut. Cultivars are available 

mainly in white (‘Musgrave’s White’) and pink (‘Spring Beauty’). 


Many diseases of carnations also infect sweet william. Do not grow sweet william 

and greenhouse carnations in the same bench. In the field, several diseases are 

particularly destructive to sweet william. 

Rust (Puccinia arenariae) can be a serious disease and is particularly destructive 

to the lower foliage. 

Wilt (Fusarium oxysporum var. barbati) manifests itself in a yellowing of new 

growth. Leaves point downward, and plants are stunted. Remove infected plants, 

and sterilize infected soil.

Dianthus plumarius

250 DIGITALIS PURPUREA 


“‘Hollandia’ grew beautifully for me, producing many stems per plant. When I 

thought about how much I saved not having to have a whole row of young 

plants not producing for a whole year, and no die back over winter, the seed 

seems cheap. The plants all produced flowers for me last year—beautiful colors, 

highly fragrant.” Susan O’Connell, Fertile Crescent Farm, Hardwick, Vt. 

“A couple years ago I grew ‘Provencal’—they look like sweet william and are 

annual-blooming like ‘Hollandia’—but the unique thing about this strain was 

that it bloomed all winter without protection; it went through a couple of 20degree 

spells, a few inches of snow, and still kept blooming. Because the weather 

was pretty hard on the blooms, they weren’t what I would consider sellable, but 

if they had been in a cold frame with top cover they would have been really nice. 

Even as they were, without any special treatment, they lasted 2 weeks in a vase. 

They grew about 18" tall, but in a greenhouse they will grow 24" tall. I mention 

this for those who are looking for crops for their cold frames.” Janet Foss, J. Foss 

Garden Flowers, Everett, Wash. 

Reading 

Bang, C. S., C. Y. Song, J. S. Song, K. Y. Huh, and H. K. Kim. 1996. Effects of pretreatment, 

storage methods, and preservative solutions on vase life and quality 

of Dianthus barbatus ‘Kag Kwang’. J. Agr. Sci. 38(1):621–626. 

Cockshull, K. E. 1985. Dianthus. In The Handbook of Flowering.Vol. 2. A. H. Halevy, 


Katz, P., and M. Kreidermacher. 2000. Double-duty beauty. Greenhouse Grower 

(July). 


Netherlands. 



Serek, M., E. C. Sisler, and M. S. Reid. 1995. Effects of 1-MCP on the vase life 

and ethylene response of cut flowers. Plant Growth Regulation 16(1):93–97. 

Takeda, T. 1996. The differences in the effects of low temperature and day length 

on flowering within seed-propagated Dianthus spp. and cultivars. J. Jap. Soc. 

Hort. Sci. 65(3):615–623. 

Digitalis purpurea foxglove Scrophulariaceae 

biennial, Zones 4–8 Europe purple 1–4'/2' (0.3–1.2 m/0.6 m) 

This is an underused cut flower, and we don’t know why. It is easy to propagate, 

easy to grow, tolerates cold, and produces spike-like flowers. That it is a biennial 

(requires a cold treatment, needs a winter to produce flowers) may keep some 

growers from producing it, but once in the rotation, plants can be harvested 

every year. The genus is best known for Digitalis purpurea, the common foxglove,

DIGITALIS PURPUREA 251 

but a few more species, true perennials, deserve to be looked at as cut flower 

crops. 

Digitalis purpurea is the source of digitalin, the powerful drug used for heart 

diseases. It was introduced into the London Pharmacopoeia in 1650, and the British 

physician William Withering published a clinical report on its usefulness in 

1785; but for centuries prior, all sorts of fabulous medicinal properties were 

attributed to these plants. In the 13th century, leaves were used to treat “scrofulous 

complaints,” and this is thought to be the origin of the family name. 

Propagation 

Plants are always propagated by seed. Seed is small and should not be covered. 

Sow at approximately 70F (21C). Direct sowing is not recommended; significant 

reduction in germination will occur. Plugs may also be purchased. 

Growing-on 

Grow young plants on at 58–62F (14–17C) night temperatures, the cooler the 

temperatures the better. Plants grow fine for 4–6 weeks in containers as small as 

a 72-pack flat to as large as 4" (10 cm) pot; they may be transplanted to the field 

in September–October. The popular ‘Foxy’ does not require cool temperatures 

to flower and can be started in a greenhouse in the winter for transplanting to 

the field in early spring. Grow on ‘Foxy’ at 48–55F (9–13C). 


Seed requires light to germinate; do not cover them. Foxgloves need a cold treatment 

for best flower production; if no cold is provided, some plants will flower 

(under long days), but the population will be uneven and a poor crop will result. 

The cold is usually provided by winter temperatures imposed on the plants. In 

Zones 4–8, natural winters suffice for flowering; in Zones 3 and 4, plants should 

be cooled in a greenhouse or cold frame prior to planting out for summer production. 

In mild winters, Zone 8 plants may not receive sufficient cold. Vince- 

Prue (1975) suggested that a temperature below 46F (8C) was needed for several 

weeks. Work at Georgia with noncooled plants showed that long days 

(nightbreak lighting) could substitute for the cold but that the crop was not 

uniform; no flowering occurred under short days if cooling was not provided. 


Location: All foxgloves perform better with afternoon shade. Full sun in the 

winter and early spring is not a problem but will result in wilt and poor flower 

stems if harvests persist into the summer. 

Transplants: Place transplants in the field in the fall, early enough so that they 

have time to grow before the onset of freezing temperatures. If placed in the 

ground too late, some plants will die. In Zone 4 and below, plants cooled in the

252 DIGITALIS PURPUREA 

greenhouse or cold frame will flower the same summer; otherwise, they will not 

flower until the following year. 

Spacing: Place plants 12–15" (30–38 cm) apart. Stake only if winds are a 

problem. 

Yield: Mature plants should yield 2–4 stems/plant. A second flush of shorter 

flowers may occur in more northerly latitudes. In Zones 6–8, some small secondary 

flowers may form, but their value is marginal. It is probably better to 

replace the foxgloves after first flowering with a different crop. 


Little forcing is done; however, the plugs may be cooled for 8 weeks, then placed 

in the greenhouse in large containers or in ground beds. Plants will flower 

regardless of photoperiod. If LD are provided, a higher percentage of flowering 

plants will occur. Force at temperatures of 55–65F (13–18C). Flowers occur 

approximately 12 weeks after transplanting to the greenhouse. 


Harvest when 2–3 lower flowers are beginning to open, or as late as when ½ the 

flowers are open (Dole and Wilkins 1999). 

Postharvest 

Cut flowers should be immediately rehydrated and cooled. Fresh flowers persist 

for approximately 7 days. 

Cultivars 

All but ‘Foxy’ should be treated as biennials. 

‘Alba’, a good, clean white form of the species, is particularly sought after. 

‘Apricot Beauty’ is about 4' (1.2 m) tall with handsome apricot-orange flowers. 

Excelsior hybrids produce their flowers around the entire flower stalk and 

are held more upright than those of the species. The 2–3" (5–8 cm) flowers are almost 

horizontal, allowing an easier view of the handsome markings. Plants grow 

5–7' (1.5–2.1 m) tall. A dwarf Excelsior mix with 2' (60 cm) tall stems is also 

available. 

‘Foxy’ is only 1–2' (30–60 cm) tall but has more side shoots than others. Flowers 

in a mixture of colors are produced the first year from seed. 

Giant Shirley hybrids are 4–5' (1.2–1.5 m) in height, with the potential of 

reaching up to 8' (2.4 m). The large bell-shaped flowers are densely packed and 

usually mottled in shades of pink. 

‘Snow Thimble’ is a pure white cultivar. 

‘Sutton’s Apricot’ bears large flowers in fabulous shades of apricot and 

salmon.


DIGITALIS PURPUREA 253 

Most are hardy in Zones 5–8, but some will overwinter to Zone 4. Few have been 

tested for postharvest or other characteristics, but all are available to the cut 

flower grower. All are true perennials, not biennials. 

Digitalis ferruginea (rusty foxglove) has rusty red and white flowers on 3–4' 

(0.9–1.2 m) flower stems. Unusual, may have potential as a cut flower. 

Digitalis grandiflora (syn. D. ambigua; large-flowered foxglove) is a perennial species 

and among the best performers in the genus. The 2" (5 cm) long pendant 

flowers, pale yellowish on the outside and netted with brown on the inside, are 

mainly borne on one side of the inflorescence. The more we see this plant, the 

more we are taken with its understated charm and tough disposition. Excellent 

heat tolerance. Seed germinates rapidly at 70–75F (21–24C) and high humidity. 

Digitalis lanata (Grecian foxglove) has 1" (2.5 cm) long pale flowers held in an 

erect, dense inflorescence. The flowers are almost white with purplish netting 

within. Only 1–2' (30–60 cm) tall, and, unlike other species mentioned here, the 

lower lip of its flower is longer than the other flower segments. Flowers are interesting, 

and few buyers have seen them. 

Digitalis lutea (yellow foxglove) also bears yellow flowers, but they are much 

smaller (¾", 2 cm) and more numerous than those of D. grandiflora. A tough perennial 

but not as heat tolerant as D. grandiflora and seldom grown in the South. 

Digitalis ×mertonensis (strawberry foxglove) is a hybrid that produces handsome, 

pale strawberry-red flowers on short (1–2', 30–60 cm) plants. Good-looking 

foliage as well. 

Digitalis viridiflora (green foxglove) is more interesting than colorful. If designers 

need a greenish yellow flower that complements green foliage in the bouquet, 

this may be worth growing. Plants are 2–3' (60–90 cm) tall. 


Aphids and thrips can be very troublesome. Preventative programs must begin 

as soon as temperatures rise above 50F (10C). In hot weather, plants will succumb 

to root rot organisms; if plants have already flowered once, simply remove 

them. 


“Large digitalis is harder to get and as desirable as large delphiniums (in my market 

area) and priced approximately the same. . . . Aphids can be a problem if you 

don’t watch closely. One spring I just had a major blowout; didn’t know anything 

could multiply that fast. Foxglove seed was very easy to start. Whatever 

system you use to grow plants, put the seed on top of the media. Took a few days 

to come up, and I swear it was 110% germ. The seeds are tiny, so very easy to get 

it too thick.” Ann Trimble, Trimble Field Flowers, Princeton, Ky. 

“I have grown digitalis every year I’ve been in business and tried most of them. 

I’ve finally narrowed down to growing just ‘Alba’. The ‘Alba’ is sown in July, and 

the plugs are put out in Sepember and covered with row cover. The initial flush

254 ECHINACEA PURPUREA 

the next June is the best, and while we have been able to keep the plants producing 

shorter spikes in July and August, I think we’ll plow them down sometime in 

July and plant something else, like late sunflowers. We easily sell the initial stems 

for $7.50 per bunch to florist and $1 each at the farmers’ market. Our biggest 

problem is thrips! If we don’t spray for them (it’s the only insect I spray for on 

this farm), then we don’t have any stems to sell at all.” Bob Wollam, Wollam 

Gardens, Jeffersonton, Va. 

“Here in northern Michigan, we grow ‘Foxy’ foxglove every year, starting it 

around the 21st of February. It is one of the first to bloom in the spring, usually 

in June in cool summers; we have it all summer long. We don’t cover the seed 

when trying to germinate it, and it has a cooler germination temperature than 

many, at 65–70 degrees. ‘Foxy’ is grown as an annual for us—they are much nicer 

if new each year. As a cut flower, they do seem to last well if picked when only a 

few blossoms are open on the bottom. They sell medium well as a bunch, but we 

mostly use them in our mixed bouquets.” Phyllis Wells, Wells Family Farm, 

Williamsburg, Mich. 

“We started [‘Foxy’] in March last year, and they bloomed for us July, August, 

and September. Stems were way too short, about 12–16", and flower tubes 

spaced too far apart. We will not use this one again. We grew Shirleys . . . and 

Exclesior hybrids that should bloom for us this year. Shirleys planted the year 

before did dandy for us!” Michelle Smith, Blossoms, Inc, Fletcher, N.C. 

Reading 



Vince-Prue, D. 1975. Photoperiodism in Plants. McGraw-Hill, New York. 

Echinacea purpurea purple coneflower Asteraceae 

perennial, Zones 3–8 eastern United States purple 1 

3–4'/3' (0.9–1.2 m/0.9 m) 

Native from the Great Plains to Georgia to Louisiana, the species may be cultivated 

over a wide range of environmental conditions. Drooping, mauve-purple 

ray flowers surround a copper-brown cylindrical disk atop 3–4' (0.9–1.2 m) 

stems. They may be sold fresh as cut flowers, but often the petals are removed 

and the disk is sold as a dried flower. 

As a supplement for combating colds and flu, Echinacea, particularly Echinacea 

angustifolia, has become a bit of a medical celebrity. The chemical, pharmacological, 

and clinical applications of Echinacea have been the subject of more than 350 

scientific studies, which have proven coneflower’s tissue-regenerative, antiinflammatory, 

and immuno-stimulatory properties; and interest in the plant’s 

ability to help in the treatment of cancer, AIDS, and other debilitating diseases 

continues. More and more these plants are cultivated for their medicinal rather 

than their ornamental uses.

Echinacea purpurea ‘Bright Star’


Propagation 

Seed: Seed germinates in 15–20 days if sown at 70–75F (21–24C) and in the 

light under mist or a sweat tent (Pinnell et al. 1985). Cooler temperatures result 

in slower and less uniform germination. Approximately 0.25 oz (7 g) of seed 

yields 1000 seedlings (Nau 1999). 

Seeds of Echinacea can go into a deep dormancy. Priming in an aerated solution 

of distilled water containing 50 mM potassium nitrate for 6 days enhanced 

uniformity and rate of germination (Samfield et al. 1991); and GA3 was also 

found to enhance uniformity and rate if included in the priming substrate (Pill 

and Haynes 1996). Stratification at 40F (4C) for 4 weeks increases uniformity 

and germination percentage, and reduces the time to germination (Bratcher et 

al. 1993); and acid scarification enhanced germination of Echinacea angustifolia 

seeds (Feghahati and Reese 1994). Stratification should be routinely practiced. 

Division: Plants may be carefully divided in the spring or fall. Division may be 

accomplished every 3 years. 

Cuttings: In early spring, take root cuttings 1–3" (2.5–8 cm) in length and insert 

upright in a loose sand/peat mix (60/40, v/v). A mild concentration of rooting 

hormone is also useful. Cuttings may also be laid flat and barely covered 

with medium. 

Growing-on 

If seedlings are grown in plugs, grow for 4–6 weeks in full sun at 60–65F (15– 

18C) before transplanting to cell packs, 4" (10 cm) pots, or field. Fertilize with 

50–100 ppm N constant liquid feed using a complete fertilizer. If grown in seed 

flats, transplant to cell packs as soon as seedlings can be handled without damage 

(approximately 5–6 weeks). 

Divisions and root cuttings should be sorted to size; large propagules may be 

transplanted directly to the field, smaller ones may be placed in pots or cell packs 

and grown on in the greenhouse or cold frame. 


Cold is not necessary for flower initiation and development, although stem 

length and yield are greater when at least 6 weeks of temperatures at 40F (4C) are 

provided. When plants are grown to force flowers in the greenhouse, cooling the 

seedlings or plugs results in accelerated flowering. Plants require a LD for flowering, 

and flower more completely with nightbreak lighting (2–4 hours), cyclic 

lighting, or daylength extension between 12 and 16 hours (Finical et al. 1998). 

Little difference in stem length occurs between northern and southern plantings. 


Longevity: Expect 3–5 years of performance. 

Spacing: Space plants as close as 15 × 15" (38 × 38 cm) to as much as 2 × 2' (60 

× 60 cm). Plants spaced closer than 15" (38 cm) centers are more prone to foliar

ECHINACEA PURPUREA 257 

disease. If spaced greater than 2' (60 cm) apart, plants may require support. 

Research in Burlington, Vt., resulted in 15 stems/plant at a spacing of 2 × 2' (60 

× 60 cm) (Perry 1989). The average stem length was approximately 31" (78 cm). 


Few crops are forced for cut flowers in the greenhouse; however, work by Finical 

et al. (1998) provides guidelines for forcing flowers during winter months. They 

suggest growing-on plants at 68F (20C) under LD (>14 hours or night interruption) 

until at least 4 leaves have formed. Temperatures may then be set to 

time the crop. If forced at 63F (17C), 17–18 weeks are required; if forced at 73F 

(23C), flowering occurs in 14–15 weeks. Long days are necessary (14 hours or 

NI) until flower buds are visible. The difficulty in forcing is the tall, thin stems 

that result. Reducing the number of hours of exposure to incandescent lamps is 

recommended, and the cooler the forcing temperature (we recommend 50–55F, 

10–13C), the stronger the stems. More time is needed at cooler temperatures, 

but better stems result. Sumagic (15 ppm), A-Rest (100 ppm), B-Nine 

(5000 ppm), or other growth regulators can be applied once flowers begin to 

bolt; Bonzi appears to be ineffective (Finical et al. 1998). 


If sold as fresh flowers, harvest when petals are expanding and place in preservative. 

If used as a disk flower only, additional time on the plant is useful to color 

the disk and to allow easier removal of the petals. Place at 40F (4C) after harvest. 

Postharvest 

Fresh: Petals of the species (not necessarily the cultivars) tend to droop regardless 

of the time of harvest; this detracts from the beauty of the flower, and consumers 

may think the flower is wilted. Flowers last 7–10 days in preservative 

solution. 

Dried: Once petals are removed, the disk may be hung to dry and will last 

indefinitely. 

Cultivars 

Many of the cultivars differ only slightly in the color of the ray flowers (petals), 

and the angle at which the ray flowers are held in relation to the disk; those that 

are held at right angles are more appropriate as fresh cuts. Yellows, oranges, and 

other unheard of colors will hit the marketplace in the next few years. 

‘Abendsonne’ has lighter, more cerise-pink flowers than the species. 

‘Alba’ has creamy white flowers that contrast well with the copper-brown 

cone. Plants may be propagated from seed. 

‘Amado’ bears 4" (10 cm) white flowers on 36" (90 cm) stems.


‘Bravado’ has 4–5" (10–13 cm) rosy red flowers with excellent horizontal ray 

flowers. 

‘Bressingham Hybrids’ is a seed strain of ‘Robert Bloom’. Plants vary slightly 

from light rose to red and are excellent garden performers. 

‘Bright Star’ (‘Starbright’, ‘Starlight’) is a rose-colored, free-flowering cultivar 

that has performed well throughout the country. Plants are 2.5–3' (75–90 

cm) tall and seed-propagated, so significant variability occurs. 

‘Dwarf Star’ is a little shorter than ‘Bright Star’ and yields shorter stems for 

bouquet work. Seldom offered but a good plant. 

‘Kim’s Knee-Hi’ and ‘Kim’s Mop Head’ are dwarf forms with purple and white 

flowers, respectively. Not useful if long stems are desired. 

‘Magnus’ is a fine, 3' (90 cm) tall cultivar with large, deep purple flowers. Horizontal 

ray flowers are its claim to fame; but plants are seed-propagated and therefore 

variable, and many flowers do not hold out their petals. 

‘Overton’ is a seed-propagated form with drooping, rosy pink ray flowers. 

‘Robert Bloom’ bears 4–5" (10–13 cm) wide purple-rose flowers with upright 

petals on 3' (90 cm) stems. More commonly available in Europe than in the 

United States. 

‘Ruby Giant’ is vegetatively propagated and has 4" (10 cm) flowers on 36" 

(90 cm) stems. 

‘Ruby Star’ grows to 36–40" (90–100 cm) with carmine-red petals. 

‘The King’ is 4–5' (1.2–1.5 m) tall with rose-red flowers 4–5" (10–13 cm) in 

diameter. 

‘White Lustre’ differs from ‘White Swan’ by having more-horizontal ray flowers 

and a center a little more bronze-orange. Plants are often vegetatively propagated 

and so are more uniform. 

‘White Swan’ is a seed-propagated white form with drooping ray flowers. 


Echinacea angustifolia is a western species with a similar cone, but the petals 

are straplike and are not useful as fresh flowers. 

Echinacea pallida (pale coneflower) has narrow, drooping petals and is most 

useful as a dried cone. 

Echinacea paradoxa is the yellow purple coneflower, a paradox for sure. The 

ray flowers are yellow and outward-facing, and stems stand upright. Mimo Davis 

and Kelly Anderson of WildThang Farms in Ashland, Mo., think this species has 

great potential as a cut flower. 

Echinacea tennesseensis (Tennessee coneflower) has dark mauve, upturned ray 

petals and a greenish pink center. It has some potential for drying but probably 

not as good as cultivars of E. purpurea, and it is on the Federal Endangered Species 

list, so its availability is severely limited. 


Leaf spots (Cercospora rudbeckiae, Septoria lepachydis) result in marginal necrosis 

followed by blackening of leaves. Treat with a general-purpose foliar fungicide.


ECHINOPS BANNATICUS 259 

“The disks of our native Echinacea purpurea are coppery red, rather than brown. 

The color and intensity of the disk make it appear to glow, and it is excellent as 

a fresh cut, lasting about 2 weeks in the vase. Remove all foliage when bunching. 

The disk does turn brown when dried. Even when fresh, however, the disks of 

other species (E. pallida, E. tennesseensis) are brown and therefore not so useful as 

fresh cuts.” Mimo Davis and Kelly Anderson, Wild Thang Farms, Ashland, Mo. 

Reading 

Bratcher, C. B., J. M. Dole, and J. C. Cole. 1993. Stratification improves seed germination 

of five native wildflower species. HortScience 28(9):899–901. 

Feghahati, S. M., and R. N. Reese. 1994. Ethylene-, light-, and prechill-enhanced 

germination of Echinacea angustifolia seeds. J. Amer. Soc. Hort. Sci. 119(4):853– 

858. 

Finical, L., E. S. Runkle, R. D. Heins, A. Cameron, and W. Carlson. 1998. Forcing 

perennials: Echinacea. Greenhouse Grower 16(10):49–52. 



Athens, Ga. 

Pill, W. G., and J. G. Haynes. 1996. Gibberellic acid during priming of Echinacea 

purpurea (L.) Moench seeds improves performance after seed storage. J. Hort. 

Sci. 71(2):287–295. 

Pinnell, M., A. M. Armitage, and D. Seaborn. 1985. Germination needs of common 

perennial seeds. Univ. of Georgia Research Report 331. 

Samfield, D. M., J. M. Zajicek, and B. G. Cobb. 1991. Rate and uniformity of herbaceous 

perennial seed germination and emergence as affected by priming. 

J. Amer. Soc. Hort. Sci. 116(1):10–13. 

Many thanks to Leonard Perry (first edition) and Mimo Davis and Kelly Anderson 


Echinops bannaticus globe thistle Asteraceae 

perennial, Zones 3–8 southern Europe blue 3–5'/3' (0.9–1.5 m/0.9 m) 

Echinops bannaticus is the proper name for E. ritro, but since nobody pays much 

attention to botanical names anyway, it will likely continue to be grown and 

sold as E. ritro. Grown for the globular, metallic-blue flowers, the species is useful 

as a fresh and dried cut flower. The foliage, green on top and gray-green 

beneath, has pointed lobes but is not prickly like other thistles. The flower heads 

consist of many individual flowers, each surrounded by bristly bracts; they are 

coarse and can be difficult to handle.

260 ECHINOPS BANNATICUS 

Propagation 

Echinops bannaticus 

Seed: Sow seed in a greenhouse under mist or sweat tent at 65–70F (18–21C). 

Seed germinates in 14–21 days and may be transplanted to 4" (10 cm) containers 

2–3 weeks later. Approximately 1 oz (28 g) of seed yields 1000 seedlings (Nau 

1999). 

Division: Divide plants in spring or in summer after flowering. A portion of the 

root must accompany the vegetative division. Plantlets occur naturally around 

the main stem.

Root cuttings: Take a 1–2" (2.5–5 cm) long piece of healthy root in the spring, 

and place vertically in rooting medium in a warm, moist location. New shoots 

appear in 2–3 weeks. 

Growing-on 

Temperature in the greenhouse should be 55–65F (13–18C). Avoid temperatures 

above 70F (21C). Fertilize plantlets with 50–100 ppm N until large enough 

to transplant to the field (6–8 weeks). If plants are left in the greenhouse longer 

than 8 weeks, transplant to a larger container to minimize root restriction. 


Temperature: Cold is necessary for best flowering. Plants will not flower uniformly 

unless a cold treatment is provided, usually by natural winter cooling. 

Most rapid development occurs if crowns are provided with at least 6 weeks at 

40F (Iversen and Weiler 1989). Hot summers, such as those experienced in the 

South, reduce the quality of stems and flowers, particularly the intensity of the 

blue color; a hot spell during the summer in the Midwest or Northeast has little 

effect on the color. Cooler summers intensify the color and reduce foliar chlorosis—but 

also reduce stem length. Its cold hardiness makes this plant useful as far 

north as the prairie provinces of Canada. 

Photoperiod: After vernalization, plants flower most rapidly under LD (>16 

hours). Plants will also be taller under LD than SD (8 hours) (Iversen and Weiler 

1989). 


Longevity: Globe thistle is a long-lived perennial and will be productive for 

many years. Commercial growers can expect 3–5 years of flower production; 

some report up to 10 years of production. 

Longevity of Echinops bannaticus. Fall-planted, spacing 2' (60 cm), 

full sun. 

Stem Stem 

Year Stems/plant Stems/ft 2z length (in) y width (mm) x 

1 1 0.4 27.0 6.5 

2 4 1.0 38.4 7.2 

3 5 1.3 38.3 6.8 

4 7 1.8 33.2 6.4 




ECHINOPS BANNATICUS 261

262 ECHINOPS BANNATICUS 

Shelley McGeathy of McGeathy Farms reported stem lengths of 30–46" (0.75– 

1.2 m) under full sun in Hemlock, Mich. 

Spacing: Plants grow 3–5' (0.9–1.5 m) tall and equally wide over time. If plants 

are to remain in the ground longer than 3 years, space 2' (60 cm) apart. If plants 

are to be removed in 3 years or less, spacing may be reduced to 18" (45 cm) 

centers. 

Shading: In the North, shade is not needed or recommended; plants are normally 

grown in full sun. Afternoon shade is beneficial in the South (Zone 7 and 

below); the addition of shade cloth (up to 55%) increases yield and stem length, 

as well as providing protection from winds and rain. 

Shade level (%) Stems/plant Stem length (in) z 

0 5 33 

55 7 43 

67 6 36 



For best greenhouse production, cool potted crowns for 6 weeks at 40F (4C) followed 

by 12 weeks in the greenhouse at 60F (15C) under 16- to 24-hour photoperiod 

(Iversen and Weiler 1989). Nightbreak lighting (2–3 hours) with 40-watt 

incandescent lamps may be used to provide LD. Cool plants to 50F (10C) a few 

weeks prior to harvest to enhance blue color. 


Flowers should be harvested when ½ to ¾ of the globe has turned blue. Flowers 

on inflorescences harvested too early fail to open (Gast and Inch 2000). Leaves 

decline more rapidly than the flowers. If harvested for dried flower use, flowers 

should be harvested when the globe has turned blue but before the individual 

flowers begin to open. 

Postharvest 

Fresh: Flowers persist 6–12 days in water; foliage persists only about 5 days. 

Storage: Placing flowers in a 40F (4C) cooler intensifies color. Stems may be 

stored wet for 7–10 days. 

Dried: Air dry by hanging bunches upside down. Do not strip leaves. If harvested 

after the individual flowers begin to open, the globe will shatter.

Cultivars 

‘Taplow Blue’ has more intense blue flowers than the species. It is the most 

popular cultivar of the genus and is often sold as a selection of Echinops ritro. 

‘Veitch’s Blue’ is similar and more common in Europe than in America. 


Echinops exaltatus (syn. E. commutatus) and E. sphaerocephalus grow up to 7' (2.1 

m) in height. They have prickly leaves, green on the upper side, gray beneath, 

with gray stems and large dusty whitish flower heads. ‘Arctic Glow’ has large 

white flowers on reddish stems. Differences between the two species have more 

to do with leaf shape than with their usefulness as cuts. 


Crown rot (Pellicularia rolfsii) infects roots and crown, often the result of waterlogged 

soils. 

European corn borer has become more of a problem, particularly in the 

Midwest. 


“After harvest, we clean up the field by mowing off any remaining vegetation. 

Plants will begin to green up again.” Shelley McGeathy, McGeathy Farms, Hemlock, 

Mich. 

“Each stem [of Echinops sphaerocephalus] will branch out and have 5–10 blooms 

on it, which makes an excellent filler for large bouquets. The stems are grayish 

green and cobwebby, and develop maroon striping before they flower. Your average 

gladiolus customer may not want these on her dining room table, but I like 

to carry something striking and unusual. And even if I didn’t sell a single stem, 

they would be worth the effort just for the attention they draw.” Susan O’Connell, 

Fertile Crescent Farm, Hardwick, Vt. 

Reading 

Gast, K. L. B, and R. J. Inch. 2000. 2000 evaluation of postharvest life of selected 

fresh-cut flowers and greenery. Kansas State Univ. Agr. Exp. Sta. and Coop. Ext. 

Serv. Report 859. 

Iversen, R., and T. Weiler. 1989. Forcing the issue: a guide to forcing garden perennials 

into bloom for flower show exhibitions. American Nurseryman 169(8): 

95–103. 


Many thanks to Shelley McGeathy for reviewing this section. 

ECHINOPS BANNATICUS 263

264 EMILIA JAVANICA 

Emilia javanica tassel flower Asteraceae 

annual tropics scarlet, orange 1½–2'/2' (45–60 cm/60 cm) 

This species, sometimes sold as Cacalia javanica, makes a colorful filler. Plants 

bear numerous fuzzy, scarlet and orange flowers, ½" (13 mm) wide, on 12–15" 

(30–38 cm) stems. Each main stem produces many lateral flower stems, and each 

lateral may be used as a short-stemmed (6–8", 15–20 cm) filler. Although plants 

are annuals, they self-sow prolifically. 

Propagation 

Direct sowing is recommended. Seed may be direct sown, in fall in the South or 

in early spring in the North, at the rate of 0.09 oz per 100' (10 g per 100 m) (Kieft 

1996). If not direct sown, 0.03 oz (0.9 g) yields 1000 plants (Nau 1999). Directsown 

seed should germinate in 10–14 days; in a 68–72F (20–22C) mist bench in 

the greenhouse, expect germination in 7–10 days. 

Growing-on 

Plantlets produced in the greenhouse should be grown at 55–60F (13–15C) 

night temperatures and fertilized with no more than 100 ppm N prior to setting 

out in the field or greenhouse. Plants are large enough to transplant in approximately 

8 weeks. 


Based on trials at the University of Georgia, Emilia appears to have little photoperiodic 

sensitivity. Plants also continue to flower in heat and humidity, showing 

that such conditions do not inhibit flower initiation or development. 


Spacing: Space plants 6 × 6" (15 × 15 cm) or as far apart as 10 × 12" (25 × 30 

cm). They fill in readily. 

Yield: In trials at Athens, Ga., we were overwhelmed by the number of flower 

stems produced in a single season. Students revolted at the sight of yet another 

5000 Emilia stems awaiting their gentle harvest, by hand—only Cirsium and Eryngium 

were viewed with more dislike. In our trials, plants produced over 100 stems/ 

plant with an average length of 17.7" (44.3 cm); each stem carried approximately 

7 small flowers. Flowers are produced continuously, so plants lend themselves 

well to mechanical harvesting. If mechanical harvesting is employed, yield would 

be significantly reduced; labor costs, however, would plunge: cutting one stem 

at a time is a never-ending process. To be honest, how much Emilia can one use? 


Plants are seldom produced commercially as cut flowers in the greenhouse. If 

one is determined to produce these in the greenhouse, high light conditions,

EREMURUS 265 

warm temperatures, and moderate fertility practices (100 ppm N) should be 

maintained. 


Harvest stems when the first flower is fully open. Not all flowers on the individual 

stem may open. 

Postharvest 

Fresh: Flowers persist 3–6 days in plain water. Short stems persist longer than 

long stems; water does not move well through the longer stems. If needed, store 

in water in 35F (2C) rooms. 

Dried: Flowers may be air-dried, but some of the color is lost. 

Cultivars 

None available, but seed-grown plants result in scarlet and orange flowers. 


Emilia coccinea, E. flammea, and E. sagittata are synonyms of E. javanica. 

Emilia sonchifolia differs slightly from E. javanica; it has toothed or wavy margins, 

and the flowers are usually rose or purple. ‘Scarlet Magic’ is likely a selection 

of E. sonchifolia. Both E. sonchifolia and E. javanica are naturalized in southern Florida. 


The only problem in field trials in Georgia was the incidence of botrytis (Botrytis 

cinerea) during times of heavy rains. 

Reading 


Netherlands. 


Eremurus foxtail lily Asphodelaceae 

perennial, Zones 5–7 Asia many colors 3–6'/2' (0.9–1.8 m/0.6 m) 

Foxtail lilies are native to the drier regions of western and central Asia, occurring 

in areas with long, hot summers and fall-spring rains. Excellent cut flowers, they 

are grown successfully on the West Coast and in the Northeast. Their compact 

rhizome has 1 or 2 central buds (crown buds), and long fleshy roots radiate from

266 EREMURUS 

all sides. The inflorescences consist of hundreds of small individual flowers borne 

on unbranched racemes. Few plants are as impressive as a foxtail lily in flower. 

They come into flower in early summer to fall and are always in demand from 

high-end wholesalers and retailers. Plants are winter hardy to Zones 4 and 5. 

Propagation 

Seed can be used. Pretreat seeds in warm (86F, 30C), moist conditions for 30–60 

days, then germinate them at 35F (2C) in the dark. If seeds are pretreated, germination 

occurs within 6 weeks (Zimmer 1985). It can take up to 5 years from 

seed to flowering rhizome; vegetative propagation by division, in contrast, 

results in new flowers in about 2 years. Rhizomes behave like gladioli corms; 

that is, the old root dies while a new one is formed each year. After the foliage disappears, 

the rhizome can be lifted and divided. If the rhizomes are left in the 

ground for many years, the roots become highly tangled and are difficult to lift. 

Dividing rhizomes: Rhizomes are dug for overwintering purposes or for division, 

in the summer. After clearing the weeds and spraying a nontranslocatable 

foliage killer, dig the rhizomes with a small subsoiler. The rhizomes are very brittle; 

allow them to dry for a couple of days; when they are limp, they are less prone 

to handling damage. Grade them (singles and so forth), soak in a fungicide, and 

place them in bins with dry peat moss at 55–60F (13–15C) (definitely below 70F, 

21C). Allow them to remain dormant until mid September, and plant them early 

enough to have roots develop in the field before winter sets in. This process is not 

for everyone; it may make more sense to let someone else do this. For most growers, 

buying well-developed rhizomes from a reputable supplier makes the most 

sense. 

Growing-on 

Plant rhizomes in the fall. They need a thoroughly drained, rich soil and will not 

do well in heavy clays. Since rhizomes can be infected with viruses spread 

through cutting tools, new stock should be reintroduced after 2–3 years. 


Flowers initiate during the winter and cold is necessary. Previous research suggested 

16–18 weeks at temperatures less than 50F (10C) was required for flowering 

and leaf development (Zimmer 1985). 

Photoperiod is unimportant. 


Planting: Dig a hole that easily accommodates the long, fleshy tentacle roots. 

Fill in gently so as not to damage the roots. Mulch plants as soon as the leaves 

emerge in the spring: spring frosts can be deadly. Plant the crowns about 2–4" 

(5–10 cm) deep, and do not allow them to dry out. If the rhizomes appear to be

Eremurus ×isabellinus 

‘Rosalind’

268 EREMURUS 

dried out, soak them for a few hours prior to planting. Choose a site in full sun 

out of prevailing winds. Avoid wet areas. Mulch in the fall to prevent winter damage. 

Rhizomes can double in size in a single year. 

Yield: Two to 3 stems per mature rhizome can be realized. 

Spacing: Space rhizomes 3½–4' (1.1–1.2 m) apart, with 4–6" (10–15 cm) of soil 

above the nose, in raised hills; leave 1–2' (30–60 cm) between rows. 


Rhizomes can be forced in the greenhouse after rhizomes are cooled, then grown 

on at 50–55F (10–13C). Plant in ground beds and provide suitable support for 

the tall stems. Crop time is approximately 17 weeks (Dole and Wilkins 1999). 


Jan Roozen of Choice Bulbs in Mt. Vernon, Wash., cuts stems when the bottom 

flowers are becoming colored but not fully open. This is the best stage if stems 

need to be stored in a cooler. If harvested too open, they cannot be stored for any 

length of time, and if too tight, they will not open. Some experimentation is necessary. 

If sold fresh for immediate consumption, stems are harvested when about 

½ the flowers are open (Dole and Wilkins 1999). 

Postharvest 

Store stems at 36F (2C) to inhibit additional flower opening. Flowers persist up 

to 3 weeks in a properly vented cooler. Eremurus should be shipped and stored 

upright: the stems are geotropic (they bend upward if laid on their sides). 

Postharvest treatments with a biocide and ethylene inhibitor (STS) have been 

shown to benefit postharvest life (Nowak and Rudnicki 1990). 


Eremurus himalaicus, a 3–5' (0.9–1.5 m) tall white-flowered species, is a parent 

in many hybrids. One of the earliest to flower. 

Eremurus ×isabellinus (syn. E. ×shelfordii) bears 3–4' (0.9–1.2 m) long racemes in 

shades of yellow, pink, white, and copper in summer. These free-flowering hybrids 

are the result of crossing E. stenophyllus and E. olgae, a medium to tall, whiteflowered 

species. Cultivars include ‘Isobel’ (rosy orange), ‘Moonlight’ (pale yellow), 

‘Rosalind’ (bright rose), and ‘White Beauty’ (clear white). 

Eremurus robustus is the most stately species, growing 8–10' (2.4–3.0 m) and 

bearing long spike-like inflorescences crowded with fragrant peachy pink flowers. 

Exceptional, among the finest forms for cuts. ‘Albus’ is a white-flowered 

selection. 

Eremurus stenophyllus (syn. E. bungei) is one of the shorter species, growing to 2– 

3' (60–90 cm), but as lovely as any. Plants produce bright yellow flowers that 

open slowly, resulting in a full-flowered spike. All the few cultivars have flowers 

in yellow shades.

Ruiter hybrids are the preferred cultivars for cut flower production. They are 

usually sold in mixed colors but include such single colors as ‘Cleopatra’ (orange 

with red midribs on the flowers), ‘Copperboy’ (yellow), ‘Oase’ (pale pink), 

‘Obelisk’ (white-tinged green), ‘Odessa’ (yellowish green), ‘Romance’ (salmonpink), 

and ‘Sahara’ (coral-pink). 


Botrytis is a serious problem and fungicide applications may be necessary. 

Aphids, slugs (put out bait early), and thrips can be a problem. Because plants are 

large and persistent, weeds can be a nuisance. 


“Eremurus are very slow for me from seed. Time to bloom depends on variety 

and is probably 3–7 years. I recommend buying the spidery tubers, which can 

exceed 24" across. My favorite is probably the 9-foot-tall pink Eremurus robustus. 

I do love the 4-plus-foot-tall, May-blooming, white E. himalaicus, as it is my earliest 

and easier to use in arrangements.” Kelly O’Neill, Wet Rock Gardens, 

Springfield, Ore. 

Reading 





Zimmer, K. 1985. Eremurus. In The Handbook of Flowering. Vol. 2. A. H. Halevy, ed. 


Many thanks to Jan Roozen for reviewing this section. 

ERYNGIUM PLANUM 269 

Eryngium planum sea holly Apiaceae 

perennial, Zones 3–7 eastern Europe blue 2–4'/3' (0.6–1.2 m/0.9 m) 

As striking as the blue stems, blue flowers, and exotic-looking inflorescence of 

Eryngium are, the demand for sea holly fluctuates. Several of the available species 

are difficult to handle, and some ship poorly, but these things are true of many 

cut flowers, particularly the problem of fluctuating demand. Most sea hollies 

tolerate saline conditions and are cold hardy throughout the country. Some 

people complain that the flowers are malodorous. The few people growing this 

crop may find significant profit if and when demand rises. 

Eryngium planum, one of the smaller-flowered sea hollies, is as useful and decorative 

as any, even the larger-flowered forms. It is also one of the most economical 

sea hollies to ship: the relatively small flowers allow more stems to be

270 ERYNGIUM PLANUM 

placed in the shipping container. The small blue flowers are arranged in a tight 

globose head, and each inflorescence is subtended by bracts, which turn metallic 

blue in the summer. 

Propagation 

Seed: If possible, collect ripe seed from stock plants and sow immediately in a 

loose mixture of sand and vermiculite or other seed medium. Seed enters a dormancy 

phase rapidly after harvest, and purchased seed takes many months for 

germination. In the following work (Pinnell et al. 1985), seed was germinated 

under intermittent mist at 70–72F (21–22C). 

Germination of Eryngium planum over time. 

Age of seed Germination (%) 

fresh 55 

1 month 48 

2 months 32 

3 months 6 

4 months 5 

5 months 0 

6 months 1 

For purchased seed, sow in seed trays; cover lightly with soil; and place in a cold 

frame, unheated greenhouse, or outside under snow. Germination occurs the 

next spring. Another season of warmth and cold, however, is necessary to germinate 

all viable seed. Approximately 0.7–1 oz (9–28 g) of seed yields 1000 seedlings 

(Nau 1999). Eryngium alpinum (alpine sea holly) germinates less uniformly 

and more slowly than E. planum. 

Division: Plantlets are formed at the base of plants and may be carefully 

removed. 

Cuttings: Root cuttings are an excellent means of propagation. Remove sections 

of mature root, 2–4" (4–10 cm) long, and plant upright in containers of 

porous medium. Place containers at 68–75F (20–24C) and keep moist. 

Growing-on 

Grow at 55–60F (13–15C) and avoid temperatures above 75F (24C) to minimize 

stretching. Fertilize sparingly (50–100 ppm N) until large enough to transplant 

to the field or bench. Seed-propagated material may be transplanted 5–8 weeks 

after emergence. Medium to large divisions should be grown for 3–4 weeks 

before placing in the field; small divisions can be placed in growing-on beds for 

a year before being placed in the production area. Plantlets tolerate full sun in 

the greenhouse in winter, spring, and fall, but shade is necessary in the summer.


Cold is necessary for flowering, and temperatures of 40F (4C) or below may be 

provided by winter, cold frames, or unheated greenhouses. Hot summers are 

tolerated, but the metallic blue color of the flowers, stems, and bracts is not as 

intense as those grown under cool summer nights. Plants grown north of Zone 

5 are of high quality, but stem lengths are shorter than those grown further 

south. Eryngium is sensitive to overwatering; well-drained soils are a must. 


Longevity: Sea holly is a long-lived perennial, and flower production continues 

for many years. For commercial growers, 3–5 years of production are easily 

obtainable. Yield declines after approximately 3 years, although stem length and 

diameter are not seriously affected over time, as the following table shows. 

Longevity of Eryngium planum. Fall-planted, spacing 2' (60 cm), 

full sun. 

Stem Stem 

Year Stems/plant Stems/ft 2z length (in) y width (mm) x 

1 3 0.6 30.4 9.1 

2 6 1.4 32.4 9.4 

3 9 2.1 36.2 9.2 

4 6 1.5 37.0 8.9 

5 5 1.3 37.1 8.9 




ERYNGIUM PLANUM 271 

Spacing: Plants grow 2–4' (0.6–1.2 m) tall with equal spread. If plants are to 

remain in production for more than 3 years, space 2' (60 cm) apart. If plants are 

to be removed at the end of the third year, spacing may be reduced to 18" (45 cm) 

centers. 

Shading: Plants are usually grown in full sun in the North but are occasionally 

shaded in the South. Work at the University of Georgia showed that yield was 

significantly reduced as plants were covered by 0, 55, or 67% shade (7, 5, and 1 

stems/plant, respectively); stem length was only slightly increased. Shade cloth 

protects against damage by wind and rain, but the decrease in yield is too great 

to warrant its use. 



healthy plants when flower buds were visible but prior to flower opening. These

272 ERYNGIUM PLANUM 



(%) 

N P K Ca Mg 

4.05 0.63 3.36 1.19 0.47 

(ppm) 

Fe Mn B Al Zn 

257 84 28 83 61 


Flowers should be harvested when the entire flower head, including bracts, turns 

blue. 

Postharvest 

Fresh: Flowers persist 10–12 days; foliage lasts only 5–8 days. 

Storage: Placing flowers in 40F (4C) coolers intensifies color. Stems may be 

stored 7–10 days at 38–40F (3–4C). 

Dried: Air drying is successful, but drying in silica gel or other desiccant preserves 

more color. 

Cultivars 

‘Blue Cap’ (‘Blaukappe’) bears deep blue flowers on 2' (60 cm) tall plants. 

‘Blue Diamond’ is a dwarf form selected for the deep blue flowers. Not much 

different from the next form. 

‘Blue Dwarf’ (‘Blauer Zwerg’) is similar to Eryngium planum but grows only 

15–18" (38–45 cm) high. 

‘Blue Ribbon’ has larger flowers, appearing to be double blue. Plants grow 

about 2' (60 cm) tall. 

‘Sapphire Blue’ has large blue flowers on strong 28" (70 cm) stems. 

‘Silver Stone’ has creamy white flowers and stands 3–4' (0.9–1.2 m) tall. 


Eryngium alpinum (alpine sea holly), the most popular species in Europe, bears 

larger bracts than E. planum and is more ornamental. Shipping quality is not as 

good, however. ‘Amethyst’ is 2½–3' (75–90 cm) tall with metallic, light blue 

bracts and serrated foliage. ‘Blue Star’ has been popular because it has been one 

of the few cultivars available from seed, even though half the seed may never 

come up; plants grow 2–3' (60–90 cm) tall and bear large lavender-blue involucres. 

‘Opal’ is 2' (60 cm) tall and bears more silvery blue flowers than ‘Amethyst’.

‘Slieve Donard’ has handsome light blue bracts around dark blue flowers. ‘Superbum’ 

has large dark blue flowers on 2–3' (60–90 cm) stems. 

Eryngium amethystinum is popular in the United States. 

Eryngium bourgatii is also used for cut flowers. 

Eryngium giganteum (Miss Willmott’s ghost) is a biennial that provides large 

gray flowers the second year from seeding. Quite eye-catching in a ghost-like 

way. Seldom used in this country, but then again, not much cut sea holly is seen 

in this country anyway, so perhaps worth a small space. 

Eryngium yuccifolium (rattlesnake master) is also grown as a cut flower. People 

who grow it find demand is excellent. 


Leaf spots are common; treat with a general-purpose foliar fungicide. 


“I like sea holly very much, even though it smells pretty bad. When the stems 

are tall and straight it works really well in bouquets. If they have flopped over and 

gotten a bit twisted, I just bunch several stems and sell it straight. It always sells, 

and I can get $2 per stem for the twisted stuff, more for the straight beauties. I 

have grown Eryngium planum from seed. Also got some E. p. ‘Blaukappe’. My 

seeded stuff did not require netting, ‘Blaukappe’ should have been netted. It’s 

the first year with the ‘Blaukappe’, though, and I think that they’ll be straighter 

and taller next year. In my experience, Eryngium takes 2 years to establish itself 

[and needs] to be lifted and rejuvenated on the third or fourth year. It does dry 

beautifully. Looks great in artichoke bouquets.” Debbie Barber, Double Decker 

Farm, Hillsdale, N.Y. 

“I have Eryngium alpinum and E. giganteum. I love alpinum; it is very challenging 

for me to grow, but it sells well. Eryngium giganteum is okay; it’s easy enough, just 

very prickly.” Janet Foss, J. Foss Garden Flowers, Everett, Wash. 

Reading 


Pinnell, M., A. M. Armitage and D. Seaborn. 1985. Germination needs of common 

perennial seeds. Univ. of Georgia Research Report 331. 

Many thanks to Tom Wikstrom for reviewing this section. 

EUPHORBIA MARGINATA 273 

Euphorbia marginata snow-on-the-mountain Euphorbiaceae 

annual North America white bracts 2–4'/3' (0.6–1.2 m/0.9 m) 

The long-lasting cut stems are most useful in bouquets: well-branched plants 

have variegated or entirely white upper foliage, and the inconsequential flowers

Eryngium alpinum


are surrounded by large, white bracts. The sap causes severe dermatitis in sensitive 

individuals; gloves and long-sleeved shirts should be worn when harvesting. 

Eyes too are highly sensitive to the sap (Eke et al. 2000), and firsthand evidence 

suggests that caution, as well as eye protection, is essential (see comments 

by Hartenfeld). If sap solution has been handled, workers should be warned not 

to rub their eyes. 

Propagation 

Sow seed at the rate of approximately 1 oz (28 g) for 1000 plants (Seals 1991) at 

60–68F (15–20C) under intermittent mist. Although seed may emerge in 10–14 

days, germination is erratic and may require 1–2 months. For field germination, 

seed approximately 0.7 oz (20 g) per 100' (30.5 m) (Kieft 1996). In southern latitudes, 

3 or 4 successive sowings, 2 weeks apart, may be recommended; in northern 

latitudes, with their early frosts and long summer photoperiods, 2 successive 

sowings are the limit, suggests Ginny Kristl of Albion, Maine. 

Growing-on 

Seed germinated in the greenhouse or frame should be grown at 60F (15C) and 

fertilized with 75–100 ppm N. Plants may be transplanted to the field in 4–6 

weeks. 


Photoperiod: Snow-on-the-mountain is a short day species. Flowers are initiated 

under short days, and vegetative growth occurs under long days. However, 

SD are not exactly short. Daylengths of 14 hours can still result in flowering; 

more than 14 hours inhibits flowering. 

Temperature: Stems are thicker and flowers larger when average temperatures 

remain below 75F (24C). High temperatures result in poor initiation and spindly 

stems. 


Yield: The goal of 5–10 stems per plant is not unrealistic. 

Spacing: Space plants 6 × 6" (15 × 15 cm), 6 × 9" (15 × 23 cm), or 9 × 9" (23 × 

23 cm). No shade is necessary. 

Plants are of a better quality when night temperatures remain below 75F 

(24C), although we have seen some outstanding material in Raleigh, N.C. If 

plants are produced in the South (Zones 7–10), they should be scheduled to 

flower in late summer and fall. The following data were submitted by Ginny 

Kristl of Johnny’s Selected Seeds, Albion, Maine.

276 EUPHORBIA MARGINATA 

Growth of Euphorbia marginata and cultivars in the North. Seeds were sown in 

situ 28 May, germinated 7 June. 

First Peak Spread Height Uniformity Rating 

flower bloom (in) z (in) z (1–5) (1–5) 

species 23 Aug 1 Sep 28–32 46–53 3.0 3.5 

Icicle 23 Aug 1 Sep 30–32 43–49 2.5 3.0 

Kilimanjaro 4 Aug 24 Aug 24–27 34–40 4.0 4.0 

Summer Icicle 23 Aug 1 Sep 30–37 42–52 2.5 3.5 


Euphorbia marginata


All taxa had similar stem strength and bract diameters of about 3½" (9 cm). 

Ginny noted that standout performer ‘Kilimanjaro’ was also excellent in terms of 

flower yield and showed variegation almost 3 weeks earlier than the others 

(although earliness to flower and to show variegation are not necessarily benefits). 


Plant in ground beds or raised beds at 6 × 6" (15 × 15 cm) or 6 × 9" (15 × 23 cm) 

spacing. Fertilize with approximately 100 ppm N and grow plants under long 

days (14- to 16-hour photoperiod) for 6–8 weeks. If flowers are desired, provide 

shorter days (

278 EUPHORBIA MARGINATA 

hour photoperiods at 68F (20C). They are excellent cut flowers, mainly imported 

from Europe. Short days provided on 1 August, 1 September, and 1 October 

resulted in plants that flowered on 20 September, 30 October, and 15 December, 

respectively (Post 1955, Runger 1985). 


Few problems occur with Euphorbia marginata, although warm temperatures 

result in root rots, botrytis, and other stress-related infections. Damping off of 

seedlings occurs in cool weather. Plants grown north of Zone 7 appear to have 

fewer problems than those further south. 


“After inadvertently splashing a very diluted solution of sap into my eyes, I wound 

up in the emergency room, couldn’t see for 2 days, and lost a week of work at the 

height of the cutting season. I no longer grow Euphorbia marginata.” Jeff Hartenfeld, 

Hart Farm, Solsberry, Ind. 

“I grow Euphorbia marginata from seed. [It] grows 4' tall and is quite a hit at 

market. The sap is mildly irritating to sensitive skin, and after a long day messing 

with it at market, I have felt a slight burn on my hands and arms, but it didn’t 

last too long.” Tom Wikstrom, Happy Trowels Farm, Ogden, Utah. 

“Although it can be a great cut, it can go down if cared for improperly, and 

once florists have this problem, they don’t seem to want to try it again. The only 

way I could get Euphorbia not to go down . . . was to cut it under water. I also cut 

it early, while stems were still stiff; the stems absolutely have to be cut under 

water. I also wore long-sleeved shirts, and I would recommend gloves.” Ralph 

Thurston, Bindweed Farm, Blackfoot, Idaho. 

“We have had trouble with damping off, but if you sterilize your soil (we heat 

ours), the success rate is great and damping off is not a problem. You must take 

cut stems inside within 10 minutes of picking, sear (we use a candle), and then put 

into water with Floralife. I would cut the stems at various lengths that I thought 

I would use for that day, and after searing, I put them directly into the bouquet 

jars arranged as filler.” Phyllis Wells, Wells Family Farm, Williamsburg, Mich. 

Reading 

Eke, T., S. Al-Husainy, and M. K. Raynor. 2000. The spectrum of ocular inflammation 

caused by Euphorbia plant sap. Archives of Ophthalmology 118(1):13–16. 


Netherlands. 


Runger, W. 1985. Euphorbia fulgens. In The Handbook of Flowering. Vol. 2. A. H. 


Seals, J. 1991. Some uncommon and common (but choice) cut flowers from seed 

for field growing. The Cut Flower Quarterly 3(2):13–14.

EUSTOMA GRANDIFLORUM 279 

Many thanks to Ginny Kristl and Jeff Hartenfeld for reviewing this section. 

Eustoma grandiflorum lisianthus, prairie gentian Gentianaceae 

annual Nebraska, Colorado, Texas many colors 1 

2–3'/2' (60–90 cm/60 cm) 

This great cut flower has come a long way from its humble origins on the western 

plains, and growers, sellers, and consumers are wild about it. Perhaps Dave 

Lines of Dave Lines’ Cut Flowers says it best: “Many of us feel passionately that 

its customer acceptance and popularity will continue to soar. Lisianthus is without 

doubt the best cut flower that has come along in years. Customers love them 

and particularly appreciate their beauty and long vase life.” 

Now among the most important greenhouse cut flowers, this North American 

species continues to be crossed by American, Dutch, Japanese, and Israeli 

breeders and shows no sign of losing popularity in world markets. The blue 

flower color of the species has been complemented by cultivars with flowers of 

white, pink, yellow, red, and purple, and various combinations thereof. Though 

plants are biennials in their native habitat, they may be treated as annuals in the 

field; however, some growers find that overwintered plants produce the best crop 

the following spring. Flower production is challenging, particularly in warm 

climates, and the environment plays a major role in plant development and 

flower initiation. 

Propagation 

Seed: Plants are raised almost exclusively from seed by specialist propagators; 

terminal cuttings are only occasionally used because they tend to flower irregularly. 

For the small- to medium-sized operation, mature plugs should be purchased; 

however, if seed propagation is attempted, sow seed on top of medium 

(do not cover) at 70–75F (21–24C). Germination usually occurs in 10–15 days. 

Chilling seed at around 35F (2C) for 11–15 days dramatically increases germination 

(Ecker et al. 1994), but for most commercial seed, germination is not 

seen as a problem. Seed is small, with approximately 600,000 seeds/oz (22,000 

seeds/g), 20,000 pelleted seeds/oz (715/g). For 1000 plants, only about 1/256 

oz (110 mg) is needed (Nau 1999). Pelleted seed is available for most cultivars. 

Cuttings: Not recommended unless stock plants are available. Terminal cuttings 

root under mist in approximately 2 weeks at 75F (24C). Stock plants 

should be maintained under LD (>12 hours) for maximum cutting production. 

Some plants, once established from cuttings, are shorter and weaker and have 

fewer flowers than those propagated from seed (Roh et al. 1989). 

Growing-on 

Two distinct growing phases occur, according to the plant’s response to temperature. 

In the first phase, growth occurs slowly; seedlings require up to 3

280 EUSTOMA GRANDIFLORUM 

Eustoma grandiflorum 

‘Heidi Pink’ 

months to form approximately 3–5 leaf pairs. During the seedling stage, maintain 

temperatures of 45–65F (7–18C). This ensures subsequent stem elongation, 

taller flower stems, and increased flower number (Roh 1999). Temperatures 

above 70F (21C), particularly at night, result in rosetting of the plants, something 

that must be avoided like the plague. If rosetting occurs, flowering is significantly 

delayed, and flowers are generally second-rate. Rosetting of the seedlings 

can be reversed (with difficulty) by application of 55F (13C) temperatures


and LD for 4 weeks (Ohkawa et al. 1996), but it is far better to try to keep temperatures 

below 70F (21C). Research has shown that cooling the seedlings for 5 

weeks at 54F (12C) prior to greenhouse planting accelerated flowering by 10 

days (Sclomo and Halevy 1987). The seedling stage continues until 4 or 5 leaf 

pairs have formed and usually takes about 90 days. If possible, short days (



Most lisianthus worldwide are greenhouse-produced; however, significant field 

production in the United States is accomplished. Field production in Maryland 

(Gill et al. 1998) has been reviewed and provides excellent information for much 

of the country; the planting schedule that follows is based on methods used in 

La Plata, Md., by Dave Lines. Plugs received by 1 March are moved up to 48-cell 

packs and planted out in raised beds, using an 8 × 8" (20 × 20 cm) spacing. Three 

plantings are accomplished, and plants are overwintered. 

Plant to field 1st harvest* 2nd harvest** 

previous year’s overwintered z 15 Jun 1 Aug 

15 Apr 1 Jul 15 Aug 

15 May 15 Jul 1 Sep 

15 Jun 1 Aug 15 Sep 

z = 20–40% survival; average stem length of overwintered stems was >2' 

(60 cm) 

* = average length of non-overwintered stems was 16–24" (40–60 cm); 

harvest dates spread out over 3–4 weeks 

** = average length of non-overwintered stems was 8–16" (20–40 cm); 

harvest dates spread out over 3–4 weeks 

Flowers are susceptible to numerous diseases and must be protected from rain. 

Rain will cause spotting on fully developed flower petals, especially on darker 

colors, and those flowers should be removed before sale. Good drainage is essential: 

plant in raised beds if drainage is suspect or in areas where summer rains are 

plentiful. Uniform irrigation is necessary after transplanting to the field; drying 

out at this stage reduces yield and quality. At least one tier of support is recommended; 

2 tiers of support netting are often used. 

Do not accept rosetted seedlings; they have been grown too warm in the seedling 

stage and will give nothing but headaches. Plug sizes of 288 are common 

when placing seedlings in the field; plants should have at least 4 leaf pairs, but 

the larger the better for transplanting. Growing-on plugs in the greenhouse to 

fill 48-cell trays results in better establishment in the field and faster harvests. 

Work in Kentucky showed that plugs moved up to cell packs (48 cells/tray) 

could be planted to the field as soon as threat of frost was passed. Approximately 

4–6 weeks were necessary from transplant to the field until the first flowers were 

harvested. Yield was 3–4 stems/plant over 3–4 weeks, and stem length was 15– 

30" (38–75 cm) (White-Mays 1992). 

After the harvest, cut the plants back to stimulate a second harvest. The second 

harvest occurs 6–8 weeks after the first and will be about 30% of the initial 

harvest. Some growers plant seedlings about 3 weeks apart to allow for successive 

harvests. 

Nutrition: A slow-release fertilizer (usually a 3-month formulation) can be provided 

immediately after transplanting to the field. If applying nitrogen, use a


nitrate form. Potassium should be equal to nitrogen (e.g., 15-0-15), and supplemental 

calcium is recommended (Gill et al. 1998). 

Shading: All sorts of claims are made about shading. In areas of bright summer 

sun, shading may increase stem length, but we are not convinced that the additional 

stem length makes up for the reduction in flower number or stem diameter. 

If shading is employed, approximately 30% shade should do the job; some 

growers use up to 70% shade, which seems way too high to us. Eustoma grandiflorum 

is a species of the prairies, where full sun is common. Try shading if stem 

length in the field is a problem; otherwise, the only protection should be for rain 

and inclement weather. 

Overwintering: The key benefit to overwintering is that plants produce multiple 

stems the next spring, each with greater stem length and diameter than those 

produced from annual cropping. The quality and yield can be so much better 

that many growers do all they can to overwinter their plants. Some protect by 

using row covers or a hoop house (Gill et al. 1998), although growers in areas 

south of Zone 7 will likely not need to use protection. Overwintering also brings 

on additional stem and soil pathogens. Reduce problems by cutting back plants 

to 2–4" (5–10 cm) and removing debris. Cleanliness is a must. Survival rate depends 

on severity of winter, protection methods, incidence of disease, and rodent 

problems. Plant losses that occur during attempts at overwintering may negate 

the increased value. 


Winter greenhouse production, centered in northern or alpine areas of the 

world, provides flowers that can command excellent prices; however, the long 

time needed between sowing and flowering (up to 6 months) limits the usefulness 

of self-sowing the crop for greenhouse operators. The details of producing 

seedlings were discussed earlier; obviously, unless one has an overwhelming 

desire for masochism, mature plugs should be purchased from reputable seedling 

producers. Some large growers do the entire job themselves, particularly in 

areas of cool night temperatures, and once a schedule has been established, 

weekly sowings are the norm. 

Place plugs in ground beds on 4–9" (10–23 cm) centers; alternatively, place 1 

or 2 plants per 4" (10 cm) pot or 3–5 per 6" (15 cm) pot. One tier of support is 

usually needed. Natural daylength is appropriate, but LD (>12 hours) can accelerate 

flowering. Additional flowers may be formed if HID sodium or metal halide 

lamps are used, but it is questionable whether this is cost-effective. Day temperatures 

of 78–86F (26–30C) and 65F (18C) nights result in faster flowering than 

68–75F (20–24C) days and 55F (13C) nights (Halevy and Kofranek 1984). Pinching 

results in shorter stems and delayed flowering and is not recommended for 

cut flower cultivars (Dennis et al. 1989). One to 2 months are required between 

visible flower bud and open flower, depending on temperature. When plants are 

grown well, more than 10 flower buds are formed from the 4–6 upper shoots. 

Nutrition: Lisianthus thrives in a higher pH than most crops. Maintaining a 

pH of 6.5 to 7.0 is highly recommended; a pH lower than 6.0 causes significant


problems. The use of a nitrate form of nitrogen is recommended, particularly at 

lower pH values (Alt 1993). Excessive pH (>7.0) can result in reduced flower color 

intensity; a 7% increase in pH can reduce flower intensity by up to 10% (Griesbach 

1992). Maintain high levels of fertility; underfertilization reduces growth. 

The major deficient nutrient appears to be calcium, which shows up as tip burn 

on young leaves; foliar application of calcium fertilizers helps prevent the problem. 

Tissue and soil analysis is recommended. 


Smaller flower buds can be removed as the terminal starts to open. Many growers 

find that best results occur when the central bud is removed, so that more 

flowers will be open simultaneously. Harvest when one flower is fully colored 

(e.g., when the white flower is totally white, not partially green). The flower need 

not be fully open. 

Postharvest 

Fresh: Postharvest life is excellent, 10–15 days. Small buds often fail to develop 

after harvesting, and flowers (particularly blue and pink flowers) fade badly in 

low light conditions; if placed in high light, these conditions become less severe 

(Kawabata 1995). A 25% decrease in light intensity results in a 40% decrease in 

color intensity (Griesbach 1992). 

Preservatives are effective in lengthening postharvest life and should be used. 

Several solutions have been tested, with varying results. Ethylene production in 

cut flowers was shown to peak approximately 12 days after harvest; flowers are 

far more sensitive to ethylene as they age than when they open (Ichimura et al. 

1998). Interestingly, Song et al. (1994) found that pretreating stems with STS or 

Chrysal AVB prior to placing in preservatives had little effect on longevity but 

resulted in more flowers opening in the vase. Other research showed that treatment 

with 0.1 mM STS for 24 hours before placing in distilled water increased 

the vase life significantly. Sucrose too has been studied and recommended as an 

alternative to STS. Continuous use of a solution of 20 g/l plus hydroxyquinoline 

(HQS, an antimicrobial agent) increased the pigment coloration and extended 

the vase life (Ichimura 1998). Continuous use of 4% sucrose solutions plus 

antimicrobial agents resulted in stems persisting for 30 days, each flower lasting 

approximately 13 days (Grueber et al. 1984). Another recipe, consisting of 10% 

sugar, citric acid, and antimicrobial agents, pulsed for 24 hours, resulted in 13day 

postharvest life and opening of all flower buds on the cut stem. All this seems 

very confusing! In general, 2–4% sugar solutions used continuously have proven 

successful, as has pulsing with up to 10% sugar in combination with antimicrobial 

agents (8-HQC). Anti-ethylene compounds are probably not warranted. 

Cultivars 

The recent avalanche of cultivars reflects the interest and importance of this 

crop to the florist trade. Cultivars make be classified into early (winter flowering), 

mid (spring flowering), and late season (summer flowering).


Single flowers 

Early season (winter flowering): 

Polestar is intermediate in timing between Ventura and Heidi. Eight separate 

colors. 

Tyrol series flowers early, with 1½–2" (4–5 cm) flowers in white to rose-pink 

to deep blue shades. Noted for uniformity and vigor (Dole 1998). 

Ventura is 3 weeks earlier than Heidi, on 30" (75 cm) flowering stems. Eight 

colors. 

‘Winter Pink’ is used for the short days of winter production. 

Mid season (spring flowering): 

Heidi series bears sprays of single flowers atop 2–2½' (60–75 cm) stems. Nine 

separate colors plus a mix are offered. ‘Heidi Wine Red Improved’ has deeper 

colored flowers than its predecessor. 

Malibu series can finish 2 weeks earlier than Heidi. Eight colors. 

Royal series is earlier than some others and is available in pink, light purple, 

purple, violet, and white. 

Late season (summer flowering): 

Flamenco series was developed to follow Heidi and Echo during higher temperatures 

and longer days. Plants bear long stems about 2 weeks after Heidi. 

Thirteen separate colors plus a mix are available. 

Laguna series carries 40–45" (1–1.1 m) stems and includes ‘Blue Blush’, ‘Deep 

Blue’, ‘Deep Rose’, and ‘Pink Rim’. 

Mirage series appears to be daylength neutral. Flowers are 2½–3" (6–8 cm) 

wide. ‘Blue Rim’, ‘Light Pink’, and ‘Pure White’ are available. 

‘Red Glass’ is very nearly red, with 12–18" (30–45 cm) stems. 

Double flowers 

Early season (winter flowering): 

Avila series flowers under low light and lower temperatures than Echo. Five 

colors are available, including ‘Avila Deep Rose’. 

Mid season (spring flowering): 

Balboa series was bred to flower during longer daylengths and warmer temperatures 

and appears to be a good choice for the field. In Maryland, flowers 

were harvested 11–14 weeks after transplanting and provided 22" (56 cm) stems 

(Gill et al. 1998). Longer stems occur in the greenhouse. ‘Blue’, ‘Blue Blush’, and 

‘Blue Rim’ are available from plugs. 

‘Blue Rose’ has double blue flowers on 18–24" (45–60 cm) stems. 

Candy series was bred for moderate temperatures and low light conditions. 

‘Double Up Pink’ carries delicate pink, fully double flowers on 30–36" (75–90 

cm) stems. 

Echo series is nearly 100% double and flowers a little earlier than some of the 

single mid-season forms. Available in chiffon blue (‘Misty Blue’), light blue, midblue, 

picotee blue, picotee pink, pink, white, and a mix. Cut stems are approxi-


mately 2' (60 cm) long. Still one of the most popular doubles, and the ASCFG’s 

2002 Fresh Cut Flower of the Year. 

Late season (summer flowering): 

Catalina series exhibits less rosetting and larger flowers on 40–45" (1–1.1 m) 

stems. Recommended for field production. 

Mariachi’s round-petaled flowers are carried on 20–26" (50–66 cm) stems. 

Colors include ‘Lime Green’, ‘Orchid’, ‘Yellow’, and 3 picotee forms. Good for 

field and greenhouse production. 


Lisianthus has been evaluated since the inception of the ASCFG’s national trials 


lengths and yields of eustoma submitted for trialing. These data are averages 

over a wide geographical range and must be viewed as guidelines only; individual 




Avila Ivory 2000 20 2 

Balboa Blue 2000 17 3 

Catalina Yellow 2000 16 2 

Double Up Pink 1994 12 2 

Flamenco Blue Rim 2000 14 2 

Flamenco Purple Rose 2000 17 2 

Heidi Champagne 2000 18 2 

Heidi Mix 1996 18 3 

Laguna Blue Blush 2000 16 2 

Malibu Blue Blush 1998 13 5 

Malibu Blue Rim 1998 14 6 

Malibu Deep Blue 1998 13 9 

Malibu Lilac 1998 17 6 

Malibu White 1998 16 6 

Mirage Blue Rim 1998 20 6 

Mirage Light Pink Rim 1998 22 5 

Mirage Pure White Rim 1998 21 5 

Sentinel Porcelain 1994 11 2 

Tyrol Blue 1997 12 3 

Tyrol Blue Rim 1997 19 5 

Tyrol Rose 1997 15 3 

Tyrol Rose Pink 1997 17 4 

Tyrol White 1997 17 3 

z = multiply (in) by 2.54 to obtain (cm)



The major problem in the greenhouse occurs during the long seedling stage. 

Seedlings develop so slowly that plants may be inadvertently overwatered, allowing 

water molds such as Pythium and Rhizoctonia to strike. Attention to watering 

is very important during the seedling stage. In the field, poor drainage is a serious 

problem. Stem blight, caused by Sclerotium rolfsii has also been isolated (Mc- 

Govern et al. 2000). Where drainage has not been improved, heavy summer rains 

often result in root rots. This can be particularly devastating in hot, humid summers; 

raised beds or well-drained fields are recommended in such areas. Fusarium, 

Alternaria, Botrytis, and other fungi can also be present on lisianthus. Drenching 

the seedlings and the production beds with a fungicide is highly recommended, 

and good management practices, such as crop rotation, are a must. 

Tomato spotted wilt virus and impatiens necrotic spot virus (mainly spread 

by thrips), bean yellow mosaic virus (aphids), tobacco mosaic virus (humans), 

and tomato yellow leaf curl virus (whiteflies) have been reported on lisianthus. 

Symptoms vary with the causal virus but include yellowing, mottling or chlorosis 

of the foliage, lack of flowering, and leaf distortion. Affected plants must be 

destroyed. 

Aphids, thrips, and whiteflies also cause significant damage on their own, 

besides being vectors for the spread of viral diseases. 


“I grow my lissies in the field in full sun, and get about a 20" plant with Echo. I 

sell at the farmers’ market, and that stem length is fine with my customers. I cut 

out the first bloom with as little as a 4" stem and sell them. They look great 

bunched in pint jars and make a pretty bouquet.” Julie Marlette, Blue Heron 

Gardens, Fall Creek, Wis. 

“When raised beds are covered with white-on-black plastic, increased natural 

light reflectivity helps increase plant vigor, stem diameter, and stem length.” 

Dave Lines, Dave Lines’ Cut Flowers, La Plata, Md. 

“We grow the lisianthus [in] hoops all summer [with] a shade cloth on the 

hoop. We use about 70% shade. Our overwintered crop of lisianthus is in its second 

week of blooming [28 June], and the smallest stems per plant are 40", the 

taller ones are 48"; there are 7–10 stems per plant, all saleable [at] $18 to $20 for 

a 10-stem bunch.” Mimo Davis, WildThang Farms, Ashland, Mo. 

“Lisianthus are a bit susceptible to root rots. Pull a few plants and take a good 

look at the roots. A healthy root system [has] lots of fine, white root hairs. It is 

definitely worthwhile to have a disease analysis done.” Laurie Constable, Avalon 

Flowers, Santa Barbara, Calif. 

“I use both Rootshield ® and Clearys 3336 ® . I mix [them together] and water 

in every lisianthus plug when we plant in the field. The plugs have also been 

lightly drenched in the watering process while the plugs are growing-on. I always 

plant lissies in a new bed—I have about 2 more years before every annual bed will 

have had lisianthus—and I know that drenching is a must.” Bob Wollam, Wollam 

Gardens, Jeffersonton, Va.


Reading 

Alt, D., R. Strunk, and A. Thielking. 1993. Nutrient requirements of Eustoma 

and Impatiens. Gartenbau 2(10):59–61. 

Dennis, D. J., T. Ohteki, and J. Doreen. 1989. Responses of three cut flower selections 

of lisianthus (Eustoma grandiflorum) to spacing, pruning and nitrogen 

application rate under plastic tunnel protection. Acta Hortic. 246:237–246. 



10(1):1–13. 

Ecker, R., A. Barzilay, and E. Osherenko. 1994. Inheritance of seed dormancy in 

lisianthus (Eustoma grandiflorum). Plant Breeding 113(4):335–338. 

Gill, S. A., T. Blessington, E. Dutky, R. Balge, D. Ross, G. Rosenkranz, B. Butler, 

S. Klick, and R. Reeser. 1998. Production of lisianthus as a cut flower. Maryland 

Cooperative Extension Fact Sheet 770. 

Griesbach, R. J. 1992. Correlation of pH and light intensity on flower color in 

potted Eustoma grandiflorum Grise. HortScience 27(7):817–818. 

Grueber, K. L., B. E. Corr, and H. F. Wilkins. 1984. Eustoma grandiflorum, Lisianthius 

russellianus. Minn. State Flor. Bul. 33(6):10–14. 

Halevy, A. H., and A. M. Kofranek. 1984. Evaluation of lisianthus as a new flower 

crop. HortScience 19:845–847. 

Huh, K. Y., C. S. Bang, J. S. Song, B. Y. Choi, B. H. Kim, and C. Y. Song. 1998. Effect 

of long day treatments on the flowering of Eustoma grandiflorum raised at 

low temperature. RDA J. Hort. Sci. 40(2):77–81. 

Ichimura, K. 1998. Improvement of postharvest life in several cut flowers by the 

addition of sucrose. Japan Agr. Research Quarterly 32(4):275–280. 

Ichimura, K., M. Shimamura, and T. Hisamatsu. 1998. Role of ethylene in senescence 

of cut Eustoma flowers. Postharvest Biology and Technology 14(2):193–198. 

Kawabata, S., M. Ohta, Y. Kusuhara, and R. Sakiyama. 1995. Influences of low 

light intensities on the pigmentation of Eustoma grandiflorum flowers. Acta 

Hortic. 405:173–178. 

McGovern, R. J., H. Bouzar, and B. K. Harbaugh. 2000. Stem blight of Eustoma 

grandiflorum caused by Sclerotium rolfsii. Plant Disease 84(4):490. 


Ohkawa, K., A. Kano, K. Kanematsu, and M. Korenaga. 1991. Effects of air temperature 

and time on rosette formation in seedlings of Eustoma grandiflorum 

(Raf.) Shinn. Scientia Hortic. 48(1–2):171–176. 

Ohkawa, K., S. Yamaguchi, M. Miyoshi, and A. Yamazaki. 1996. Forcing of rosetted 

Eustoma grandiflorum seedlings by low temperature treatments. Environmental 

Control in Biology 34 (1):45–52. 

Ohta, K., A. Taniguchi, N. Konishi, and T. Hosoki. 1999. Chitosan treatment affects 

plant growth and flower quality in Eustoma grandiflorum. HortScience 

34(2):233–234. 

Roh, M. S. 1999. Lisianthus (Eustoma). Ohio Florists’ Assoc. Bul. 838:3–6. 

Roh, M. S., A. H. Halevy, and H. F. Wilkins. 1989. Eustoma grandiflorum. In The 

Handbook of Flowering. Vol. 6. A. H. Halevy, ed. CRC Press, Boca Raton, Fla.

FREESIA ×HYBRIDA 289 

Sclomo, E., and A. H. Halevy. 1987. Studies on the growth and flowering of lisianthus 

(in Hebrew). Hassadeh 67:1628–1631. 

Song, C. Y., C. S. Bang, K. Y. Huh, D. W. Lee, and J. S. Lee. 1994. Effect of postharvest 

treatment and preservative solutions on the vase life of cut Eustoma. J. 

Korean Soc. Hort. Sci. 35(5):487–492. 

Tsukada, T., T. Kobayashi, and Y. Nagase. 1982. Studies on the physiological 

characters and cultivation of prairie gentian. Part 2: effect of temperature 

and photoperiod on growth and flowering. Bul. Nagano Veg. Ornam. Crops Exp. 

Sta. 2:77–88. 

White-Mays, L. 1992. Eustoma grandiflorum, Lisianthus. In Proc. 4th Natl. Conf. on 

Specialty Cut Flowers. Cleveland, Ohio. 

Many thanks to Philip Katz and Dave Lines for reviewing this section. 

Freesia ×hybrida Iridaceae 

bulb, greenhouse hybrid origin many colors 1 

12–15"/9" (30–38 cm/23 cm) 

Precooled freesias are still produced in Florida as a winter crop, but nearly all current 

production occurs under protected structures, largely in California and the 

Northeast. Although significant field production occurred in southern California 

from the 1950s through the 1970s, problems with disease and insects reduced 

outdoor productivity. Freesias are native to the Cape Province of South 

Africa; thus, for optimum flowering, they require a warm, dry storage followed 

by cool soil temperatures (Imanishi 1993). For year-round forcing, a soil-cooling 

system is required. In their native habitat, corms initiate growth in the fall and 

flower in winter at temperatures around 46–50F (8–10C). 

Propagation 

Seed: Seed sown at 60–66F (15–19C) soil temperature in the dark germinate in 

approximately 3 weeks and may be transplanted to pots or flats 1–2 weeks later 

(Gilbertson-Ferriss 1985). 

Corms: Most growers purchase prepared corms produced by specialists in 

Holland. 


Temperature: Bulb specialists pretreat corms for at least 3 months at 86F (30C) 

prior to shipping (De Hertogh 2001). Corms must therefore be ordered well in 

advance. 

Flowering: Plants are similar to Alstroemeria in that soil temperature is the main 

trigger for flower initiation and development. Freesias initiate flowers at 40–68F 

(4–20C), but 54–60F (12–15C) is optimal (Heide 1965). Air temperatures above 

62F (17C) should be avoided. Although research has suggested that tempera-

290 FREESIA ×HYBRIDA 

Freesia ×hybrida ‘Elegance’ 

tures greater than 61F (16C) hasten flower stem development once flowers have 

initiated, the time savings is often offset by a reduction in flower quality. Abnormal 

inflorescences develop: the flowers are more widely spaced on the spike, 

fewer flowers occur per spike, and flower stems are shorter (Gilbertson-Ferriss 

and Wilkins 1978). The crop is best forced at 54–60F (12–15C). 

Photoperiod: Temperature is more important than photoperiod, particularly as 

temperatures increase (Heide 1965). Research has shown that flower initiation

FREESIA ×HYBRIDA 291 

is enhanced by SD, while flower development (stage after initiation) is enhanced 

by LD (Gilbertson-Ferriss and Wilkins 1978). Short days increase the number of 

flowers per raceme, the stem length, and the number of lateral flower stems (De- 

Lint 1969, Gilbertson-Ferriss and Wilkins 1978). Most growers, however, do not 

consider photoperiod a major factor. 

Greenhouse Performance (corms) 

Planting: If corms cannot be planted immediately upon arrival, store at 55F 

(13C), high relative humidity, and no ventilation, but only for a maximum of 3 

weeks (De Hertogh 1996). Plant 5/7 cm corms with the tops approximately 2" (5 

cm) below the surface in well-drained, fluoride-free soil. Never use superphosphate 

or water that contains fluorine. A pH of 6.5–7.2 is recommended (De Hertogh 

2001). Space corms about 2–3" (5–8 cm) apart, which is approximately 90– 

110 corms/100 ft2 (10–12 corms/m2 ) (De Hertogh 2001). Provide at least 2 layers 

of mesh support system over the bed. 

Planting time: The planting date depends on the prevailing soil temperatures. 

Warm temperatures of 55–63F (13–17C) can be maintained by under-bench 

heating to delay flower initiation for the first 3–4 weeks, or until 5–7 leaves are 

visible. At this time, air temperatures can be up to 70F (21C) days and 65F (18C) 

nights. Then, air temperatures should be lowered and soil temperatures maintained 

at 50–55F (10–13C). Low soil temperatures limit production to winter 

months in much of the country unless a soil-cooling system is used when temperatures 

become warm. Warmer temperatures cause problems (see “Environmental 

Factors”). 

Light intensity: Provide as much light as possible (2500–5000 fc) by keeping 

the covering clean. Most crops are grown in glass or acrylic houses, as double 

polyhouses do not offer sufficient light in the winter months. In areas where 

winter light is poor (e.g., the Northwest), supplemental lighting enhances flower 

quality. In the relatively bright winter light area of southwestern Ontario, supplemental 

lighting did not enhance flower quality (Blom and Piott 1992). As 

temperatures begin to rise, a light shading for spring flowering is recommended. 

Fertilization: Once well rooted, fertilize twice with 100 ppm nitrogen, and then 

raise fertility no higher than 200 ppm nitrogen. 

Carbon dioxide: CO2 at 1000 ppm is effective during daylight hours. 

Flowering time: Flowering generally starts 110–120 days after corms are 

planted and persists for 4 weeks (De Hertogh 1996). Planting of corms must be 

staggered for a long season of flower production. 

Greenhouse Performance (seedlings) 

Seedlings can be used from plugs and transplanted when they are 2–3" (5–8 cm) 

tall (4–5 weeks from sowing) and grown at 70F (21C) days and 65F (18C) nights 

until 6–8 leaves are visible (Gilbertson-Ferriss 1985). Lower temperatures to continuous 

50–55F (10–13C) soil temperatures for flower initiation and development. 

Follow cultural practices as outlined for corms.

292 FREESIA ×HYBRIDA 


For local markets, harvest when first flower is open and at least 2 additional 

flowers are showing color (De Hertogh 2001). For wholesale markets, flowers 

may be picked sufficiently early in the bud stage so they may be sold when they 

are in the balloon stage, showing color only. John LaSalle, who has been growing 

freesias in Whately, Mass., for many years, harvests a slightly shorter first cut 

(than used in Dutch markets), then picks 1 or 2 second-cut side shoots and 

bunches them to sell in retail shops and grocery stores, or as bouquets with 

greens and baby’s breath added. 

Postharvest 

Fresh: Flowers last approximately one week (Vaughan 1988). Freesias are susceptible 

to ethylene and should be kept away from fruit or other ethylene 

sources. A treatment with 1-MCP is effective (De Hertogh 2001), as is an 18hour 

pulse with a sugar solution carried out in the dark at 70F (21C) and 85% 

relative humidity (Evans and Reid 1990). Such treatments will increase flower 

size and allow more flowers to open. Immature flowers (cut before the first flower 

has opened) should be held in a preservative solution containing 4% sucrose at 

50–70F (10–21C) to open flowers well (Evans and Reid 1990). Always avoid fluoridated 

water. 

Storage: Avoid storage of fresh cut flowers when possible. Botrytis can occur in 

coolers in as little as 3 days. For the short term, flowers may be stored dry at 32– 

35F (0–2C) and 95% relative humidity (Nowak and Rudnicki 1990). They can 

be held longer in water at 33–35F (1–2C). Stems also benefit from a pulse of 200 

ppm 8-HQC plus 20% sucrose for 24 hours at 70F (21C) and 60% relative humidity 

prior to shipping (Woodson 1987). Ship wet if at all possible. 

Dried: Freesias may be dried with silica gel desiccant (Vaughan 1988). They do 

not air dry well. 

Cultivars 

Cultivars with single or double flowers are available in an array of colors. Some 

of the more common include ‘Blue Heaven’ (blue), ‘Dukaat’ (yellow), ‘Elegance’ 

(white), ‘Golden Wave’ (double yellow), and ‘Volante’ (double white). Consult a 

bulb specialist for the best cultivars for your area. 


Botrytis and aphids, the most common pests, are best treated with an IPM program. 

For botrytis on blooms, apply some heat and ventilate the greenhouse. 

Some fungicides are effective, but others may disfigure open flowers. Do a small 

experimental spray prior to treating the entire crop. Dip corms on arrival into an 

appropriate fungicide to reduce incidence of botrytis and apply proper aphicides 

when necessary. Thrips, especially in late plantings, can be a large problem.

GLADIOLUS 293 

Physiological disorders 

“Thumbing” describes an inflorescence in which the lowermost 2 or 3 flowers are 

unevenly spaced along the spike, and the spike is nearly straight. Warm temperatures 

during floral induction is thought to be the cause; provide shade to reduce 

the temperature. 

Leaf scorch appears to be a fluoride problem. Reduce the use of phosphorus 

sources. 

Reading 

Blom, T. J., and B. D. Piott. 1992. Assimilative lighting with high pressure 

sodium lights reduces Freesia quality. HortScience 27:1267–1268. 

De Hertogh, A. A. 2001. Growing freesias. FloraCulture International 11(12):38–39. 

———. 1996. Holland Bulb Forcer’s Guide. 5th ed. International Flower Bulb Center, 

Hillegom, The Netherlands. 

DeLint, P. J. 1969. Flowering in Freesia: temperature and corms. Acta Hortic. 14: 

125–131. 



Gilbertson-Ferriss, T. L. 1985. Freesia ×hybrida. In The Handbook of Flowering. Vol. 

3. A. H. Halevy, ed. CRC Press, Boca Raton, Fla. 

Gilbertson-Ferriss, T. L., and H. F. Wilkins. 1978. Flower production of Freesia 

hybrida seedlings under night interruption lighting and short day influence. 


Heide, O. M. 1965. Factors controlling flowering in seed-raised Freesia plants. 

J. Hort. Sci. 40:267–284. 

Imanishi, H. 1993. Freesia. In Physiology of Flower Bulbs. A. De Hertogh and M. Le 

Nard, eds. Elsevier Press, Amsterdam. 




Ore. 

Smith, D. 1985. Freesias. 2nd ed. Grower Books, London. 

Woodson, R. M. 1987. Postharvest handling of bud-cut freesia flowers. Hort- 

Science 22:456–458. 

Many thanks to August De Hertogh, John LaSalle, and Roy Snow for reviewing 

this section. 

Gladiolus Iridaceae 

bulb 

Glads are well established as a mainstream cut flower, and a staggering volume 

of spikes are produced in this country as well as in Europe, South America, and 

Israel. Two main types of gladioli are used: standard types produce one spike

294 GLADIOLUS CALLIANTHUS 

per corm, with up to 30 large flowers per spike; miniatures may produce several 

stems per corm. The largest production areas are in Florida, California, and 

Michigan. The need for large, bold stems in everyday flower arranging and funerals 

is declining, and while the market for standard glads is reasonably strong, 

other forms or species must be examined. The new “orchidola” glads are useful 

for their shorter stems, shorter production time, and “different” look. Some oldfashioned 

species also have charm and practicality, including Gladiolus callianthus, 

G. communis subsp. byzantinus, and G. tristis. 

Gladiolus callianthus Abyssinian glad Iridaceae 

bulb, Zones 7–10 Ethiopia white with purple throat 1 

3–4'/3' (0.9–1.2 m/0.9 m) 

Gladiolus callianthus (syn. Acidanthera bicolor) is an excellent fragrant cut flower. 

Approximately 5 flowers, 3" (8 cm) wide, are formed on the spike, and they open 

from bottom to top. The “bulb” is a small tunicated corm, about ½" (13 mm) 

wide. Shelf life is reasonable, if not exceptional. Treat as an annual in most areas 

of the country. 


Photoperiod: Photoperiod likely has an effect on flowering time, and LD may be 

beneficial. 

Temperature: Temperature affects the rate of development and crop timing 

(see under Gladiolus hybrids). Abyssinian glad does not require cold for flowering, 

and temperatures below 40F (4C) should be avoided. 


Spacing: Space 3–4", up to 16 corms/ft2 (8–10 cm, 170 corms/m2 ). 

Longevity: Yield is reduced significantly after the first year, although stem 

length and diameter are not adversely affected, as shown in the following table 

(Armitage and Laushman 1990). 

Longevity of Gladiolus callianthus ‘Muralis’. Fall-planted, Athens, 

Ga. 

Year Scapes/corm Stem length (in) z Stem width (mm) y 

1 1.2 28.6 8.0 

2 0.6 32.2 7.5 

3 0.5 34.4 7.5 


y = divide (mm) by 25.4 to obtain (in)

If corms are to be replanted (not recommended), lift in late fall and overwinter 

in dry, 60–65F (15–18C) conditions in a well-ventilated area. In Zones 7b and 

south, corms may be left in the ground, but yield declines each season. Corms are 

inexpensive and should be replanted every year. 

Planting time: In the North, corms may be field-planted after the last frost date. 

In the South, corms may be planted in the fall. Plants normally flower in late 

summer in the South, fall in the North. When corms were planted at different 

times between November and March, differences in yield and stem quality were 

minimal (Armitage and Laushman 1990). 

The effect of planting date on Gladiolus callianthus ‘Muralis’. 

Month Corm Flw/ First Stem Stem 

planted survival (%) corm harvest length (in) z width (mm) y 

Nov 98 1.2 2 Jul 28.9 8.2 

Feb 97 1.3 2 Jul 28.3 8.5 

Mar 84 0.8 11 Jul 28.1 7.7 



The harvest lasted approximately 22 days, regardless of planting date. 


GLADIOLUS CALLIANTHUS 295 





(%) 

N P K Ca Mg 

2.5 0.29 1.54 0.47 0.16 

(ppm) 

Fe Mn B Al Zn 

110 32 15 27 50 

Calcium deficiency during production results in brittle stems that break when 

harvested, a disorder known as topple. 


Harvest when 1 or 2 flowers are open; other flowers will open in a preservative solution. 

The earlier the preservative is applied, the longer the vase life.

296 GLADIOLUS CALLIANTHUS 

Postharvest 

Fresh: Flowers persist 5–7 days at room temperature in a commercial preservative. 

Most commercial preservative solutions are effective and should be used 

for rehydration of stems. 

Storage: Flowers may be stored in an upright position for 6–8 days at 36–41F 

(3–5C). Lower temperatures result in injury and prevent flower opening. Leaving 

lights on in the storage area helps to open buds. 

Stem tips of Abyssinian glad bend if placed on their sides and therefore 

should be maintained upright unless refrigerated throughout the market chain. 

The problem is not as severe as with standard hybrid gladioli (see “Postharvest” 

under Gladiolus hybrids, which are closely related—and more studied). 

Cultivars 

‘Muralis’ has larger flowers and stronger stems than the species. 


Gladiolus communis subsp. byzantinus (syn. G. byzantinus; Byzantine gladiolus) 

bears brilliant rusty red flowers. Quite different, has naturalized in the South. 


Rust and thrips, which disfigure the foliage, are common problems. Voles and 

other rodents can be serious pests. Problems inherent with hybrid gladiolus production 

should be considered when producing this species. 


“Acidanthera is a great cut [but] harvest period is very compressed. I plant 3 or 

4 plantings 2–3 weeks apart. Spacing about 6 × 6". Probably could go closer. 

Problems that may crop up are thrips (of course) and rust. Basically, it is cultured 

like gladiolus.” Paul Shumaker, Never Should Have Started Farm, Bangor, 

Pa. 

“Our acidanthera ‘Muralis’ has been selling to a local florist for $6.50 per 

bunch of 10 and to an art gallery owner in the trendy/pricey Berkshires for $15 

per bunch. They are blooming now and have huge, gorgeous flowers. But we 

find we can’t wholesale them because 1) you have to pick after the first 1 or 2 

flowers are open, and they’d get crushed if you tried to bunch them tightly or 

pack them for shipping, and 2) storing in our cooler, which cycles between 33 

and 39F, damages the buds. They are beautiful, long-lasting, and heavenly 

scented, and the customers love them.” Alice Vigliani, Maple Ridge Peony Farm, 

Conway, Mass.

Gladiolus hybrids Iridaceae 

bulb, Zones 8–10 hybrid origin many colors 1–3'/1' (30–60 cm/30 cm) 

Propagation 

GLADIOLUS HYBRIDS 297 

All flowers are produced from corms by specialist propagators. Corms are usually 

harvested when dormant, and the degree of dormancy depends on where 

they were harvested and on the cultivar. In general, corms are placed, after digging, 

at 100F (38C) for a few days, and then in a 41F (5C) cooler for up to 5 

months (Cohat 1993, Jean et al. 1997). With Gladiolus tristis, corms stored 3 or 6 

weeks at 41F (5C) and 90% relative humidity flowered 20 or 11 days earlier, 

respectively, than those that were not stored. The corms stored 6 weeks flowered 

35 days longer than those given other treatments (Gonzalez et al. 1998). 

Some growers use the same corm for up to 3 years, but most replant each year. 


All gladioli are vegetative when planted, and flowers are initiated after a certain 

number of leaves are formed. The number of leaves formed differs from cultivar 

to cultivar, and the exact time of flower development depends on water balance, 

light, and temperature. The flowering shoot emerges after the last leaf; 8–10 

leaves are formed in most cultivars. Gladioli that do not flower are said to be 

blind. Blind mature gladioli are plants in which the flowers were formed but 

aborted, a phenomenon known as blasting. Blasting is a result of poor light conditions 

or the drying out of developing plants. 

Light and photoperiod: Low light and short days during winter production 

increase the incidence of flower blasting. Plants are most sensitive to low light 

and SD during the first to fifth leaf stage (reduced flower percentage) and the 

fourth to sixth leaf stage (increased flower blasting). Long days, either natural or 

by applying nightbreak lighting in the greenhouse or field, reduce the incidence 

of blindness and improve the length and quality of the spikes (Shillo and Halevy 

1976, McKay et al. 1981). Long days, however, may delay flowering in some cultivars. 

Corm development continues during SD but is arrested when LD are 

applied and does not continue until after flowering (Shillo and Halevy 1981). 

Supplemental light of 460 fc for 12 hours significantly reduced bud abortion 

during winter forcing. Once 3 leaves have appeared, the plants are responsive to 

supplemental light (Zhang 1995). 

In summary, high light and long days are best for flower production of gladioli. 

During winter production, a day extension of 4–5 hours or a nightbreak of 

2–4 hours is used in the field or greenhouse (McKay et al. 1981, Shillo and Halevy 

1981). Miniature and standard cultivars also respond positively to supplemental 

photoperiodic lighting (Halevy 1985). 

Temperature: Temperature is the most important environmental factor: it 

affects the rate of floral development, and therefore, the rate of flowering. Summer-grown 

gladioli bloom in about 70 days, while the same cultivars require 

approximately 130 days to flower in the winter. Low night temperatures of 33–

Gladiolus hybrid


38F (1–3C) cause flower blasting when light intensities are low. Chilling during 

the day appears to inhibit flowering but does not cause blasting. Blasting caused 

by high temperature is usually the result of poor water balance (plants dry out) 

and not temperature per se. 

Water: Water stress affects the developing flowers much more than the corm; 

therefore, drying out causes more flower blasting than actual damage to the 

plant itself. The stages immediately after planting and the 4- to 7-leaf stage 

(when flowers are developing) are the most sensitive to water stress. 


Corm size: Use large corms. Nearly all published research has shown that larger 

corms result in faster sprouting, taller plants, more shoots, and thicker stems 

than smaller ones (Mohanty et al. 1994, Kalasareddi et al. 1998). If forcing in 

the winter or under low light, it is particularly important to use the biggest (i.e., 

#1 size) corms. Smaller sizes may be used for summer production. 

Planting: Plant when frost is no longer a danger. In the Midwest, corms may be 

planted as soon as the ground can be worked. Place as close as 2" (5 cm) apart, 

with as little as 2" (5 cm) to as much as 5" (13 cm) of soil above. Although corms 

may be planted “corm to corm,” the probability of disease increases with dense 

plantings. For production of cormels, a planting density of 6 × 6" (15 × 15 cm) 

is recommended (Bahar and Korkut 1998). 

Soil: Fresh or fumigated soils should be used, and 2- to 3-year crop rotations 

are most important. Soil pH of 6.0–6.5 is best, and well-drained soils are necessary 

to reduce root and foliar problems. 

Scheduling: Depending on cultivar and time of year, flowering occurs 60–100 

days from planting (De Hertogh 1996). Howard Lubbers of Holland, Mich., suggests 

that up to 5 plantings may be conducted, starting 1 April and each month 

thereafter until 15 June. 

Weeding: Weeds have a serious impact on flower yield and stem length. Weeds 

should be controlled before the 3-leaf stage to allow for good-quality cut flowers 

(Cheong et al. 2000). 

Fertilization: Plants in sandy soils require more frequent fertilization than 

those in heavier soils. For sturdier stems, a complete fertilizer, such as 5-10-10 or 

5-15-5, should be applied before planting and as a side dressing about one 

month later. An additional side dressing may be used when the spikes are visible 

but is probably not needed in clay-loam soils. 

Photoperiodic control: For growers producing a winter field crop, incandescent 

lights should be strung over the plants to provide long days. Sixty- or 100-watt 

bulbs spaced at a distance to provide 10–20 fc during the night are most effective. 

Provide 13-hour days by lighting from one hour before dusk until about 10 

p.m. to midnight, depending on natural daylength. Nightbreak lighting and 

cyclic lighting may also be used. 

Digging corms: Corms may be removed after the foliage has declined (about 

8 weeks after flowering) or after first frost. Remove foliage and place no more 

than 4 layers of corms in trays with screen or slat bottoms. Cure at 75–85F (24–

300 GLADIOLUS HYBRIDS 

29C) for 10–15 days. After curing, store corms at 40F (4C), 70–75% relative humidity. 

To avoid problems of digging, curing, and storage, purchase new corms 

annually. 


Plant corms in ground beds at a spacing of 5–8 corms per running foot (15–25 

per running meter). In greenhouse work in South America, a planting density of 

25 corms/m2 produced the best stem length and yield compared to 15, 35, or 45 

plants/m2 (Klasman et al. 1995). The number of cormels produced was also 

greatest at that density. 

Provide LD (13–15 hours) with incandescent lights (10–20 fc) during late fall, 

winter, and early spring production. Temperatures should be maintained at 70/ 

65F (21/18C) day/night throughout the crop. Higher temperatures may be used 

to accelerate leaf emergence, therefore flowering, but high temperatures are not 

necessary for high-quality flowers. Flowers occur 60–75 days after planting, 

depending on cultivar. Fertilize with liquid (nitrate forms of nitrogen are best) 

or granular fertilizers at planting and again after 3–4 leaves have emerged. 


Cut when 1–5 flowers on the spike are showing color. For local distribution, cut 

when bottom flower is thumb-sized to fully open. When bunching, position the 

stems so that the flowers are on the outside of the bunch. 

Postharvest 

Fresh: Cut stems respond well to being placed in a preservative solution containing 

up to 20% sugar and a germicide; sugar (4%) and HQC (250 ppm) 

appears to be a good combination for flower shelf life (Zhou et al. 1995, De et al. 

1996). Allow stems to remain in solution overnight at 70F (21C). Use warm, 

deionized water for rehydration; deionized water is best for gladioli because they 

are susceptible to fluoride levels as low as 0.25 ppm. Stems should be placed at 

68–76F (20–25C) for maximum bud opening. 

The tips of gladioli stems are very prone to bending if placed on their sides. 

Unless they can be refrigerated throughout the market chain, they must remain 

upright during storage and transport. 

Storage: Stems may be stored dry if conditioned with 10% sucrose solution 

plus STS at 68F (20C) for 24 hours. Older research suggested that flowers should 

be stored at 40–42F (4–6C) to prevent chill injury, but recent research (Nell and 

Reid 2000) has shown that flowers can be stored at 33–35C (1–3C), wrapped in 

moisture-proof paper and placed in polyethylene bags. After storage, recut stems 

and place in an opening solution until flowers reach the desired flowering stage 


Wet storage is easier to accomplish if stems are placed in a floral preservative. 

Stems should be stored at 33–38F (1–3C) (Nowak and Rudnicki 1990).

Corms may be stored by growers after curing and cleaning. Corms are placed 

at about 40F (4C) for 60–90 days (Pirone 1970). 

Cultivars 

Many standard, hybrid, and miniature gladioli are available. Discuss optimum 

cultivars with a reputable bulb salesperson. 

The North American Gladiolus Council classifies glads into miniature (under 

2½", 6 cm), small-flowered (under 3½", 9 cm), medium-flowered (under 4½", 11 

cm), large-flowered (under 5½", 14 cm), and giant-flowered (over 5½", 14 cm). 



Insects 

The main insect-type pests are thrips, red spider mites, aphids, and wire worms. 

Gladiolus thrips are most prevalent and damaging. They feed by rasping the 

foliage and flowers; surfaces of infected tissue appear whitish gray. They feed 

mainly in cloudy weather, seldom in full sunlight. Infected flowers are discolored 

and spotted and eventually dry up as if burned (Pirone 1970). Corms may also be 

attacked and become sticky from the sap that oozes out as a result of the infestation. 

Apply an insecticide early in the growing season. If possible, refrain from 

spraying when flowers are open. 

Wire worms (the larvae of click beetles) feed on the corms and roots, boring 

holes in the base of the foliage. They are reddish brown, long, and narrow, with a 

hard, many-jointed shell (Pirone 1970). Infestations are more common and debilitating 

in heavy soils that lack adequate drainage. Well-drained light soils reduce 

the presence of wire worms, and most soil insecticidal drenches are effective. 

Diseases 

Botrytis dry rot, corm rot, hard rot, leaf and flower spot, fusarium rot, and 

viruses affect gladioli. 

Botrytis gladiolorum, which causes botrytis dry rot, is the most common cause 

of corm rot and leaf and flower spot in glads. The foliage turns brown so suddenly, 

it appears as if the field has been burned. Infected spikes may appear 

healthy at harvest but rot in transit. Control methods include fungicides, roguing, 

and planting in a well-drained field. 

Corm rots can be caused by many organisms. Penicillium gladioli causes redbrown 

sunken, corky lesions and is usually introduced through physical injury. 

Handle the corms carefully to avoid wounding; if corms are dug, proper curing 

procedures should include covering any wounded tissue. Fusarium oxysporum 

f. gladioli, which causes fusarium dry rot of corms, is the most serious storage 

disease organism of gladioli corms. Infected areas appear as concentric watersoaked 

sunken spots, varying in color from very light brown to tan (Pirone 1970). 

Treatments vary from plunging cormels in hot water (128F, 53C) to roguing 

infected plants. Where infection has occurred, it is essential that soils be well

302 GLADIOLUS HYBRIDS 

drained and sterilized, and that drying and curing time be accomplished prior to 

storage. 

Leaf and flower spotting caused by Curvularia trifolii f. gladioli shows up as 

oval, tan spots on the leaves and stems. The spots may grow from pinhead size 

to 1" (2.5 cm) in diameter in a few days. Spots may be seen on both sides of the 

leaf, and black powdery spores occur in the middle of the lesions. Flowers fail to 

open when the disease is advanced. Foliar fungicide may have to be applied every 

week to control the disease. 

Viruses include cucumber mosaic and tobacco mosaic virus. Streaking of the 

foliage and flowers is a common symptom of infection. Most viruses are transmitted 

by aphids, leafhoppers, or infected tools. Control viruses by disinfecting 

tools and controlling the insects. Viruses are carried over from one season to the 

next in the corms; therefore, infected corms should be discarded. 


“My experience is limited, but the mini-glad Nanus ‘Atom’ was terrific for me. 

Red with a paintstroke of white around the edges and a lavender tickle in the 

throat. Excellent stems, with about 50% giving a second smaller and later shoot. 

If you’re planting 5000–6000, you’ll cut ’em all, and the second shoot will come 

with the first cutting. On my smaller scale, I can cut the first and leave the second. 

I also tried Nanus ‘Impressive’ and only got a few blooms. But they were indeed 

so ‘impressive’ that I’m trying them again this year, thinking that perhaps I 

planted too deep. These were a deep shell-pink with a bicolor coral- and whitepainted 

throat.” Karen Hanley, Stork Road Farm, North Creek, N.Y. 

Reading 



Science 25:1236–1238. 

Bahar, S. N., and A. B. Korkut. 1998. Research on the effects of planting densities 

on the yield of corm and cormel in some gladiolus (Gladiolus L.) varieties. Turkish 

J. Agr & Forestry 22(1):51–58. 

Cheong, D., J. Kim, and H. Park. 2000. Effects of weeding time on growth and 

flowering of Gladiolus ‘Spic and Span’. J. Korean Soc. Hort. Sci. 41(2):201–206. 

Cohat, J. 1993. Gladiolus. In Physiology of Flower Bulbs. A. De Hertogh and M. Le 

Nard, eds. Elsevier Press, Amsterdam. 

De, L. C., S. K. Bhattacharjee, and R. L. Misra. 1996. Postharvest of pulsed gladiolus 

spikes as affected by different chemicals. J. Orn. Hortic. 4(½):18–22. 



Gonzalez, A., S. Banon, J. A. Fernandez, J. A. Franco, J. L. Casas, and J. Ochoa. 

1998. Flowering responses of Gladiolus tristris L. corms to cold treatment. Sci. 

Hortic. 74(4):279–284.

Halevy, A. H. 1985. Gladiolus. In The Handbook of Flowering. Vol. 3. A. H. Halevy, ed. 


Jean, M., T. Lin, C. Sheng, G. Wu, W. Chen, and T. Huang. 1997. The optimum 

period of constant cold temperature storage for breaking dormancy in Gladiolus 

flower bulbs. Report of the Taiwan Sugar Institute 156:37–48. 

Kalasareddi, P. T., B. S. Reddy, S. R. Patil, Y. H. Ryagi, and P. M. Gangadharappa. 

1998. Effect of corm size on growth and spike yield of Gladiolus cv. Snow 

White. Karanataka J. Agr. Sci. 11(4):1133–1135. 

Klasman, R., J. Molinari, and A. di Benedetto. 1995. Greenhouse cultivation of 

cut gladiolus at four planting densities. Hortic. Argentina 14(36):65–68. 

McKay, M. E., D. E. Blyth, and J. A. Tommerup. 1981. The influence of photoperiod 

and plant density on yield of winter-grown gladioli in Queensland. 

Scientia Hortic. 14:171–179. 

Mohanty, C. R., D. K. Sena, and R. C. Das. 1994. Studies on the effect of corm size 

and pre-planting chemical treatment of corms on growth and flowering of 

gladiolus. Orissa J. Hort. 22(½):1–4. 



Nowak, J., and R. M. Rudnicki. 1984. Cold storage of cut gladiolus spikes. Rosliny 

Ozdobne, Ser. B. 9:67–72. Skierniewice, Poland. 

———. 1990. Postharvest Handling and Storage of Cut Flowers, Florist Greens, and Potted 

Plants. Timber Press, Portland, Ore. 

Pirone, P. P. 1970. Diseases and Pests of Ornamental Plants. Ronald Press, New York. 

Shillo, R., and A. H. Halevy. 1976. The effect of various environmental factors on 

flowering of gladiolus. Scientia Hortic. 4:139–155. 

———. 1981. Flower and corm development in gladiolus as affected by photoperiod. 

Scientia Hortic. 15:187–196. 

Shillo, R., G. Valis, and A. H. Halevy. 1981. Promotion of flowering by photoperiodic 

lighting in winter-grown gladiolus planted at high densities. Scientia 

Hortic. 14:367–375. 

Zhang, X. 1995. Effect of light intensity and CO2 supplement on growth and 

flowering of Gladiolus. Acta Hortic. Sinica. 22(1):73–76. 

Zhou, W., B. Li, Y. Wang, C. Zhang, and M. Xu. 1995. Experiments on a preservative 

for flower of vase gladiolus (Gladiolus hybridus Hort.). J. Jiangsu Agr. College 

16(4):27–30. 

Many thanks to Howard Lubbers for reviewing this section. 

GOMPHRENA GLOBOSA 303 

Gomphrena globosa globe amaranth Amaranthaceae 

annual Mediterranean many colors 2–3'/2' (60–90 cm/60 cm) 

Gomphrena globosa is widely used as a dried flower. Excellent selections of it and 

G. haageana, and hybrids between them, in various colors and sizes, have been 

offered. Plants are a mixed blessing: they are extraordinarily heat tolerant yet 

grow like weeds—sometimes a little too exuberantly. Take the tongue-in-cheek

304 GOMPHRENA GLOBOSA 

comments of one of America’s fine cut flower growers, Frank Arnosky of Texas 

Specialty Cut Flowers, who has perhaps seen more of these amaranths than most 

of us: 

Gomphrena likes it hot because it originally grew in Hades’ garden at the 

gates of hell. Hades kidnapped Persephone, the daughter of Demeter, 

while she was out picking flowers (of course). Zeus worked out a compromise 

to get Persephone back for at least half of the year (summer). Hades 

was none too happy about it. He decided to curse Demeter, the goddess of 

agriculture and fertility, by sending gomphrena seeds up with Persephone. 

Of course they grew like hell, and since then, all of us who farm flowers 

for a living share in Hades’ curse. Gomphrena grows best here in Texas 

because our climate most closely matches that of gomphrena’s native environment. 

Frank’s version of the story notwithstanding, plants probably came over to this 

country with some of the first settlers and have been part of the cut flower scene 

for a long time. They are easy to grow and may be harvested mechanically. 

Propagation 

It is ludicrous not to purchase clean seed—few things are as messy as uncleaned 

gomphrena seed. Gomphrena globosa has approximately 19,000 clean seeds/oz 

(700 seeds/g), but there are only about 8000 (300) uncleaned seeds for the same 

weight. Gomphrena haageana has 11,000 clean seeds/oz (400/g). Although more 

expensive, greater percentages and more uniform germination can be expected 

from properly cleaned seed. Various other treatments can improve erratic seed 

emergence. Germination is approximately doubled by scarification; always purchase 

scarified seed if available. Seed may also be separated by size for higher 

germination (the larger the seed, the better the germination), and “high-tech” 

seed is recommended. Use 1.5–2 oz (42–56 g) of clean seed for 1000 seedlings 

(Nau 1999). 

Germination occurs in as little as 4–5 days in a sweat chamber at 78–80F (26– 

27C) or may take as long as 10 days when sown in the greenhouse at 70–72F 

(21–22C) under mist. One grower has had successful and rapid germination at 

temperatures as high as 100F (38C). No difference in germination between light 

and dark conditions has been shown. Because untreated seed germinates so 

erratically, direct sowing is not recommended; however, if direct sowing is to be 

accomplished, use clean, scarified, and, preferably, sized seed. 

Growing-on 

Grow seedlings at 65F (18C) nights, 70F (21C) days for most rapid growth. Capillary 

mats and temperatures of 70–72F (21–22C) are useful for growing-on seedlings 

after the first flush of germination. Capillary mats also minimize damping 

off, a problem common to overwatered plants. Seedlings from open packs may 

be transplanted to cell packs or small containers about 3 weeks from sowing


Gomphrena 

‘Strawberry Fields’ 

and planted to the field 4–5 weeks later. Transplant prior to flowering. If grown 

in plugs, allow 4–6 weeks (in a 200-cell pack) before transplanting to container 

or field, depending on size of plug. 

Fertilize seedlings initially with 50–100 ppm N; over 50% of the nitrogen 

should be in the nitrate form. As seedlings grow more actively, fertility may be 

increased to 100–150 ppm N and K. Overfertilizing results in tall, soft growth, 

which transplants poorly. 


Photoperiod: Flowering occurs as plants mature, regardless of photoperiod. 

Flowers initiate as the plant produces additional nodes; the number of nodes is 

directly affected by light intensity and temperature.


Temperature: Plants grow and flower more rapidly as temperatures rise above 

70F (21C); temperatures below 65F (18C) result in slow growth and reduced 

flowering. Their tolerance of warm, humid weather makes these excellent plants 

for the Midwest and Southeast. 


Spacing: Gomphrena behaves like most other field crops, in that as spacing is 

increased, yield per plant increases but yield/ft2 decreases. For example, research 

in India showed that as spacing increased from 9 × 12" (23 × 30 cm) to 9 × 24" 

(23 × 60 cm), plant width, number of branches per plant, and number and 

weight of flowers per plant increased but the highest yield/unit area was at the 

densest spacing (Jhon and Paul 1992). The same holds true in Sioux City, Iowa, 

or Waynesville, N.C. Our work in Athens suggested that plants be grown on 

approximately 6–9" (15–23 cm) centers, although wider spacing may reduce disease 

incidence. Some growers plant a double row on ridges 16" (40 cm) apart. 

Two rows are planted 8" (20 cm) apart on top of each ridge. This computes to 

approximately 16,000 plants/acre (39,500 plants/hectare). No pinching or support 

is necessary. 

Harvesting: Yield is often measured in dry weight per acre or plant. An average 

of ½ to ¾ pound of dried stems per plant occurred at Woodcreek Farm in Ohio; 

red cultivars yielded up to 1 lb/plant. Flowers may be picked all summer long 

from single spring plantings. Little mechanical harvesting is done, but it is a 

crop that lends itself to such a practice: although fewer stems/plant would be 

harvested compared with hand harvesting, the labor savings would outweigh 

the value of the lost stems. 

Shelley McGeathy obtains stem lengths of 10–12" (25–30 cm) in Michigan 

(Zone 5). Work at the University of Georgia (Zone 7) in which stems of Gomphrena 

‘Strawberry Fields’ were hand-harvested resulted in approximately 58 

stems/plant with an average stem length over the entire season of 15" (38 cm). 

Distribution of yield is shown in the following table. 

Yield and percentage of total stems on Gomphrena ‘Strawberry 

Fields’. Based on 50 plants. 

Week no. No. of stems Percentage of harvest 

19–22 230 7.4 

23–26 265 8.5 

27–30 200 6.4 

31–34 678 21.8 

35–38 1050 33.7 

39–42 696 22.4 

Stem quality: The length of stems is not as critical a quality in Gomphrena as it 

is with other cut flower genera because fresh flowers are normally used in

wreaths and table designs, where short stems are useful. Stem length cannot be 

ignored, however, and breeding efforts have concentrated on flower color and 

shape as well as on longer, stronger stems. The distribution of stem length from 

field trials at the University of Georgia is provided in the following table. 

Stem length of Gomphrena ‘Strawberry Fields’. 

Week no. Stem length (in) z 

19–22 12 

23–26 14 

27–30 15 

31–34 16 

35–38 18 

39–42 15 

z multiply (in) by 2.54 to obtain (cm) 


Shading: Shading is not recommended for these full-sun plants. 


Gomphrena is seldom grown in the greenhouse for cut flower production; however, 

if grown in the greenhouse, use 63–65F (17–18C) nights and 70F (21C) 

days. Allow as much light penetration as possible and fertilize at 200 ppm N 

with nitrate nitrogen. Space on 6–9" (15–23 cm) centers or grow in containers. 


Harvest when flowers are in color but before fully open. If stems are mechanically 

harvested, select only those flowers that are swollen and nearly fully colored. If 

harvested for drying, allow flowers to open completely. 

Postharvest 

Fresh: Fresh flowers persist approximately one week. 

Dried: Most flowers grown in the United States are used for drying. Flowers 

may be air-dried and held indefinitely. Hang upside down in small bunches; 

leaves need not be stripped prior to drying. To prevent mold, reduce field moisture 

as much as possible, use good air circulation, and reduce humidity. Stems 

are sometimes treated with glycerine, but this is more costly than air drying. 

Storage: Storage of fresh flowers is not recommended. Store at 36–41F (3–4C) 

only if necessary.



Gomphrena haageana (golden amaranth), native to India, has a longer, less 

rounded flower and is an attractive yellow-orange color. Cultivation is similar to 

G. globosa. 

Cultivars 

Most of the recent cut flowers selections are likely hybrids between Gomphrena 

globosa and G. haageana; however, bedding plant cultivars of G. globosa are also 

available (e.g., Buddy, Gnome series). Only 12–14" (30–36 cm) tall, they cannot 

be recommended for cut flower production unless short-stem forms are in 

demand. 

‘All Around Purple’ performed exceptionally well in national field trials in 

2001. Plants averaged 11 stems per plant with a stem length of approximately 

16" (40 cm). Nominated for Cut Flower of the Year by the ASCFG (Dole 2002). 

‘Bicolor Rose’ has rose and white flowers and strong, upright stems. Excellent, 

among the best of the recent cultivars. In national field trials, ‘Bicolor Rose’ was 

a hit for just about all trialers, receiving some of the highest scores that year; 

stems averaged 16" (40 cm) with over 50 stems per plant reported (Dole 1996). 

‘Flashing Light’ bears large red flowers on 16–18" (40–45 cm) plants. Probably 

a selection of Gomphrena haageana and quite similar to ‘Strawberry Fields’. 

QIS series enjoyed enormous popularity in the late 1990s and early 2000s. 

Available in purple, red (which has had some excellent reviews), and several other 

colors. ‘QIS Carmine’ was the ASCFG’s 1999 Dried Cut Flower of the Year. 

‘Strawberry Fields’ was a standard for cut gomphrena, and although it has 

been superseded by others, it is still a fine selection. The long stems bear deep red 

flowers, which hold their color exceptionally well when dried. Probably a selection 

of Gomphrena haageana. 


Several leaf-spotting fungi, the worst being Cercospora gomphrenae, occur on globe 

amaranth in the southern United States. It is also host to several viral diseases; 

particularly unwelcome is the impatiens form of tomato spotted wilted virus 

(TMSV-I), first found in Georgia in the early 1990s (Ruter and Gitaitis 1993). 

Seed-borne pathogens, such as Colletotrichum dematium (part of the Anthracnose 

complex) and Phoma spp., reduce seed germination (Chou and Wu 1995). 

Pests include aphids, thrips, and two-spotted spider mite. The good news is 

that gomphrena is quite resistant to elevated levels of ozone (Findley et al. 1997), 

so it can be a weed almost anywhere. 


“Seed is the least expensive part of production, and therefore I am willing to pay 

more for better seed. I do not pick continuously, rather one time and the entire

GONIOLIMON TATARICUM 309 

plant. I do this when the central or primary flower shows signs of age. I have 

picked it too late, and it shattered horribly in the barn.” Tom Wikstrom, Happy 

Trowels Farm, Ogden, Utah. 

Reading 

Chou, J. K., and W. S. Wu. 1995. Seed borne fungal pathogens of ornamental 

flowering plants. Seed Science and Technology 23(1):201–209. 


8(1):7–12. 

———. 2002. 2001 ASCFG National Cut Flower Trials. The Cut Flower Quarterly. 

Findley, D. A., G. J. Keever, A. H. Chappelka, C. H. Gilliam, and D. J. Eakes. 1997. 

Ozone sensitivity of selected southeastern landscape plants. J. Env. Hort. 15(1): 

51–55. 

Jhon, A. Q., and T. M. Paul. 1992. Effect of spacing, nitrogen and pinching on 

globe amaranth (Gomphrena globosa). Indian J. of Agronomy 37(3):627–628. 


Ruter, J. M., and R. D. Gitaitis. 1993. First report of tomato spotted wilt virus on 

bedding plants in Georgia. Plant Disease 77(1):101. 

Many thanks to Ralph Cramer and Mike Wallace (first edition) and Ralph 

Cramer, Shelley McGeathy, and Frank Arnosky (second edition) for reviewing 

this section. 

Goniolimon tataricum German statice Plumbaginaceae 

perennial, Zones 6–8 Asia lavender 2–2½'/2' (60–75 cm/60 cm) 

Although it is chiefly applied to Goniolimon tataricum (once known as Limonium 

tataricum), German statice serves as the common name for many species, such as 

L. latifolium and L. altaica, and hybrids between them. In general, plants have 

glossy green leathery leaves, and the flowers are faintly to strongly malodorous. 

They grow as rosettes, and the flower stems arise in early to mid summer with 

clouds of lavender to light blue. They do not have the vigor or the stem length of 

Limonium hybrids, such as ‘Misty Blue’. 

Unfortunately the market for many dried flowers, and particularly for German 

statice, has declined in the last few years. The comments submitted by Mary 

Ellen and Bob Schultz, long-time statice growers in Montana, are typical: 

We’ve been growing German statice for 10-plus years, and in that time 

frame, the market has been on a continuous decline, more or less following 

the dried flower market decline. We periodically call around to other 

German statice growers, and the story seems to be the same. Besides the 

general dried flower market shift, one of the principal problems from our 

perspective has been with large growers that give little attention to quality 

and sell it cheap. Time and again we’d get samples from big volume grow-

310 GONIOLIMON TATARICUM 

ers, where the product was totally faded and brown and smashed-packed 

into boxes. We believe most of this product goes to the discount hobby/ 

craft stores, where quality seems to be a secondary concern. The fallout is, 

of course, that this practice establishes a very bad reputation for the product 

in general and puts the onus on the better producers to convince buyers 

there is better product out there—but it necessarily costs more too. 

Much of the field information presented in this section is from work at the University 

of Georgia with Limonium altaica (altaica statice), but it is pertinent to 

Goniolimon tataricum and German statice in general. 

Propagation 

Seed: Seed is difficult to locate but not particularly difficult to germinate. Sow 

seed lightly and place under mist or sweat tent at 70–72F (21–22C). Germination 

occurs in 12–21 days. 

Division: Seed or explants are preferable; however, plants may be cut apart 

carefully, retaining as much root system on plantlets as possible. Plantlets recover 

slowly, and little production occurs the first year from division. Spring 

division is best if plantlets are to be replanted immediately. Otherwise, divide 

in fall and grow in the greenhouse for 3–4 weeks; overwinter in cold frames or 

unheated greenhouses. 

Cuttings: The best method of vegetative propagation is by root cuttings. Cut 1– 

3" (2.5–8 cm) long pieces of the fleshy roots. The thickest roots may be placed 

upright in sandy soil; the thinner ones may be placed horizontally and covered 

lightly. Cuttings are most successful in early spring, but fall cuttings may also be 

used. 

Growing-on 

Grow seedlings and small divisions in the greenhouse, under full light and 55– 

60F (13–15C) night temperatures, for 6–8 weeks or until ready for transplanting. 

Large root divisions may be placed immediately in nursery beds, but smaller 

divisions require growing in the greenhouse or cold frame. Little or no flower 

production occurs the first year from seed. Flowers are cut when 75% of the inflorescences 

are open (Hodgkin 1992). 


Cold treatment is necessary for best flower production. Hot summers have no 

detrimental effect on yield or quality, although flower color is more striking 

under cool nights. No photoperiodic response has been reported, although LD 

appear to accelerate flowering. 

German statice produces few flowers the first season from seed, indicating 

that a vernalization period is probably necessary. Therefore, it appears that cool 

temperatures, followed by warm temperatures and LD should be recommended 

for flowering in perennial statice.


Longevity: German statice can stay in production for 3 years without any 

decline in yield. Work with Limonium altaica in the Georgia trials suggested 4–5 

years of cutting was possible. 

Spacing: Plants can be spaced as widely as 2 × 2' (60 × 60 cm), but 1' (30 cm) 

centers are adequate. Tight spacing can be a problem if foliar diseases or botrytis 

is present. The wider the spacing, the less the disease pressure. 

Shading: Grow under full sun. Light shade may result in longer stems; however, 

stem diameter is not as strong. 





dry weight analysis for Limonium altaica, a species similar to German statice. 

(%) 

N P K Ca Mg 

3.85 0.40 3.60 0.48 0.40 

(ppm) 

Fe Mn B Al Zn 

129 47 22 102 36 


Flowers are cut when 75–80% of the inflorescences are open (Hodgkin 1992). 

Harvesting too early results in poor opening and small flower heads, although 

earlier harvesting and placing stems in an opening solution can help reduce the 

offensive smell. Harvesting too late results in discoloration and poor vase life. 

Place stems in floral preservative or sugar immediately after harvesting. 

Postharvest 

Fresh: Flowers persist in preservative for up to 2 weeks. 

Dried: Hang stems upside down in a cool, well-ventilated room. Dried flowers 

last 1–2 years. 


See Limonium. 

GONIOLIMON TATARICUM 311

312 GYPSOPHILA PANICULATA 

Reading 

Hodgkin, G. W. 1992. Growing German statice. In Proc. 4th Natl. Conf. on Specialty 

Cut Flowers. Cleveland, Ohio. 

Gypsophila paniculata baby’s breath Caryophyllaceae 

perennial, Zones 3–7 northern Asia, Europe white 1 

2–4'/3' (0.6–1.2 m/0.9 m) 

A mainstay of the cut flower industry, baby’s breath is grown for its airy panicle 

of flowers. Production occurs in the field and year-round in greenhouses. Some 

cultivars have been selected for their double flowers, some for their gray-green 

foliage. In warmer areas of the country, such as Florida, gypsophila is grown as 

an annual; in Michigan, California, and overseas, it is produced as a perennial. 

Propagation 

Seed: Seed is used for the species and a few cultivars (‘Snowflake’, for one), 

but most cultivars are propagated vegetatively; with seed, the quality of resultant 

plants varies. If seed is used, 0.06–0.12 oz (1.8–3.5 g) yields 1000 plants (Nau 

1999). 

Grafting: Double-flowered cultivars were grafted on the rootstock of the more 

vigorous, single Gypsophila paniculata. The practice is very labor intensive and expensive 

and has all but disappeared. 

Cuttings: Vegetative cuttings taken in the summer root in 10–14 days under 

mist and warm temperatures. Cuttings are more uniform and healthy, and 

flower production is equal to that of grafted plants. 

Tissue culture: Most commercial propagation is done by stem tip culture. 

Growing-on 

Plants should be grown under short days, high light, and cool temperatures of 

50–55F (10–13C)—but only until plants are large enough to be planted to the 

field or greenhouse bench. At an early stage of development, cool temperatures 

result in better branching than warmer (65–70F, 18–21C) temperatures. 


Photoperiod: Gypsophila species are long day plants; flowering is inhibited by 

short days. Under SD and low temperatures, plants form a rosette of leaves. For 

most cultivars, the critical photoperiod for flowering is 12–14 hours (Krogt 

1982); however, longer daylengths are commonly used. Plants must have at least 

12 nodes before LD are perceived (Kusey et al. 1981). Under normal growing 

conditions, this occurs 3–5 weeks after transplanting. The more LD cycles 

received, the more flowers produced. Approximately 56 cycles are needed by

Gypsophila paniculata ‘Bristol Fairy’ 

GYPSOPHILA PANICULATA 313 

‘Bristol Fairy’, fewer (about 28 cycles) by ‘Bridal Veil’, for maximum flower yield 

and stem elongation (Hicklenton et al. 1993a, 1993b). Also, the longer the 

photoperiod, the earlier the flowering (Shillo 1985). Stem length and quality are 

greatest at 16- to 18-hour photoperiods (Kusey et al. 1981, Karagüzel and Altan 

1999). Work in Holland with many different sources of light showed that incandescent 

lamps were best for forcing flowers, particularly during winter months, 

and the higher the light intensity (up to 2 moles m-2s-1), the more rapid the rate 

of stem elongation (Graaf-van der Zande and de Blacquiere 1997). 

Temperature: Cooling young plants prior to application of LD makes the 

plants receptive to subsequent photoperiod and temperature treatments.


Rooted cuttings cooled at 32–35F (0–2C) in the dark for 7 weeks become vernalized 

(Shillo 1985), as do plants cooled under SD conditions and temperatures 

of 52/41F (11/5C) day/night for 8 weeks (Davies et al. 1996). Temperatures 

can be as high as 50–54F (10–12C) for 7 weeks if sufficient light is provided 

(Shillo 1985). The cool treatment is not a requirement for flowering; however, it 

results in plants flowering regardless of daylength. Using precooled clumps 

allows flower production in cool greenhouses under natural winter daylengths 

and promotes winter flowering of field-grown plants in warm climates, such as 

Florida. Plants that have been cooled have more flowers under LD compared 

with those that have not been cooled. If plants are grown under warm temperatures 

and never see cool temperatures, they will not flower under SD; under LD, 

will flower rapidly but quality will not be optimum. 

Once precooled and subsequently grown on the bench or in the field, plants 

will flower at 55F (13C), but flowering is significantly delayed compared with 

plants grown under warmer temperatures (Shillo and Halevy 1982, Moe 1988). 

GA application may be used to grow plants at 55F (13C), but in general, day 

temperatures should be maintained by setting venting temperature to 70–75F 

(21–24C). 

Carbon dioxide: CO2 is effective in promoting growth and development (Shillo 

1985). 

Light intensity: The number of flowers increases with an increase in light intensity. 

Lack of light is often a limiting factor in northern greenhouse during the 

winter. 

Gibberellic acid: GA is used to help with bolting. It does not substitute for LD 

(Shillo 1985); however, if GA (500 ppm) is applied, plants respond to LD even 

below 55F (13C). Do not spray more than once a week. 


Natural flowering is from late spring through late summer, with 2 or 3 flowering 

flushes obtained. In California, flowering starts in early spring and continues 

into the fall but significantly declines in the winter. Yield of 5–6 stems/plant is 

normal in winter production; 20–25 stems/plant occur under field conditions in 

the summer, depending on cultivar. An earlier crop may be forced in the field, 

with plastic frames to warm air and soil, and incandescent or HID lamps to provide 

16-hour days. Stems of plants produced in the South are usually shorter 

than those grown in the North, where summer photoperiods are longer. 

Spacing: Plant on 18–24" (45–60 cm) centers with 1–2' (30–60 cm) between 

rows. Approximately 0.4–0.6 plants/ft2 (5–6 plants/m2 ) is recommended. 

Longevity: Plants may be kept in production in temperate zones for 2–3 years, 

although, if desired, precooled plants may be set out every year from March to 

June. In Florida, precooled clumps are planted from September to February for 

winter and early spring production. After flowering, plants are removed. Some 

cultivars exhibit a strong apical dominance and should be pinched close to the 

ground in the spring to encourage additional shoots. 

Shading: Shading is not necessary.

Soil: Soil must be well drained for best production; plants do poorly if placed 

where the water table is high. Soil low in calcium and magnesium should be liberally 

fertilized with dolomitic lime; gypsophila absorbs large amounts of those 

elements (see “Guideline for Foliar Analyses”). 

Timing: When high temperatures above 80F (27C) and LD of 14–16 hours 

occur, the time between planting and harvesting can be as short as 60 days, but 

quality is poor. Under cooler temperatures and LD, up to 120 days are required, 

but quality is significantly better. Under SD and low temperatures, flowering 

will not occur unless daylength, temperature, or light intensity is changed. 


Gypsophila is produced year-round, but greenhouse culture is mainly for winter 

and spring production. 

Cuttings: Cuttings may be planted in August and September and grown at 60– 

70F (15–21C) until plants have at least 12 nodes (3–5 weeks). Double-row spacing 

may be used, in which plants are spaced 18–20" (45–51 cm) apart and rows 

are 3–3½' (0.9–1.1 m) apart. 

Long days of at least 16 hours should then be provided at least until flower 

stalks are visible. Continuous lighting (24 hours) is better than 16-hour lighting, 

but nightbreak lighting and cyclic lighting may also be used. Incandescent bulbs 

are best for photoperiodic lighting. Do not allow temperatures to drop below 

55F (13C). If precooled crowns or cuttings are used, LD treatments are not necessary 

for flowering, but weaker stems may result. 

Light: In northern climates, the use of sodium HID during early development 

enhances subsequent flower yield and quality (Hicklenton 1987). Approximately 

6 weeks of high-pressure sodium lighting (600 fc) applied after pinching resulted 

in flowers approximately 10 weeks after pinching (Hicklenton 1986). The number 

of flowering stems and quality of stems and flowers are highly correlated to 

light intensity in northern climates. In the South, high-intensity lighting is not 

as useful as in the North. 

Fertilization: Except for magnesium and calcium, nutritional requirements of 

gypsophila are not high. The use of 100–150 ppm N and K once or twice a week 

is sufficient. 






dry weight analysis.


‘Bristol Fairy’ 


(%) 

N P K Ca Mg 

3.72 0.68 2.15 5.32 1.30 

(ppm) 

Fe Mn B Al Zn 

287 70 29 159 76 

For the local fresh flower market, stems can be cut when 80% of the flowers are 

open, but for shipping, fewer than 30% of the flowers are open when cut (Doi et 

al. 1999a). For drying, 80–90% of the flowers should be open. For immediate 

local sale of fresh flowers, 80–90% flowers open is also appropriate. Plants may 

also be harvested in tight bud (5–10% open) if placed in a bud-opening solution 

(see “Postharvest”). Most gypsophila is sold by weight (e.g., 11 oz per bunch, 300 

g per bunch) or in 10 stems per bunch, minimum. 

Postharvest 

Fresh: To open tight buds so that plants can be shipped with about 40% open 

flowers, stems should be immediately placed in a solution containing 2–4 mM 

silver (STS), 4% sugar, and a bactericide (such as 8-HQS), and placed under 

approximately 90% relative humidity and bright light (Doorn et al. 1992). Temperatures 

should be 62–68F (17–20C). Using this or a similar regime results in 

open flowers, but with no flower browning, even if temperatures rise (Doi et al. 

1999b). Gypsophila is sensitive to ethylene (Doorn et al. 1992) and bacterial contamination; 

use of silver thiosulfate (STS) and a germicide is recommended. 

Using a combination STS/preservative solution is a one-solution system for 

postharvest treatment. Treatments may be pulsed for 30 minutes or held overnight 

in the solution if necessary. Other work with various chemicals shows that 

an anti-ethylene agent is necessary if plants are to be shipped. 1-MCP inhibited 

the effects of ethylene on open flowers, but was of no benefit to subsequent flowers 

(Newman et al. 1998). 

Dried: Two methods are commonly used. In the first method, flowers are airdried 

upright in a container of water, with the water just covering the cut ends, 

at a room temperature of 50F (10C) (Vaughan 1988). 

In the second method, flowers are dried in a solution of 1 part glycerine to 2 

parts water (Moe 1988). The plants can be removed from the glycerine solution 

when beads of moisture form on the leaf surface (Vaughan 1988). Stems should 

then be dried upside down in a well-ventilated room. 

Storage: Stems should not be stored dry more than 2–3 days unless absolutely 

necessary: the incidence of botrytis under storage conditions is high; however, if


fungicides are applied and good air movement is present in the cooler, stems 

with 50% of flowers open persist up to 3 weeks if held at 33–35F (1–2C). 

Cultivars 

Fewer than half a dozen of the many available cultivars provide more than 90% 

of the gypsophila sold by florists. 

‘Arbel’ and ‘Tavor’ are less sensitive to daylength and will flower with photoperiods 

as short as 11 hours. They flower rapidly but have strong apical dominance 

and must be pinched. 

‘Bristol Fairy’ is the traditional double white-flowered baby’s breath and 

grows about 2' (60 cm) tall. Less widely grown, superseded by ‘Perfecta’. 

Festival series is seed-propagated. Both ‘Festival Pink’ and ‘Festival White’ 

are only 12–18" (30–45 cm) tall and bear both single and double flowers. 

‘Flamingo’, a popular double pink, is vigorous, attaining heights of 3–4' (0.9– 

1.2 m). Yields are low compared to ‘Perfecta’. 

‘Gilboa’ and ‘Golan’ are part of the Magic series from Danziger. Rapid flowering, 

even under lower temperatures, and strong stems. 

‘Lucky Stars’ has single white flowers. 

‘Million Stars’ has enjoyed success among gypsophila growers. Plants attain 

the same size as ‘Perfecta’, but the smaller flowers tend to be more terminal, providing 

a fuller look and less tangling, a major concern when using gypsophila in 

bouquet work because it slows things down and side shoots are torn off. The 

buds tend to open more evenly, and the crop time is shorter than ‘Perfecta’. Stem 

lengths of 24–30" (60–75 cm). 

‘New Hope’ is similar to ‘Perfecta’ with bright white, slightly smaller flowers. 

It too is less prone to tangle. Flower stems are 24–28" (60–70 cm) and grow relatively 

straight. 

‘Perfecta’ has long been the worldwide standard, having replaced ‘Bristol 

Fairy’. Plants are about 4' (1.2 m) tall and equally wide, with larger white double 

flowers and more vigor than ‘Bristol Fairy’. It is in jeopardy of being superseded 

by ‘Million Stars’. 

‘Pink Fairy’, a pink version of ‘Bristol Fairy’, is about 18" (45 cm) tall. 

‘Pink Star’ has bright pink flowers on 18" (45 cm), compact plants. 

‘Red Sea’ bears double rose-pink flowers on 3–4' (0.9–1.2 m) stems. 

‘Rosy Veil’ is a paler form of ‘Pink Star’. 

‘Single White’ is as the name implies. About 3' (90 cm) tall. 

‘Snowball’ has bigger flowers than ‘Perfecta’ and a slightly faster growth rate. 

‘Snowflake’ (‘Schneeflocke’) consists of pure white double flowers. Also sold 

as ‘Double Snowflake’. 

‘Viette’s Dwarf’, from Viette’s Nursery in Virginia, is only 12–18" (30–45 cm) 

tall with pinkish double flowers. Terrific for short stems. 

‘Virgo’ stands 3–4' (0.9–1.2 m) tall and carries mostly double white flowers. 

‘Yukinko’ is a fast-flowering cultivar, less sensitive to daylength than ‘Perfecta’. 

Also less sensitive to hot weather, thus useful for summer production.



Gypsophila elegans may be used as a short-stemmed filler. The stems are only 9– 

15" (23–38 cm) long, but the many pink or creamy white flowers fill the plant. 

May be propagated from seed or cuttings. Treat plants as an annual crop. 

Gypsophila oldhamiana bears pink to deep pink, fragrant flowers in a large, 9– 

12" (23–30 cm) long panicle. Plants are native to northeast Asia and Korea and 

are hardy to Zone 5. 


Crown gall (Agrobacterium gypsophilae) results in soft, nodular galls about 1" (2.5 

cm) in diameter. Much more prevalent on grafted plants than on plants propagated 

from cuttings or seed because it is often spread with grafting knives. Avoid 

propagation from infected plants, and dip plants and knives in a bacterial solution. 

Blight from Botrytis cinerea causes ash-gray spots to develop on buds and stems. 

Damping off (Pythium debaryanum, Pellicularia filamentosa) results in rotting at 

the soil line followed by stem rot and topple. 

Red spider mites and thrips can be a problem, particularly in perennial crops. 

Reading 

Davies, L. J., P. R. Hicklenton, and J. L. Catley. 1996. Vernalization and growth 

regulator effects on flowering of Gypsophila paniculata L. cvs. Bristol Fairy and 

Bridal Veil. J. Hort. Sci. 71(1):1–9. 

Doi, M., T. Kobata, K. Ohizumi, and H. Imanishi. 1999a. Cultural schedule for 

forcing three floral flushes on Gypsophila paniculata L. ‘Bristol Fairy’ selections. 

J. Jap. Soc. Hort. Sci. 61(2):421–429. 

Doi, M., T. Sato, N. Nagai, and H. Imanishi. 1999b. Occurrence of “flower browning” 

of cut Gypsophila paniculata L. and its prevention by harvesting at bud 

stage. J. Jap. Soc. Hort. Sci. 68(4):854–860. 

Doorn, W. G. van, and M. S. Reid. 1992. Role of ethylene in flower senescence of 

Gypsophila paniculata L. Postharvest Biology and Technology 1(3):265–272. 

Graaf-van der Zande, M. T., and T. de Blacquiere. 1997. Alternative sources for 

photoperiodic lighting on Gypsophila. Acta Hortic. 418:119–125. 

Hicklenton, P. R. 1986. The effect of supplemental lighting on winter flowering 

of transplanted Gypsophila paniculata. Can. J. Plant Sci. 66:653–658. 

———. 1987. Flowering of Gypsophila paniculata cv. Bristol Fairy in relation to 

irradiance. Acta Hortic. 205:103–111. 

Hicklenton, P. R., S. M. Newman, and L. J. Davies. 1993. Growth and flowering 

of Gypsophila paniculata L. ‘Bristol Fairy’ and ‘Bridal Veil’ in relation to temperature 

and photosynthetic photon flux. Scientia Hortic. 53(4):319–331. 

———. 1993. Night temperature, photosynthetic photon flux, and long days 

affect Gypsophila paniculata flowering. HortScience 28(9):888–890. 

Karagüzel, O., and S. Altan. 1999. The effects of planting-date and photoperiod 

on the growth and flowering of Gypsophila paniculata L. ‘Perfecta’. Turkish J. Agr 

and Forestry 23 (supp. 2): 275–280.

HELIANTHUS ANNUUS 319 

Krogt, T. M. van der. 1982. Betere bloeispreiding in Gypsophila door teeltplaning. 

Bloemistry 6:34–35. 

Kusey, W. E., Jr., T. C. Weiler, P. A. Hammer, B. K. Harbaugh, and G. J. Wilfret. 

1981. Seasonal and chemical influences on the flowering control of Gypsophila 

paniculata. J. Amer. Soc. Hort. Sci. 106:84–88. 

Moe, R. 1988. Flowering physiology of gypsophila. Acta Hortic. 218:153–158. 

Nau, J. 1999. 1999. Ball Culture Guide. 3rd ed. Ball Publishing, Batavia, Ill. 

Newman, J. P., L. L. Dodge, and M. S. Reid. 1998. Evaluation of ethylene inhibitors 

for postharvest treatment of Gypsophila paniculata L. HortTechnology 

8(1):58–63. 

Shillo, R. 1985. Gypsophila paniculata. In The Handbook of Flowering. Vol. 3. A. H. 


Shillo, R., and A. H. Halevy. 1982. Interaction of photoperiod and temperature 

in flowering control of Gypsophila paniculata L. Scientia Hortic. 16(4):385–393. 


Ore. 

Many thanks to Whiting Preston, Bob Pollioni, and Peter Hicklenton (first edition) 

and Gay Smith (second edition) for reviewing this section. 

Helianthus annuus annual sunflower Asteraceae 

annual western U.S., Midwest red, gold, yellow, bicolor 1 

4–7'/3' (1.2–2.1 m/0.9 m) 

So many sunflowers, so little time. The lowly sunflower of the 1980s was the star 

of the 1990s. From coffee cups to T-shirts, placemats to aprons, the sunflower 

shone everywhere. Sunflowers in hotel lobbies, in wedding bouquets, dried in 

potpourri—you couldn’t escape them. While the excitement of the sunflower 

has waned a bit, plants are still grown for cuts by the acre, under protection and 

under the noonday sun. Of course, the economic importance of sunflowers is felt 

much further than the cut flower industry: they are among the most important 

crops in the world for their oil and forage properties. The annual sunflower is 

native from Minnesota to Washington and California, and cultivars suitable for 

cutting have emerged from the greenhouses of Japanese, European, and United 

States breeders. Plants are relatively easy to grow, and flowers are prolifically 

produced. 

Propagation 

All plants are produced from seed; there are approximately 920–1840 seeds/oz 

(32–65 seeds/g), depending on species and cultivar. If plants are to be direct 

sown, use 0.7 oz per 100' (67 g per 100 m) (Kieft 1996). Approximately 1.5 oz (42 

g) of seed yields 1000 plants when direct sown (Nau 1999). 

Greenhouse: Although sunflower seed is usually direct sown, seed may be 

greenhouse sown at 70–75F (21–24C) in final containers (72-cell plugs or small

Helianthus annuus 

‘Sunrich Orange’


pots) 3–4 weeks prior to placing in the field. Do not sow too early, or plants 

become lanky and will not transplant well. 

Field: Most seed is direct sown 9–12" (23–30 cm) apart in the field after all 

threat of frost has passed; some growers direct seed as close as 6" (15 cm) apart 

when using nonbranched forms. The danger of dense planting is the lack of air 

movement and the subsequent potential for disease. For best germination and 

growth, soil should be at least 50F (10C) before sowing and well drained. 

Growing-on 

If plants are to be grown outdoors, seedlings should be held in the greenhouse 

for no more than 3 weeks prior to planting in the field. Provide full light, high 

fertility levels (150–200 ppm N), and good air movement. 


Photoperiod: Plants show a remarkable cultivar-dependent response to photoperiod 

(Shuster 1985), but most appear to be day-neutral or flower somewhat 

faster under short days. The critical photoperiod is between 11 and 13 hours. 

One reason for the increased popularity of sunflowers was the breeding of dayneutral 

cultivars. 

Temperature: Warm temperatures result in faster flower development than 

cool temperatures. Temperatures below 50F (10C) slow development significantly; 

temperatures of 65–75F (18–24C) appear optimal for growth and development 

of cut flower cultivars. People sometimes attribute faster summer flowering 

to photoperiod (concluding that sunflowers must be LD), but the faster 

flowering is simply a function of warmer summer temperatures. For earlier flowering, 

wait 2–3 weeks as temperatures warm up rather start plants too early in 

spring. Similarly, if plants are started in late summer as temperature decreases, 

flowering will be delayed. 

Gibberellic acid: The use of gibberellic acid shortens the vegetative stage and 

slightly accelerates flowering (Shuster 1985). 


Spacing: Space seed or transplants as close as 9" (23 cm) or as wide as 24" (60 

cm) apart. A 20 × 20" (50 × 50 cm) spacing is reasonable for branching forms or 

larger cultivars; less can be used for nonbranching and smaller ones. The closer 

together, the less chance of branching; therefore, if cultivars are said to be well 

branched, space them out accordingly. A plant density of 30,000 to 40,000 plants 

per acre (75,000–100,000 plants/hectare) is reasonable. 

Fertilization: Sunflowers are heavy feeders, and plants should be fed at least 3 

times a season. Side dress with granular 10-10-10 or liquid feed of 20-5-30 at 

200 ppm N with a complete soluble fertilizer. 

Support: Some cultivars can grow 8' (2.4 m) tall and may fall over from the 

weight of the heavy foliage and flowers. Stems of newer cultivars are sufficiently

322 HELIANTHUS ANNUUS 

strong to carry the flowers under calm conditions but support may be necessary 

in windy areas. 

Planting: Sequential planting, as often as every week (Deep South) to every 3 

weeks, is useful to take advantage of long terminal flower stems. Laterals are 

shorter, and flowers are smaller after the terminal has been cut. 

Pinching and harvesting: Cultivars that are naturally basal branching do not 

need to be pinched; they do fine on their own, at a 20 × 20" (50 × 50 cm) spacing. 

For standard cultivars, the primary flower is the largest and of higher quality, 

with a longer stem than the axillary shoots. Pinching promotes uniformly developing 

side shoots with consistent flowers, albeit smaller than the terminal would 

have been; each flower in the resulting spray formation can be used where 

smaller flowers and stems are useful. If longer stems are desired, pinch early, 

when plants have 4–6 leaf pairs. Multiflora cultivars are especially suited to being 

pinched. The resulting side shoots will be long-stemmed with intermediatesized 

flower heads, but shorter than single-stemmed flowers (Dole and Wilkins 

1999). 


Sunflowers may be produced during the winter in the greenhouse if market price 

and demand so warrant. Supplemental light (use HID lamps) may be necessary 

in northern greenhouses. 

For single-stem production, sow seed directly in the bench at 6 × 9" (15 × 23 

cm) spacing or in a 6–8" (15–20 cm) container. For branching varieties, spacing 

at 20 × 20" (50 × 50 cm) is recommended in the greenhouse. According to Dole 

and Wilkins (1999), greenhouse-grown cuts can be planted in 1801 bedding 

plant flats for quick crops. The size of the flower head and the thickness of the 

stem will vary with the number of plants per flat; 10–18 plants per flat provide 

2–3' (60–90 cm) stems with 3–4" (8–10 cm) wide flower heads. The small volume 

of soil limits the size of the plants and decreases crop time compared with field 

production but requires that plants be irrigated frequently. Stems are generally 

harvestable 8–9 weeks from sowing seed. 

For tallest plants, grow under long days for 4–6 weeks, then change to short 

days (12 hours or less), but photoperiod manipulation is not necessary for flowering, 

especially if plants are grown at a dense spacing. Plants may be grown 

under natural photoperiod throughout. Fertilize with a constant liquid feed of 

100–150 ppm N or once a week with 300 ppm N. In all cases, fertilize lightly 

(100 ppm N) when seedlings have emerged. Maintain 50–55F (10–13C) night 

temperatures and 65–70F (18–21C) day temperatures. Liquid rates of 150 ppm 

nitrogen, 15 ppm phosphorus, 200 ppm potassium, 4 ppm calcium, and 50 ppm 

magnesium have shown excellent results in greenhouse production (Heaton 

and Denny 1999). An excellent article on nutrient deficiencies was written by 

Brian Whipker and his colleagues (2000). 

Plants must be supported with stakes or strong netting. With newer cultivars, 

a crop time of 13 weeks in winter, 11 weeks in summer is common; however, 

some growers report crop times as little as 6 weeks from sowing.



Some growers have been successful in harvesting tight, when yellow petals (ray 

flowers) were barely visible; others wait until 1 or 2 petals lift off the disk; and 

some will wait until the flowers are almost completely open. Put in preservative 

immediately. The most important considerations are that the center should still 

be “tight” and dark and that no petals should have started to curl back. 

Flower deformities: The subject of deformed flowers comes up whenever sunflowers 

are discussed. Blooms are distorted, half-opened, or stunted—some look 

like trolls, others are missing significant flower parts. Some years are worse than 

others, and some areas of the country are more affected than others, yet it seems 

like deformities have always been present. 

Some deformities can be attributed to insects, particularly aphids, sunflower 

midges, lygus bugs (see “Grower Comments”), and thrips; proper insect control 

goes a long way to reducing the problem in this case. Extremes of temperatures 

(too cool, too hot) during flower initiation can be blamed when some of the 

flowers are deformed but subsequent ones are not; cold is a more common problem 

than heat. Anything that interferes with good root growth—clay soil, poor 

nutrition practices, root rots—may influence flower structure. Finally, some cultivars 

are genetically unsuited to your area; if you find one is worse than the others, 

don’t grow it. 

Postharvest 

Fresh: Flowers remain fresh in a flower preservative, such as Floralife, for 7– 

9 days (Gast 1998). The foliage declines more rapidly than the flower and should 

be stripped immediately. Pollenless cultivars exhibit longer vase life and offer 

consumers flowers that don’t drop pollen or irritate allergies. Recutting and 

immediately plunging the stems in warm water reduces the tendency of some 

cultivars to droop. Drooping of the heads indicates either blocked stems or other 

reasons for poor water transit to the flower. Stems can be pretreated for 15–30 

minutes in a solution of clean water plus 0.02% detergent (Tween-20, Triton X- 

100, or even some dishwashing solution) (Nell and Reid 2000). 

Storage: Flowers may be stored at 36–41F (3–5C) for up to one week. Flowers 

picked too tight and stored cool may not open properly. 

Dried: Flowers air dry well. Some growers have had great success with silica gel 

(see “Grower Comments”). 

Dyeing: Some growers have experimented with dyeing sunflowers using commercial 

dyes, sometimes mixed together, yielding flowers in varying shades of 

brown, orange, and red. These novelty items were hot sellers at local farmers’ 

markets. No accounting for taste—if there is a market for painted sunflowers, 

who are we to argue? 

Cultivars 

Describing sunflower cultivars is like describing rocks: they are infinitely different 

to a geologist but sort of look the same to the rest of the world. Many have


been trialed in Texas (Arnosky 2000), Connecticut (Shashok and McAvoy 1997), 

Kansas (Gast 1995), and nationally (Dole 1995–2001). Some are grown for the 

natural branching, others are best as single stems. Many of the newer cultivars 

are pollenless, and most of these are F1 hybrids, providing far better uniformity 

and vigor than the older cultivars. There are far too many sunflowers claiming to 

be the best this or the most colorful that. Here are a few descriptions—you be the 

judge. 

‘Abendsonne’ is 7–8' (2.1–2.4 m) tall with yellow flowers around a bronze 

center. 

‘Apricot Twist’ has a yellow center surrounded by apricot petals. Pollenless 

flowers. Grows to 5' (1.5 m). 

‘Autumn Beauty’ can grow to 6' (1.8 m), with flowers of bronze, yellow, and 

mahogany. Flowers are 6" (15 cm) wide. Two harvests can be taken. 

‘Bellezza d’Autunno’ produces 4" (10 cm) flower heads with light cream to 

deep mahogany petals. Plants grow to 6' (1.8 m) in height. 

‘Claret’ is multibranched about ⅔ up the 5–6' (1.5–1.8 m) tall plant. Flowers 

are 4–5" (10–13 cm) wide, overlapping red petals surrounding a dark center. The 

dark green leaves are attached to the stems with red petioles. Winner of the Royal 

Horticultural Society’s Award of Garden Merit. 

‘Color Fashion’ has yellow and bronze petals with yellow and orange tips, 

plants grow to 5½' (1.7 m) tall. 

‘Cutting Gold’ produces large heads on 3½' (1.1 m) nonbranching stems. 

Flowers have golden-yellow petals with a dark center, similar to ‘Sunbright’. 

‘Del Sol’ carries medium-sized heads on 3' (90 cm) single-stemmed plants. 

‘Double Shine’ was very popular in the 1999 ASCFG Seed Trials for its sturdy 

20–28" (50–70 cm) tall stems, large flower heads, and long vase life. 

‘Double Sun Gold’ averaged 6' (1.8 m) in Connecticut trials. 

‘Elite Sun’ is similar to ‘Sunbright’, with uniform flowering. 

‘Evening Sun’ is tall enough to play in the NBA, at 7' (2.1 m). The 6" (15 cm) 

flowers are a mix of red and bronze shades with dark centers. 

‘Eversun Deep Yellow’ is traditional-looking and disease resistant, according 

to 1997 trials. Large flower heads on 40" (1 m) stems were common. ‘Eversun 

2001’ has more uniformity and improved stem quality. 

Fantasia Mix is an F1 mixture in single, semi-double, and double flowers. 

‘Florenza’ is a red and yellow bicolor form, producing flowers up to 5" (12 

cm) in diameter. 

‘Floristan’ is a distinctive bicolor (dark red with yellow tips). They were well 

received by participants in the 1994 ASCFG Seed Trials. Branching plants are 


‘Full Sun’ is 3–4' (0.9–1.2 m) tall and bears gold-yellow flowers. It is day-neutral 

and does not produce pollen. 

‘Giant Sungold’, a branching variety, has 8" (20 cm) wide double flowers with 

golden-yellow petals. 

‘Goldburst’ is an excellent cultivar with 3–4" (8–10 cm) wide, golden, double 

flowers on 4–6' (1.2–1.8 m) stems. In national trials in 1992, it scored higher 

than any other tested.


‘Golden Glory’ is similar to ‘Sunbright’, but taller and with lighter-colored 

centers. Flower heads have been reported as large as 18" (45 cm) across. 

‘Golden Pheasant’ has double flowers with golden-orange florets. Plants grow 

3½' (1.1 m) tall. 

‘Hallo’ is a productive 5' (1.5 m) plant with dense side branches up to 3' (90 

cm) long. Flowers are single with a dark brown disk. 

‘Happy Face’ bears golden-yellow ray florets with a greenish yellow disc; flowers 

are about 4" (10 cm) in diameter. 

‘Henry Wilde’, Oscar’s little brother, grows 6–8' (1.8–2.4 m) tall, branching 

with 6" (15 cm) golden-petaled flowers with dark centers. 

‘Holiday’ has 4' (1.2 m) plants with golden-yellow flowers 6–8" (15–20 cm) 

wide. A traditional sunflower color and form. 

‘Ikarus’ was the darling of 2000, carrying light lemon-yellow flowers on 24– 

26" (60–66 cm) stems. Under favorable conditions, plants can grow nearly 4' 

(1.2 m) tall. Almost pollenless flowers have a dark velvet eye. It is basal branching, 

forming long side shoots. To encourage optimal branching, plant 20 × 20" (50 

× 50 cm). 

‘Inca Jewels’ is said to be heat and drought tolerant, with multicolored gold to 

burgundy to orange petals. Plants grow 5–7' (1.5–2.1 m) tall. 

‘Indian Blanket’ bears double and semi-double flowers in mixes of red, lemon, 

cream, and bicolors. The branching plants are about 5½' (1.7 m) tall. 

‘Jade’ has interesting lime-green flowers. Pollenless and single, the flowers are 

borne on branching 4' (1.2 m) plants. 

‘Joker’ is a pollenless bicolor, full double to semi-double, with petals curling 

around the disk. Plants can grow to 6' (1.8 m). 

‘Moonbright’ is floriferous with uniform flowering of pale yellow blooms 

with a dark disk. Averaged almost 3½' (1.1 m) in ASCFG trials. 

‘Moonwalker’ has creamy, pale yellow petals and produces many flowers per 

plant. 

‘Moulin Rouge’ bears pollenless flowers with velvet burgundy petals. Many 

growers consider this similar to ‘Prado Red’. Postharvest life has been disappointing, 

but the flowers are beautiful. 

‘Music Box’ has been called a good cut flower, although stems are only 24–30" 

(60–75 cm) long. Flowers are creamy yellow and gold to mahogany red with dark 

brown centers. 

‘Pacino’ is a pot plant variety, producing bright yellow flowers on branched 

12–16" (30–40 cm) stems. 

‘Prado Red’ and ‘Prado Gold’ are branched forms, which produce smaller flowers 

useful for bouquets. ‘Prado Gold’ is quite handsome, with overlapping petals. 

‘Prado Red’ is pollenless and also offers dark bronzy red on stems and leaves. 

‘Premiere Cream Yellow’ is an early-flowering cultivar with small leaves and 

creamy yellow pollenless flowers. The centers are black. Plants are about 3' (90 

cm) tall. 

Provence Mixture is a branching variety, about 6' (1.8 m) tall. 

‘Purple Sun’ is an F1 variety with 5" (13 cm) flowers and black to purple pollenless 

center, growing to 6' (1.8 m).


‘Red Treasures’ is not as tall as some varieties but has been called valuable for 

its branching. It bears 3" (8 cm) yellow and orange flowers. 

‘Ring of Fire’ grows 2–4' (0.6–1.2 m) with contrasting bronze and yellow petals. 

Approximate flowering time is 10 weeks from sowing. 

‘Ruby Eclipse’ (‘Strawberry Blonde’) has pollenless flowers in shades of rubyred 

to pale pink with pale lemon tips and a dark center. 

‘Shine’ is a semi-double variety, branching, with yellow-orange flowers. 

‘Silverleaf’ is disease resistant and tolerant of extreme temperatures. Flowers 

have long yellow ray florets and chocolate disks. Plants grow 4–6' (1.2–1.8 m) 

tall. 

‘Sonja’ (‘Sonia’) bears nice small golden-orange flowers with brown centers. 

Plants grow about 3' (90 cm) tall. A branching form. Approximate flowering 

time is 8–9 weeks from sowing. 

‘Soraya’ (formerly ‘Large Flowered Orange’) has upward-facing, almost pollenless 

flowers and a branching habit. An All-America Selection, it bears orange 

flowers with a dark center and can yield up to 15 stems/plant. Approximate flowering 

time is 13 weeks from sowing. 

‘Starburst Aura’ is a starburst-type, semi-double yellow flower with a small 

green center. Plants can grow to 6' (1.8 m). 

‘Sunbeam’ has a light green pollenless center and golden-yellow petals. Grows 

to 5' (1.5 m) and flowers early. Inconsistent petaling has been reported. Few laterals 

were produced. 

‘Sunbright’ is a uniform F1 hybrid with 4–5" (10–13 cm) wide pollenless flowers. 

Among the earliest pollenless cultivars developed and still one of the best— 

so good, in fact that it was the ASCFG’s 2001 Fresh Cut Flower of the Year. In 

vase life trials, it remained fresh for 11 days, significantly longer than other cultivars 

in the same test (Gast 1997). 

‘Sunbright Supreme’ has 30" (75 cm) flowering stems. Pollenless flowers have 

bright yellow petals and a dark brown center. Some cold tolerance. 

‘Sundance Kid’, a pot plant variety, may not be tall enough for cut production 

but is useful for small settings. 

‘Sundown’ is about 5' (1.5 m) tall with strong yellow and red bicolor flower 

heads. 

‘Sunny’, an early-flowerer, carries single golden-yellow flowers with a dark 

center on 5–6' (1.5–1.8 m) stems. 

‘Sunray’ is very early flowering, almost 2 weeks earlier than the standard ‘Sunbright’. 

‘Sunrich Lemon’ is a pollenless, day-neutral F1 hybrid. Flowers are more 

yellow than lemon, but they contrast well with the black center. Plants flower 

earlier than ‘Sunbright’. 

‘Sunrich Orange’ has 4" (10 cm) wide pollenless flowers, deep golden petals 

surrounding a black center. Day-neutral. Plants grow 3–4' (0.9–1.2 m) tall. 

‘Sunrise’ bears lemon-yellow flowers on 5' (1.5 m) plants. 

‘Superior Gold’ is similar to ‘Superior Sunset’ but is a brighter yellow and 

flowers a little earlier. Not quite as tough in the vase as ‘Superior Sunset’. The 

gaps between the petals are considered undesirable by some.

‘Superior Sunset’ produces large 8–10" (20–25 cm) flowers with yelloworange 

petals. Some people really like this cultivar. 

‘Tangina’ has golden-orange ray florets around a dark center; flowers are 

about 2" (5 cm) wide. 

‘Tiffany’ produces bright orange pollenless flowers on 3–4' (0.9–1.2 m) unbranched 

stems. The flowers consist of short petals around a relatively large disk. 

Tiger’s Eye Mix flowered early in Connecticut. Good lateral branching provided 

additional harvests. 

‘Valentine’ has little pollen in its lemon-yellow flowers on 30" (75 cm) stems. 

‘Velvet Queen’ grows to 5' (1.5 m), with velvety-crimson flowers. Well 

branched. 

‘Watermelon Shades’ is a branching variety in a mix of bright petal colors. 

‘Zebulon’ produces 30" (75 cm) tall, single stems with bright yellow flowers. 


Sunflowers have been evaluated since the inception of the ASCFG’s national trials 

in 1994. The following table (Dole 1995–2001) is a summary of the average 

stem lengths and yields of sunflowers submitted for trialing. These data are averages 




Cultivar of trial length plant (in) z 

Cutting Gold 1995 42 3 

Del Sol 1997 35 3 

Double Shine 1999 28 5 

Eversun Deep Yellow 1997 41 2 

Floristan 1994 24 6 

Golden Glory 2000 38 2 

Holiday 1994 29 5 

Ikarus 1999 25 5 

Moonbright 1995 44 3 

Prado Gold 1998 32 4 

Prado Gold Imp. 1999 24 5 

Prado Red 1998 32 4 

Ring of Fire 1999 22 6 

Sonja 1994 19 7 

Soraya 1998 38 4 

Sunbeam 1994 66 2 

Sunbright 1994 44 3 

Sunbright Supreme 1999 30 2 

Sunrich Lemon 1994 37 1 

Valentine 1994 32 5 


HELIANTHUS ANNUUS 327



Helianthus decapetalus (thinleaf sunflower) has smaller flowers than H. annuus 

and may bear multiple flowers per stem. ‘Italian White’ has creamy white flowers 

with a contrasting black center but has not been a particularly good cut 

flower. Variety multiflorus is excellent for cut flower production, bearing numerous, 

single light yellow flowers on 4–6' (1.2–1.8 m) tall plants; it is a perennial in 

most areas of the country. ‘Soleil d’Or’ is a good cut flower, with semi-double 

primrose-yellow flowers. 

Helianthus debilis ‘Vanilla Ice’ has creamy lemon-yellow 4" (10 cm) flowers with 

black centers on branching 4' (1.2 m) plants. 

Helianthus maximiliani, native to Texas, Missouri, and north to southern Canada, 

bears yellow flowers in late September and October. The very tall plants (up 

to 9', 3 m) can be used to lengthen the season. They are perennial (Zone 4) and 

can be invasive. 

Helianthus salicifolius (willow-leaf sunflower) and H. angustifolius (swamp sunflower) 

are both perennial forms of sunflowers (Zones 6–9). The plants are 4–7' 

(1.2–2.1 m) tall and produce many small yellow single daisy-like flowers on short 

branched stems. The stem length on the individual flowers is too short to be 

considered a mainstream cut flower, and the blooms are much smaller than 

those of H. annuus; however, some people may find a market for them. ‘First 

Light’ and ‘Lemon Queen’ (H. salicifolius) both produce light yellow flowers, on 3' 

(0.9 m) and 4' (1.2 m) tall plants, respectively. 


Aphids are the most common pest of sunflowers. Control with aphicides if 

necessary. 

Caterpillar species prefer sunflowers and can quickly damage and defoliate 

plants. The larvae of other moths tunnel through flower heads. The female headclipper 

weevil is well named: it girdles the stem just below the flower head and 

lays eggs on the head (Stevens et al. 1993). The heads often fall off, leaving growers 

wondering who cut the flowers off their plants. The weevils are rare, and 

although damage can occasionally be significant, it is usually limited. 

Cutworms are the larvae of moths. The eggs are laid on grass or weeds, and 

the worms burrow into the ground. They feed at night on the surface, cutting off 

the plants near the ground or damaging them so they wilt and die. They can also 

crawl up the plant and munch on leaves and even the flowers. Cutworms are 

extremely destructive, killing far more plants than they can possibly consume. 

To prevent infestation, clean up weeds and keep grass mowed. Sprays containing 

carbaryl (e.g., Sevin) have also been effective. 

Grasshoppers can be a terrible scourge, particularly in dry seasons. They 

eat foliage and flowers and seem to appear just before harvest. Control early 

with bait. 

Leaf spots, caused by Alternaria and other fungal genera, result in brown to 

black spotting of the foliage. Alternating fungicides provides some control.


Downy mildew can be a serious pathogen, particularly under moist, cool 

conditions. 

Lygus bug is partly responsible for deformities in the flower head, gaps in the 

petal rings, and contortions where you don’t want them. The nymphs are light 

green and somewhat resemble aphids. There may be 2 or 3 generations a season. 

Reduce weeds and apply a general insecticide while plants are young. 

Midges can lay eggs and burrow into the flower head. They are destructive 

while feeding, then emerge and return to the soil, where they overwinter. They 

are quite small, the adult is only about 1/8" (3.2 mm) long. 

Powdery mildew (Erysiphe cichoracearum) causes white, powdery growth, particularly 

on the undersides of leaves. This can be quite severe, depending on cultivar 

and seasonal weather. Use of appropriate fungicides or sulfur is recommended. 

Stem rot (Sclerotinia sclerotiorum) normally affects plants when they are several 

feet tall. The thick, white, feltlike growth occurs on the stems, and the tissue 

beneath becomes discolored. The disease is worse in hot, wet summers. Destroy 

infected plants, pasteurize the soil, and rotate crops every other year. Avoid close 

spacings and moist conditions. 

Rust, in the form of red-brown pustules, affects the undersides of leaves and 

causes the foliage to dry up and fall. Several organisms cause rust, but the main 

fungus is Puccinia helianthi. Destroy infected tissue. 

Wilt symptoms are caused by various organisms (Plasmopara, Verticillium) and 

cause young plants to wilt and die. Older plants may survive, but the leaves may 

be mottled with mosaic patterns of light yellow. Pasteurize soil and rotate crops. 

Do not put sunflowers in the same area more than 2 years in a row. 


“We grow about 2500 stems a week, and we plant every week for 28 weeks, starting 

with transplants sown March 15. We plant them 4 rows in a 4' bed, 1' between 

the rows, 1' between the plants in the row. If you want smaller flowers, just 

decrease the spacing. . . . I think if we gave our ‘Sundown’ sunflower plants a lot 

of room, they would be more branching, but we spaced them close (1 × 1') and 

they went straight up. They did have a cluster of buds at the top, and these buds 

continue to bloom out after the main flower goes. For us, the necks were significantly 

stronger than other reds. We don’t even grow any other reds now because 

of that weakness.” Frank Arnosky, Texas Specialty Cut Flowers, Blanco, Tex. 

“With all the erratic weather this year, sunflowers have been the trouper. We 

are growing just about every one you can think of. Actually, we have almost 

decided to change our name to Broken Gate Sunflower Farm.” Lynette Lowrance, 

Broken Gate Farms, Bay City, Tex. 

“Lygus bugs and sunflower midges [cause] deformities. Short of perfectly 

timed spraying, I am not sure there’s anything you can do. Since the field that 

suffered most is bordered by alfalfa, which often draws lygus bugs, I believe that 

the sunflower midge is not the culprit, in my area.” Ralph Thurston, Bindweed 

Farm, Blackfoot, Idaho.


“The ‘Sunbright Supreme’ began blooming on June 27 and peaked today. We 

cut the deformed and unsellable central blooms off at least 60% of the plants 

today.” Cheryl Shuett, 4 Friends Flower Farm, Pickens, S.C. 

“‘Sunbright Supreme’ bailed me out so far this season! It bloomed about 10 

days earlier and had no problems [with deformities] of any sort.” Susan O’Connell, 

Fertile Crescent Farm, Hardwick, Vt. 

“We’ve noticed a big difference in droop propensity dependent upon cultivar. 

We no longer grow the branching-type sunflower cultivars because of this characteristic. 

We currently grow almost exclusively ‘Sunrich Orange’, largely because 

of the very strong stems. Even these on occasion will get the ‘droop,’ but not 

often, and only a very few at a time. . . . We started dyeing [‘Sunbright’ and ‘Sunrich 

Orange’] as part of our fall collection. Our farmers’ market customers went 

wild over them. We tried several colors, as you never know how it is going to 

turn out. The dyes are taken up better and faster when the solution is very warm. 

You can reuse the same dye for about a week, or until it is all gone.” Tammy 

Ford, Perennial Favorites, Leopold, Ind. 

“I dry lots of sunflowers in silica—all small types, as the center would never dry 

on the very large ones. I bury them face down for about a week. They are best 

used where they have support for the petals in arrangements, as they reabsorb 

humidity and droop if unsupported. Spraying with clear acrylic helps keep them 

nice.” Karen Yasui, Petalland, Tullahoma, Tenn. 

“I dry my ‘Sunrich’ by hanging them upside down on the drying rack.” Julie 

Marlette, Blue Heron Gardens, Fall Creek, Wis. 

“Concerning dyeing of sunflowers, we take a $1 sunflower and send it through 

our dehydration-rehydration process (which are words we use with customers 

who ask how we do it), and the words alone up the price of the sunflower to $1.50 

a stem, $12.50 a bunch. We do this only for farmers’ market; our florists consistently 

do not liked dyed flowers.” Mimo Davis, WildThang Farms, Ashland, Mo. 

“If you are really obsessed with finding the ultimate red sunnie, absorption 

dye is also an interesting alternative, as long as it doesn’t offend your sense of aesthetics. 

Shameless marketer that I am, we had great fun with red ‘Giant Sungold’—they 

were spectacular and walked out faster than we could produce them, 

at the market and wholesale level.” Ruth Merrett, Merrett Farms, Upper Kingsclear, 

N.B. 

Reading 

Arnosky, P., and F. Arnosky. 2000. Sunflowers assessed: details on 27 varieties. 

Growing for Market 9(1):19–21 




Gast, K. L. B. 1995. 1995 production and postharvest evaluation of fresh-cut 

sunflowers. Kansas State Univ. Agr. Exp. Sta. and Coop. Ext. Serv. Report 751. 

———. 1997. 1997 evaluation of postharvest life of perennial fresh-cut flowers. 

Kansas State Univ. Agr. Exp. Sta. and Coop. Ext. Serv. Report 805.

———. 1998. 1998 evaluation of postharvest life of selected fresh-cut flowers. 

Kansas State Univ. Agr. Exp. Sta. and Coop. Ext. Serv. Report 840. 

Heaton, T. C., and P. Denny. 1999. Growing the new sunflowers. GrowerTalks 

62(15):95–96, 100. 


Netherlands. 




Shashok, T., and R. McAvoy. 1997. Sunflower cultivars for field grown cuts: a 

cultivar evaluation. Connecticut Greenhouse Newsletter. 200:6–10. 

Shuster, W. H. 1985. Helianthus annuus. In The Handbook of Flowering. Vol. 3. A. H. 


Stevens, S., A. B. Stevens, K. B. Gast, J. A. Mara, N. Tisseret, and R. Bauerfind. 

1993. Sunflowers. Kansas State Univ. Coop. Ext. Serv. 1084. 

Whipker, B. E., C. R. Campbell, C. Dharmalingam, S. Pitchay, P. V. Nelson, and 

J. L. Gibson. 2000. Nutrient deficiencies of sunflower. GMPRO 20(10):42–45 

Many thanks to Jim Garner (first edition) and Frank Arnosky and Rudolf Sterkel 


Helichrysum bracteatum strawflower Asteraceae 

annual Australia many colors 15–30"/2' (38–75 cm/60 cm) 

The genus consists of about 300 species of annuals, perennials, subshrubs, and 

shrubs, most native to Australia and South Africa. The flowers are surrounded 

by dry, papery ornamental bracts and are easily dried. Taxonomic rumblings 

have been rolling over Helichrysum, and some authorities have placed the Australian 

members in a separate genus, Bracteantha. This includes the popular strawflower, 

Helichrysum bracteatum (now known as B. bracteata, or even Xerochrysum 

bracteatum), while H. rosmarinifolium (rosemary strawflower) has been transferred 

to Ozothamnus. Common names for flowers of the genus include strawflower, 

everlasting, and immortelle. So for now, let’s leave these plants under Helichrysum, 

with the understanding that if Bracteantha, or Ozothamnus, or Xerochrysum is 

listed on someone’s availability list, it is the same thing. 

Propagation 

HELICHRYSUM BRACTEATUM 331 

Seed may be started at 70–75F (21–24C) in a sweat tent and lightly covered. Germination 

occurs in 7–10 days, and seedlings may be transplanted in 3–4 weeks. 

Approximately 0.03 oz (0.9 g) of seed yields 1000 plants (Nau 1999). If direct 

sown in the field, use 0.2 oz per 100' (20 g per 100 m) (Kieft 1996).

332 HELICHRYSUM BRACTEATUM 

Growing-on 

Helichrysum bracteatum 

‘Florabella Pink’ 

Provide seedlings with 60F (15C) night temperatures, 65–70F (18–21C) day 

temperatures. If sown in open flats, transplant to cells or small pots 3–4 weeks 

from sowing. If germinated in plugs, maintain the plug for 5–6 weeks before 

transplanting to the field. Fertilize with 75–100 ppm N with a complete fertilizer. 

Overfertilization results in tall, lanky seedlings. Maintain low moisture levels; 

plants are susceptible to overwatering and should be allowed to dry out. Transplant 

to the field or final greenhouse spacing when plants are still vegetative or 

in small flower bud; do not transplant with flowers.


HELICHRYSUM BRACTEATUM 333 

Photoperiod: Long days result in faster flowering, but flowering occurs regardless 

of photoperiod. Flowering is mainly a result of light intensity and temperature. 

Growth is more rapid, and therefore flowering occurs faster, under full sun 

and warm temperatures. 

Temperature: Temperatures below 55F (13C) result in slow growth and additional 

problems with root rot fungi. Temperatures of 70–75F (21–24C) are optimum 

for growth and flowering. 


Spacing: Space on 10–12" (25–30 cm) centers. 

Support: Plants, particularly tetraploids, require at least one tier of support. 

Planting: Sequentially direct sow or transplant every 2–4 weeks. The main 

flower head may be removed to harvest the resulting laterals. With sequential 

planting, only the first 2–4 lateral flowers are harvested; subsequent flower stems 

are disregarded. If only a single planting occurs, lateral stems eventually become 

too short for high-quality stems. 

Location: Plants are not tolerant of poorly drained soils or areas of heavy rainfall. 

Warm temperatures in combination with wet weather result in root rots 

and foliar spotting. Plants do better for a longer period of time in areas of dry 

summers (California, Arizona) than in areas of high moisture (Southeast); sequential 

plantings are a must in such challenging locales. 


Place on 6–9" (15–23 cm) centers; maintain 65–75F (18–24C) temperatures and 

high light intensity. 


Cut when flowers are unfolding and centers are visible. Always harvest before 

flowers are fully open (Bullivant 1989). If picked open, petals turn backward as 

they dry, resulting in a particularly ugly blossom. 

Postharvest 

Fresh: Fresh flowers persist 7–10 days. 

Storage: Storage of fresh flowers is not recommended; store at 36–41F (3–5C) 

if necessary. 

Dried: When dried, flowers persist indefinitely. Strip leaves and hang in tight 

bunches upside down in a warm, well-ventilated area. Flower heads themselves 

may be wired singly and dried straight up. Leave ½–1" (1.3–2.5 cm) of stem and 

stand them in a shallow container to dry.

334 HELICHRYSUM BRACTEATUM 

Cultivars 

Ball Florists series is a tetraploid series growing 2–3' (60–90 cm) tall with little 

basal branching. Bronze, gold, purple, red, white, and a mix are available. 

Bikini series grows only 18–24" (45–60 cm), shorter than most cultivars, and 

is available in gold, red, and a mix. 

Double Giant Florist series has 3" (8 cm) double flowers in a wide variety of 

colors. 

Double Pastel Mix grows to about 3' (90 cm) with pale pink, clear yellow, 

bright salmon, and apricot flowers. 

Dwarf Mixture is also on the short end—about 18" (45 cm)—but is recommended 

for dried bouquets. 

Finest Mixed is about 3' (90 cm) tall with colors ranging from salmon-rose to 

golden-yellow to purple and white. 

‘Flaming Ball’ has dark reddish flowers. 

Florabella series was developed for the landscape, but if 12–18" (30–45 cm) 

stems are not a problem, it provides excellent colors on strong, compact plants. 

Other landscape forms produce excellent flowers but are probably too short. 

Giant Flowered series has rounded flowers, about 2½" (6 cm) wide. Plants 

grow 24–30" (60–75 cm). 

King Size series bears double flowers on 2½–3' (75–90 cm) stems. Available in 

sulphur-yellow, orange, red, rose, and white. King Mix is a reselection with larger 

flowers. 

var. monstrosum, the most common variety in the trade, has double flowers 

and has been selected in numerous colors and heights. Often sold as Monster 

series. In national field trials, plants averaged 7 stems/plant, but they were only 

7–12" (18–30 cm) long (Dole 1997). 

‘Moreska’ produces early 2–2½' (60–75 cm) stems with flowers in gold, deep 

rose, pink, white, yellow, and tangerine. 

‘Paper Daisy’ produces many 1" (2.5 cm) wide, yellow flowers on 15–18" (38– 

45 cm) stems. 

‘Perfect Jewels’ has large 3" (8 cm) wide flowers on vigorous stems. 

Salsa Mix contains hot, spicy colors. 

Standard series grows approximately 3' (90 cm) tall and has double flowers in 

single colors or as a mix. Pink, red, purple, yellow, orange, salmon, and white 

flowers are available. Seed is less expensive than some other series but has not 

been as aggressively selected. 

Swiss Giants Mixed bears large double flowers on 36" (90 cm) stems. 

Victorian Pastels Mix is a mix of pale, soft colors. 


A few “minor” species of Helichrysum are available through specialty sources. In 

general, they are native to Australia, New Zealand, or South Africa and are best 

suited to the Pacific Northwest, northern California, or the Northeast. High 

temperatures and high humidity are not to their liking.

Helichrysum cassianum has single to semi-double pink flowers and grows approximately 

1½–2' (40–60 cm) tall. ‘Rose Beauty’ has rose-pink flowers. Germination 

is erratic and slow, and seed order should be double that of H. bracteatum. 

Helichrysum subulifolium, although relatively difficult to find, grows 1½–2' tall 

(30–45 cm) and bears many clear yellow flowers. ‘Golden Sun’ bears 1" (2.5 cm) 

wide bright yellow flowers on 24" (60 cm) stems. Unlike H. bracteatum, they 

should be harvested when flowers are fully open. 

Helichrysum thianshanicum ‘Golden Baby’ has silvery gray foliage and yellow to 

orange double flowers on 12" (30 cm) stems. Better grown for the foliage than 

the forgettable flower. Plants require excellent drainage and relatively high fertility 

levels. Perennial in warmer areas of the country. 


Ozothamnus is closely related to Helichrysum. The main species used for cut flowers 

is Ozothamnus diosmifolius (syn. Helichrysum diosmifolium; rice flower), a large 

shrubby plant native to Australia and harvested from natural stands there 

(Turnbull and Beal 1998). Cultivated production is becoming more common. 

Plants require mild winters and warm summers; cut flower production in this 

country has been limited to coastal California. 


Aster leafhoppers suck the juice from the plant and transmit aster yellows disease. 

Root and stem rot fungi result in loss of plants in areas of poor drainage and 

high rainfall. Sclerotinia rot (Sclerotinia sclerotiorum) has been reported (Takeuchi 

and Horie 1999). Wilt (Verticillium albo-atrum) may cause severe damage, particularly 

in California. 

Reading 




9(1):31–37. 


Netherlands. 

Nau, J. 1999. 1999. Ball Culture Guide. 3rd ed. Ball Publishing, Batavia, Ill. 

Takeuchi, J., and H. Horie. 1999. First occurrence of Sclerotinia rot in aster and 

strawflower in Japan. Annual Report of the Kanto-Tosan Plant Protection Society 

46:55–59. 

Turnbull, L. V., and P. R. Beal. 1998. Ozothamnus and Cassinia species with potential 

for commercialization. Acta Hortic. 454:147–156. 

Many thanks to Maureen Charde for reviewing this section. 

HELICHRYSUM BRACTEATUM 335

336 HELLEBORUS ORIENTALIS 

Helleborus orientalis Lenten rose Ranunculaceae 

perennial, Zones 4–9 Asia Minor white, purple 1 

12–18"/12" (30–45 cm/30 cm) 

Lenten rose has not been used a great deal for cut flowers, mainly because of 

limited availability and the cost of new plants. Once established, however, all 

hellebores are persistent and produce for many years. 

Propagation 

Propagation from purchased seed is difficult and exacting. Sow seeds in welldrained 

medium and place at 75–80F (24–27C) for 7 weeks. Move tray to approximately 

32F (0C) for 8 weeks and then raise temperature slowly to 40F (4C). Germination 

should commence at that temperature, after which soil temperature 

may be elevated to 50–55F (10–13C) until germination is complete. 

Mother Nature, however, has no such difficulties and is much more efficient 

than most growers. Seedlings may be found under the plant litter at the base of 

2- to 3-year-old plants. Gentle removal and subsequent transplanting provides 

abundant plants. In the field, we have seen growers simply remove mature flower 

heads, lay them in rows over well-prepared soil, and cover them lightly with compost. 

The next spring, thousands of seedlings appear. 

If necessary, roots of mature plants may also be divided in the spring, but 

large clumps will result only if plants remain undisturbed. 

Growing-on 

If propagated from seedlings in the field, gently remove the seedlings and place 

where desired. Seedlings can be transplanted to small containers, grown during 

the summer in a shaded area outdoors, and transplanted in the fall. 


Temperature: Cold temperatures are beneficial for growth and flowering. Flowers 

initiate in the fall, and cold temperature appears necessary to break dormancy. 


Yield: Flowers may be harvested no earlier than the second year, but once 

plants are established, flowers may be harvested every year. Approximately 2–6 

stems per plant, each bearing 3–6 flowers, can be harvested without damage to 

the plant. Stems are 12–15" (30–38 cm) long. 

Spacing: We recommend 12–18" (30–45 cm) spacing.

Helleborus orientalis

338 HELLEBORUS ORIENTALIS 


Flowers persist a long time, opening in late winter to early spring and essentially 

“drying” on the plant. For fresh flowers, cut when stamens become visible. For 

drying, flowers can be cut any time but are also useful later when the follicles 

(seed capsules) become visible in the inside of the flower. 

Postharvest 

Flowers persist 10–14 days in the vase. 

Cultivars 

Since all plants are propagated from seed, a good deal of variability occurs in 

flower color. White, lavender, purple, and bicolor flowers occur in any population. 

Breeding work has yielded new and single colors; however, numbers are 

low, and prices are high. 


Helleborus foetidus (stinking hellebore) bears small flowers and long finger-like 

foliage. Stems can be a little longer than H. orientalis, but flowers are smaller and 

occur in chartreuse only. 

Helleborus niger (Christmas rose) produces beautiful clean white flowers. 

Plants are shorter and more difficult to establish than H. orientalis. 


Few problems occur with Helleborus, but black spot and crown rot are possible 

(Perry 1998). 


“I have been selling [hellebores] for a couple of years, mostly orientalis. They 

have a wonderful long vase life, 10-plus days easy, and I give no special treatment 

other than Floralife. I have cut early in the season, when they are mauve, 

or waited ’til they turn chartreuse in late April–May. They command a good 

price: $1.50 and up per stem—and basically are completely maintenance free. 

Mine are well established at the base of very large trees and reseed freely, with 

basically no irrigation. They bloom for the big day—February 14—and grow 

where most other things would not.” Lisa Ziegler, Ziegler Garden, Newport 

News, Va. 

“Hellebore flowers hang way over, so they don’t make the greatest cut flower, 

since—unless you are lying on the ground and looking up into it—you can’t see 

that lovely color. I dry mine in silica gel and then use them in wreaths. The 

foetidus variety does last for weeks and weeks in a vase and may be worth mar-

HYDRANGEA 339 

keting. I doubt we could sell it here in the Northwest, but maybe in other parts 

of the country.” Sally Senior, Queen Bee Flowers & Gardens, Portland, Ore. 

“We sell hellebores in a 5-stem bunch, 12–16" in length, $5 to $12 a bunch. 

Lasts up to 2 weeks.” Leon Carrier, PlantMasters, Laytonsville, Md. 

Reading 



Hydrangea hortensia Hydrangeaceae 

woody 

Approximately 80 species occur, many with potential as cut flowers, either fresh 

or dried. The most popular is Hydrangea macrophylla (bigleaf hydrangea). Long 

staples of landscape horticulture, these mopheads, as they are also known, have 

become the darlings of the florist industry. Other useful species of this fine genus 

include H. arborescens (smooth hydrangea), H. paniculata (panicle hydrangea), 

and H. quercifolia (oakleaf hydrangea). All have undergone significant selection, 

and many cultivars are available. 

Hydrangea macrophylla bigleaf hydrangea Hydrangeaceae 

woody, Zones 5–8 hybrid origin many colors 3–5'/5' (0.9–1.5 m/1.5 m) 

The buying public has become enamored with hydrangeas of all kinds, in the 

garden, in commercial landscapes, and in vases and bouquets. Mopheads have 

always had a place in cut flower coolers, but broadened demand and choice of 

cultivars have enhanced the reasons a grower should invest capital and time in 

a crop that requires 2–3 years before the first flower is cut. Inflorescences consist 

of showy sterile flowers and small fertile flowers. When the head is made up 

mostly of sterile flowers, and the fertile ones are hardly noticed, the rounded 

flower head is referred to as a mophead; when only the outer ring of the inflorescence 

consists of sterile flowers, and the center is flattened, the head is referred 

to as a lacecap. The fullness of the mopheads has made that form most popular 

in the cut flower trade. 

Propagation 

In general, 1- or 2-node softwood cuttings are used from May to early July in 

most areas of the country. Don Mitchell of Flora Pacifica in southern Oregon 

developed his own method of propagation, the “box” method, which he shares 

as follows. Take tip cuttings (usually in April and May) and with a sharp knife, 

cut and remove about 50% of the leaf tissue. Dip the entire cutting in a mild systemic 

fungicide, allow the excess to drain, then dip the stem end in rooting hor-

340 HYDRANGEA MACROPHYLLA 

Hydrangea macrophylla 

mone solution. Place the cuttings in a waxed cardboard box, close the lid, and 

place the box in an undisturbed location at room temperature (55–75F, 13–24C 

is ideal). In approximately 10–15 days the cuttings should be calloused, with 

small roots starting. Plant these cuttings in 4" pots in a protected area until fully 

rooted and ready to harden off. 

Paul and Jhon (1992) found that only 27–33% of control cuttings rooted, and 

that the use of IBA, regardless of node numbers, resulted in far better rooting, 

with more roots per cutting and longer roots than cuttings receiving no dip. 

The greatest number of roots (about 21) were produced by 1- or 2-node cuttings 

treated with 1500 ppm IBA. Dirr (1998) recommends 1000 ppm KIBA and 

media consisting of 3 parts perlite to 1 part peat under mist; roots occur in 10–20 

days.

Growing-on 

HYDRANGEA MACROPHYLLA 341 

Pot up rooted cuttings in well-drained medium. Plants may be grown on in large 

containers. Most cultivars flower on the previous years’ wood and require at least 

2 years to flower. 


Most research on flowering centered on how to force containerized hydrangeas 

as gift plants for Mother’s Day or Easter. The resulting forcing schedules were 

attempts to simulate what happens naturally. Essentially, hydrangeas begin 

flower initiation in late summer and fall, as photoperiod shortens and temperatures 

fall. As plants go into winter, leaves fall off and flowers are completely 

formed. Winter cold is necessary to break the dormancy of latent buds; plants 

flower as temperatures warm up. In greenhouse forcing, flower induction, initiation, 

and development are done under 8-hour photoperiods at night temperatures 

below 65F (18C) (Dole and Wilkins 1999). Plants are moved into cold storage 

areas, where leaves abscise naturally or with the help of ethylene gas or an 

ethylene-inducing chemical, such as 2-butyne-1,4-diol (Blom and Smith 1994). 

Defoliation is necessary; otherwise, botrytis will spread rapidly in the cooler and 

seriously damage plant quality. Without a chilling period, flowers will abort in 

most cultivars (Guo et al. 1995). A common cooling regime is around 40F (4C) 

for 6–8 weeks, although less time and colder temperatures can be used. Upon 

removal from the cooler, plants are placed into final containers and forced 

around 60–62F (15–17C) (Bailey 1989). 


Most hydrangeas grown for cut flowers are field-produced, so nature provides 

the environment necessary for flower initiation, breaking dormancy, and flower 

formation. 

Spacing: Spacing varies, 3–4' (0.9–1.2 m) between plants and 5–8' (1.5–2.4 m) 

between rows. The more stems removed, the closer the spacer can be; however, 

too dense a planting results in thinner stems and more disease problems. At 

Flora Pacifica, plants are spaced 3' (90 cm) apart in 8' (2.4 m) rows. 

Harvesting: Flowers are generally harvested so that 2–4 nodes remain on the 

stem. Many flowers are dried, and stem length for dried flowers is not as important 

as it is in other plants. Most fresh cuts are harvested with stem length of 18– 

30" (45–75 cm); for dried flowers, 6–12" (15–30 cm) stems are adequate. At Flora 

Pacifica, harvesters cut alternate rows back to about knee height on alternate 

years. They find that this opens up the field for better air circulation and keeps 

the plants at manageable heights. In southern Oregon, flower size can be too 

big for fresh cuts, and this method of cutting also helps to keep flower size 

smaller. 

Support: Not all growers use support; those that do recommend using supports 

along the rows to a height of 18–24" (45–60 cm).


Shade: Hydrangeas perform best when provided with afternoon shade; the 

further south one grows hydrangeas, the more important shade becomes. Even 

in the Northwest, some shade is used. Natural shade is preferred, but shade cloth 

over frames is also useful. Recommendations of 30–50% have been made. White 

hydrangeas appear to need more shade; around 40–50% would be appropriate. 

In some areas, shade is employed only when the daytime temperature reaches 

85F (29C) and above. 

Flower color: The concentration of free aluminum in the soil can strongly affect 

flower color. The concentration of aluminum is highest in acid soils and 

lowest in alkaline soils. In general, blue flowers will occur in acid soils, pink in 

alkaline soils. In greenhouse-forcing cultivars, Blom and Piott (1992) suggested 

that application of aluminum sulphate (approximately 0.5 oz/6" pot, 14 g/15 

cm pot) induced blue coloration. Not all flowers have sufficient pigment to 

change colors, however, and many will remain the same color regardless of aluminum 

or pH. 


Most cultivars require a cold treatment before flowering, although new cultivars 

for which no cold is necessary have been selected. Hydrangeas (and other 

woodies) are particularly good candidates for outdoor “moveable” greenhouses 

or tunnels, in which in-field plantings can be covered and forced when prices 

are at their peak. If noncooled hydrangeas are moved into a greenhouse in the 

fall, provide about 6 weeks of 40–45F (4–7C) in the greenhouse, cooler, or outdoors. 

Plants are usually in containers, so they can be moved in or out of the 

greenhouse as needed. Flowers can be harvested, depending on cultivar, 4–8 

weeks after temperatures are raised. 


Fresh: Cut flowers when they are completely open. But keep in mind Don 

Mitchell’s experience: “Sometimes we have ‘gotta have’ customers, who have to 

have hydrangeas before they are ready. [We’ve] cut them with considerable white 

showing on the inflorescence, and they still make a good cut flower, though in 

my opinion not the best.” 

Dried: Hydrangeas for drying are not ready for harvest until about 1 September, 

depending on locale. Generally, they are not ready to harvest until the true 

flowers in the center of the colorful inflorescence have dropped off and the flowers 

feel rubbery (not papery) to the touch. With experience, a harvester can readily 

tell by the feel of the flowers. If harvested too soon, they shrivel into the unattractive 

product sometimes creatively marketed as “crinkles.” 

Postharvest 

Fresh: Defoliate and bunch in groups of 10 in the field. As soon as practical get 

them to the barn and place them in buckets with about 5–7" (13–18 cm) of hot 

water (110–120F, 43–49C) and immediately place them in a 34–36F (1–2C)


cooler. They should remain in the cooler at least 8 hours or until they are 

shipped. Don Mitchell finds that hydrangeas conditioned in this way ship well 

and considers floral preservative optional. Customers should be told to recut 

the stems and immediately put them in similarly heated water (110–120F, 43– 

49C). Using this procedure, completely wilted flowers will revive and become 

turgid. Vase life of conditioned flowers is easily 7–14 days. A word of caution to 

florists: hydrangeas need lots of water and do not do well in floral foam; the stem 

needs to be in water. 

Dried: Mopheads are far better for drying than lacecaps, lacecaps dry poorly. 

Wait until flowers feel somewhat leathery or rubbery before harvesting. If cut 

too early, the petals shrivel. When flowers are harvested as outlined earlier, they 

can be stripped of leaves and bunched in threes using a rubber band. Hang 

upside down on a drying rack, in a warm, dry, dark place. A barn loft or an attic 

work fine. It is the combination of repeated drying and rehydration as well as 

sunlight that causes the loss of color. Don Mitchell has found that if placed in 

a dryer, the flowers will dry overnight, and the stems may take 2 or 3 days. Add 

fans for ventilation and a dehumidifier to reduce humidity. Direct sunlight 

results in discoloration; dampness results in flowers turning brown. Some growers, 

such as J. B. Barzo-Reinke of Small Pleasures Farm in Bandon, Ore., dry thousands 

of flowers in 2 days in a 20 × 16' room. 

And Don Mitchell has the last word on drying: “I have no idea where this idea 

originated, that you need to place hydrangeas in a vase of water to dry. Other 

than perhaps a backyard operation, this is pure bunk. Try drying 100,000 

hydrangeas in vases of water! I understand Martha Stewart suggested putting 

vodka in the water to increase uptake. I say, drink the vodka and hang the 

hydrangeas!” 

Cultivars 

‘Ayesha’ bears pink or blue semi-double flowers. 

‘Deutschland’ has pink flowers. Good hydrangea for outside cultivation. 

‘Dooley’ has handsome blue flowers and is distinguished by having many 

flower buds on the flowering stem. If a late frost kills the terminal buds, the additional 

buds will subsequently develop. 

‘Glowing Embers’ is floriferous, but stems are short. The mostly red main 

flowers on the top of the bush do not dry well (they tend to be muddy-looking); 

however, the more protected flowers develop an attractive buttery yellow-green 

color. One of Don Mitchell’s top 5. 

‘Green Shadow’ produces greenish red flowers in summer, dried in autumn. 

‘Hamburg’, Don Mitchell’s favorite, is excellent for early fresh cut flowers and 

drying. It has good-sized flower heads (6–10", 15–25 cm), and the individual florets 

are fairly large. Flowers develop nice burgundy tinges as they mature. 

‘Kuhnert’, another of Don Mitchell’s top 5, is an excellent mid-blue hydrangea 

with small flowers (6–8", 15–20 cm) that also dries well. In southern Oregon, 

plants flower all winter, though with all the heavy rain, the flowers are of poor 

quality.


‘Nikko Blue’ is a popular small-flowered blue hydrangea. Perfect for florists 

who prefer small flowers. 

‘Red Star’ is late-bloomer with mid-blue flowers. Good as a fresh cut, with 

large (8–12", 20–30 cm) flower heads. As a dried flower, it tends to have a floppy 

head; however, the blue color seems to hold with much less burgundy coloration 

than ‘Hamburg’. In Don Mitchell’s top 5. 

‘Regula’ is a nice white that flowers later in the season and continues on into 

the winter. It is a good fresh cut, and the mature flowers turn an attractive green. 

In Don Mitchell’s top 5. 

‘Romantic Fantasy’ is a picotee form, red-violet with a white edge. 

Old wood, new wood 

Hydrangea macrophylla produces flower buds on stems in late summer and fall. 

These buds go through the winter, which breaks their dormancy, then go on to 

form flowers next spring, on “old wood.” Outdoors, when plants are pruned 

hard in winter (after the buds have set), or late frosts kill back stems, or deer eat 

the plants to the ground, flowering is nil or very sparse. Plants are still healthy 

and a few flowers may form, but flowering is significantly diminished. Plants 

that flower on old wood flush only once a season. This is also why plants forced 

in the greenhouse must undergo a cold treatment on the old wood, or flowering 

is unsatisfactory. 

A few cultivars seem to be able to flower without cold. Buds are formed on 

developing stems (“new wood”), and cold is not necessary for flowering. Butterfly-bush 

and deciduous hollies also flower on new wood; with such plants, greenhouse 

forcing is significantly easier, and additional flushes may occur throughout 

the season. Very few cultivars of Hydrangea macrophylla that bloom on new 

wood are available in adequate numbers, although a few, such as ‘Endless Summer’ 

and ‘PennyMac’, are being investigated and may prove useful. 


Several species can be used for cut flowers; some bloom early, others do not 

bloom until the fall. Hydrangeas, as cuts, have been looked at as a possible alternative 

source of income for row crop farmers (Wolfe and Dunwell 1999), but in 

general, literature on growing a diverse range of Hydrangea species as cuts is 

scanty. Products like hydrangeas and peonies fit well into a niche market. 

Hydrangea arborescens is hardy in Zones 4–9. ‘Annabelle’, the most readily available 

cultivar, bears large, 10–12" (25–30 cm) wide, creamy white flowers in late 

June through September. Plants flower on new wood and, therefore, may be cut 

to the ground in late winter; the resulting growth will produce sufficient flowers 

for cutting. A second flush of flowers is possible in southern climates in September 

if the first flush is removed by early July. The inflorescences are excellent 

for drying. 

Hydrangea paniculata is hardy in Zones 3–8, the hardiest of all hydrangeas, 

and also flowers on new wood. ‘Grandiflora’ (PG, peegee hydrangea) is very common 

and bears large panicles of white, sterile flowers in early to mid summer.


The panicles are usually 6–8" (15–20 cm) long but can reach 12–18" (30–45 cm) 

in length if branches are selectively pruned; such large inflorescences may be too 

big for the cut flower market. ‘Kyushu’ has white pyramidal plumes of flowers 

from late June to late summer. ‘Praecox’ is similar to ‘Grandiflora’ but flowers 

approximately 2 weeks earlier. ‘Tardiva’ bears numerous sterile flowers on a 6" 

(15 cm) long inflorescence; its late-flowering habit (late September) makes it a 

useful option for extending the hydrangea market. ‘White Diamond’ and ‘Pink 

Diamond’ have become quite popular as easy-to-grow cut flower candidates. 

‘Unique’ produces white flowers in July–September, which dry to pink in September–October. 

See Dirr (1998) for additional cultivars. 

Hydrangea quercifolia (oakleaf hydrangea) is a stoloniferous shrub with few 

branches when young but significant branching at maturity. White flowers are 

formed in long terminal panicles on old wood. The outer showy flowers are sterile, 

the inner nonornamental ones, fertile. Plants are hardy in Zones 6–9, marginal, 

at best, in Zone 5 and below. Cultivars include ‘Alice’ (long panicles), 

‘Snowflake’ (double flowers), and ‘Snow Queen’ (heavier flowers than the species); 

all are better candidates than the species for cut flowers. Needs shade. 


Bud blight, leaf spots, rust, mildew, and assorted thrips, aphids, and whiteflies 

have all been known to associate with hydrangeas. Slugs and snails are particularly 

nasty pests, and botrytis is a serious problem. Petal spotting, in which distinct, 

multiple purple spots (like chicken pox) occur on the flowers, has been 

reported (Leite and Barreto 2000); J. B. Barzo-Reinke actually points affected 

plants out to her customers: she finds that they love her “printed mops.” 


“My hydrangeas are planted in rows 7' apart, plants 4' apart in the rows. I trim 

back to 2 or 3 nodes every winter. This gives me lots of nice long stems for cut 

flower production. I have been using 33% shade but am changing to 50% this 

year.” Ray Gray, Sunset Flowers of New Zealand, Oregon City, Ore. 

“I’m selling to a wholesaler for $4/5 stems. These are somewhat small, 30" 

stems, from tree PGs set out this spring. Larger stems I would sell for $1/stem. 

They liked them cut about half green, half white.” Ron Smith, R. Smith Farm, 

Renfew, Pa. 

Reading 

Bailey, D. A. 1989. Hydrangea Production. Timber Press, Portland, Ore. 

Blom, T. J., and B. D. Piott. 1992. Florists’ hydrangea blueing with aluminum sulfate 

applications during forcing. HortScience 27(10):1084–1087. 

Blom, T. J., and R. B. Smith. 1994. Ethylene gas for defoliation of hydrangeas. 


Bucks, C. 1998. Simply hydrangeas. Organic Gardening 45(2):23–27.


Hydrangea quercifolia ‘Snow Queen’ 





Guo, Z., M. Goi, M. Tanaka, and S. Fukai. 1995. Effects of temperature and 

photoperiod on the bud formation of Hydrangea. Tech. Bul. Fac. Agric. Kagawa 

Univ. 47(1):23–31. 

Leite, R. S., and R. W. Barreto. 2000. Petal spotting of hydrangea flowers caused 

by Corynespora cassiicola: old pathogen—new disease. Mycologist 14(2):80–83. 

Paul, T. M., and A. Q. Jhon. 1992. Influence of node number and IBA treatments 

on rooting of Hydrangea macrophylla (Thunb.) cuttings. Advances in Plant Sciences 

5(2):619–622. 

Wolfe, D., and W. Dunwell. 1999. Production of cut flowers from field-grown 

hydrangeas. HortScience 34(3):476 (abstr.). 

Many thanks to J. B. Barzo-Reinke, Don Mitchell, and Bob Wollam for reviewing 

this section.

HYPERICUM 347 

Hypericum Clusiaceae 

perennial, Zones 5–7 Europe, North Africa fruit 1 

2–3'/2' (60–90 cm/60 cm) 

The species used for cut fruit production are Hypericum androsaemum (tutsan) 

and a related hybrid, H. ×inodorum. The former bears rounded, fleshy red fruit; 

the latter has elliptical, orange-red fruit. Most cultivars in use are hybrids 

between the two. The hybrids are based on fruit color and size, all varieties of 

which have found acceptance in the marketplace. Stems are being produced 

around the world and are imported into the United States year-round. Susceptibility 

to rust has made American growers more reliant on overseas material. 

Propagation 

Plants can be grown from seed, rooted from terminal cuttings, or purchased as 

bare root plants. Cultivars do not come true from seed. Bare root plants, if 

shipped dormant, must be “sweated” (placed in a hot, moist environment prior 

to planting) to break dormancy or shipped after dormancy has been broken. 

Some cultivars are patented and must be purchased from a licensed propagator; 

these newer cultivars are always identified by a plant patent number. Cultivars 

without plant patent numbers can be propagated without a royalty payment. 

Growing-on 

If small plantlets are received, transplant to larger containers until ready for 

transplanting to the field or greenhouse. Grow on at 55–65C (13–18C) in bright 

light. Plants can be placed in the field when roots fill the container. 


Plants are long day and respond by flowering when daylength is greater than 14 

hours; some recommendations suggest that daylength should be extended to 

18–20 hours. This is possible in the greenhouse; however, fruit still forms under 

natural daylengths in most of the country. Plants produce more fruit at northern 

latitudes, where daylengths are naturally longer than those at southern latitudes. 

Lighting in the field to provide 18- to 20-hour daylengths may prove useful. 

Lighting programs in this case would be started before dusk. 


Planting: Plant to the field when roots are well developed. Spacing on 18–24" 

(45–60 cm) centers is sufficient. As daylength increases, flowers and fruit are 

produced. Outdoors, stems are harvested in late summer. Areas for high-quality 

production are limited in the United States. Hypericum androsaemum does poorly 

in areas of hot, humid conditions, being highly susceptible to fungi under such 

environments. Plants are cold hardy to about Zone 5, but winter damage can be 

significant if plants are not protected.

348 HYPERICUM 

Pinching: Plants should be pinched when cuttings are starting to elongate, 

leaving at least 3 leaf pairs. 

Fertilization: Reduce N fertilization when the first shoots are branching, to reduce 

lateral growth. Reduce irrigation when the berries are ripening, to prevent 

bursting. 

Yield: Production in the first flush is approximately 2 stems/plant; the second 

flush is about 6 stems/plant, and additional flushes may be as high as 15 

stems per mature plant (Bartels 2000). 

Overwintering: Hypericum is essentially a woody shrub, and any stems remaining 

after harvest should be left uncut (similar to other woodies). Winter kill is 

always related to desiccation from wind without snow cover; after the ground 

has frozen, plants can be mulched to increase winter survival in colder zones 

without snow cover. Plants should be cut back to 1" (2.5 cm) after they have 

begun to sprout in spring. 


Year-round demand has resulted in increased cultivation under protection. 

Plants may be grown in winter conditions if long days (>14 hours, up to 20 

hours) and warm temperatures (65–75F, 18–24C) are provided. Data concerning 

yield, fertility, and spacing are few. 


Harvest stems close to the ground when fruit is fully colored. Stems are usually 

sold in bundles of 5–10. 

Postharvest 

Stems have a vase life of 9–14 days (Anon. 2001). Leaves deteriorate before the 

fruit. Treat stems immediately after cutting. 

Cultivars 

‘Albury Purple’, a cultivar of Hypericum androsaemum, has bronzed purple 

foliage with a round red berry, surrounded by purple bracts. Plants are cut for the 

foliage and the fruit. 

‘Annebel’, a hybrid between Hypericum androsaemum and H. ×inodorum, bears 

a rounded fruit of brown-red. 

‘Autumn Blaze’, a cultivar of Hypericum androsaemum, bears brown-black fruit. 

Very similar to ‘Excellent Flair’ but sets fruit approximately 2 weeks later and is 

more rust prone. 

‘Dolly Parton’ has pink fruit. Individual berries, twice as large as other cultivars, 

seem to require the even daylength of the equator and the bright light of 

higher elevations; the fruit reportedly occurs consistently only in Ecuador or 

Peru.

Flair series, the most prevalent of available groups, has greatly encouraged 

the production and sale of the species. ‘Excellent Flair’ (red-brown fruit), the 

standby cultivar, grows 3–4' (0.9–1.2 m) tall and has good rust resistance. Others 

include ‘Candy Flair’ (pink), ‘Envy Flair’ (red), ‘Jade Flair’ (green), and ‘Pinky 

Flair’ (pink). 

‘Glacier’ has variegated foliage, green and white with some pink. Must be 

grown in shade or cool coastal conditions. 

Magical series includes ‘Magical Beauty’ (salmon), ‘Magical Dream’ (green), 

and ‘Magical Flame’ (deep red). 

‘October Revolution’ is late to set but finally produces small red-brown fruit 

with a pointed shape. Good rust resistance. 

‘Rheingold’ is comparable to ‘Annebel’ (similar parentage) with earlier, 

slightly smaller, more pointed, oval brown-red fruit. Plants are vigorous growers 

with good rust resistance. 

‘Summer’ is also a hybrid with very early, dark red fruit. Rust resistance 

appears to be marginal. 


Aphids and whiteflies can be a problem early in the growing season. Timely control 

will prevent the loss of stem length that can occur if new growth becomes 

stunted. 

Hypericum rust (Melampsora hypericorum) shows up as yellow spots on top of 

the leaves and as orange spots beneath. Heavy infection can cause brown or dead 

leaves. Rust spores can spread rapidly via wind, rain, and clothes. Remove dead 

leaves, keep the beds clean, and apply a fungicide early in the plant cycle. Paul 

Sansone of Here & Now Garden in Gales Creek, Ore., has further suggestions: 

“Each spring a copper spray [is] applied when plants are dormant. . . . If chemical 

control is used, apply systemic control early, when the second or third sets of 

leaves have emerged, and again 30 days later. Nonchemical control can be 

achieved with foliar sprays of compost tea. Rust tends to appear when hot dry 

weather settles in. [Control] by shifting to overhead irrigation and soaking 

plants daily with ½" of water.” 

Nematodes have been reported as a serious problem. 

Root rots appear frequently in hot, humid weather. 

Reading 

Anon. 2001. Dutch hypericum produces large berries, profits. Flower News (Sept. 

8): 4. 


Many thanks to Paul Sansone for reviewing this section. 

HYPERICUM 349

350 ILEX 

Ilex deciduous holly Aquifoliaceae 

woody, Zones 3–9 North America fruit 6–10'/6' (1.8–3 m/1.8 m) 

Hollies have been vigorously bred and selected, and with the dozens of species 

and hundreds of cultivars available in the nursery trade, one would expect to 

find some in cut flower markets. But the many species native to China and Japan 

usually bear evergreen, often spiny foliage that is of limited value for cut sales; 

the evergreen species also tend to be less cold hardy than deciduous species, and 

while they may occasionally be seen in local markets, little widespread interest 

has developed. The deciduous species, by contrast, such as Ilex decidua, I. verticillata, 

and I. serrata and hybrids, have been in cut flower markets for years, and 

enjoy such poetic names as winterberry, coralberry, sparkleberry, and possumhaw. 

The stems are cherished for their berrylike fruits (drupes), which are harvested 

for the Christmas and Easter markets. Most hollies are dioecious, meaning 

that plants are either male or female. Only the female plants bear fruit, but 

some males are necessary for pollination; approximately one male plant for every 

20 females is sufficient. Generally, any male holly can pollinate any female if 

flowering times overlap. 

Propagation 

Cuttings: Softwood cuttings root easily. Treat June or July cuttings with a 

quick dip of 1000–3000 ppm IBA, stick in peat/perlite medium, and place under 

intermittent mist. Ninety to 100% rooting occurs in 6–8 weeks (Dirr 1998). 

Seed: Seed exhibits a deep dormancy, and patience is a must. Some seed may 

require up to 18 months. Remove the mealy outside layers of the fruit and sow 

the hard seeds (nutlets) in a suitable medium. Place at 70–75F (21–24C) in a 

humid area (Dirr 1998). 

Growing-on 

Plants are slow-growing and generally grown in containers. Acid conditions (pH 

4.5–6.5) and moderate fertility levels are recommended. They can be transplanted 

to the field as rooted cuttings in the spring, but fibrous roots dry out 

rapidly and significant losses may occur. To reduce losses, use 1 gallon (4 l) containerized 

plants. 


Habit: Plants are oval to rounded in shape and tend to form large multistemmed 

clumps. The foliage is deciduous but persists into late fall. 

Spacing: Plants can grow 10–15' (3–4.5 m) wide if left undisturbed; spacing of 

20 × 20' (6 × 6 m) has been used to facilitate mechanical harvesting. With selective 

cutting, denser spacing may be provided to produce mass plantings. Some 

growers space as densely as 4' (1.2 m) apart and 10' (3 m) between rows. Wider 

spacing allows more stems/plant but fewer stems/ft2 . With large plantings, spacing 

should be dictated by the equipment available for cultivating and harvesting.

Ilex verticillata 

‘Winter Red’ 

ILEX 351 

Harvesting: Flower buds are set a year prior to flowering; severe harvesting 

therefore retards subsequent fruiting. If plants are cut back severely, approximately 

3 years are necessary before plants can be reharvested. Mechanical mowing 

of 15–18" (38–45 cm) stems is also practiced (Eisel 1989). Harvesting is generally 

accomplished after the leaves have fallen—most retailers don’t want to 

mess with pulling off leaves. Stems are generally sold by the pound, so harvested 

material needs to be weighed prior to boxing. 

Soils: Plants are native to swampy areas and can be grown with the entire root 

system submerged. Plants are also adaptable to “normal” field conditions. Drainage 

is not as important with these species as with other woody plants. 

Wild material: Some people still simply harvest from the wild. This is not the 

place to get into ecological and ethical discussions on the benefits or detriments 

of such practices; however, there is no doubt that commercial cultivars bear 

larger stems and more fruit and will bring a better price than wild-collected 

stems. Also, cultivation practice such as watering, appropriate fertility, and plant 

management invariably improve production and yield. Last but not least, the

352 ILEX 

“gatherers,” with their lack of overhead, tend to price their material too cheap, 

hurting the market in general. 


Branches should be harvested before the fruit reaches maturity (Eisel 1989). 

While it’s not necessary to remove the foliage from holly branches, some wholesalers 

believe the fruit is more ornamental when the branches are defoliated. If 

stems are to be defoliated, defoliation must be done prior to shipping. 

Postharvest 

Abscission of foliage: A problem occurs when some, but not all, of the leaves and 

fruits abscise, resulting in an unattractive branch. Storage of cut branches in 

high-humidity chambers helps in the removal of foliage, whether foliage is 

finally removed mechanically or by hand. Tammy and John Ford, excellent growers 

in south-central Indiana, share their experience: “We cut early to mid November 

but will leave the stems in the field as long as possible until 1) we have orders 

to fill or 2) a hard freeze is forecast. The holly will take a few light frosts okay, but 

a hard freeze [decreases] the longevity of the berries after cutting. After cutting, 

we like to store the stems, for a few days at least, in plastic bags in the cooler. 

This helps to loosen the leaves if some are still hanging tight. When you pull 

them from the cooler, a good shake will drop most of the leaves, and the rest 

pull off very easily. We try to remove the majority of the leaves, but if there are a 

few tight ones, we won’t worry about it—figure they’ll be loosened by the time 

they reach their destination.” 

Banko and Stefani (1999) compared combinations, concentrations, and timing 

of chemical defoliants. Using Ilex verticillata ‘Winter Red’, they found that 

the most promising chemicals were Dropp (thidiazuron) and Harvade (dimethipin); 

other chemicals resulted in premature berry softening and drop. A 

single application of Harvade at 1600 ppm provided reasonably good defoliation 

(71%) and minimal berry drop (1%), with little additional loss of berries 

from the stems during a 3-month storage period. 

Storage: Stems should be stored dry (Eisel 1989). Branches may be stored at 

32F (0C) for 1–3 weeks in moisture-retentive boxes (Nowak and Rudnicki 1990). 


Ilex decidua (possumhaw) is fall-fruiting with scarlet-red berries. Plants grow 

7–15' (2.1–4.5) tall and about 10' (3 m) wide at maturity. Plants are hardy in 

Zones 5–9, although differences among cultivars occur. Useful cultivars include 

‘Byers Golden’ (yellow fruit); ‘Council Fire’ (orange fruit); ‘Red Cascade’ (red 

fruit); ‘Sentry’ (red fruit); ‘Sundance’ (orange-red fruit); and ‘Warren’s Red’ (red 

fruit). ‘Red Escort’ is a good male form. 

Ilex serrata (fine-tooth holly) bears ¼" (6 mm) wide fruit and generally grows 

about 6–8' (1.8–2.4 m) tall. The abundant fruit ripens early and is showy. Unfortunately, 

the fruit on many selections does not hold well and fades on the side

ILEX 353 

facing the sun. Cultivars include ‘Leucocarpa’ (white fruit) and ‘Xanthocarpa’ 

(yellow fruit). 

Ilex verticillata cultivars are available by the dozen, most with red fruit but a 

few with yellow and orange-red fruit (see Dirr 1998 for discussion). ‘Jim Dandy’, 

‘Southern Gentleman’, ‘Raritan Chief’, or ‘Rhett Butler’ are good male forms. 

‘Berry Nice’ has vivid large fruit. ‘Cacapon’ produces an abundance of truly red 

fruit on 6–8' (1.5–2.4 m) tall plants. ‘Christmas Gem’, introduced by Jenkins 

Nursery in Maryland, bears dark red fruit. ‘Chrysocarpa’ bears yellow fruit but 

does not fruit as heavily as many of the red-fruited forms. ‘Maryland Beauty’, 

another Jenkins introduction, is a heavy producer. ‘Shaver’ has perhaps the 

largest fruit of all selections; the fruit is orange-red and produced on uprightgrowing 

plants. ‘Sunset’ bears bright red fruit that is slightly longer than that of 

‘Winter Red’. ‘Tiasquam’ produces excellent, persistent red fruit. ‘Winter Gold’, 

a branch sport of ‘Winter Red’, produces ¼" (6 mm) wide, pinkish orange fruit. 

‘Winter Red’, introduced by Simpson Nursery in Indiana, has performed exceptionally 

well in trials at the University of Georgia and many other sites; bright red 

fruit, ⅜" (10 mm) wide, is borne in great profusion and maintained through the 

winter. 

Ilex verticillata × I. serrata crosses have resulted in some useful cultivars; however, 

they are less suitable than I. verticillata forms for cut fruit. The fruit, in general, 

is slightly smaller than I. verticillata forms and usually less persistent. 

‘Autumn Glow’ is 6–8' (1.8–2.4 m) tall and produces red fruit that fades on the 

side facing the sun by Christmas. ‘Bonfire’ is a vigorous grower with red fruit. 

‘Sparkleberry’ is one of the best cultivars, bearing persistent, brilliant red fruit, 

often throughout the winter. Use ‘Apollo’ as the male form. 


Tar spot (Rhytisma concavum) results in yellow spots on the foliage in spring, 

which turn reddish brown in summer and black in fall. Treat with a fungicide in 

early spring. 

Spittlebugs can be a problem. Ruter and Bramen (1999) found that the number 

of adult spittlebugs per plant varied, by species, from 0 to 28, while the number 

of damaged tops per plant ranged from 0 to 62. Ilex cassine and I. opaca and 

hybrids of these species were the most susceptible; I. cornuta, I. glabra, I. verticillata, 

and I. vomitoria and their hybrids were least susceptible. 

Leaf spots, caused by numerous fungi, result in small, brown to black spots 

on the foliage. Increasing the vigor of the plants by reducing stress (keeping 

them well watered and so forth) will reduce the incidence of leaf spotting. 

Powdery mildew is sometimes a problem, particularly in the South. Fungicides 

may be necessary. 


“Ilex verticillata is always sold here with the leaves removed. I think it’s important 

to keep the humidity pretty high, but not enough to harm the berries—we

354 IRIS 

use a method similar to this for bittersweet. [If] they dry out too much the leaves 

never come off and are even difficult to pull off.” Janet Foss, J. Foss Garden Flowers, 

Everett, Wash. 

“I just bunch the stuff up at 10 branches to the bunch and store it outside on 

the ground.” Jim Link, Sandgate Flower Farm, Sandgate, Vt. 

“Cultivars of Ilex verticillata like ‘Winter Red’ are significantly different from 

wild populations. They are very heavily berried, and the berries are very persistent. 

The price to a wholesaler is $5 to $8/lb; somewhat more, $12/lb, to high-end 

florists and restaurants in Louisville; and as much as $12 to $14/lb retail (at late 

season farmers’ markets). A single stem of ‘Winter Red’ may weigh as much as 2 

lbs or more! ‘Winter Red’ stems are too bulky to be bunched! We pack 5 lbs in a 

box for our wholesale customers. A 3–6' stem carries a lot of heft if covered with 

berries.” Tammy Ford, Perennial Favorites, Leopold, Ind. 

Reading 

Banko, T. J and M. Stefani. 1999. Defoliating deciduous hollies grown for the cut 

floral market. Holly Society Journal 17(4):14–18 



Eisel, M. C. 1989. Deciduous woody plants for the florist trade. In Proc. Commercial 

Field Production of Cut and Dried Flowers. Univ. of Minnesota, The Center 

for Alternative Crops and Products, St. Paul. 



Ruter, J. M., and S. K. Bramen. 1999. Twolined spittlebug damage on Ilex species, 

hybrids, and cultivars. Holly Society Journal 17(1):3–12. 

Iris Iridaceae 

bulb/perennial 

It is hard to argue with the beauty of an iris flower, regardless of the species or 

cultivar. Japanese iris, Siberian iris, Louisiana iris, and the ubiquitous bearded 

iris are all beautiful, but they are not commonly found in floral markets. They all 

are easy to grow and bear handsome flowers, but their limited shelf life tends to 

make them local items only. That in itself is not a problem as long as the consumer 

realizes that vase life is not one of their headier characteristics. No worry 

about overseas competition with most irises. 

Bulbous iris are forced year-round and are the most widely grown. The most 

popular form of the bulbous iris is the Dutch iris (Iris xiphium); English iris (Iris 

latifolia) is occasionally grown.

Iris (bearded form)

356 IRIS XIPHIUM 

Iris xiphium group Dutch iris Iridaceae 

bulb/perennial, Zones 8–10 hybrid origin many colors 1 

1.5–2'/1' (45–60 cm/30 cm) 

Dutch iris are the most sought after because of their hybrid vigor, diversity of 

color, ease of flowering, and shelf life. In the United States they are more commonly 

grown as a greenhouse crop, but field production is possible in the southern 

states and on the West Coast (Zones 8–10). Iris bulbs can be found from as 

small as 6/7 cm to 10+ cm in diameter. The smaller sizes (6/7, 7/8, and 8/9) are 

used for garden and outdoor forcing; the 8/9, 9/10, and 10+ cm are used for 

greenhouse forcing. The larger sizes respond better to cold treatments and produce 

longer stems. 

Propagation 

Dutch iris are true bulbs, and offsets are formed after flowering. Bulb growers in 

Holland propagate iris bulbs by replanting the offsets or clusters in the fall. All 

bulbs graded over 6 cm for the small bulbous group and over 8 cm in the large 

bulbous group are made available to the commercial trade. France also produces 

a considerable number of bulbs; they are harvested earlier and can therefore be 

cold treated and forced earlier than the bulbs grown in Holland. 

Cut flower growers may propagate their own clusters. Offsets may be divided, 

cleaned, sized, and replanted each summer. Most growers, however, treat the 

bulbs as annuals and discard them each year. This is particularly true for greenhouse 

production. Bulbs should be immediately planted upon arrival. 


Temperature: Dutch iris do poorly above 70F (21C) for extended periods of 

time. Recommended greenhouse temperatures are 62F (17C) days and 53F (11C) 

nights. This limits the time bulbs can be forced in the field or greenhouse in 

many parts of the country. In the East, greenhouse forcing is difficult during 

the summer months without excellent soil-cooling facilities; on the West Coast, 

more production during the summer is possible. 

Warm temperatures after digging are necessary for successful flower forcing. 

The temperatures provided and the durations the temperatures are applied 

depend on where the bulbs are grown and when they are lifted. When lifted from 

warm soils, the heat requirement is partially fulfilled. Warm storage recommendations 

differ for various areas but are given for approximately 2 weeks. For 

example, bulbs grown in Holland may be stored at 86–95F (30–35C) for 2 weeks 

followed by 3 days at 110F (43C); in western Washington, bulbs are stored 2 

weeks at 90F (32C); in the United Kingdom 86F (30C) for 2 weeks followed by 3 

days of 110F (43C) are satisfactory (Rees 1985). The most common treatment, 

however, is 2–3 weeks at 86F (30C); this appears to be the optimum combination 

to make an iris bulb go dormant. Most iris varieties can be kept dormant up to 

one year at 86F (30C), allowing bulb suppliers to make cold-treated bulbs avail-

IRIS XIPHIUM 357 

Iris ‘Purple Sensation’ 

able to growers on a year-round basis; bulbs used for this purpose are said to be 

retarded. Bulbs that must be immediately placed in cold storage (for early forcing) 

receive a treatment of ethylene gas or banana gas, which boosts the flowering 

performance of the bulbs, especially the ones that are must be planted early. 

After the heat treatment, low temperatures are necessary for flower initiation. 

These treatments are nearly always provided by the bulb supplier; however, 

forcers with proper equipment for temperature treatment may do their own. 

Various cold treatments are used, depending on the variety of bulb, the climate, 

and the greenhouse conditions under which the bulbs are grown. Generally cold 

treatments are done in a combination: 1–2 weeks of 62F (17C) followed by 6–11


weeks of 48F (9C). In the spring and toward the summer, these cooling periods 

are shorter. 

Light: Bulbs produce more flowers of better quality under high light conditions. 

In the winter, provide clean greenhouses and supplemental light if appropriate; 

in the summer, houses may have to be shaded to maintain optimum 

temperatures. 

Photoperiod/CO2: No photoperiodic response or benefit of supplemental CO2 

is evident. 


Bulb size: Bulb size should be greater than 8/9 cm for optimum flowering (De 

Hertogh 1996); however, optimum bulb size varies with cultivar. 

Spacing: Different cultivars require different spacing. Bulbs in the Ideal 

Group, for example, may be planted at high densities of 21–24 bulbs/ft2 (230– 

260 bulbs/m2 ), whereas those in the Small Bulb Group are spaced at 10–12 

bulbs/ft2 (110–130 bulbs/m2 ) (Buschman 2000). This computes to as wide as 

4" (10 cm) apart to as close as bulb to bulb. There is no hard and fast rule for 

spacing; however, some cultivars can be planted closer together without adversely 

affecting yield or quality. Denser spacings are more appropriate in greenhouse 

production than field production. 

Bulbs should be planted 4–5" (10–13 cm) below the soil surface (De Hertogh 

1996). If planted too shallow, bulbs dry out more quickly and stems are more 

likely to topple in winds. 

Planting time: Bulbs should be planted when soil temperature is 60F (15C) (De 

Hertogh 1996). The optimum growing temperatures for field production is 60– 

62C (15–17C). Soil temperatures should be no higher than 68F (20C), air temperature 

no higher than 77F (25C). In mild climates, bulbs planted in the fall 

produce flowers in late spring and summer. Information concerning planting 

time on 5 cultivars of Dutch iris, planted approximately 6" (15 cm) apart at 

Athens, Ga. (Zone 7b), follows (Armitage and Laushman 1990). 

The effect of planting date on Dutch iris z . 

Month Stems/ First Harvest Stem Stem 

planted bulb harvest duration (days) length (in) y width (mm) x 

Nov 0.84 15 Apr 15 16.2 9.5 

Dec 0.89 13 Apr 17 15.0 9.5 

Jan 0.94 24 Apr 14 14.7 9.3 

Feb 0.80 30 Apr 13 12.3 7.5 

Mar 0.73 20 May 15 11.2 7.4 

z = data are averages of ‘Blue Ideal’, ‘Blue Ribbon’, ‘White Wedgwood’, ‘White Bell’, 

and ‘White Cloud’ 


x = divide (mm) by 25.4 to obtain (in)


Notice that little difference in yield occurred between November and January 

plantings. Harvest was delayed after December, however, and stem length and 

diameter were reduced as planting was delayed. It is obvious that, at least in Zone 

7b, planting after January cannot be recommended: the rising soil and air temperatures, 

March through June, reduce quality. 

Longevity: Most growers replace bulbs annually, and even in areas where bulbs 

may be perennialized, late frosts can devastate emerging flowers. In areas where 

no frost occurs, bulbs must be precooled. 


Planting time: Plant bulbs every week in beds or crates for as long as quality can 

be maintained. 

Bulb size: In general, a large bulb size is preferable, and for most cultivars a 

circumference of 9/10 cm is recommended. But some cultivars—‘Crown Jewel’, 

‘Golden Beauty’, ‘Purple Sensation’, and ‘Yellow Queen’, for example—naturally 

produce smaller bulbs, and the maximum circumference for this Small Bulb 

Group is 8 cm (Buschman 2000). Whatever the cultivar, a less than optimal bulb 

size increases the incidence of flower blindness. 

Bulb depth: Plant by pushing ¾ of the bulb (“thumbing in”) into loosened soil, 

then cover with 3–4" (8–10 cm) of soil. If planted too shallow, the bulbs are more 

likely to be affected by drying out. Some growers in northern areas place a thin 

plastic film over the beds for the first 4 weeks after planting to maintain a high 

relative humidity and soil temperature around 62F (17C) (Buschman 2000). 

Spacing: See “Field Performance.” Depending on the cultivars, spacing of the 

bulbs for greenhouse production should be no higher than 20 bulbs/ft2 (about 

220 bulbs/m2 ). 

Temperature: Maintaining soil temperatures below 68F (20C) is the most 

important measurement. The optimum soil temperature is 62–65F (16–18C). 

Use 55F (13C) night temperature and 60–63F (15–17C) day temperatures when 

possible; the optimum greenhouse temperature appears to be 60F (15C). To 

reduce flowering time, bulbs can be grown as high as 65F (18C) for the first 3–4 

weeks; however, temperatures should be lowered to 55–60 (13–15C) after that 

time. Avoid average temperatures above 65F (18C), particularly under short days 

or time of low light (De Hertogh 1996). Low night temperatures (near 50F, 10C) 

enhances postharvest life (Nowak and Rudnicki 1990); the lowest temperature 

is 41F (5C). 

Light: In temperate areas, low light increases the incidence of flower blasting 

(see “Pests and Diseases”). Add more light or reduce temperatures to 50–55F 

(10–13C). 

Fertilization: Fertilize weekly with calcium nitrate at approximately 200 ppm N. 

Scheduling: Harvest occurs 6–8 weeks after planting in greenhouse. The following 

table provides scheduling guidelines for the various groups of Dutch iris 

(see “Cultivars”) based on “normal” greenhouse production.


Ideal Group 50–60 days 

Prof. Blaauw Group 60–80 days 

Blue Magic Group 65–85 days 

Tingitana Group 70–90 days 

Small Bulb Group 60–85 days 

Miscellaneous Group 55–75 days 


Cut all Dutch iris when the tight flower has fully emerged from the sheath. In the 

fall and winter, wait until the colored tip is about 1½" (4 cm) long. In the spring, 

only about ½" (13 mm) of colored tip is needed (Buschman 2000). This is 

referred to as the pencil stage, when a pencil of color is visible. Some cultivars 

need to be harvested more open than others; this is learned by experience. Harvest 

by pulling the entire plant, bulb and all. After harvesting, the bulbs are 

removed, as are yellow or disfigured leaf tips, and stems are sorted by stem length 

for uniformity and bunched in groups of 10. The bulbs are usually discarded. 

Postharvest 

Fresh: After harvesting, place immediately into a cooler at approximately 35F 

(2C) for precooling. Be sure the stems and flowers are dry to prevent fungal disease. 

The cooler should be set at approximately 80% humidity to keep flowers 

from dehydrating. If bunches are limp, place them in water in the cooler. Flowers 

are not sensitive to ethylene, and anti-ethylene agents do little to extend vase 

life. Vase life is 3–6 days. 

Storage: Store for as short a period as possible. Flowers may be stored dry at 

31–32F ( −1–0C) upright for no more than a week (Sacalis 1989) or stored wet 

upright for 5–10 days at 33F (1C). However, be careful that the cooler does not 

freeze the product. Prolonged storage time results in failure of flowers to open 

(Evans and Reid 1990). 

If flowers are conditioned in a solution containing 1.5 oz/5 gallons citric acid 

and 1.5 oz/5 gallons sucrose for 12 hours at 68F (20C), the vase life of dry 

shipped flowers improves; the retailer or consumer should rehydrate iris in warm 

water (100F, 38C) for 3 hours (Nowak and Rudnicki 1990). 

Cultivars 

The International Flower Bulb Center (Buschman 2000) has separated cultivars 

into 6 main groups, shown here. Consult wholesale bulb catalog or the Holland 

Bulb Forcer’s Guide (De Hertogh 1996) for more details.


Max. Plant 

Bulb group Color bulb size z height (in) y 

Ideal Group 

Blue Diamond deep blue 10 26 

Ideal light blue 10 26 

White Wedgwood white 10 26 

Prof. Blaauw Group 

Prof. Blaauw deep blue 10 30 

White Bridge white 10 28 

White Cloud white 10 30 

Blue Magic Group 

Blue Magic violet 10 24 

Casablanca white 10 32 

Madonna blue 10 24 

Mercedes blue 10 24 

Pickwick white-violet 10 24 

Tingitana Group 

Acapulco purple 10 30 

Holland Knight violet/purple 10 32 

Hong Kong dark purple 10 30 

Paris violet 10 32 

Small Bulb Group 

Crown Jewel yellow 8 26 

Frans Hals bronze/yellow 8 26 

Golden Beauty yellow 8 28 

Golden Harvest yellow 8 24 

Oriental Beauty yellow/blue 8 28 

Purple Jacket purple 8 24 

Purple Sensation purple 8 24 

Romano yellow/blue 8 24 

Royal Yellow yellow 8 32 

Sapphire Beauty blue 8 26 

Symphony yellow/white 8 26 

White van Vliet white 8 24 

Yellow Queen yellow 7 28 

Miscellaneous Group 

Apollo* yellow/white 10 32 

Atlantis light blue 10 30 

Blue King blue 10 32 

Deep River blue 10 28 

(continued)


Max. Plant 

Bulb group Color bulb size z height (in) y 

Hildegarde light blue 10 32 

Holland Lilac lilac 10 30 

Holland Sapphire dark blue +10+ 32 

Miss America purple 10 30 

Nova Blue light blue 10 32 

Nova Sun yellow/white 10 32 

Saturnus* white 10 32 

Telstar* blue/violet 10 28 

White Giant white 10 32 

z = bulb size in (cm) 


* = triploid 

‘Blue Magic’ and members of the Miscellaneous Group make up almost 95% of 

all commercially produced cut flowers. Most cultivars in the Miscellaneous 

Group are hybrids, and some of them are triploids; they open well and have an 

excellent vase life. 


With so many cultivars and species of Iris available, it is naive to believe that only 

bulbous iris are used as cut flowers. Without doubt, bearded iris, Siberian iris, 

Japanese iris, Louisiana iris, and others are sold, mostly in farmers’ markets and 

occasionally through florists; their beauty is unquestioned, but their market is 

limited by the perception that they have a short vase life. 

Ray Schreiner of Schreiner’s Iris Gardens in Salem, Ore., strongly disagrees 

that 3–4 days of vase life for bearded iris is generous. He says that if flowers are 

picked at the right time, they persist a week or longer. Newer cultivars are bred 

to have 10–12 flowers per stem and should be harvested when 1 or 2 flowers 

are open on the stem. After harvesting, remove spent flowers (should be only 1 

or 2 of those), cut to size for uniformity for bunching, or simply incorporate in 

bouquets, where their beauty can be appreciated. Spent flowers should be 

removed throughout the life of the cut stem for optimum vase life. In summary, 

there is no end to the colors, sizes, flowers, and fruit (particularly in the 

Japanese iris) that can be harvested within the genus Iris, but attention to recutting 

stems and water levels in the final containers and removing spent flowers 

is critical. For most growers, vase life is best for local consumption. This is actually 

a plus for incorporating more diversity and thinking about off-season forcing 

of some of these “garden” forms; they ship poorly and will not be coming in 

from overseas.


Dipping the bulbs in a fungicide (e.g., benomyl or thiabenzadole) immediately 

before planting is recommended to reduce fungal infection. Dipping for approximately 

15 minutes at the normal concentration should be sufficient. 

Bulb rot (Fusarium oxysporum), crown rot (Sclerotium rolfsii), gray mold (Botrytis), 

rhizoctonia (Rhizoctonia solani), root rot (Pythium ultimum) and blue mold 

(Penicillium) are all caused by fungi. Dipping the bulbs and good environmental 

sanitation practices will reduce the incidence of these problems. Soft rot (Erwinia 

carotovora) is a bacterial disease, easily recognized by the unpleasant odor and 

mushy feel of affected bulbs. There is no chemical defense against erwinia. Further 

infestation can be controlled only by lowering temperatures and salt levels 

(no fertilizing) and by reducing the amount of water. Sterile soil in greenhouse 

forcing is highly recommended. 

Bud blasting is a physiological problem in which the flower bud develops but 

fails to open. Ultimately the flower bud becomes limp and dries out. Bud blasting 

can occur at any time. The cause appears to be insufficient light combined 

with temperatures that are too high. It can be caused by too high a planting density 

and a sudden drop in temperature, or by a root infection in which water is 

not taken up efficiently. Bud blasting is a far greater problem in winter months; 

provide as much light as possible and reduce temperatures during dull periods. 

Another factor is high humidity levels in the greenhouse in the winter months. 

When temperatures are cold outside and the heaters in the greenhouse are running, 

humidity levels increase dramatically, especially if irrigation recently took 

place. Venting the greenhouse slightly by turning just one fan on or cracking 

the roof vents (even though heaters are running) can reduce the humidity. It 

might seem like a waste of energy, but it is a lot cheaper than losing flowers to 

blasting or blindness. 



“We have found that the tall bearded iris flowers last 1–2 days in the vase, then 

become unsightly and have to be picked off, by which time others on the stem 

have opened (a little like Hemerocallis). Japanese iris (Iris kaempferi) makes what I 

think is the most beautiful cut flower, each of the 2 buds lasts 2 days in the vase. 

Culture is difficult and opening the flower in the vase makes it too difficult for 

us to grow commercially. It’s a real niche flower, most appropriate to sell to 

designers. Siberian iris (I. sibirica) is a substitute for Dutch iris (the florist’s iris), 

but the blossoms are even shorter lived (2 days for each). I prefer their look to 

that of Dutch iris. They can be also grown for their seed pods. We don’t grow 

Dutch iris because they are not hardy in our Zone [3–4].” Ed Pincus, Third 

Branch Flower, Roxbury, Vt. 

“I am not an expert but I have been growing Louisiana iris for about 4 years. 

They have the entire color range represented, including blues, yellows, and reds. 

I started growing Louisiana iris in a swampy section of my property, and they 

really took off. They generally don’t make long-lasting cuts. However, I have

364 LATHYRUS ODORATUS 

taken them to sell at the local farmers’ market. Like most iris, they do best if 

harvested in the pencil stage. If your iris are in a location they like (they need 

plenty of water, fertilizer, and organic matter in the planting beds), each stem 

should produce 3 or 4 blooms, which will open from the top down the stem. My 

farmers’ market customers are used to picking off the spent flowers. In my area 

these are considered unusual cuts, and I get $1.50 to $2.00 per stem. Most of 

my customers buy them in bouquets though not in straight bunches.” Kate 

Sparks, Lilies and Lavender, Doylestown, Pa. 

Reading 

Armitage, A. M., and J. M. Laushman. 1990. Planting date and in-ground time 

affect cut flowers of Liatris, Polianthes, and Iris. HortScience 25:1239–1241. 

Buschman, J. C. M. 2000. The Iris As Cut Flower. International Flower Bulb Center, 

Hillegom, The Netherlands. 







Rees, A. R. 1985. Iris. In The Handbook of Flowering. Vol. 1. A. H. Halevy, ed. CRC 

Press, Boca Raton, Fla. 



Many thanks to Mark Hommes and Ray Schreiner for reviewing this section. 

Lathyrus odoratus sweet pea Papilionaceae 

annual Sicily, Crete many colors vine 

The history of the popularity of ornamental horticulture is reflected in the history 

of the popularity of the sweet pea, Lathyrus odoratus, once a foundation of the 

traditional English garden. Sweet peas were introduced there around 1699 and 

were first offered for sale in catalogs in 1730. The Invincible series of sweet peas, 

which first appeared in England in 1866, were introduced to America in 1870; 

they were intended to be grown as sweet pea hedges and screens and used for 

their fragrance in bouquets. By the turn of the century, over 130 cultivars had 

been bred. Interestingly, while most “peas” are edible, the sweet pea is poisonous. 

A medical term, lathyrism, is used to describe the convulsions, leg paralysis, and 

unconsciousness associated with eating sweet pea seeds. Fortunately, a lot of 

seeds must be eaten, and few cases have occurred. 

There’s renewed interest in this plant, which still win hands down in the cut 

flower fragrance category. Sweet peas are now grown under elaborate systems in 

greenhouses, mainly in the West, and are field-grown where climates allow. With

LATHYRUS ODORATUS 365 

Lathyrus odoratus 

‘Mammoth Mix’ 

low light requirements and tolerance of lower temperatures, sweet peas are ideal 

for low-cost winter production. Plants are vines, growing on strings, trellises, or 

walls, and are most popular in May and June for wedding flowers. 

Propagation 

Soaking sweet pea seed is always recommended. Soak seed for approximately 

24 hours prior to planting, and change the water once, whether seeds are to be 

germinated in a greenhouse or in situ outdoors.


If sowing in a greenhouse, germination takes 10–21 days at 60F (15C). If 

plants are eventually going to be placed outdoors, seed is usually sown in plugs 

or peat pots, 2 seeds in a 4" (10 cm) peat pots. Place pots at 68F (20C) until the 

plants are 2–3" (5–8 cm) tall. 

If sowing in situ, sow as soon as weather allows. Steve Houck of Accent Gardens 

in Boulder, Colo., sows seed in March (sometimes even on a nice day in 

February); it germinates by April. 

Growing-on 

Lower the temperature in the greenhouse to 48–50F (9–10C). For indoor production, 

presoaked seeds can be direct sown in ground beds, placing 2 or 3 seeds 

per hole. The greenhouse must be warm (around 68F, 20C) for uniform germination. 

Seedlings may be thinned to one plant at this time. When plants are 2–3" 

(5–8 cm) tall, lower the greenhouse temperature to 50F (10C). 

When plants are sufficiently tall (approximately 6", 15 cm), tie them to bamboo 

canes. Sweet peas can be grown naturally or, as is the case with most cut 

flower growers, using a modified cordon culture. In the natural system, plants 

are allowed to grow up the supporting structures, and no pinching is done; this 

provides more flowers but of smaller size and of less value. 

The cordon system is more labor intensive, requiring the selection of a leader 

stem and subsequent pinching of side shoots; this results in fewer shoots but significantly 

larger and showier flowers. The selection of a leader stem is done early 

in the growing-on phase for greenhouse production (plants around 6", 15 cm 

tall), and prior to placing plants outdoors for field culture. Pinch to one branch 

per plant, allowing the leader to grow. Train stems to grow up lengths of twine, 

bamboo stakes, trellis, or netting. Plants should not be subjected to temperatures 

below 32F (0C) or above 60F (15C). 


The major limiting factor to widespread production of sweet peas is their poor 

tolerance to heat. Temperatures should not exceed 70F (21C) for any length 

of time, and therefore most outdoor production is limited to areas of cool 

summers. Greenhouse production can be carried out if temperatures can be 

maintained around 60F (15C) or lower during the winter. Photoperiod has little 

influence on flowering; high light levels in the winter, combined with cool temperatures, 

are recommended. Low light levels result in smaller flowers, bud abortion, 

and fewer flowers per stem. 


For earliest flowering regardless of location, plants should be started and grown 

on in a greenhouse or cold frame. Two to 3 weeks before planting in the field, the 

crop should be placed in a cold frame or in a cold greenhouse where tempera-

LATHYRUS ODORATUS 367 

tures are held above freezing. Once planted outdoors, spacing varies; Ethan 

Kayes of Kansas City used a spacing of one plant every 4–6" (10–15 cm). Plants 

should always be kept off the ground, first by tying them to their stakes and 

later by weaving the vines in and out of support netting, which will help to 

reduce powdery mildew and a variety of stem rots. Side shoots may be removed 

as they appear; in general, when the vines are 3–4' (0.9–1.2 m), lateral branches 

should be pinched off. This will produce longer stems with a greater number of 

flowers per stem. Kayes (1993) allowed that, while the process may seem tedious, 

they spent only 15–20 minutes 3 times a week. 

If started outdoors, thin seedlings to an appropriate spacing, and train either 

to a single leader or let grow naturally. 

Fertilization: Because the soil temperature during most of the production cycle 

is below 60F (15C), nitrate should be the source of nitrogen. Kayes (1993) recommended 

no more than 5% of the total nitrogen applied should be in the 

ammonia form. He used fertilizer with an analysis of 150 ppm N, 100 ppm P, 150 

ppm K, 100 ppm Ca, and 50 ppm of Mg. In addition, some production problems, 

such as bud drop, may be reduced by inoculating the sweet peas with a 

commercial legume bacteria. Several growers recommend mulching to keep 

roots cool. 

Yield: Steve Houck harvested about 3 bunches of sweet peas per plant (based 

on 10–15 stems/bunch) and shared a useful hint: “I planted seeds or plants in 

east-west rows in 5-gallon buckets. The trellis was always on the north side in the 

buckets, which facilitated the harvest [because] the flowers always [leaned] 

toward the south. This really made a difference with the speed of harvest and [we 

had] fewer broken stems.” 


Yields are higher and quality is usually better (less breakage, longer, fuller stems) 

when sweet peas are greenhouse-produced compared to outdoor production. 

Greenhouse temperatures are more easily controlled than those outdoors. Planting 

so that a bed is near the cool pads makes sense. Houck started his August 

planting near the pad, and subsequent plantings were moved further from the 

pads during the winter. As spring approached, he would pull out the August 

planting and replant for the last crop in May. 

Steve grows sweet peas by the natural trellising method in his greenhouse. 

Details vary among growers, but his comments are excellent guidelines. He 

sowed seeds in 200-cell plug trays in September and transplanted about 4 weeks 

later into Dutch bulb crates. In general, he planted 3 sweet peas per bulb crate 

and ran them against the wall on netting. The netting was also on the north side 

of the planting. The drainage was enhanced by sitting the crate on gravel on the 

greenhouse floor. The sweet peas performed better in the crates than in a ground 

bed, but many growers use ground beds quite successfully. Houck grew the 

plants at 48F (9C) during the winter and kept them trellised; they began blooming 

in late February or March. Temperatures above 55F (13C) resulted in spindly 

stems and poor flowering.


Houck fertilized with 350 ppm N and 300 ppm K, alternating with a complete 

20-18-20. He harvested 4.8 bunches per plant (each bunch this time with 10–12 

stems), about 440 bunches during the greenhouse season. 


Harvest sweet peas when 2 or 3 flowers start to show color and stems are about 

12" (30 cm) long. Cut the stems or snap the stem with the fingers near the base. 

Bunch and place cut bunches immediately in floral preservative. 

Postharvest 

Sweet peas are highly sensitive to ethylene, and use of silver thiosulfate (STS), if 

available, as a postharvest treatment is highly recommended. Untreated sweet 

peas last about 3 days; a one-hour pulse of STS at 200 ppm can increase the shelf 

life to 12 days (Kayes 1993). 

Storage: Sweet peas should be sold as soon as possible; however, if storage is 

necessary, place the stems in a 35F (2C) cooler. If stored more than 24 hours, 

supply about 12 hours of incandescent light in the cooler. 

Cultivars 

‘America’ is an heirloom variety valued for its fragrance and wavy red and 

white striping. 

‘Annie Gilroy’ produces cerise-pink flowers on 5–6' (1.5–1.8 m) stems. 

‘Cupani’, purported to be the “original” sweet pea, is extremely fragrant. 

Plants grow 4–5' (1.2–1.5 m). 

Cuthbertson Floridbunda Mix, a spring-flowerer that grows 5–6' (1.5–1.8 m), 

is used for both spring greenhouse production and field production. Reasonably 

heat tolerant. 

Early Multiflora Gigantea series has large, early flowers on 60–74" (1.5–1.8 m) 

stems. The series includes ‘Chloe’ (navy blue), ‘Eleanor’ (mid-blue), ‘Gloria’ (deep 

rose-pink), ‘Grace’ (lavender), ‘Lily’ (white), ‘Marilyn’ (scarlet-cerise), ‘Susie’ 

(salmon-pink), and a mix. 

Late Spencer types appear in an almost infinite variety of flower form, size, 

and color, including such classics as ‘Noel Sutton’, a favorite of the floral industry 

and a Gold Medal winner in England, with violet, ruffled-edge flowers; ‘Mrs. 

R. Bolton’, with large, deep almond-pink flowers; ‘Air Warden Improved’, with 

bicolor flowers of red and yellow; ‘Leamington’, with lilac flowers; and the crimson 

flowers of ‘Winston Churchill’. This group performs best in areas of cool 

summers. 

Mammoth series is a spring-flowering group, considered an improvement 

over Early Multiflora Gigantea and recommended for its heat resistance, large 

flowers, and long stems. It comes in a mix of colors ranging from scarlet to rosepink 

to navy blue to lavender, plus a mix. Reasonably heat tolerant. 

Old Spice series bears highly fragrant flowers on 60–74" (1.5–1.8 m) stems.

‘Painted Lady’ is an old sweet pea cultivar. The bicolor flowers are small, but 

flowers are early and have a pleasant fragrance. 

Royal series flowers in spring to early summer, between Early Multiflora Gigantea 

and the Late Spencer types. Colors include blue, crimson, lavender, navy 

blue, rose-pink, salmon, scarlet, white, and a mix. 

Unwin’s Striped Mix is an unusual mix of flower shapes and colors, in blends 

of scarlet, purple, and deep scarlet. 

Winter Elegance series is available in 7 colors: ‘White’, ‘Scarlet’, ‘Pink-Diana’, 

‘Rose’, ‘Deep Rose’, ‘Salmon Cream Pink’, and ‘Lavender’. Tolerant of cool temperatures 

(55F, 13C), Winter Elegance is ideal for December–January harvesting, 

and, if a grower sows by early August, a crop can be sold during the Christmas 

season. 


Seedlings in the field are susceptible to slug damage: be sure to get them off the 

ground as soon as possible. Thrips and aphids can be destructive. Aphids can 

carry various viruses, causing symptoms such as mottling, yellowing, and color 

breaks in the flowers. Root rots (Thielaviopsis, Rhizoctonia) cause discolored stem 

bases and eventual decay; control by using sterile media and fungicides. 


“Last year I used the Mammoth mix with good success. Stems averaged 17" with 

comparative blossom size. I liked the fast-and-furious crop time: direct seeded 

April 12, first bunches sold June 23. Ground replanted to sunflowers July 25. 

Biggest marketing problem was the lack of white blooms in the mix—only about 

1%. Although they were trellised, harvest was slow. I sold to distributors for $3 

for 12-stem bunch, and $4 on my florist route. The market saturated before the 

crop diminished, and later sales were slow.” Joanne Harrison, Harrison Flowers, 

Hood River, Ore. 

Reading 

Kayes, E. 1993. Proc. 6th Natl. Conf. on Specialty Cut Flowers. Overland Park, Kans. 

Many thanks to Steve Houck for reviewing this section 

LAVATERA TRIMESTRIS 369 

Lavatera trimestris mallow Malvaceae 

annual Mediterranean white, pink 2–2½'/2' (60–75 cm/60 cm) 

Mallow bears some of the most handsome cut flowers in the plant kingdom. 

The 3–4" (8–10 cm) wide flowers are normally rose-pink, but some separate colors 

are available. Given the number of diseases that affect mallow in wet, hot 

summers, the West Coast of the United States is more suitable for production 

than the East Coast.

370 LAVATERA TRIMESTRIS 

Propagation 

Seed sown under mist or sweat tent at 70–72F (21–22C) germinates in 7–14 days. 

Approximately 0.5 oz (14 g) of seed yields 1000 plants (Nau 1999). Seed is also 

direct sown after threat of frost. Sow at the rate of 0.5 oz per 100' (60 g per 100 

m) (Kieft 1996). Thin to 12" (30 cm) apart or more in the rows. 

Growing-on 

Grow at 60F (15C) night temperature, 65–70F (18–21C) during the day. Fertilize 

sparingly (50–75 ppm N) with a nitrate-type fertilizer. Overwatering results 

in proliferation of root rot organisms; maintain plants on the dry side of moist. 


Photoperiod: Flower initiation and development are not dependent on photoperiod. 

Temperature: Warm temperatures result in more rapid growth and flowering; 

however, cool night temperatures of 55–60F (13–15C) produce higher-quality 

plants and flowers than nights above 70F (21C). 

Humidity: Plants are susceptible to numerous foliar diseases and should not 

be grown in areas of high humidity (e.g., Southeast) without an aggressive spray 

program for pests and diseases. Mallow has been trialed at the University of 

Georgia on 3 separate occasions, and each time has ended in a dismal, diseaseridden 

and pest-infested failure. 


Spacing: Space plants 18–24" (45–60 cm) apart. Although plants can be spaced 

as closely as 12" (30 cm) centers, wider spacing helps reduce disease and insect 

pressure. 

Yield: An average of 10 stems/plant is not uncommon. 


Cut flower production is seldom accomplished in the greenhouse; however, if 

mallow is produced under cover, grow 12" (30 cm) apart at 58–60F (14–15C) 

night temperatures, 70–75F (21–24C) during the day. Fertilize with 100–150 

ppm N constant liquid feed or with 300 ppm N once a week. 


Cut when the flowers are uncurling or when they have just begun to open. Harvest 

before flowers lie flat.

Postharvest 

LAVATERA TRIMESTRIS 371 

Lavatera trimestris ‘Mont Rose’ 

Flowers persist approximately one week; storage is not recommended. Flowers 

do not dry well. 

Cultivars 

Beauty Mix produces strong stems in pink, rose, salmon, and white. Quite a 

popular mix. 

‘Easter Parade’ is 24–30" (60–75 cm) tall, with 3–4" (8–10 cm) trumpetshaped 

flowers in pink, plum, and white.

372 LAVATERA TRIMESTRIS 

‘Loveliness’ produces bright flowers of carmine-rose. 

‘Mont Blanc’ has white flowers and grows 2–3' (60–90 cm) tall. 

‘Mont Rose’ bears pink flowers. 

‘Ruby Regis’ has cerise-pink flowers on 30" (75 cm) stems. 

‘Silver Cup’ has salmon-rose flowers with dark veins. 

‘Tanagra’, a tetraploid cultivar, has 4–5" (10–13 cm) wide, deep rose flowers 

on plants 2–3' (60–90 cm) tall. 


Mallow was evaluated in the ASCFG’s national trials. The following table (Dole 

1995–1997) is a summary of the average stem lengths and yields of plants submitted 

for trialing. These data are averages over a wide geographical range and 

must be viewed as guidelines only; individual experience may differ significantly. 

Cultivar Year of trial Stem length (in) z Stems/plant 

Pink Beauty 1994 16 7 

Rose Beauty 1994 8 3 

Salmon Beauty 1996 14 11 

White Beauty 1994 20 11 



Lavatera thuringiaca, a half-hardy perennial, bears rose flowers on 4' (1.2 m) 

tall plants. ‘Barnsley’ is 6–8' (1.8–2.4 m) tall and bears handsome pink fringed 

flowers. 


Leaf spots, caused by at least 5 fungi, are very common. Leaf and stem blights 

(from 3 fungi) and rust are common, particularly in warm climates. 

Aphids, spider mites, and western flower thrips also enjoy dining on lavatera. 

In fact, mallow seems to be a preferred appetizer for most beasties in the field and 

greenhouse. 


“We produce about 500 bunches per annum as field production and will likely 

do a greenhouse crop later this spring.” Martin Connaughton, Wilderness Flowers, 

Santa Fe, N.M. 

“I love the silver cup (pink) lavatera—lovely hollyhock-type blooms that make 

the older ladies nostalgic. Limited sales, as it is delicate, and doesn’t hold up well 

in transit and in the heat.” Susan O’Connell, Fertile Crescent Farm, Hardwick, Vt.

Reading 

LIATRIS SPICATA 373 



Netherlands. 


Liatris spicata gayfeather Asteraceae 

bulb, Zones 3–9 North America purple, white 2–4'/2' (0.6–1.2 m/0.6 m) 

Liatris is grown throughout the world and has become a mainstay in florists’ 

coolers and designers’ arrangements. In the United States, it is difficult to compete 

with overseas production; however, fresh liatris will always have a place in 

the local market. Approximately 30 species and over 10 hybrid forms are known. 

Liatris spicata is most commonly produced, but L. aspera (button gayfeather), L. 

pycnostachya (tall gayfeather), and other species are also excellent cut flowers. 

Using different species and colors helps to extend the harvest time. 

Propagation 

Liatris corms (often referred to as tubers) may be divided and replanted in the 

field or greenhouse. Allow to cure (place in warm, well-ventilated area) for 3–7 

days after dividing. Small offsets from the corm (bulbils) can also be used for 

propagation (Choi et al. 1999). 

Seed may be sown in soilless media at 75–78F (24–26C) and high humidity. 

However, the time required from seed to harvest (approximately 12 months) 

versus from corm to harvest (approximately 8 weeks) should be taken into 

account when deciding which method is more profitable. 

Cuttings from newly emerged stems may be rooted in approximately 21 days. 

Vegetatively produced corms are more productive than those grown from seed 

(Salac and Fitzgerald 1983). 


Temperature: Cold temperatures are essential for flowering in liatris. Storage 

of corms at 28–36F ( −2–2C) for 8–15 weeks results in a majority of corms flowering. 

Prolonged cooling also reduces the time to flower when forced in the 

greenhouse. For example, corms stored 3 weeks at 32F (0C) flowered in 99 days 

from planting in the greenhouse, while corms stored 15 weeks flowered in 72 

days (Moe and Berland 1986). 

Gibberellic acid: Soaking corms for one hour in 500 ppm GA3 after 5 weeks 

cold storage resulted in 100% flowering (Zieslin 1985). Use of GA may partially 

substitute for the cold treatment. Cold treatment/GA dip combinations are particularly 

useful for early forcing dates. 

Ethephon: Preliminary work showed that preplant application of approximately 

1000 ppm ethephon resulted in more flowering shoots (Banon et al.

374 LIATRIS SPICATA 

Liatris spicata 

1998). High applications may result in many small shoots—useful perhaps for 

pot plants but not for cut flowers. 

Photoperiod: Flower initiation occurs regardless of photoperiod; however, 

plants respond to LD through accelerated flowering and longer stems. If corms 

are provided a sufficient cooling period, LD result in accelerated flowering. However, 

if plants receive a short cooling period, then SD enhances flowering 

(Berland 1983). Similar interactions with forcing temperature were found if 

corms were forced in the greenhouse. At cool forcing temperatures of 55F (13C), 

LD hastened flowering; but at warmer forcing temperatures, photoperiod had 

little effect, or sometimes SD resulted in more reproductive than vegetative

shoots (Evans 1994). For greatest flower acceleration, LD (14 hours) should be 

applied in the first 5 weeks after emergence of the foliage. Long days also result 

in greater stem elongation regardless of cooling treatments or forcing (Espinosa 

et al. 1991). 

Studies have shown that continuous LD after emergence reduced the number 

of flowers per corm (Zieslin and Geller 1983). A short period of SD prior to application 

of LD may be useful to increase the number of flowers (Espinosa et al. 

1991). When all is said and done, it appears that temperature and photoperiod 

influence flowering mainly during the first 5 weeks of development. 


Orientation and terminal bud removal: Research showed that planting the corms 

on their sides or upside down resulted in a delay of flowering and reduced the 

length of shoots, the proportion of the shoot bearing flowers, and the shoot 

diameter, compared to upright corms. Removing the terminal bud delayed flowering 

by about 11 days but resulted in approximately 3 flowering shoots compared 

to one for the intact corm (Evans 1992). Some find this to be a profitable 

method for growing liatris (see “Grower Comments”). 

Spacing: Plant corms 2–4" (5–10 cm) apart, about 6–8 corms per ft2 (65–86 

corms per m2 ), and 2–3" (5–8 cm) beneath the soil surface. 

Corm size: Small corms result in poor yield and short stems. In general, the 

larger the corm, the more rapid the flowering and the higher the percentage of 

flowering corms (Waithaka and Wanjao 1982). Use of 6/8 or 8/10 cm circumference 

corms is recommended. 

Planting and harvest time: Typically, planting in northern climates (Zone 5 and 

colder) is accomplished in early spring, usually April. Corms planted in April 

are generally harvested in July, the white forms usually a week or so earlier than 

the purple forms. Stored frozen corms may be planted in the field at any time; 

however, differences in yield and stem length occur. The effect of different planting 

times in Zone 7b, Athens, Ga., is shown in the following table (Armitage and 

Laushman 1990). 

The effect of planting date on Liatris spicata. 

Month Flw/ First Harvest Stem Stem 

planted corm harvest duration (days) length (in) z width (mm) y 

Nov 2.2 1 Jul 14 25.0 7.1 

Dec 1.2 1 Jul 15 22.8 6.9 

Jan 2.0 8 Jul 14 20.0 6.9 

Feb 3.4 12 Jul 12 26.5 7.9 

Mar 4.5 21 Jul 15 28.9 6.0 



LIATRIS SPICATA 375


Three weeks’ extension of flowering occurred when planting was delayed until 

March, but this was likely due to the increase in number of weeks of cold storage. 

No difference in harvest duration occurred due to planting date, nor did any 

differences occur in subsequent years of production. 

Longevity: Liatris can be considered perennial (at least 3 years of production) 

in most of the country. Continued corm growth from year to year results in 

increased yield and stem length each year. Three years are often needed for best 

stem length, as the following table of work done at Athens, Ga., shows (Armitage 

and Laushman 1990). 

Longevity of Liatris spicata. 

Year Flw/corm Stem length (in) z 

1 2.7 24.7 

2 8.0 30.0 

3 15.0 39.2 


Liatris spicata may be productive for up to 5 years although partial replacement 

after 3 years is recommended. Work with L. pycnostachya, however, showed that 

maximum production was 3 years (Armitage 1987). 

Support: Support is necessary, especially after the first year. Use 2 layers of 

floriculture netting. If stems topple, flowers turn up and become distorted. 

Grading: Stems are generally graded by stem length. Kent Miles of Botanicals 

by K&V in Seymour, Ill., sells 3 grades: short (20–24", 50–60 cm), medium (26– 

36", 66–90 cm), and long (>36", 90 cm). 


Use large corms for greenhouse forcing, which may be accomplished year-round. 

Pot 3 corms in 6–8" (15–20 cm) pots or in ground beds, using sterilized soils to 

reduce soil fungi. Maintain soil temperatures as close to 60F (15C) as possible 

and place under short days (8–10 hours) for first 2–3 weeks after emergence. Fertilize 

with 100–150 ppm N after foliar emergence. Provide LD (14–16 hours) by 

extending the day or with nightbreak lighting after SD for maximum stem elongation 

and most rapid flowering. Use temperatures of 65–68F (18–20C) for forcing. 

Flowers may be harvested 60–70 days after emergence, depending on light 

intensity and temperature. 



vigorously growing healthy plants when flower buds were visible but prior to


standards. Numbers are averages for both sites and are based on dry weight 

analysis. 

(%) 

N P K Ca Mg 

3.0 0.20 1.73 1.30 0.43 

(ppm) 

Fe Mn B Al Zn 

207 170 27 59 90 



Inflorescences may be harvested when 3–4 flowers have opened if stems are 

pulsed in a bud-opening solution. If no preservative is used after harvesting, 

stems should be harvested when at least ½ the flowers are open. Flowers should 

be harvested in the morning, preferably before noon. 

Postharvest 

Fresh: Flowers treated with preservatives persist 7–12 days (Salac and Fitzgerald 

1983). The foliage may decline more rapidly. Lower foliage must be removed 

prior to placing cut stems in solution. Shipping occurs dry or wet. 

A 24- to 72-hour pulse in a bud-opening solution that includes 5% sucrose is 

recommended for tight cut flowers (Borochov and Karten-Paz 1984, Sacalis 

1989). 

Storage: Stems may be stored about one week in water at 32–35F (0–2C) after 

pulsing, about 5 days dry (Vaughan 1988). Good air circulation is necessary in 

the storage room because liatris is susceptible to botrytis. For long-term transport, 

flowers may be cut in tight bud stage and opened after arrival in a preservative 

solution or a solution of 1 ppm 8-HQC and 50 g/l sucrose (Nowak and 

Rudnicki 1990). 

Dried: Allow all flowers on spike to open. Strip leaves and air dry by hanging 

upside down in a well-ventilated area (Bullivant 1989). 

Cultivars 

The only flower colors are purple and white. Purple colors are best filled by the 

species itself or ‘Floristan Purple’. Other garden forms such as ‘Kobold’ may be 

too short (12–18", 30–45 cm) for cut flower production. 

var. alba is white and similar to the species except for flower color. 

‘Floristan White’ is excellent, with creamy white flowers. The Floristan series 

may be raised from seed. 

‘Gloriosa’ is a vigorous purple cultivar but not readily available in the United 

States.



Liatris aspera (button gayfeather, rough gayfeather) has recently been discovered 

by growers and retailers. The lilac flowers are rounded and spaced well apart. 

People also enjoy the greenish to lilac cone-like flower buds; stems may be harvested 

even before the flowers open. Another excellent North American native, it 

grows from North Dakota to Ontario and Ohio in the North, and Texas and 

Florida in the South. 

Liatris callilepis is a synonym for L. spicata, and plants should be treated the 

same. Some bulb specialists sell vegetatively propagated plants as L. callilepis and 

seed-propagated material as L. spicata. 

Liatris pycnostachya (tall gayfeather, Kansas gayfeather) is a taller, coarser plant 

than L. spicata. In trials in Georgia, stems were over 3' (90 cm) tall and plants 

persisted only 3 years. ‘Eureka’, a selection developed by the University of 

Nebraska and the U.S. Soil Conservation Service, is not nationally available. 

Liatris scariosa (tall gayfeather) also has a place in a cut flower program. The 

flowers are more button-like than L. spicata and provide a handsome stem. ‘September 

Glory’ has purple flowers that open almost simultaneously; ‘White 

Spires’ has white flowers. 


Leaf spots (Phyllostricta liatridis, Septoria liatridis) occur as brown to black spots 

on the foliage. Fungicides may be applied when plants are young. 

Rusts may infect plants. Certain grasses and pine trees act as alternate hosts 

for liatris rust (Coleosporium laciniariae, Puccinia liatridis). Destroy infected plants. 


“A wholesaler showed me something called ‘spray liatris,’ new to him last season. 

It’s apparently regular purple Liatris spicata that has been pinched or topped, to 

force it to form 10–20 side shoots. The story he had was that a grower in Ecuador 

had problems in a liatris field, so he mowed it down and forgot about it. 

Later he found that the stems had branched nicely, so he sold it as spray liatris. 

He was the only source for it. My wholesaler paid $4.50 for a 5-stem bunch. It 

looked like the stems had been cut about 6–8" from the ground.” Ron Smith, R. 

Smith Farm, Renfew, Pa. 

“I grow the common stuff, which is sold as spicata and alba. I treat them as 

quasi annuals. I dig them every fall and store the undivided tubers/corms in a 

refrigerator. The following season I plant every 3 weeks until the end of July. I 

divide the tubers as I plant, cutting them into halves and quarters if needed. 

Nothing fancy, but it works well. Figure on 50–60 days from planting to harvest 

with the later plantings.” Paul Shumaker, Never Should Have Started Farm, 

Bangor, Pa. 

“As cheap as liatris corms are, I use them instead of seed. You have to decide 

if your time and space are worth the wait for flowers from seeds. I plant the 

corms about 3" on center.” Dave Dowling, Farmhouse Flowers, Brookeville, Md.


“There are two button-type liatris. Liatris scariosa (my favorite liatris) has buttons 

that stand slightly away from the stems on short pedicels. It has rich burgundy 

buds that open to the typical liatris lilac. Liatris aspera has buttons about 

the same size, only they are more tightly next to the stem; they are more distinctly 

spiral around the stem, but their buds are lilac as are the flowers.” Kelly 

Anderson, WildThang Farms, Ashland, Mo. 

Reading 





Banon, S., A. Gonzalez, J. A. Fernandez, and J. A. Franco. 1998. The effect of 

ethephon on the growth and development of Liatris spicata. J. Hort. Sci. and 

Technology 73(6):851–855. 

Berland, M. 1983. Growth and flowering in Liatris spicata. M.S. thesis, Agr. University 

of Norway, Aas. 

Borochov, A., and V. Karten-Paz. 1984. Bud opening of cut liatris flowers. Scientia 

Hortic. 23:85–89. 



Choi, S., Y. Chang, H. Ahn, W. Jung, I. Park, and K. Jung. 1999. Use of bulbil for 

corm production and cut flower cultivation in Liatris spicata ‘Floristan Violet’. 

J. Korean Soc. Hort. Sci. 40(1):117–121. 

Espinosa, I., W. Healy, and M. Roh. 1991. The role of temperature and photoperiod 

on Liatris spicata shoot development. J. Amer. Soc. Hort. Sci. 116(1):27–29. 

Evans, M. R. 1992. Effect of terminal bud removal and tuber orientation on floral 

development of Liatris spicata ‘Callilepis’. Proc. Inter. Soc. Tropical Hort. 36: 

127–131 

———. 1994. Photoperiod affects meristem development of Liatris spicata 

‘Callilepis’. Proc. Fla. State Hort. Soc. 106:288–290. 

Moe, R., and M. Berland. 1986. Effect of various corm treatments on flowering 

of Liatris spicata. Acta Hortic. 177:197–201. 





Salac, S. S., and J. B. Fitzgerald. 1983. Influence of propagation method and fertilizer 

rate on growth and development of Liatris pycnostachya. HortScience 18: 

198–199. 


Ore. 

Waithaka, K., and L. W. Wanjao. 1982. The influence of corm source, age and size 

on growth and flowering of Liatris. Abstract International Horticultural Congress 

(Hamburg, Germany) 2.:1724.

380 LILIUM HYBRIDS 

Zieslin, N. 1985. Liatris. In The Handbook of Flowering. Vol. 3. A. H. Halevy, ed. CRC 

Press, Boca Raton, Fla. 

Zieslin, N., and Z. Geller. 1983. Studies with Liatris spicata Willd. Part 2:effects of 

photoperiod on stem extension, flowering, and gibberellin content. Ann. Bot. 

52:855–859. 

Many thanks Jack Zonneveld (first edition) and Kelly Anderson, Mimo Davis, 

and Kent Miles (second edition) for reviewing this section. 

Lilium hybrids lily Liliaceae 

bulb, Zones 3–7 hybrid origin many colors 3–8'/2' (0.9–2.4 m/0.6 m) 

Lilies, major cut flowers in global markets, are predominantly grown under 

cover. The huge number of hybrid lilies bred for the cut flower market are sold 

under 3 group names, Asiatic, Oriental, and LA lilies—taxonomically, Lilium ×elegans, 

L. speciosum, and L. longiflorum × Asiatic hybrids, respectively. Additionally, 

hybrids between Oriental and Trumpet (OT) lilies are appearing on the market. 

So much hybridization has occurred as to render these categories dubious at 

best (Beattie and White 1993), but they do work as shorthand references to the 

appearance of the flowers and foliage. In contrast to Oriental hybrids, Asiatic 

hybrids are earlier to flower, have smaller leaves, are often shorter, and—generally 

but not always—have upward-facing flowers; they are available in a wide color 

range and are more tolerant of a range of soil and fertility types. Orientals are 

taller than Asiatics and have larger flowers (often outward-facing or nodding) 

with much wider, more succulent leaves along the stem; the flowers are generally 

more fragrant than those of Asiatics, most of which have no fragrance. The LA 

hybrids will differ depending on the percentage of Asiatic in the parentage. Some 

of the original LA’s (e.g., Royal series) were too similar to Asiatics and demanded 

too high a price for the small difference seen in flowering. They have come a long 

way. Now more varieties are available, with better bud count and prices that are 

on a par with Asiatics; in fact, some Asiatic customers are switching to LA varieties. 

Breeding of all lily groups continues unabated, and hybridization among 

groups continues. Expect many additional combinations to hit the market, and 

know that, with the constant breeding, hybrid cultivars have only a 3- to 5-year 

life span in the market. 

Propagation 

The majority of lilies used for cut flowers are produced either in the Netherlands 

or in the northwestern United States. Hybridizers propagate by scaling, offsets, 

and seed.

Lilium ‘Acapulco’ (Oriental hybrid)


Growing-on 

Bulbs should be given a 10- to 20-second preplant dip in a fungicide solution to 

control the root rot complex associated with lilies (see “Pests and Diseases”). 

After treatment, immediately plant the bulbs in the field or greenhouse. 


Temperature: All lilies require cold temperatures for flowering (bulb vernalization). 

Lilies harvested in late summer and fall are precooled at 35F (2C) for 6– 

8 weeks in moist peat moss. For later plantings, bulbs may be frozen at 30F ( − 1C) 

after being precooled. Problems can occur, particularly if bulbs are allowed to dry 

out. Sealing the bulbs in plastic bags and keeping them in peat moss is a common 

practice to maintain humidity around the bulbs. Bulbs that have been dried 

out are susceptible to floral abortion and abscission later in the growth cycle. 

Small differences in storage temperature are recommended for the different 

bulb groups. For example, some exporters feel that Orientals should be stored at 

29F ( − 1.5C) and Asiatic and LA hybrids at 28F ( − 2C). Most growers don’t have 

that degree of sophistication in their coolers, thus it is best to allow the distributor 

to do it. Long-term storage of all lilies at a lower temperature than recommended 

(25F, − 4C) can lead to freezer burn, which manifests itself when the 

plant is being forced, resulting in twisted foliage and buds and sometimes bud 

abortion. 

Koike and Imanishi (1993) determined that precooling bulbs at 33F (1C) for 

4–6 weeks followed by storage at 28F ( − 2C) resulted in excellent flower count 

and quality. They also found that long-term storage of bulbs at 25F ( − 4C) did not 

affect quality but delayed flowering. Planting frozen bulbs during hot summer 

months reduced quality. 

Light intensity: Lilies require high light for optimal flowering, particularly if 

forced in the greenhouse during the winter months. Low light levels result in 

flower bud abortion, abscission (bud drop), and taller plants. 

Photoperiod: In Oriental and LA lilies, flowering can be accelerated by LD given 

to shoots after emergence, but LD are not effective for Asiatic lilies (Roh 1999). 

Application of LD can substitute for the cold requirement in Easter lilies (Lilium 

longiflorum) (Wilkins 1980), but the relationship between photoperiod and vernalization 

has not been established for the other groups of bulbs. 


Bulb size: Large bulb sizes are preferable over smaller sizes, but differences between 

species and cultivars occur. Bulbs from 4/5" (10/12 cm) to 8/9" (20/22 

cm) in circumference are used. 

Spacing: Spacing depends on the size of the bulb circumference and the flower 

group. Generally, bulbs are placed about 4–6" (10–15 cm) apart, with 2" (5 cm) 

of soil above the nose. 

Planting time: Lilies are generally planted in the fall. Properly cooled bulbs may 

be planted year-round, depending on the local weather patterns.

LILIUM HYBRIDS 383 

Longevity: Most growers treat lilies as annuals, replanting after each crop 

regardless of locale. Longevity depends on temperature, fertility, light, and the 

amount of stem leaves allowed to remain on the plant after harvest. Bulbs 

planted in USDA Zones 8–10 are always treated as annuals. 


Bulb size: Use large bulb sizes for greenhouse forcing. Mark Hommes of Bulbmark, 

Inc., recommends the following sizes (all given in centimeters) for greenhouse 

production: 

Asiatics Orientals LA’s 

spring/summer 12/14 14/16 or 16/18 12/14 or 14/16 

fall/winter 12/14 or 14/16 16/18 12/14 or 14/16 

Generally, smaller bulb sizes have fewer flowers and are prone to abscission. 

Bulbs used for greenhouse forcing must receive 6 weeks (LA lilies), 6–9 weeks 

(Asiatic), and 9 weeks (Oriental) of cold moist treatment (Roh 1999). For later 

forcings and year-round flowering, bulbs should be frozen at 28–30F ( − 2– − 1C) 

after being precooled for 6–8 weeks (De Hertogh 1996). Temperatures should 

not fall below 28F ( − 2C), or freezing injury to the bulbs may occur. 

Arrival: On arrival, bulbs should be planted immediately in sterile ground 

beds in well-drained media lacking superphosphate at a pH of 6.8–7.0. All cultivars 

can be forced for the spring (March through June) while some may be forced 

during the winter (December through March). Four crops may be produced on 

a year-round basis. In warm months (for year-round forcers) bulbs are often 

rooted for about 2 weeks in the cases; they are then planted in crates and stacked 

on pallets in the cooler, where they remain for a week at 50–60F (10–15C) before 

being moved to the greenhouse. In such cases, pay close attention to the moisture 

level in the growing medium. 

Planting density: Plant bulbs with at least 2" (5 cm) of media above the nose. 

Bulbs are planted in the ground or in standard bulb crates. Mark Hommes recommends 

the following planting densities, based on bulb size. 

Bulb crate Square foot 

12/14 14/16 12/14 14/16 

Asiatic 22 19 8 1 ⁄2 7 1 ⁄2 

Oriental 17 14 6 1 ⁄2 5 1 ⁄2 

LA 21 18 8 1 ⁄2 7 1 ⁄2 

Under high temperatures and high light conditions (e.g., summer), the planting 

density may be increased up to 2 bulbs per crate. Under low light and low tem-


peratures, the planting density may be decreased by 2 bulbs per crate. Many 

growers plant in bulb crates because bulbs can be preplanted, cooled in place, 

and then moved to the greenhouse. 

After planting in crates, beds, or other containers, lilies should be supported 

with grow wire. This is especially important during the rapid growth of summer, 

when the stems of the plants are not as firm as they would be in early spring. 

Light intensity: High light is necessary for greenhouse forcing. It is often insufficient 

during the winter; therefore, supplemental light is useful for areas of low 

light, particularly in the Northwest. Low light is a major cause of bud drop. Orientals 

need more light (and heat) than Asiatics and LA hybrids. During high 

light conditions in late spring and summer, shading may be required. 

Temperature: Large fluctuations in temperatures should be avoided; forcing 

temperatures of 55–65F (13–18C) are optimal. Avoid prolonged temperatures 

above 70F (21C). During warm seasons, use mulch to reduce soil temperatures. 

Nutrition: Fertilize with calcium nitrate and potassium nitrate (2 lbs and 1 lb 

per 100 gallons water, respectively) once a week (De Hertogh 1996). 

Scheduling: Asiatic lilies require 8–12 weeks in the greenhouse, and normally 

require 30–35 days to flower after reaching visible buds. LA’s also need 8–12 

weeks. Oriental lilies need 12–16 weeks in the greenhouse and normally require 

50–55 days from visible bud to open flower (De Hertogh 1996). 



healthy Asiatic lilies when flower buds were visible but prior to flower opening. 



(%) 

N P K Ca Mg 

2.0 0.12 2.51 1.09 0.30 

(ppm) 

Fe Mn B Al Zn 

63 30 17 60 25 


Cut when the first flower is fully colored but not yet open. Open flowers are easily 

damaged in transit. 

Postharvest 

Fresh: The vase life of most cut lily flowers is 5–9 days, depending on cultivar 

and environmental conditions. Son and Suh (1999) found that ethylene production 

from ‘Casa Blanca’ lily rises steeply from the fifth day after flowering,

LILIUM HYBRIDS 385 

also that ethylene production was higher from stamens and pistils than from the 

tepals. STS pretreatment significantly enhanced vase life (Ranwala and Miller 

2002). 

Pulsing stems for approximately 20 minutes with a preservative containing 

STS extends vase life. Longer pulse times with more dilute STS are also effective. 

After pulsing, place stems in preservative solutions. Placing stems in a combination 

of STS and 10% sugar for 24 hours followed by placement in 50 ppm 

GA3 greatly increases vase life of ‘Enchantment’ lilies (Evans and Reid 1990). 

Vacuum cooling, similar to that used for vegetables, is effective as long as 

adequate water is sprayed on the flowers prior to their going into the apparatus. 

No weight loss occurred, and the vase life of the flowers was extended (Brosnan 

and Sun 2001). 

Storage: Lilies may be stored dry at 33F (1C) for up to 4 weeks if initially pulsed 

for 24 hours with STS and 10% sucrose. Flowers should be wrapped in polyethylene 

film to reduce water loss during storage. Do not store more than 3 days 

without chemical pretreatment. For wet storage, flowers are cut at bud stage, 

conditioned as above, and placed in containers of water at 32–34F (0–1C). Flowers 

may be stored up to 4 weeks (Nowak and Rudnicki 1990). 

Cultivars 

The numbers of cultivars are many and continually changing. Consult a reputable 

bulb distributor who specializes in lilies for cut flowers. A good deal of effort 

has been expended in the last 10 years to breed dwarf cultivars for pot plant use; 

stay away from these if stem length is important. Here are some excellent cut 

flower cultivars planted for bulb production in Holland in 2001, sent in by Ben 

Kneppers of Zabo Plant and Mark Hommes. The list will be different each year. 

Orientals Asiatics LA’s Longiflorum 

Stargazer Pollyanna Bestseller Snow Queen 

Siberia Navona Royal Sea White Fox 

Casa Blanca Brunello Royal Song Gelria 

Sorbonne Vivaldi Algarve Lorina 

Simplon Gironde Aladdin Dazzle Pausini 

Acapulco Elite Royal Trinity S. Coeur 

Merostar Dreamland Dazzle White Elegance 

Marco Polo Nova Cento Canillo Snowcap 

Tiber Prato Brandizzi White America 

Barbaresco Marrakesh Moneymaker Como 


Lilium auratum (goldband lily) is an excellent cut flower. The best variety is 

var. platyphyllum, which has fragrant outward-facing white flowers with a band 

of gold on the inside.


Lilium formosanum (Formosa lily) has demonstrated excellent stem strength 

and vigorous growth during field trials in Georgia. The fruit are also large and 

useful for cutting. Its advantages are ease of growth, ease of propagation (seeds 

sown in summer will flower the following summer), and stem strength. Disadvantages 

are lack of “exciting” colors and susceptibility to lily mosaic virus. 

Lilium longiflorum (Easter lily) also produces good cut flowers. See the previous 

table for top cut cultivars. 


Root rot complex (Fusarium, Pythium, Rhizoctonia) discolors and rots roots. Bulbs 

should be dipped in appropriate fungicides for 10–30 seconds prior to planting. 

Because of the different fungi involved, it is necessary to alternate fungicides 

or use a combination of fungicides. Check with local extension agents concerning 

the availability of chemicals. 

Botrytis, the lily’s biggest enemy, can devastate a crop in no time. Preventative 

spraying against botrytis is highly recommended, especially in climates with 

high humidity levels. 

Lily mosaic virus was a serious disease, but efforts to clean up propagation 

stock, particularly on greenhouse-grown material, have paid off, and its incidence 

has been considerably reduced. Where present, yellowing and mottling 

appear on the leaves, which may become twisted and distorted. Aphids spread 

the disease from plant to plant. Discard bulbs if virus is present. 


Bud abscission: Low light intensity is the most common reason for flower bud 

abortion, but not the only one. Improper cold storage conditions or lack of moisture 

in the first week after planting can cause similar problems. When cold bulbs 

are planted in warm soil, it is critical to have ample water in the ground. Do not 

allow the soil to dry out. Also, be certain bulbs are completely thawed after moving 

out of frozen storage. Do not touch them if they are still even slightly frozen. 

It is even better to open the bags or crates and let them sit in a cool place for a 

couple of days; a little sprouting is not a problem. 

Leaf scorch: Leaf scorch is normally associated with fluoride toxicity. Maintaining 

media free of fluoride and a pH near 7.0 reduces the problem. Beside 

fluoride toxicity, leaf scorch can become a problem when lilies are grown at very 

high temperatures and during the winter months in greenhouses when bulbs are 

used from the previous harvest. Generally, leaf scorch occurs when the plant 

evaporates more water than it is able to take up through its root system. Larger 

bulbs are more susceptible then small bulbs. Certain varieties are more tolerant 

of leaf scorch than others. To help reduce problems with leaf scorch, spray with 

calcium chloride (1%), lower day temperature in greenhouse, and, if possible, 

preroot your bulbs for at least 2 weeks at 53F (12C) before moving containers or 

trays into the greenhouse. 

Flower abortion and flower abscission result from high temperatures and 

low light intensity, respectively.


LIMONIUM 387 

“We are growing lilies in bulb crates in the greenhouse, and they have come out 

great! We figured cheaper than pots, maybe less soil—6–8 bulbs per crate. We 

grew ‘Black Beauty’ for Valentine’s Day, and they came up great—5 buds, with 

[stems] 48" on average. We will be trying more like this in just a few weeks!” Michelle 

Smith, Blossoms, Inc., Fletcher, N.C. 

“We don’t have problems with petals dropping on their own, but petals will 

snap off if bent backward, and they do show crease lines and bruises if handled 

roughly. Orientals are much tougher and can take the rough treatment some 

florists give them. Sell your lilies in bud stage, and tell the customers to treat 

them carefully when selecting from your display.” Dave Dowling, Farmhouse 

Flowers, Brookeville, Md. 

Reading 

Beattie, D. J., and J. W. White. 1993. Lilium—hybrids and species. In Physiology of 

Flower Bulbs. A. De Hertogh and M. Le Nard, eds. Elsevier Press, Amsterdam. 

Brosnan, T., and D. Sun. 2001. Compensation for water loss in vacuum-precooled 

cut lily flowers. J. Agr. Eng. Res. 79(3):299–305. 





Koike, Y., and H. Imanishi. 1993. Long-term freezing storage of bulbs to retard 

flowering in Asiatic hybrid lilies. J. Jap. Soc. Hort. Sci. 62(1):181–187. 



Ranwala, A. P., and W. B. Miller. 2002. Using gibberellins to prevent leaf yellowing 

in cut lilies. Greenhouse Produce News 12(1):30–36. 

Roh, M. 1999. Physiology and management of Lilium bulbs. Acta Hortic. 482:30– 

45. 

Son, K., and J. Suh. 1999. Ethylene production in Lilium Oriental Hybrid ‘Casa 

Blanca’ florets during the vase life. J. Korean Soc. Hort. Sci. 40(4):467–469. 

Wilkins, H. 1980. Easter lilies. In Introduction to Floriculture. R. A. Larson, ed. Academic 

Press, New York. 

Many thanks to Gus De Hertogh, John Dole, and Mark Hommes for reviewing 

this section. 

Limonium statice Plumbaginaceae 


Statice is a mainstay of the cut flower industry, grown worldwide in fields and 

greenhouses, and since South American growers saw the sense in adding specialty 

flowers to their roses and carnations, statice has grown in volume. Many

388 LIMONIUM HYBRIDS 

species are used in the cut flower trade, the most common being annual statice 

(Limonium sinuatum) and the free-flowering statice hybrids. As more statice is 

grown, marginal species such as L. tetragonum (syn. L. sinense; confetti statice) are 

gaining favor as cut flowers. The popularity of German statice (Goniolimon tataricum, 

which see) has declined with the advent of Limonium hybrids. 

Limonium hybrids statice Plumbaginaceae 


These are the backbone of statice today. They are often, but not always, hybrids 

between Limonium latifolium and L. bellidifolium (Caspia statice) and produce outstanding 

lacy flower heads on spikes up to 4' (1.2 m) tall. Large-scale production 

is the norm, particularly of the Misty series, in the United States, Colombia, and 

Ecuador. Plants persist 3–4 years without problem, and flowering occurs at 60– 

65F (15–18C) nights. Plants of the Misty series produce up to 20 stems/plant 

about 4 months after planting (Jenkins 1992). 

Following the work of Garner and Armitage (1996), in which directed sprays 

of 400 ppm of GA3 influenced yield and accelerated flowering, gibberellic acid is 

routinely used to promote flowering and substitute for LD in the winter. Applications 

of 500 ppm are equally effective. Plants should be sprayed at weekly intervals 

for 3–4 weeks, starting when plants are young, or once growth begins after 

a harvest. GA can have unforeseen consequences, so do a little experimenting 

on your own before spraying the entire crop. 

In Central America, the bunch weight for these types is 12.5 oz (350 g). The 

stem length standard for ‘Beltlaard’, Diamond series, ‘Misty’, and ‘Ocean Blue’, 

is 30" (75 cm); in California, bunches of ‘Misty’ can be longer than 40" (1 m). 

Postharvest life of hybrids in plain water is usually only 4–5 days, although 

using a wetting agent in the water can be helpful (Burge et al. 1998). Sugar is 

the additive of choice. Work with ‘Fantasia’ showed that 20 g/l of sucrose, combined 

with a quaternary ammonium disinfectant solution, such as Physan, 

extended vase life to 17 days and promoted bud opening (Doi and Reid 1995). A 

12-hour pulse treatment of 100 g/l sucrose (with Physan) partially substituted 

for the continuous sugar supply. Ichimura (1998) found that pulsing with 20g/l 

sucrose alone had little effect but was effective if combined with 10 mM αaminoisobutyric 

acid (AIB). 

Malodorous smell is a continual problem. Limonium altaica, Goniolimon tataricum 

(German statice), and even the hybrids produce a smell some say reminds 

them of cat urine, or something equally unpleasant. A few olfactory-challenged 

people find that the hybrids are not malodorous at all, while others run away 

holding their noses. This does little to enhance sales. The Emille Group (L. altaica) 

and the Misty series seem to be less offensive than the others. Cutting 

stems when only about 30% of the flowers are open and placing in an opening 

solution (such as sugar and a biocide) in a well-ventilated room before shipping 

reduces the odor. The smell will be worse if botrytis is present, or if the flowers 

are old, or if they’re cut and packed in bunches with humidity. According to

LIMONIUM PEREZII 389 

industry specialist Gay Smith, some supermarkets have banned statice from 

bouquets because the stuff stinks so badly (heats up and sweats in the bunch or 

gets botrytis from the water sloshing in the wet pack, wrapped in nonperforated 

bouquet sleeves). 

Cultivars 

Representative hybrids include ‘Beltlaard’ (less upright than ‘Saint Pierre’), ‘Fantasia’, 

and ‘Saint Pierre’, and the Misty series. The Supreme varieties of the Misty 

series were bred in southern California for superior performance in southern 

climates, but flowering appears to be especially strong in cool conditions; they 

produce 6–7 cut flowers the first year, 10 or more the second. Misty colors 

include blue, pink, rose, and white. 

‘Ocean Blue’ is compact, growing 3–3½' (0.9–1.1 m) with light blue flowers. 

Appears to be a good grower with many useful lateral stems. 

‘Supreme Bluenight’ produces many stems of blue flowers. 

‘Topian Blue’ and ‘Splash Blue’ are relatively new to the statice market. 

Limonium perezii Perez statice, seafoam statice Plumbaginaceae 

perennial, Zones 8–11 Canary Islands blue, white 1 

1–2'/1' (30–60 cm/30 cm) 

Seafoam statice has large, leathery basal leaves and produces coarse, blue and 

white inflorescences. According to Gay Smith, it is a slow wholesale seller because 

people are looking for more stems per bunch, especially for bouquet work; 

Limonium perezii has compound laterals, so it only takes 3–6 stems to make a 

beefy bunch. Drainage must be excellent if plants are to be perennial, which they 

are to Zone 7 with mulch; and they can be grown as annuals in most of the 

United States (they are almost weeds in southern California). 

Propagation 

Seed germinates in 5–14 days if planted at 70–72F (21–22C). Purchase clean 

(rubbed) seed. Although a little more expensive, clean seed facilitates seeding 

and reduces frustration. If seed is soaked in water for 24 hours prior to sowing, 

germination is enhanced (Kieft 1996). Approximately 0.12 oz (3.5 g) of seed 

yields 1000 seedlings. Division may be tried, particularly if plants are perennial. 

Growing-on 

Transplant to cell packs or 4" (10 cm) pots as soon as seedlings can be handled. 

Fertilize with 75–100 ppm N using potassium nitrate or a complete fertilizer 

and maintain temperatures at approximately 65F (18C). Plants may be placed in 

the field as soon as threat of frost has passed. Expect 8–10 weeks from seed to 

field transplant.

390 LIMONIUM PEREZII 


Likely LD and warm temperatures promote flowering, similar to annual statice 

(Limonium sinuatum, which see). If sown early, plants produce some flowers the 

first year. 


Plants perform better in Mediterranean climates than in eastern or southeastern 

climes. First-year results from trials at the University of Georgia resulted in only 

5 stems/plant, averaging 20" (50 cm), the minimum stem length for bouquet 

work. Plants did not overwinter. 


At field trials in Athens, Ga., and Watsonville, Calif., foliage was sampled from vigorously 

growing healthy plants when flower buds were visible but prior to flower 

opening. These are guidelines only and should not be considered absolute standards. 

Numbers are averages for both sites and are based on dry weight analysis. 

(%) 

N P K Ca Mg 

3.28 0.42 2.26 0.61 0.55 

(ppm) 

Fe Mn B Al Zn 

105 78 17 71 181 


Harvest when approximately 80% of the flower head has opened. 

Postharvest 

Fresh: All statice is sensitive to ethylene and benefits from pretreatment with 

STS or 1-MCP. A vase solution containing 10% sugar pulse (12 hours) is highly 

effective in extending the vase life (Nell and Reid 2000). Flowers persist 10–14 

days if properly treated and placed in fresh flower food. 

Storage: Plants may be stored dry for 4–5 days at 35–38F (2–3C). 

Dried: Flowers may be air-dried upside down in a well-ventilated room. 

Cultivars 

‘Atlantis’, a seed-propagated cultivar, has darker blue flowers than the species. 

Plants grow 2–3' (60–90 cm) tall.

LIMONIUM SINUATUM 391 

Limonium sinuatum annual statice Plumbaginaceae 

annual Mediterranean many colors 18–24"/2' (45–60 cm/60 cm) 

Among the most popular cut flowers in the world, annual or sinuata statice continues 

to be produced in vast quantities. Breeding of annual statice has provided 

myriad hybrids of various strains and colors, suitable for both drying and fresh 

use. Flowers may be grown everywhere in the United States, although California 

and Florida are the leading producers. 

Propagation 

Approximately 10,000 clean seeds/oz occur. At “normal” germination percentages, 

0.25 oz (7 g) produces 1000 seedlings (Nau 1999). Clean seed is more expensive 

than unprocessed seed but is easier to handle and germinates more rapidly. 

Seed should be sown and covered lightly or left exposed to ensure that light 

reaches the seed. Seed provided with 70F (21C) germinates in 5–14 days, depending 

on cultivar, and may be transplanted in 3 weeks. Large plugs or transplants 

may be placed in the field 6–8 weeks after sowing. 

Growing-on 

Provide 60F (15C) temperatures for 1–2 weeks after cotyledons emerge to 

encourage rooting. Plants flower more rapidly and are of better quality if subjected 

to a cold treatment (vernalized) when young and should initially be grown 

at temperatures of 50–55F (10–13C) (Krizek and Semeniuk 1972). This is best 

accomplished in a cool greenhouse, although work using 8 weeks in a 40F (4C) 

illuminated storage area was also successful, as long as light was present (Katsutani 

et al. 1998). Twelve hours of photosynthetic light (about 300 fc) should 

be provided in the cold chambers (Shillo 1976). The seedling is most responsive 

to vernalization; cold treatment of seeds is ineffective. Plants should be cooled 

from the cotyledon to the 5-leaf stage, which requires 5–8 weeks, although waiting 

until 15 leaves have expanded before cooling was equally effective (Katsutani 

et al. 1998). Some growers germinate seed in the greenhouse and then place seedling 

or plug flats in cold frames for cool temperature treatment. As daylength 

increases, the length of the cold treatment can be decreased. If seedlings are vernalized 

under LD, however, flowering is also enhanced (Shillo 1976). Fertilize 

seedlings with 50–100 ppm N and K. 


Photoperiod: Long days promote earlier flowering, greater percentage of flowering 

plants, and higher yields; they are most effective after plants have been 

cooled and are actively growing. The optimum photoperiod is greater than 13 

hours (Shillo and Zamski 1985), but around 12 hours seems sufficient. This is 

borne out by the fact that LD have little effect in the tropics. Growers in Ecuador

Limonium sinuatum 

‘Sunset Blue’


and Colombia, however, routinely light their crops in the field. If LD are provided 

during the seedling stage, the length of the vernalization may be reduced. 

Long days without vernalization are relatively ineffective. Long days applied to 

actively growing plants induce a greater percentage of flowering plants regardless 

of temperature compared with short days, but LD applied to seedlings have 

little effect if not accompanied by cool temperatures. Plants will still flower 

under SD of winter, but yield, flowering time, and stem length may be negatively 

affected. 

Temperature: A cold treatment hastens flower initiation. High temperatures 

promote leaf initiation, leaf growth, and stem elongation but inhibit flowering. 

This explains why nonvernalized plants placed under warm field conditions 

grow well but have poor yield. Researchers at Beltsville, Md., placed seedlings in 

controlled temperature chambers for 6 weeks (Krizek and Semeniuk 1972). They 

showed that plants grown at 80/75F (29/24C) day/night temperature formed a 

vegetative rosette that persisted approximately 4 months. Day/night temperatures 

of 70/64F (21/18C) resulted in only 20% flowering plants, but temperatures 

below 65F (18C) caused flower initiation in all plants. The optimum temperatures 

were 60/55F (15/13C) day/night. In general, blue-flowered cultivars 

have the greatest cold requirement (lower temperature and longer duration), 

followed by lavender, pink, white, and yellow (Semeniuk and Krizek 1973). 

In summary, high temperature during the seedling stage is the chief constraint 

to flowering. Temperatures of 50–55F (10–13C) should be applied at the 

seedling stage for 3–8 weeks depending on season and cultivar. This treatment 

may occur naturally in the field with spring-planted crops or may be applied 

artificially in coolers for summer-planted crops. 

The length of precooling varies with the season. This was shown in Israel, 

where plants are cropped throughout the winter; in fall plantings, a maximum 

flowering response was obtained with 8 weeks of precooling, but in early spring 

plantings, only 3 weeks precooling was necessary (Shillo 1977). The reduction in 

precooling time in the spring plantings can likely be attributed to cooler night 

temperatures when plants were young and longer photoperiods as plants 

matured. 

After vernalization is completed, high temperatures speed flower development 

but should not be applied immediately after planting. In practical terms, 

this means that precooled plants should not immediately be transplanted to 

80–90F (27–32C) fields; transplanting in the spring is recommended. An optimum 

temperature regime for early and profuse flowering is 73/60F (23/15C) 

day/night temperatures (Semeniuk and Krizek 1973). 

Gibberellic acid: Gibberellic acid (GA3) has been used to reduce the need for 

precooling in annual statice. Work in Florida and Israel has shown that application 

of GA3 partially overcomes the precooling requirement. The following 

table (Wilfret and Raulston 1975) shows the influence of GA on ‘Midnight Blue’ 

statice; notice that it is relatively ineffective if the precooling requirements have 

been satisfied.

394 LIMONIUM SINUATUM 

The effect of GA on flowering of ‘Midnight Blue’ statice. 

No. of days of precooling GA applied Plants in flower (%) 

0 no 40 

yes 83 

6 no 42 

yes 94 

12 no 72 

yes 100 

28 no 95 

yes 100 

The table shows that as more precooling was applied, GA became less effective, 

but with 0–12 days of precooling, the application of GA was effective in promoting 

flowering. GA does not appear to be useful if plants have had no precooling 

or if precooling has been saturated. 

GA is routinely applied to most statice, including the hybrids. The optimum 

application time appears to be 12 weeks after seeding (Wilfret and Raulston 

1975) or about 3 weeks after planting (KunYang et al. 1995); the optimum concentration 

is 500 ppm. GA should not be applied when plants are budded. An 

application in the amount of 10 ml/plant is effective. Work by Wilfret and 

Raulston (1975) showed that ‘Iceberg’ and ‘Midnight Blue’ flowered in 134 and 

160 days from seed, respectively, with a GA application, but required 238 and 

229 days without GA. 


Soil: Annual statice prefers soil high in lime: pH 6.5–7.5. 

Spacing: Space either on 1' (30 cm) centers or 10 × 12" (25 × 30 cm). Plants may 

be grown in rows that are 12–14" (30–36 cm) wide, allowing for 2–3 staggered 

rows per bed. Space plants 14–16" (35–40 cm) apart down the length of the bed. 

Wider spacing is also effective. In India, the greatest plant height and spread occurred 

at spacings of 2 × 1' (60 × 30 cm), the closest spacing in the work (Ramesh 

and Kiranjeet 1997). Neither support nor pinching is necessary. 

Scheduling: The first harvest occurs in the South approximately 3–5 months 

after sowing; in the North 4–6 months may be necessary. Place in the field after 

danger of frost has passed but before night temperatures rise above 55–60F (13– 

15C). In northern California, plant from October to January for April to October 

production. Harvest is heavy for the first 4–6 weeks and levels off as plants 

mature. 

Plants may be planted at 2-week or monthly intervals; precooling (see “Environmental 

Factors”) or gibberellic acid application is recommended. The longer 

days of summer reduce the need for such additional inputs, but in areas where 

temperatures seldom go below 55F (13C), the use of GA is warranted, particu-

larly in shorter daylength times of the year. Plants will begin to flower 6–10 weeks 

after transplanting. In warm winter areas, continuous cropping may be accomplished 

by sowing at 2- to 4-week intervals. 

Yield: In northern California, approximately 20 stems/plant are produced 

from April to October. This translates to approximately 25,000 bunches (12 

stems/bunch) per acre from 15,000 plants. At Watsonville, Calif., stems were 

harvested from week 14 to week 39 (April to September), but the highest yield 

was between weeks 21 and 26 (week 25 alone yielded 12,000 bunches); distribution 

of total yield by month is shown in the following table. 

Month Yield (%) 

Apr 5 

May 22 

Jun 26 

Jul 20 

Aug 14 

Sep 13 

Research at the University of Georgia using hand-harvest methods resulted in 22 

stems/plant between mid June and August with the Fortress series. Distribution 

patterns from these plantings are shown in the following table. The results 

are similar, although harvesting lasts for many more weeks in California than in 

Georgia. 

Week no. Yield (%) 

23 7 

24 8 

25 13 

26 15 

27 14 

28 13 

29 13 

30 10 

31 7 


Statice is often sold by the pound, and yields of 10,000–40,000 lbs/acre 

(2100–8650 kg/hectare), depending on cultivar and environment, may be 

expected. In Central America, grading is done by weight, and the standard for 

grading is the blue/purple at 450 grams/bunch. Other colors are bunched to 

appear to be the same size as purple bunches but not specifically the same 

weight. The idea is that it would take a ton of stems to get 450 grams of pink or 

yellow. Growers use the blue as a benchmark size.


Stem quality: At Georgia, stem lengths ranged from less than 12" (30 cm) to 

greater than 30" (75 cm) for the Fortress series. Longer and thicker stems 

occurred during initial harvest dates compared with later harvests. In general, 

blue-flowered stems were thicker than average, yellow-flowered stems thinner 

than average. 


Space seedlings 10 × 10" (25 × 25 cm) and grow in a greenhouse at 50–55F (10– 

13C) to initiate flowers (see “Environmental Factors”). Cool temperatures must 

be maintained for at least 6 weeks. After the cool treatment, temperatures may 

be raised to 60/70F (15/21C) night/day. In the absence of cool temperatures, a 

spray of 500 ppm gibberellic acid may be applied when plants are 6–8" (15–20 

cm) across. Maintain plants under photoperiods of approximately 16 hours, 

using incandescent nightbreak lighting or daylength extension. Fertilize with a 

nitrate-N fertilizer at 100 ppm each irrigation when plants are grown cool, and 

raise fertility levels when temperatures are raised. 

Plants sown in November and January will flower in March and May, respectively, 

depending on cultivar and location. 



vigorously growing healthy plants when flower buds were visible but prior to 


standards. Based on dry weight analysis. Numbers shown are the average of 

‘Heavenly Blue’ (Georgia) and ‘Fortress Blue’ and ‘Fortress Yellow’ (California). 

(%) 

N P K Ca Mg 

3.5 0.66 3.11 0.57 0.92 

(ppm) 

Fe Mn B Al Zn 

159 117 20 105 70 


Harvest when the individual flowers are mostly open and showing color. The 

white of the flowers (petals) should be visible and the rest of the flower color 

(sepals) well developed. The most common packing color assortment for U.S. 

wholesalers is 75% purple, 5% blue, 5% pink, 5% lavender, 5% yellow, and 5% 

white. Peach, with its high color variation, is less important. “Rainbow statice” 

bunches sell well as consumer bunches, but growers say they need about 20% 

higher prices to cover the bunching costs.

Postharvest 

Fresh: Flowers persist approximately 2 weeks in water without any particular 

care. Stems must be dry prior to shipping, or botrytis will take hold. 

Storage: Stems may be stored dry at 36–41F (3–5C) for 2 weeks. 

Dried: Strip the large, fleshy leaves and hang upside down in a warm, wellventilated 

area. The drying barn must be dark, or the color of stems and flowers 

will rapidly decline. Stems remain green if dried too rapidly. 

Cultivars 


Many cultivars are available, and more are developed each year. Tissue culture 

sinuata remains a hot item; all vegetative material is more expensive and recommended 

for protected culture only. Wholesalers usually have no problem 

selling to retailers, who will pay considerably more for tissue-cultured cultivars, 

until the market floods in with cheap material. 

Arrow series is one of a relatively new group of vegetatively propagated annual 

statice, mostly available from tissue culture. Plants grow up to 3' (90 cm) tall 

and bear 4–5" (10–13 cm) flower heads. Available in dark blue and lavender. 

‘Blue River’ has intense blue flowers with somewhat shorter stems than 

Fortress. 

Blue Waves Mixed and Pink Waves Mixed contain shades of each color on 

heavy-flowering plants. 

Compindi series is useful for fresh or dried production. Colors include white, 

deep blue, light blue, and rose. 

Excellent series comes into production more rapidly than others, and uniformity 

of its many colors is excellent. Colors include deep yellow, light blue, 

purple, sky blue, and shades of rose, pink, and salmon. 

Forever series includes blue, gold, lavender, and rose and is used for both 

fresh and dried production. ‘Forever Gold’, ‘Forever Lavender’, ‘Forever Moonlight’, 

and ‘Forever Silver’ are available. 

Fortress series has long been popular for cut flower production. Individual 

colors are apricot, dark blue, light blue (‘Heavenly Blue’), purple, rose, white, 

and yellow, most with a white center cup. Interestingly, some retailers have been 

known to reject Fortress bunches, thinking the inner white petal cup is some 

kind of problem. 

Friendly series has round stems rather than the more common flat stems of 

most sinuata. ‘Friendly Yellow’ is now available. 

‘Kampf’s Blue Improved’ has rich, dark blue flowers. 

‘Lavandin’ bears clear lavender flowers and appears to resist sunburn better 

than other cultivars. 

‘Market Grower Blue’ produces tall, uniformly blue flowers. 

‘Midnight Blue’ has uniform, rich, dark blue flowers. 

New Era series (vegetatively propagated) consists of plants with 4–5" (10–13 

cm) flowers with good color consistency on 3–3½' (0.9–1.1 m) stems. Flowers in 

about 8 weeks. Available in light pink (‘Appleblossom’) and lavender.


New Wonder series (vegetatively propagated) is a triploid form that produces 

large 5" (13 cm) flower heads on strong 3–3½' (0.9–1.1 m) stems. High yields 

and good disease resistance have been reported. Available in dark lavender, lavender, 

pink, pink-rose bicolor, and deep pink. 

‘Oriental Blue’ has been a standard cultivar for cut flower production for 

many years. The rich, deep blue color is consistent and uniform. 

Pacific Strain is available as a mix or in individual colors, including ‘American 

Beauty’ (deep rose), ‘Apricot Beauty’, ‘Gold Coast’ (deep yellow), ‘Heavenly Blue’, 

‘Iceberg’ (white), ‘Roselight’ (rose-pink), and ‘Twilight’ (lavender-pink). Names 

change like the weather. Some growers, particularly in the Northwest, claim that 

yield for Pacific Strain is significantly higher than for Fortress. Sometimes 

known as the Standard series or the Splendor series. 

‘Pastel Shades’ is a mixture of lavender and purple shades on 2–3' (60–90 cm) 

stems. ‘Sophia’ consists of rose and pale pink flowers and is part of the series. 

Petite Bouquet Mix is short (12", 30 cm) but is used as a cut. Drought tolerant. 

Mix includes blue, white, salmon, and yellow. 

‘Purple Monarch’ bears rich purple flowers. 

QIS series (formerly Sunburst series) has proven to be excellent for greenhouse 

and field production. The series has uniform colors, is fast-flowering, and 

grows 2½' (75 cm) tall. Colors include apricot, dark blue, pale blue, lilac, purple, 

red, rose (earlier than other cultivars), white, and yellow. Sometimes referred to 

as QIS Rainbow Formula Mix. 

‘Rose Strike’ has rose-pink shades and a loose flower habit. 

‘Sirima’ is a mix of pale pink to mauve to clear rose to lilac and lavender. 

Grows to 24" (60 cm). 

Soiree series is relatively new and includes apricot, rose, purple, light blue, 

white, deep blue, and a mix. 

Splendor series appears to be a “mix and match” selection of existing (see 

Pacific Strain especially) but perhaps improved cultivars. As far as we can determine, 

‘Carmine Rose’ is ‘American Beauty’, ‘Chamois’ is ‘Apricot Beauty’, ‘Dark 

Blue’ is ‘Kampf’s Blue’, ‘Golden Yellow’ is ‘Gold Coast’, ‘Midnight Blue’ is ‘Market 

Grower Blue’, ‘Rosea Splendens’ is ‘Roselight’, ‘Sky Blue’ is ‘Heavenly Blue’, 

and ‘White’ is ‘Iceberg’. And of course, there is a Splendor Mixed. 

Sunset series bears flowers in fall colors, shades of blue, yellow, orange, 

salmon, rose, and apricot. 

Supreme series produces uniform stems to about 26" (66 cm). Colors include 

apricot, deep blue, light blue, rose, white, and yellow. 

‘Swan Lake’, a selection from ‘QIS White’, bears double white flowers. 

Turbo series is known for its pastel shades, early flowering habit, and long 

stems. Plants grow 2½' (75 cm) tall. Colors are blue, carmine, peach, purple, 

white, and yellow. 

Wings series is a tissue-cultured series of statice recommended for greenhouse, 

unheated greenhouse, or plastic tunnel only as long as plants are kept 

free from frost. More botrytis resistant and quite popular in Europe and South 

America. Excellent colors, strong stems, high yield, and more flower per leaf ratio 

make this a fine series. Nearly 24 named cultivars are available, such as ‘Blue

Wings’, ‘Cherry Wings’, ‘Cobalt Wings’, ‘Polar Wings Improved’, ‘Purple Wings’, 

‘Royal Wings’, ‘Silver Wings’ (white flowers with a yellow crown), ‘Starlight 

Wings’, and ‘Velvet Wings’. 


Annual statice has been evaluated since the inception of the ASCFG’s national 

trials in 1994. The following table (Dole 1995–2000) is a summary of the average 

stem lengths and yields of plants submitted for trialing. These data are averages 





Compindi Deep Blue 1994 18 11 

Compindi Light Blue 1995 13 10 

Compindi Rose 1994 14 18 

Excellent Formula Mix 1995 17 14 

Excellent Light Pink 1995 17 15 

Fortress Apricot 1998 19 11 

Fortress Dark Blue 1998 18 11 

Fortress Heavenly Blue 1998 19 12 

Fortress Purple 1998 17 12 

Fortress Rose 1998 19 11 

Fortress White 1998 21 12 

Fortress Yellow 1998 21 15 

Mello Yellow 1999 13 7 

Pastel Shades 1994 14 12 

QIS Dark Blue XL 1995 16 20 

QIS Soft Pastel Shades 1995 15 16 

QIS White 1994 22 16 




“We have grown the QIS variety with good success, both as a fresh cut and as a 

dried flower. Colors that are most requested [in Michigan] are dark blue, sky 

blue, rose (really more a hot-pink, raspberry color), white, and more and more 

requests for yellow. We have had it bloom from mid July until the beginning of 

October. Have had it shut down on us as early as mid August, usually when it 

gets cooler and rainy. We have grown it in rows with 12–14" spacing.” Shelley 

McGeathy, McGeathy Farms, Hemlock, Mich. 

“I have had very spotty results with my statice. I have read it likes it on the dry 

side, but last year, when it rained every day and was much wetter and cooler than 

most, I had the best year ever! I believe tarnished plant bug has been the cause of

400 LIMONIUM TETRAGONUM 

a lot of my statice troubles, and last year there were fewer TPB, hence more 

blooms.” Susan O’Connell, Fertile Crescent Farm, Hardwick, Vt. 

“Favorite color is the market rose. I am using last year’s now for mixing into 

Valentine and Mother’s Day bouquets. It starts blooming here in New Hampshire, 

Zone 5, about mid July and I cut it up to frost. I get about 5 good harvests, 

which means going down one side of the 4' wide row and cutting all that is open. 

Then up the other side. It’s backbreaking, somewhat, but I sell a lot of it bunched 

up all by itself.” Heather Warren, Warren Farm, Barrington, N.H. 

“Statice needs an adequate cool period to get good stem length. We seeded 

ours February 16 in a warm greenhouse, got it hardened off and transplanted to 

the field early, while the weather is quite cool. We usually try to have it in the 

field by late March or early April here in Zone 6. If you have it out real early and 

there’s a real cold snap coming, you can cover it with Remay till the weather is 

back to normal. We plant it into black plastic mulch, and this year we plan on 

pulling up the mulch about 4 weeks after transplanting, while we still can without 

yanking the plants out of the soil. I always hated this crop because I could 

never make money on it consistently, but since I learned about the cool thing, I 

like it a lot.” Ralph Cramer, Cramers’ Posie Patch, Elizabethtown, Pa. 

Limonium tetragonum 

confetti statice, yellow statice Plumbaginaceae 

annual China, Korea, Japan yellow, white 2–3'/2' (60–90 cm/60 cm) 

This upright yellow statice, long known as Limonium sinense, has been grown on 

and off for years, but it never seems to have caught on. It is very different from 

the yellow sinuata statice and is dyed all sorts of colors. Plants hit the California 

market in a big way in the late 1980s but have never been very good sellers in the 

U.S. market. It is one of the most handsome species in the trade but lacks vigor 

and is susceptible to disease. Relatively little is grown in South America. 

Propagation is from seed or tissue culture and growing-on is similar to German 

statice (Goniolimon tataricum, which see). In Spain, greenhouse night temperatures 

of 55F (13C) advanced the onset of flowering by 6 weeks compared to 

an unheated greenhouse and also resulted in increased inflorescence width 

(Lopez et al. 1996). Provide a minimum of 18" (45 cm) centers to minimize disease 

pressure. 

Cultivars 

Diamond series is a new form, and its diversity of color (not just yellow) suggests 

that it is a hybrid. Plants appear to have a low susceptibility to mildew and 

other fungi, allowing for field production as well as greenhouse growing. Yearly 

productivity is 20–25 stems/plant. Best planting time in the greenhouse is from 

November until March; outdoor plantings can begin as soon as the risk of night 

frost has passed. Available in white, yellow, pink, deep pink (‘Festival Diamond), 

and light pink (‘Granada Diamond’).

LIMONIUM TETRAGONUM 401 

‘Stardust’ performed excellently in field trials at the University of Georgia, 

and it has been grown successfully in California and Ecuador. The handsome 

flowers are light yellow with white eyes, and plants are perennial at least as far as 

Zone 7b (north Georgia). Harvest begins in early June and continues until early 

August. First-year yields at Georgia were 10 stems/plant at 13.5" (33.8 cm) in 

length; the second-year yields were 20 stems/plant and stem length was 18.7" 

(46.8 cm). In the third year, yield fell back to 10 stems/plant, but stem length 

increased to 20.1" (50.2 cm). 


Limonium altaica is best known for its toughness even in outdoor beds, and for 

its relative resistance to downy mildew. Plants are not as well known in the 

United States, mostly because there are so many other statice available, and it 

may seem there is no overwhelming reason to seek out this species; however, 

plants tend to hold their color better than the Mistys or ‘Beltlaard’. ‘Emille’, 

‘Pink Emille’, and ‘Tall Emille’, bred by Miyoshi in Japan, are excellent older cultivars, 

although a little short, producing rosy lavender, pink, and lavender flowers, 

respectively. ‘Emille’ and ‘Pink Emille’ grow approximately 2–2½' (60–75 

cm) tall; ‘Tall Emille’ reaches about 3' (90 cm) in height. Standards for the Emille 

cultivars appear to be at least 2' (60 cm), or a 9 oz (250 g) bunch, and their flowers 

give off a less obnoxious odor than many statice. ‘Montana’ grows to about 

3' (90 cm) and is suitable for outdoor production, with an annual yield of 20–30 

stems/plant; the dark blue flowers do not shatter after harvest, and plants do 

not appear to be daylength sensitive. 

Limonium bellidifolium (syn. L. caspium) is the true Caspia statice. Seldom used 

as a cut any more, although it has been an important parent in hybrid statices 

like the Misty series. ‘Dazzling Blue’ (also known as ‘Spangle’) has light blue 

flowers and grows to a little over 3' (1 m). 

Limonium bonduellii are half-hardy annual or perennial plants. Flowers are yellow, 

borne on 1–2' (30–60 cm) tall flower stems and known by their spiny bracts. 

Plants are marginally tall enough to be included in a cut flower program. Sometimes 

yellow-flowering plants listed under L. sinuatum are actually this species. 

Limonium gmelinii (Siberian statice) bears lilac-blue flowers on 2' (60 cm) 

stems. Hardy to Zone 4 (maybe 3), flowers are formed in mid summer starting 

the second year. 

Limonium otolepis produces sterile and flowering branches from a tight rosette 

in spring and summer. Flowers are lavender to blue. In Italy, 17 flowers per plant 

were recorded the second year from seed. Monthly yield of 8 flowers per plant in 

July of the third year was noted. A 16-hour photoperiod had little effect on earliness 

to flower or on yield (Guda et al. 1998). 

Limonium peregrinum (syn. L. roseum) does best in a greenhouse. Plants have 

been grown in New Zealand but not many other areas. It is a little short, but the 

pink to rose flowers are beautiful and eye-catching. The inflorescence, comprised 

of many individual flowers, remains decorative long after the petals have deteriorated. 

Vase life is very long, up to 40 days in water. Sugar increased the number

402 LIMONIUM TETRAGONUM 

of flower buds that opened and the length of time open flowers were present 

on the inflorescence, but reduced vase life to 20–25 days (Lewis and Borst 1993). 

Storage also reduces vase life. 

Limonium suworowii (syn. Psylliostachys suworowii; rat tail statice, Russian statice) 

is an excellent flower for drying, with a terminal spike of lavender flowers up 

to 1' (30 cm) long. The flower stems are 2–2½' (60–75 cm) long. Harvest in full 

flower (no less than 80% open) and hang upside down with leaves remaining. 

Plants are best grown in a cool greenhouse in the Southeast but may be produced 

in the field in winter in Florida and California. They are not tolerant of 

warm summer conditions and should be avoided as an outdoor summer cut 

flower in the Midwest and Southeast. 


Botrytis, a serious problem, is exacerbated by high humidity and/or cool temperatures. 

Biological control from Tricoderma hamatum in combination with fungicidal 

application is effective (Diaz et al. 1999). Using warm water heating 

around the plants usually eliminates fungal disease. 

Root rots, caused by water molds, are a common problem, particularly in 

warm, wet weather. Use a fungicidal drench when transplanting to the field. Yellow-colored 

cultivars are more sensitive to root rots than other colors are. Fungal 

root rot as a result of wet soils can decimate all statice species. Maintaining 

good drainage is essential. 

Leaf spots are caused by at least 5 fungal species. Spray regularly with general 

foliar fungicide and pick off infected leaves when spots first appear. Powdery 

mildew and downy mildew are serious problems in statice production. Keep 

leaves and ground free of standing water. 

Rust can also be a serious problem. Rust never sleeps. 

Reading 

Burge, G. K., E. R. Morgan, I. Konczak, and J. F. Seelye. 1998. Postharvest characteristics 

of Limonium ‘Chorus Magenta’ inflorescences. New Zealand J. of Crop 

and Hort. Sci. 26(2):135–142. 

Diaz, N. C., M. J. Barrera, and E. G. de Grenada. 1999. Controlling Botrytis cinerea 

Pers. in statice (Limonium sinuatum Mill.) ‘Midnight Blue’ cultivar. Acta Hortic. 

482:235–238. 

Doi, M., and M. S. Reid. 1995. Sucrose improves the postharvest life of cut flowers 

of a hybrid Limonium. HortScience 30(5):1058–1060. 


Garner, J. M., and A. M. Armitage. 1996. Gibberellin applications influence the 

scheduling and flowering of Limonium ‘Misty Blue’. HortScience 31(2):247– 

248. 

Guda, C. della, B. Ruffoni, C. Cervelli, and E. Farina. 1998. Limonium otolepis as a 

new ornamental crop. Acta Hortic. 454:289–296.

LIMONIUM TETRAGONUM 403 

Ichimura, K. 1998. Improvement of postharvest life in several cut flowers by the 

addition of sucrose. Japan Agricultural Research Quarterly 32(4):275–280. 

Jenkins, J. 1992. New and different flower crops. In Proc. 4th Natl. Conf. on Specialty 

Cut Flowers. Cleveland, Ohio. 

Katsutani, N., S. Kajihara, Y. Kawamoto, and H. Hara. 1998. Forcing of statice 

(Limonium sinuatum Mill.) by low temperature of seedlings with illumination 

to prevent their rot. Bul. of the Hiroshima Prefectural Agricultural Research Center 

66:53–59. 


Netherlands. 

Krizek, D. T., and P. Semeniuk. 1972. Influence of day/night temperature under 

controlled environments on the growth and flowering of Limonium ‘Midnight 

Blue’. J. Amer. Soc. Hort. Sci. 97:597–599. 

KunYang, H., K. WanSoon, J. Soo-Jin, and L. HoonKyu. 1995. Flowering acceleration 

of chilled statice (Limonium sinuatum) by gibberellic acid. RDA J. Agr. 

Sci. 37(2):427–431. 

Lewis, D. H., and N. K. Borst. 1993. Evaluation of cool storage and preservative 

solution treatments on then display life of Limonium peregrinum inflorescences. 

New Zealand J. of Crop and Hort. Sci. 21(4):359–365. 

Lopez, D., P. Cabot, and R. Molina. 1996. Trachelium, Limonium, and Lisianthius: 

study on the advancement of flowering. Horticultura, Revista d’Agricultura de 

Hortalizas, Flores y Plantas Ornamentales 116:118–120. 




Ramesh, K., and K. Kiranjeet. 1997. Effect of planting date and spacing on 

growth parameters of different cultivars of statice. J. of Ornamental Hort. 5(½): 

20–25. 

Semeniuk, P., and D. T. Krizek. 1973. Influence of germination and growing 

temperature on flowering of six cultivars of annual statice (Limonium cv.). 


Shillo, R. 1976. Control of flower initiation and development of statice (Limonium 

sinuatum) by temperature and daylength. Acta Hortic. 64:197–203. 

———. 1977. Influence of GA and the number of cold days on flowering of statice 

‘Midnight Blue’ (in Hebrew). In Annual Report Dept. Ornamental Hort., 

Hebrew Univ. Rehovot, Israel. 

Shillo, R., and E. Zamski. 1985. Limonium sinuatum. In The Handbook of Flowering. 


Wilfret, G. J., and J. C. Raulston. 1975. Acceleration of flowering of statice. 


Many thanks to Fran Foley (first edition) and Gay Smith (second edition) for 

reviewing this section.

404 LOBELIA 

Lobelia Campanulaceae 


Lobelia consists of over 250 species of annual and perennial herbaceous plants 

native in many parts of the world, but the American species are most numerous 

and colorful. Lobelia cardinalis (cardinal flower), the most popular, has been used 

as a parent in many outstanding hybrids; L. siphilitica (big blue lobelia) and other 

species are also useful as cuts. In general, plants reach 2–4' (0.6–1.2 m) in height 

and spread to 2' (0.6 m). 

Considerable breeding has produced hybrid strains (Lobelia ×speciosa, L. ×gerardii) 

with dark stems and brilliant scarlet or purple flowers. They provide outstanding 

color on upright rigid stems. All lobelias, including the hybrids, are 

short-lived and must be replaced or divided at least every 3 years. Many are native 

to stream banks and other areas of moist soil and prefer a rich, moist, but welldrained 

location in the field. In the Northeast and Northwest, plants tolerate 

full sun or partial shade, but in the Midwest and South, some shade is beneficial. 

Regardless of where they are grown, a light (½–1", 1.5–2.5 cm deep) winter mulch 

is beneficial. If mulched heavily, plants die. Remove mulch early in the spring. 

Plants tolerate full sun as long as moisture levels are maintained. Dry sun is 

not a good combination. Too much shade, however, greatly eliminates vigor 

and reduces yield. 

Propagation 

Some lobelias may be propagated from seed or division; others must be divided. 

Seed is tiny and should be lightly covered to ensure it does not dry out. Seeds germinate 

in 10–14 days under 70–72F (21–22C) conditions using intermittent 

mist. 

Growing-on 

Transplant seedlings from trays or seed flats to larger containers, such as 72-cell 

trays or 4" (10 cm) pots, as soon as they can be handled without damage. Seedlings 

are slow to fill out, and approximately 8–10 weeks may be required from 

seed to transplant. Grow on at 62F (17C) nights and slightly warmer days. Set 

out in the field when roots fill the container, approximately 3–4 weeks from 

transplanting. 


Work with the hybrid ‘Compliment Scarlet’ showed that while plants do not require 

cold, 6 weeks of 41F (5C) resulted in more vigorous plants and more uniform 

flowering. When cold was provided, photoperiod was unimportant. When 

cold was not provided, plants required long days of at least 14 hours (Frane et al. 

2000).


Yield: For most locales, yield will be minimal the first year and increase over 

2–3 years. Yield varies, from 1 to 4 or 5 stems per plant. 

Spacing: Plants can be spaced 12–18" (30–45 cm) apart. 


LOBELIA 405 

Lobelias can be forced in the off season if plugs are cooled for 6 weeks at 40F (4C) 

then placed under long days at 68–72F (17–22C) after cooling has been completed. 

Long days may be accomplished through daylength extension or a 4hour 

nightbreak using incandescent lights. Flowering time ranges from 85 days 

at 59F (15C) to 39 days at 80F (27C) after transplanting (Frane et al. 2000). In 

general, the cooler the temperature the better the quality of stem. 

Cultivars 

Many of the following are hybrids, often referred to as Lobelia ×speciosa, a catchall 

name for the numerous hybrids developed from L. splendens (syn. L. fulgens; 

Mexican lobelia), L. cardinalis, and L. siphilitica. These hybrids are longer lived and 

more tolerant of soil types and moisture. They don’t have the winter hardiness 

of L. cardinalis or L. siphilitica, but some are most glorious plants and worth a try 

even if they flower only for a single year. Most are winter hardy to Zone 5 at best, 

many only to Zone 6. 

‘Bees’ Flame’ bears vermilion-red flowers and beet-red foliage and can reach 

heights of 5' (1.5 m). Absolutely magnificent in moist, partially shaded 

conditions. 

‘Brightness’ is 3–4' (0.9–1.2 m) tall with bright cherry-red flowers atop dark 

bronze foliage. 

Compliment series, available from seed, is mid-sized and probably the most 

popular group of lobelias for cut flowers. Hardy to Zone 4, flower colors include 

deep red, scarlet, violet, and a mix. 

‘Cranberry Crowns’ bears cranberry-red flowers and grows about 2' (60 

cm) tall. 

‘Dark Crusader’ provides dark purple foliage in combination with blood-red 

flowers. 

Fan series consists of burgundy, scarlet, and deep rose flowers. Plants are only 


‘Illumination’ bears large spikes of exceptionally bright, deep scarlet flowers 

over bronze foliage. 

‘Pink Flamingo’ has rich rosy-pink flowers in late summer. 

‘Queen Victoria’ is the most popular cardinal flower with brilliant red flowers 

over bronze foliage. In flower, plants grow 3–4' (0.9–1.2 m) tall. Not as cold hardy 

(Zone 6) as most cultivars. 

‘Royal Robe’ bears deep red flowers with maroon leaves. 

‘Ruby Slippers’ produces bright garnet-red flowers on robust plants.

406 LOBELIA 

‘Russian Princess’ has bright reddish purple flowers with purple foliage. 

‘Wildwood Splendor’ produces large lavender flowers in late summer. 


Lobelia siphilitica (big blue lobelia) flowers later than L. cardinalis, and flowers 

persist about 4 weeks. Constant moisture and partial shade are necessary for 

optimum performance; plants are short-lived and should be divided and moved 

every 2–3 years. Few cultivars have been bred; however, ‘Blue Peter’ has light blue 

flowers on a 3' (90 cm) plant and may prove more perennial than others. 


Lobelias are susceptible to crown and root rots (Pythium) and botrytis. Pests 

include fungus gnat larvae, plant bugs, red-banded leaf roller, southern rootknot 

nematodes, slugs, and thrips. 

Reading 

Frane, A., E. Runkle, R. Heins, A. Cameron, and W. H. Carlson. 2000. Forcing 

perennials, Lobelia ×speciosa ‘Compliment Scarlet’. In Firing Up Perennials: the 

2000 Edition. Greenhouse Grower, Willoughby, Ohio. 

Lunaria annua honesty Brassicaceae 

biennial Europe violet, white 2–3'/2' (60–90 cm/60 cm) 

Lunaria annua is grown as a biennial; however, plants will reseed if allowed to do 

so, so they need not be replanted each year. Interest in the species as an industrial 

crop developed from the discovery that it has a seed oil content of 30–40%, with 

high levels of erucic and nervonic acids (Cromack 1998). The flowers, although 

handsome, are of little value as cut flowers because of their tendency to shatter, 

but the slim, round, transparent fruits, which form rapidly after flowering, are 

excellent dried material (and give the species its other common name, money 

plant). 

Propagation 

Seed should be direct sown at the rate of 0.7 oz per 100' (80 g per 100 m) (Kieft 

1996). Seed may be sown in the fall in mild climates, very early spring in harsher 

climes. If sown in the fall, expect germination in late winter; spring sowings germinate 

in the field in 2–3 weeks. 

Although usually direct sown, seed may be sown in the greenhouse at 65–70F 

(18–21C) under intermittent mist and will germinate in 10–14 days. Approximately 

1 oz (28 g) of seed yields 1000 seedlings (Nau 1999). Plantlets, grown in 

open pack, may be transplanted in 3–4 weeks. If grown in plugs, transplant to the

Lunaria annua (fruit)

408 LOBELIA 

field or 4" (10 cm) containers after 6–8 weeks. Transplant with care; they decline 

if roughly handled. 

Growing-on 

Grow at 60F (15C) night temperatures. Fertilize with 100 ppm N, using a complete 

fertilizer. 


Photoperiod: Plants require a cold treatment (vernalization) for proper flowering. 

Although the main trigger to flowering is cold temperature, LD (16 hours) 

after vernalization result in faster flowering than SD (8 hours) (Wellensiek 1985). 

Once vernalized, however, plants will flower regardless of photoperiod. 

Light intensity: High light intensity results in faster flowering after vernalization. 

Temperature: Approximately 10 weeks of cold temperatures (40F, 4C) are necessary 

for flowering. Seedlings should be at least 6 weeks old before vernalization 

is applied. If vernalization is not sufficiently long or cold, some plants do not 

flower and lateral flowers predominate. Under optimal vernalization conditions, 

lateral and terminal flowers occur side by side. Seed vernalization has a partial 

effect on flower induction (Wellensiek 1985). 


Spacing: Space transplants or thin seedlings to 10 × 18" (25 × 45 cm) or 12 × 

12" (30 × 30 cm) spacing. One-year-old transplants may be purchased and 

planted at the proper spacing. Partial shade is useful in hot climates, full sun in 

more temperate areas. 

Fertilization: Apply side dressings of granular fertilizer such as 8-8-8 in the 

spring and summer, or apply 500–700 ppm N once a week with a water-soluble 

fertilizer. 


Using one-year-old precooled plants only, grow in 6–8" (15–20 cm) containers or 

space 9" (23 cm) apart in a greenhouse bench. After approximately 3 weeks in the 

greenhouse, use incandescent lights to provide 16-hour days until flower buds 

are visible. Fertilize with a water-soluble fertilizer (100–150 ppm N) with each 

irrigation. Support may be necessary. 


Harvest the pods when they are fully developed. Pods may be green, translucent, 

or purple (var. purpurea) as they dry naturally on the plant. Strip the main leaves

LOBELIA 409 

but allow the finer ones to remain. Bunch and hang upside down in a warm, 

dark place for 4–5 weeks. The pods are ready when the papery covering is easily 

removed. 

Postharvest 

The flowers, which are generally harvested in May and June, may be cut for fresh 

arrangements and persist a maximum of 3–5 days. The seed pods, once air-dried, 

should persist indefinitely. 

Cultivars 

Seeds of white-, red- and purple-flowered cultivars are available, but they all produce 

the same color and shape of fruit. If the color could be retained, the purple 

fruits of var. purpurea would be a welcome market addition. A cultivar with variegated 

foliage, var. folio-variegata, is also found. 


Lunaria rediviva (perennial honesty) bears elliptical seed pods. The plants, 

once established, are perennial and persist 3–5 years. The fruit is not considered 

to be as ornamental as the biennial form, an unfortunate misconception. 


Numerous fungal species (Alternaria oleracea, Helminthosporium lunariae) attack 

the foliage or pods, resulting in brown to black spotting of the infected areas. 

Application of a general fungicide can reduce the damage. Root rots from Phytophthora 

and Rhizoctonia spp. also occur. Waterlogged soils result in Phytophthora 

infections. Club root, in which the feeder roots are destroyed and the main roots 

develop abnormally, is a result of Plasmodiophora brassicae; fungicidal drenches 

have been effective against it. 

Leaf rollers, thrips, and aphids are the major insect pests. 


“I did sell it to upper-end shops, with repeat sales. I remember one designer 

telling me that she loved the pure white color, and although it looked very frail, 

it held up well to all her abuse.The pods work well as a fresh green cut. Green has 

been a color that everyone couldn’t get enough of over the past few years, and 

these things really fit right in. I also cut the green pods to dry. They hold the 

green color really well. I let them get just a little more mature to dry, so the pod 

will survive, but not so mature that it becomes brown and comes apart.” Bev 

Schaeffer, Schaeffer Flowers, Conestoga, Pa.

410 LYSIMACHIA CLETHROIDES 

Reading 

Cromack, H. T. H. 1998. The effect of sowing date on the growth and production 

of Lunaria annua in southern England. Industrial Crops and Products 7:217–221. 


Netherlands. 


Wellensiek, S. J. 1985. Lunaria annua. In The Handbook of Flowering. Vol. 3. A. H. 


Many thanks to Bev Schaeffer for reviewing this section. 

Lysimachia clethroides gooseneck loosestrife Primulaceae 

perennial, Zones 3–8 China, Japan white 2–2½'/3' (30–45 cm/90 cm) 

The genus consists of many excellent garden, landscape, and cut flower species, 

but gooseneck loosestrife is probably the best known. Plants are easily grown 

and can spread rapidly. Flower stem production is excellent as far south as Zone 

7, but in Zone 8 in the Southeast and Southwest, flower are smaller and stems are 

thinner. Flowers appear in late spring (Zone 7) or summer (Zone 7 and colder). 

Propagation 

Division: Division is the most common means of propagation; plants roam 

freely, and the rhizomes may be easily divided after flowering. 

Seed: Seed (not always easy to obtain) should be barely covered and placed at 

65–68F (18–20C). Germination is erratic. 

Growing-on 

Transplant to cell packs, plugs, or 4" (10 cm) pots as soon as seedlings can be 

handled. Grow at 50–60F (10–15C) for 6–8 weeks with as much light as possible. 

Fertilize lightly with 50–100 ppm N of a complete fertilizer. Transplant to field 

in fall or early spring. 


Cold is not necessary to break dormancy in rhizomes, although shoots from 

noncooled roots emerge significantly slower and flowering is greatly delayed 

compared to cooled roots; 10 weeks of case-cooling at 39–40 (3–4C) yields most 

rapid emergence and flower production (Lewis et al. 1999). Plants grown in continuous 

short day conditions did not flower, and at least 10 weeks of long day 

(nightbreak lighting) were needed for optimal development and flowering under 

greenhouse conditions (Lewis et al. 2000).


LYSIMACHIA CLETHROIDES 411 

Lysimachia clethroides 

Spacing: Plant on 12" (30 cm) centers. Plants fill in rapidly and, within 2 years, 

cover the planting area. Support netting is necessary. 

Yield: Two-year yields and stem lengths are shown in the following table. 

Yields and stem length in the second year were much better than the first. Stem 

length in California was longer than in Georgia for both years; however, yield was 

almost double in Georgia in year 2.

412 LYSIMACHIA CLETHROIDES 

Two-year yields and stem lengths in Athens, Ga., and Watsonville, 

Calif. 

Georgia California 

Shade Stems/ Stem Stems/ Stem 

Year level (%) plant length (in) z plant length (in) z 

1 0 12 *15.8* 8 27.0 

2 0 39 27.6 20 42.0 

2 55 30 34.9 * * 


* = plants in California were not grown in shade 

In the third year at Athens, Ga., plants spread with wild abandon and yield rose 

astronomically. Yield for the original 48 plants was 6030 stems, an average of 126 

stems/original plant! Stem length averaged 40" (1 m) in the full sun. We thought 

the place would be carried away with loosestrife. 

Shade: As the data in the preceding table from the University of Georgia show, 

although plants grown under 55% shade had longer stems, yield was reduced 

by 9 stems/plant. Stem diameters were unaffected. 

Field problems: Ron Smith, of Renfrew, Pa. (Zones 5 and 6), acknowledges the 

extreme aggressiveness of the plants but telegraphs their good points: “very productive, 

easy pest control, good demand; and a bunch of 10 stems, 30" (75 cm), 

is easy to handle and hardly takes up any space.” But then he gets to the “almostfatal 

flaw”: “[Their] season starts just before July 4, and lasts for 2–3 weeks in 

July, the slowest time of the year. I’ve tried cutting back the stems at various 

times and heights, in order to delay bloom time, but the secondary stems that 

result are always weaker and smaller.” 


Greenhouse production is not uncommon in Europe and on the west coast of 

Canada and the United States. Some of the finest material we have seen comes 

from Gerard Smit in Abbotsford, B.C., who rotates lysimachia along with astilbes, 

phlox, solidago, and peonies in rolling “moveable” greenhouses. Production 

is also excellent in standard greenhouse structures elsewhere. 

Lewis et al. (1999, 2000) provides useful guidelines for winter greenhouse 

production. She suggests case-cooling the rhizomes for 10 weeks at 40F 

(4C), then potting up in containers or beds. Stems emerge in approximately 2 

weeks at 68F (20C). More than 10 weeks cooling resulted in shorter stems with 

little decrease in forcing time, as seen in the following table (Garner and Lewis 

1999).

The effect of cooling rhizomes on flowering, yield, and stem 

length of Lysimachia clethroides. 

Cooling duration Greenhouse days Stems/ Stem 

at 40F (4C) to flower plant length (in) z 

0 170 1.4 37 

4 170 3.2 40 

6 165 3.7 41 

8 150 4.4 44 

10 140 4.0 47 

12 135 2.7 33 


LYSIMACHIA CLETHROIDES 413 

She suggests that LD be applied through incandescent nightbreak lighting from 

10 p.m. to 2 a.m. approximately 6 weeks after emergence. If LD are applied at 

emergence, flowering is faster than if plants do not receive LD until plants have 

grown in natural SD for 6–8 weeks; however, stem strength, yield, and raceme 

length are of poorer quality. First flowers open 15–22 weeks after cooling, depending 

on light and photoperiod regime (Lewis et al. 1999, 2000). 

Supplemental light is recommended if winter light is low, for example in the 

Midwest and Northwest. 

Day/night temperatures of approximately 68/65F (20/18C) provided excellent 

results; however, cooler temperatures of 65/60F (18/15C) day/night have 

also been successful (Iversen and Weiler 1994). The cooler the temperatures, the 

longer the forcing time. 

Scheduling: The following chart provides several schedules suggested by Garner 

and Lewis (1999) for forcing gooseneck loosestrife in the greenhouse. 


Harvest when flowers in the inflorescence are ⅓ to ½ open. This occurs when 

about 10 flowers are open. If placed in a complete preservative (e.g., Floralife), 

flowers may be harvested when the majority of flower buds are white but not 

open. 

Postharvest 

Fresh: Work conducted at the University of Georgia showed that flowers cut 

at the proper stage of harvest persisted 12 days in Floralife and Rogard but 

lasted only 5 days in water. Various concentrations of STS were ineffective. Sugar 

concentrations were better than water but not as effective as the floral preservatives 

tested—the differences were like night and day. 

Storage: Store flowers at 36–41F (3–5C) whenever possible.

Greenhouse schedules for Lysimachia clethroides. 

Valentine’s 

Day 

Easter 

Sunday 

Secretaries’ 

Day 

Mother’s 

Day 

Jul Aug Sep Oct Nov Dec Jan Feb Mar Apr May Jun 

l l l l l l l l l l l l 

26 Jul 

10 weeks cooling 

8 Sep 

4 Oct 

18 Oct 

2 

weeks 

to 

emergence 


2 Oct 

29 Nov 

14 weeks to visible 

bud formation 

2 

weeks 

to 

emergence 


20 Oct 

24 Jan 

3 

weeks 

to 

flower 

⇑ Begin lighting by 6th week 

17 Nov 

1 Dec 

11 Dec 

25 Dec 

2 

weeks 

to 

emergence 


12 Jan 


bud formation 

29 Dec 

12 Jan 

2 

weeks 

to 

emergence 

14 Feb 

5 Feb 

23 Feb 

9 Mar 

3 

weeks 

to 

flower 



bud formation 

30 Mar 

2 Apr 

3 

weeks 

to 

flower 



bud formation 

23 Apr 

20 Apr 

3 

weeks 

to 

flower 


11 May


MATTHIOLA INCANA 415 

Lysimachia ephemera is similar in that the flowers are elongated and white, 

without the distinctive “gooseneck.” They are also much less aggressive: their 

yield is far less, and the flowers provide much less “flower power.” A poor performer 

south of Zone 7a and north of Zone 5. 

Lysimachia punctata (yellow loosestrife) is a useful cut, with yellow flowers 

borne in whorls in the nodes along the stem. Plants are about 2' (60 cm) tall. 

Lysimachia purpurea has only recently been tried as a cut flower. Flowers are 

rusty purple and stand about 2½' (75 cm) tall. May have potential. 

Lysimachia vulgaris (also known as yellow loosestrife) has ½" (13 mm) wide, 

yellow flowers with orange dots clustered in panicles (like Phlox paniculata). 

Plants are 2–3' (60–90 cm) tall. 


Few problems occur if plants are provided with well-drained soils and full sun 

exposure. 


“We started both [Lysimachia clethroides] and [L. punctata] for perennial sales. They 

are prolific and aggressive growers. Punctata is excellent in the vase in its early 

blossoming—less shattering. The foliage fills the vase nicely too, and here in the 

Northeast, it’s one of the earliest bloomers. Gooseneck loosestrife is perhaps my 

favorite cut flower. It lasts up to 2 weeks in the vase and the foliage is wonderful.” 

Karen Hanley, Stork Road Farm, Reading, Pa. 

Reading 

Garner, J. M., and P. Lewis. 1999. Greenhouse production of herbaceous perennials 

for cut flowers: Lysimachia clethroides. The Cut Flower Quarterly 11(4):16– 

17. 

Iversen, R., and T. Weiler. 1994. Strategies to force flowering of six herbaceous 

garden perennials. HortTechnology 4(1):61–65. 

Lewis, P. M., A. M. Armitage, and J. M. Garner. 1999. Cooling accelerates flowering 

of Lysimachia clethroides Duby. HortScience 34(3):239–241. 

———. 2000. Photoperiod affects growth and flowering of Lysimachia clethroides 

Duby. HortScience 35(4):596–599. 

Matthiola incana stock Brassicaceae 

annual Mediterranean many colors 2–3'/2' (60–90 cm/60 cm) 

Stocks have long been a favorite cut flower for their form, color, and fragrance. 

Requiring cool temperatures for optimum flowering and quality, they are usu-

416 MATTHIOLA INCANA 

ally seen in northern flower-producing areas and the West Coast. Breeders have 

been steadily increasing the percentage of double flowers from a sowing, but 

additional work to stabilize doubleness and fragrance in flowers is still necessary. 

The greater the percentage of double flowers, the more profitable the crop will 

be. Doubleness has been genetically linked with light green leaves when grown 

at 50F (10C), and it is theoretically possible to select for 100% double flowers in 

some seed strains if started in the greenhouse. Unless cultivars have been selected 

for doubleness, most are still 50–60% double. 

Propagation 

There are about 19,000 seeds/oz (630 seeds/g), depending on cultivar. Seed sown 

at 60–68F (15–20C) germinates in 5–12 days. Approximately 0.25–0.5 oz (7–14 

g) of seed yields 1000 seedlings (Nau 1999). Direct sowing is not recommended 

for everyone, unless water management can be perfectly maintained. If sown in 

open packs, transplant to 3–4" (8–10 cm) containers 14–21 days from sowing. If 

grown in plugs, grow for 4–6 weeks. 

Growing-on 

If produced in plugs, apply 75–100 ppm N fertilizer at each irrigation. Temperatures 

of 50–55F (10–13C) should be applied as soon as plants are removed from 

the propagation area. Plants may be placed in the field in fall or early spring after 

8–10 weeks in the greenhouse. 


Temperature is the main environmental factor affecting flowering in stock, 

although photoperiod and juvenility also influence flowering time. 

Temperature: Although great diversity exists in the response of different cultivars, 

high temperature generally delays flowering while low temperature promotes 

it (Roberts and Struckmeyer 1939, Howland 1944). Most cultivars (‘Column’, 

‘Bismarck’, ‘Avalanche’, e.g.) fail to initiate flowers at temperatures above 

65F (18C), and those that do (‘Brilliant’) are usually later and produce more 

leaves than when grown below 60F (15C). 

Late-flowering types require lower temperatures for a longer period of time 

than those classified as early-flowering types. In general, early-flowering types 

require fewer than 10 days at 50–55F (10–15C); about 3 weeks may be necessary for 

late-flowering cultivars. Although floral initiation occurs rapidly, low temperatures 

should be maintained for an additional 15–20 days after floral initiation. 

Photoperiod: Long days provided before or during the cold treatment usually 

result in faster flowering at a lower leaf number compared to SD (Post 1942, 

Biswas and Rogers 1963, Heide 1963). Long days can partially substitute for cold 

in some cultivars and result in earlier flowering where temperature treatments


Matthiola incana 

‘QIS White’ 

are not fully satisfied (Biswas and Rogers 1963, Heide 1963). Long day treatments 

may be provided by daylength extension or nightbreak lighting. 

Juvenility: The timing of the application of cold treatment varies with cultivar. 

In general, cultivars classified as early flowering have a short juvenile period and 

form few leaves; those classified as late flowering have a longer juvenile period 

and form more leaves before the first flower bud (Cockshull 1985). Some flowering 

types and their response to cold treatment are shown in the following table 

(Post 1942, Kohl 1958, Heide 1963).


The effect of application time of cold treatment (50–55F, 10–13C for 14–21 

days) depends on age and cultivar. 

Juvenility No. of mature No. of 

Flowering (days from leaves at Days to leaves at 

Cultivar type sowing) time of cold visible bud visible bud 

Brilliant early 15 2 40 16 

Column medium 38 10 70 * 

Avalanche late 57 * 86 42 

* = no data available 

With most cultivars, regardless of flowering classification, the older the plant, 

the shorter the period of cold treatment needed. Vernalization of seed is of no 

benefit (Howland 1944). 

Chemical control: Work with GA3 has shown some acceleration of flowering, 

but results are inconsistent. Application of prohexadione-calcium (PCa), a GA 

inhibitor, resulted in faster flowering (Hisamatsu et al. 1999) but is still highly 

experimental. 


Stocks can be field-grown successfully only in areas of mild winters and/or cool 

summers, such as Texas, Arizona, the West Coast, and parts of Florida. Selectability 

is less important in the field, and the higher cost of selectable seed cannot 

usually be justified. If a high percentage of doubles are desired, then seedlings 

must be transplanted after selection in the greenhouse. 

Spacing: Space plants on 6–10" (15–25 cm) centers. A dense spacing such as 6 

× 8" (15 × 20 cm) increases yield/ft2 , but the potential for disease and insect 

problems is also increased. Direct sowings may be as close as 3" (8 cm) apart, 

but some thinning of seedlings must be done. Too dense a planting results in 

thin stems and additional disease pressure. 

Support: Netting is seldom used for stock production. It is necessary only 

where temperatures are too high. Night temperatures should remain around 

50F (10C) during the duration of the crop. If temperatures are consistently above 

70F (21C), support may be necessary. 


Stocks may be greenhouse-grown in the winter in all Midwestern and northern 

areas. Plants are generally sown in plugs and transplanted to final beds or containers. 

They are best grown in approximately 220-cell plugs and transplanted 

just as the root ball forms; do not allow the seedling to become root bound. 

Transplant approximately 25 days after sowing from a 220-cell plug pack (Goto 

et al. 1999). Plants grow best in a glass greenhouse, but work in Canada using 3-

year polyethylene showed that when energy savings were considered, growing 

stocks under poly resulted in saleable crops (Dansereau et al. 1998). 

Spacing: Greenhouse spacing as dense as 3 × 6" (8 × 15 cm) or as wide as 1' (30 

cm) centers is used. A spacing of 6 plants/ft 2 (65 plants/m 2 ) is common. Two 

tiers of support are recommended (Nau 1990). 

Fertilization: Nutrition is critical for best growth and flowering. Stocks are 

sensitive to potassium deficiency, and fertilizers such as potassium nitrate are 

most effective. Potassium deficiency causes leaves to die from the tip and margin 

to the base. Older leaves are most sensitive, and the symptoms are most visible at 

flowering time. Overfertilization can also be a problem. High applications of 

nitrogen result in soft, thin stems and should be avoided. 

Temperature: Seedlings should be grown at 60–65F (15–18C) until they have 

approximately 8–10 leaves (10–30 days, depending on cultivar) prior to lowering 

temperatures for the cold treatment. The length of this “warm” temperature 

influences the ultimate stem length (Post 1955). Seedlings started at low temperatures 

are dwarfed. 

Work with day/night temperature difference (DIF) showed that a positive 

DIF (day temp > night temp) resulted in taller plants than a constant temperature, 

but negative DIF resulted in suppressed growth (Ito et al. 1997). Negative 

DIF is useful in the seedling stage, to reduce stretching and maintain compact 

growth, but should be avoided during later growth. Night temperatures of 50F 

(10C) should be applied for a minimum of 3 weeks but preferably for 6 weeks. 

Once the cold treatment has been applied, temperatures should remain around 

55–60F (13–15C) for the duration of the crop. Flower buds form after the 

15th leaf on early-flowered cultivars if conditions are favorable. Temperatures 

above 65F (18C) result in weaker, taller plants and necessitate the use of support 

netting. 

Light and photoperiod: Long days, using incandescent lights as a 4-hour nightbreak 

or day extension (16 hours), are useful during or after the cold period. 

Incandescent lights, however, cause excessive elongation of the stem and should 

not be applied after the appearance of color on the flower buds (Post 1955). 

Scheduling: In the Midwest, holiday crops may be scheduled as shown in the 

following table (Nau 1990). All cultivars used should be selectable. 

Sowing times for holiday crops in the Chicago area 

(Zone 5). Night/day temperatures 45–50/55–60F 

(7–10/13–15C). 

Flowering for . . . Sow seed on . . . 

Christmas 15 Jul 

Valentine’s Day 1 Sep 

Easter (late March) 1 Oct 

Mother’s Day 15 Dec 

June weddings 25 Feb 

MATTHIOLA INCANA 419


Approximately 6–7 months are necessary for flowering in January to March 

unless supplemental lighting is used at the temperatures given earlier. 

With cultivars such as the Vegmo series, winter production (November 

December planting) requires about 4 months; spring production (January– 

March planting), 3 months; summer production (April–July planting), 2½ 

months; fall production (August–October planting), 2–3 months. 

With later sowings, it is more difficult to maintain cool temperatures, and 

quality may suffer. Crop time can be significantly reduced if temperatures are 

raised; however, quality is also reduced. 


Stems should be harvested when ½ the flowers in the inflorescences are open. 

Stems should be immediately placed in preservative and out of the sun. Do not 

allow cut stems to remain out of water or in the heat, for postharvest life will be 

significantly reduced. Do not crush stems. Retailers generally expect the lower ⅔ 

of the flowers to be open. 

Postharvest 

Fresh: If stems are recut frequently and kept away from excessive heat, fresh 

flowers persist 7–10 days in a preservative. Pretreating the stems after cutting 

with sugar (7%) and STS, even combined with GA3, increased subsequent vase 

life by only 2 days when later placed in water. Placing the stems in 1% sugar plus 

a biocide (HQC) without a pretreatment added 4 days, and the two in combination 

added 5 days to subsequent vase life after storage (Young et al. 1996). 

Dried: Harvest flowers when fully open and hang in small bunches (3–5 stems) 

in a warm place. If dried rapidly, stocks retain their fragrance. 

Storage: Stems may be stored dry for 2 days, although wet storage is recommended. 

Storage temperatures should be 36–41F (3–5C). Prolonged refrigeration 

results in loss of fragrance. Hold stocks in the dark to avoid stem elongation 

and curving of the growing tip. 

Cultivars 

Selectability 

The ability to distinguish double-flowered seedlings from single-flowered ones 

is an important issue in stock breeding. Double forms are gray-green and generally 

less vigorous than single forms, but removing the singles is a difficult job 

at best, and almost impossible if seeds are direct sown in the field. 

The currently accepted method of selection is to expose the seedlings to 41F 

(5C) for 5–7 days. Seedlings should be watered thoroughly one day prior to exposure, 

which is accomplished 15–20 days after sowing. After removal from the 

cold, the double-flowered forms appear yellow and chlorotic within a couple of 

days, while the single-flowered forms remain green and vigorous, and have


smoother leaf margins. Selection should be done early in the morning and out 

of full sun: cotyledon color is easier to differentiate in the shade than in sunlight. 

The good-looking ones are then discarded, and the chlorotic ones remain. 

They will green up in a few days. As breeding becomes more refined, selectability 

will become a thing of the past, and cultivars will be 90–100% double without 

selection. A few cultivars have already attained nonselectable double status; 

many more will be introduced in the future. 

Selectability is more important in greenhouse-grown crops than in the field; 

however, if plants are to be transplanted rather than direct sown, selectable cultivars 

can be used successfully. Selectable cultivars are more expensive and nearly 

always used in the greenhouse, because of higher costs of greenhouse forcing. 

Field cultivars 

Almost without exception, cultivars recommended for field culture are less 

expensive and less hybridized than those used for greenhouse production. They 

are usually nonselectable for doubleness. Confusion reigns in catalogs: the cultivars 

may be listed separately or they may be lumped together, as column stocks, 

excelsior stocks, mammoth stocks, or a strain of stocks. Many breeders and distributors 

have their own numbered strains, such as No. 21 Lilac Heart (Ball). 

These field cultivars offer strong stems and 50–60% double flowers. Individual 

colors include ‘American Beauty’ (carmine-red), ‘Appleblossom’, ‘Avalanche’ 

(white), ‘Illusion’ (red with yellow eye), ‘Malmaison Pink’ (pastel salmon-pink), 

‘Pacific Blue’ (mid-blue), ‘Sweetheart Pink’, and ‘White Christmas’. Numbered 

and colored strains (e.g., Apricot) and Giant Excelsior Strain are also offered in 

this potpourri. Height of the flowering plants is 2–3' (60–90 cm). 

Goddess series grows 2–3' (60–90 cm) tall and is offered in orchid, white, and 

yellow. 

Miracle series bears flowers of blue, crimson, gold, lavender, white, and yellow. 

Trysomic series is said to be 85% double in a mix of carmine, lilac, lavender, 

white, rose-pink, yellow, and purple. Height is about 15" (38 cm). 

‘White Beach’ provides double white flowers. 

Greenhouse cultivars 

All are selectable. 

Frolic series flowers with less cold and is therefore a little earlier than many 

others. Available in 7 colors and a mix and grows 2–3' (60–90 cm) tall. 

Glory series flowers a little earlier than Xmas series. Bred in cherry, lavender, 

pink, rose, and white. 

Joy series has flowers in lavender, light pink, red, white, and a mix. 

Lucinda series provides uniformity of germination and flowering and comes 

in white, cream, light rose, dark rose, red, lavender, and deep blue. 

Mid Cheerful series is later than Cheerful. Plants require more cooling to 

flower but potentially produce a longer flower stalk with closely spaced florets. 

‘Mid Cheerful White’ and ‘Mid Cheerful Yellow’ are available. 

Nordic series, bred especially for northern greenhouse conditions, is offered 

in 7 colors.


Vegmo series offers 13 colors including white (‘Aida’), dark blue (‘Debora’), 

pink (‘Lena’), deep rose (‘Nabucco’), and brick-red (‘Siberia’). Final height is 2– 

2½' (60–75 cm) and seedlings are 100% selectable. 

Wonder series bears nonbranching, 2–3' (60–90 cm) tall flower stems and is 

60–90% double. ‘White Wonder’ and ‘Snow Wonder’ have similar flowers but 

differently shaped foliage. 

Xmas series grows 3' (90 cm) tall; bears nonbranching, mostly double flowers; 

and is early to flower. Blue, purple (‘Xmas Ocean’), red, rouge, pink, rose, ruby, 

white, and violet are available. What do you think an Xmas Ocean is, anyway? 

Cultivars for greenhouse and field 

Cheerful series grows 2–3' (60–90 cm) tall. Minimum cold is necessary. Available 

in a limited number of colors, mainly white and yellow, and a mix. Its high 

percentage of doubleness makes it more popular in the greenhouse. 

Goldcut series is available in dark blue, light blue, ruby-red, rose, rosy red, 

white, yellow, and a mix. Plants are about 30" (75 cm) tall. 

QIS series is available in 10 colors. One hundred percent selectable. Best performance 

in the greenhouse. 

Regal series is said to require no selection and claims 95% doubleness. ‘Regal 

White’ is most common. 

Ultra Strain has been selected for doubleness. Plants are 2–2½' (60–75 cm) 

tall. ‘Crispy’ and ‘Madonna’ are early and midseason white selections, respectively. 


Bacterial rot (Xanthomonas incanae) produces a green water-soaked line on the 

stem of the seedling. The stem later turns dark brown and cracks, and the plant 

dies. Older plants may also be infected. When stems of older plants are cut open, 

a yellow liquid is clearly visible. The bacterial spores can overwinter on debris 

and can be spread in irrigation water and through cultivation equipment. Problems 

are greater in heavy soils and where overhead irrigation is employed. The 

bacteria can also be seed-borne; to control, soak seeds in 130F (54C) water for 10 

minutes. 

Club rot (Plasmodiophora brassicae), also known as slime mold, affects many 

plants in the Brassicaceae. Main roots develop abnormally and form swellings 

similar to crown galls; feeder roots are often destroyed and slimy in appearance. 

Plants die without flowering. Fungicides have been effective, but discarding 

infected plants may be the best solution. 

Damping off of seedlings is caused by soil fungi, which may be controlled 

with sterile soilless mixes and other standard sanitary procedures. 

Downy mildew (Peronospora parasitica) results in pale green spots on the upper 

surface of the leaves and downy mold on the lower surface. Foliage wilts, plants 

are stunted, and flowers develop poorly, if at all. Avoid crowding the plants and 

provide as much ventilation as possible. Placing warm water pipes around and 

over the crop reduces mildew considerably. Sterilize all media.


Verticillium wilt (Verticillium albo-atrum) results in yellow basal leaves and 

severe stunting. Vascular tissues are often discolored, and flowering is inhibited. 

Crop rotation and soil sterilization are essential to breaking the wilt cycle. 

Diamondback moths, flea beetles, and springtails are serious pests and cause 

significant damage to foliage and flowers. 

Aphids and thrips can also plague stock plantings. 


Short plants develop when the temperature is too low during the seedling stage. 

Sow seed when soil temperature is above 60F (15C). 

Blind plants, which fail to form flowers, likely result from an insufficient 

period of time below 60F (15C) or too long a period above 80F (27C). This was 

more of a problem with earlier types than with current cultivars; however, if 

sown between late February and late July, blindness can still be a major headache. 

“Skips” are flowers with blank areas in the middle of the inflorescence. This 

problem, which is more prevalent in northern growing areas, may be attributable 

to low light levels just after flowers have initiated. 

Reading 

Biswas, P. K., and M. N. Rogers. 1963. The effects of different light intensities 

applied during the night on the growth and development of column stocks 

(Matthiola incana). Proc. Amer. Soc. Hort. Sci. 82:586–588. 

Cockshull, K. E. 1985. Matthiola. In The Handbook of Flowering. Vol. 3. A. H. Halevy, 


Dansereau, B., Y. Zhang, S. M. Gagnon, and H. L. Hu. 1998. Stock and snapdragon 

as influenced by greenhouse covering materials and supplemental 

light. HortScience 33(4):668–671. 

Goto, T., Y. Kageyama, and K. Konishi. 1999. Effects of cell volume and transplant 

age in cell flat on growth and flowering after transplanting in Antirrhinum 

majus L. and initial growth after transplanting in Matthiola incana R. Br. 

Scientific Reports Fac. Agric. Okayama Univ. 88:47–55. 

Heide, O. M. 1963. Juvenile stage and flower initiation in juvenile stocks (Matthiola 

incana R. Br.). J. Amer. Soc. Hort. Sci. 38:4–14. 

Hisamatsu, T., S. Kubota, and M. Koshioka. 1999. Promotion of flowering in 

stock [Matthiola incana (L.) R. Br.] by prohexadione-calcium in plastic-film 

greenhouse conditions. J. Jap. Soc. Hort. Sci. 68(30): 540–545. 

Howland, J. E. 1944. Preliminary studies on low temperature vernalization of 

column stocks, Matthiola incana. Proc. Amer. Soc. Hort. Sci. 44:518–520. 

Ito, A., T. Hisamatsu, N. Soichi, M. Nonaka, M. Amano, and M. Koshioka. 1997. 

Effect of diurnal temperature alternations on the growth of annual flowers on 

the nursery stage. J. Jap. Soc. Hort. Sci. 65(4):809–816. 

Kohl, H. C., Jr. 1958. Flower initiation of stocks grown with several temperature 

regimens. Proc. Amer. Soc. Hort. Sci. 72:481–484. 

Nau, J. 1990. Stock growing comments. In Proc. 3rd Natl. Conf. on Specialty Cut 

Flowers. Ventura, Calif.

424 NARCISSUS 

Post, K. 1942. Effects of daylength and temperature on growth and flowering 

of some florist crops. Cornell Univ. Agr. Exp. Sta. Bul. 787:58–61. 

———. 1955. Florist Crop Production and Marketing. Orange Judd, New York. 

Roberts, R. H., and B. E. Struckmeyer. 1939. Further studies on the effects of 

temperature and other environmental factors upon the photoperiodic responses 

of plants. J. Agric. Res. 59:699–709. 

Young, S. C., B. ChangSeok, H. KunYang, and S. JeongSeob. 1996. Effects of 

preservatives and cold storage on vase life and quality of cut hybrid stock 

(Matthiola incana). RDA J. Agr. Sci., Hort. 38(1):598–603. 

Many thanks to Jim Nau (first edition) and Bill Borchard and Blair Winner (second 

edition) for reviewing this section. 

Narcissus daffodil Amaryllidaceae 

bulb, Zones 3–9 Spain, Portugal many colors 1 

18–24"/12" (45–60 cm/30 cm) 

Narcissus is forced for cut flowers for Valentine’s Day through Mother’s Day 

and may be produced in the greenhouse or field. Hundreds of cultivars are available, 

some far more expensive than others; registered cultivars have been divided 

into 11 classes, depending on parentage and morphological characteristics such 

as length of the trumpet or cup. Most cultivars used for cut flowers belong to the 

trumpet (class I) or large-cupped (class II) narcissus, but any classification can 

provide useable flowers. The tazetta forms (class VIII; paperwhites), which 

require no cold for forcing, are chiefly greenhouse-grown and may be field-produced 

only in nearly frost-free areas of the country. 


Most daffodils require a warm-cool-warm temperature sequence: the initial 

warmth occurs in the summer for flower initiation, and the winter cool results 

in subsequent rapid growth and synchronous flowering once warm weather 

recurs in the spring. Generally, bulbs are planted in pots or bulb crates, then 

stored at a temperature around 48F (9C) for about 120 days prior to warm temperatures 

for flower emergence. Daffodils are not as critical in their temperature 

requirements as tulips (which see); planted bulbs may be stored in cold 

frames or under straw mulch outdoors to achieve these temperatures, but more 

uniformity and better timing are gained with controlled temperature facilities. 

For proper timing of forced cut flowers, bulbs must be stored in such facilities. 


Bulb size: Use double-nosed daffodils or 4½–6½" (12–16 cm) rounds. Its shape 

makes it difficult to measure the circumference of the bulb. 

Planting: Plant with 4–6" (10–15 cm) of soil above the nose. Plant approximately 

6" (15 cm) apart.

Narcissus 

‘Holland Sensation’

426 NARCISSUS 

Planting time: In climatic Zones 4 and 5, plant in September and early October; 

Zones 6 and 7, in October and early November; Zones 7 and 8, November and 

early December. In areas with little cold temperature (e.g., Florida, coastal California), 

precooled bulbs that are cooled 8–10 weeks at 40F (4C) should be 

planted in early December (De Hertogh 1996). 

Longevity: In all but the warmest areas, daffodils will perennialize. Well-maintained 

bulbs should be productive 3–5 years. At that time bulbs are lifted and 

separated. 

Timing: Using both early- and late-flowering cultivars makes for a longer flowering 

period. Proper selection of cultivars can provide up to 8 weeks of harvest. 

Flowering begins in February in the South for Narcissus cyclamineus and other 

early species and early, small-flowered cultivars like ‘February Gold’, and continues 

through late April for large-cupped cultivars. In the North, flowering is up 

to 4 weeks later. 

Harvesting: Daffodils are often pulled rather than cut to ensure longest stem 

length. 

Stem length: The difference in stem length between northern- and southern-grown 

bulbs is not nearly as large for daffodils as for tulips (which see). 

This is because cold is not as necessary for stem extension in daffodils as it is in 

tulips. 

Fertilization: Apply 2–3 pounds of a complete granular fertilizer, such as 3-9- 

18 or 5-10-20, per 100' (2.5 kg per 100 m) immediately after planting (De Hertogh 

1996). 


Most forcers treat daffodils as they do tulips (which see). If coolers are not sensitive, 

allow bulbs to remain at 40–48F (4–9C) for about 16 weeks. With better 

coolers, however, a more specialized cooling cycle can be established. For the 

Valentine’s Day market, bulbs are usually panned in October; stored at 48F (9C) 

until roots are visible through the drainage holes; transferred to 41F (5C) until 

shoots are 1–2" (2.5–5 cm) tall; and then placed at 33–35F (1–2C) until they are 

moved to the greenhouse bench. The total time in the cooler is about 17 weeks, 

depending on cultivar, with a minimum cooling time of 15 and maximum 

around 20 weeks (De Hertogh 1996). 

This method works well but requires a good deal of cooler space and does 

not allow for additional turns once plants are moved into the greenhouse. Dole 

(1996) suggested a delayed potting method, in which the bulbs are cooled dry for 

the first 8 weeks then potted up as normal for the last 8 weeks of cooling time. 

Cooler space needed for the dry bulbs is minimal, and when pots are removed for 

greenhouse forcing, additional dry cooled bulbs may be potted to take their 

place. In this method, the cooler should remain at 41F (5C) whenever dry bulbs 

are present. 

The greenhouse temperature for forcing should be around 60F (15C), but 

time in the greenhouse (usually around 2–3 weeks) depends on cultivar and time 

of year. For market times before Valentine’s, precooled bulbs must be purchased.

NARCISSUS 427 

If height control is required, application of ethephon at 1000–2000 ppm is 

applied in the greenhouse when plants are about 3" (8 cm) tall (De Hertogh 

1996). A second application may be required 3–5 days later. Seldom used for cuts. 


Single, large flowers should be harvested when closed, but with color showing. 

This is known as the gooseneck stage. Flowers should be at a 90–120° angle 

from the stem. 

For double-flowered cultivars, harvest when flowers are just beginning to 

open. 

Stems are packed 10 to a bunch. 

Postharvest 

Fresh: Fresh flowers have a vase life of 4–6 days. Preservatives do not generally 

enhance the vase life of daffodils. 

Storage: Flowers may be stored wet or dry. For dry storage, pack in polyethylene 

and store in open boxes in a cold room. Flowers may be kept 10 days at 32– 

33F (0–1C), 8 days at 36–38F (2–3C), or 1–2 days at 50F (10C) (Nowak and Rudnicki 

1990). Flowers should be kept upright. If flowers arrive bent, they may be 

wrapped tightly in wet paper and placed in water under direct overhead light 

(Vaughan 1988). They also may be stored in 100% nitrogen for several weeks 

without loss of quality (Nell and Reid 2000). 

Hardening: Daffodils secrete a mucus that is detrimental to roses, carnations, 

freesias, tulips, and many other cut flowers. If daffodils are used in arrangements 

or stored with other flowers, they should be placed by themselves for 12–24 

hours in clear water. Change the water at least once, and wash the stems upon 

removal. If freshly cut flowers must be placed with other flowers, put daffodils in 

a bleach solution containing 5–7 drops of bleach per quart (liter) of water for 1–5 

hours (De Hertogh 1996). Rinse stems and place with other flowers. 

Cultivars 

Cultivars are far too many to list, and there are no particularly bad ones. Choice 

is based on earliness, color, stem length, fragrance, and cost. Consult a bulb specialist 

for best cultivars for your area. 


Basal rot (Fusarium) infects the basal plate of the bulb and results in brown-colored 

decay. Cull infected bulbs and use a preplant dip of benomyl on others. 

The best preventative methods are excellent drainage and proper dry storage of 

bulbs. 

Fire, manifested as reddish brown spots on leaves, flowers, and occasionally 

on bulbs, can be troublesome. The spots are somewhat elongated parallel to the

428 NIGELLA DAMASCENA 

veins. The disease occurs more often in warm, humid climates and after 2–3 days 

of rainy weather. Sprays of various fungicides (benomyl, mancozeb, iprodione) 

and smokes (exotherm) are useful. 

Aphids and bulb mites are the most serious pests for commercial growers of 

cut daffodils. 

Reading 



Dole, J. M. 1996. Spring bulb production: the delayed potting method. Ohio Florists 

Assoc. Bul. 806:1, 3–4. 






Ore. 

Many thanks to Brent Heath (first edition) and Mark Hommes (second edition) 

for reviewing this section. 

Nigella damascena love-in-a-mist Ranunculaceae 

annual Mediterranean blue, white 1½–2'/1' (45–60 cm/30 cm) 

Nigella has handsome foliage and flowers, and although the cut flowers have 

been considerably successful on the local level, plants are mainly grown for the 

attractive seed pods. Pods may be used fresh or dried in arrangements or potpourri. 

Propagation 

Sow seed directly to the field or bench. Approximately 0.25 oz (7 g) of seed yields 

1000 seedlings (Nau 1999). If sown directly to the field, sow at the rate of 0.1 oz 

per 100' (9.5 g per 100 m) (Kieft 1996). Germination occurs in 10–14 days. When 

sown in the greenhouse, maintain 60F (15C). In southern locations (Zone 7 and 

warmer), sowing may be accomplished in the fall, similar to larkspur. Fall sowing 

is also done in Zone 6, although germination may be marginal. In general, 

fall sowing results in longer stem length than spring sowing. 

Growing-on 

Grow plants at temperatures of 60–65F (15–18C) and apply 50–100 ppm N at 

each irrigation. Photoperiod has little effect on growth.

Nigella damascena ‘Miss Jekyll’

430 NIGELLA DAMASCENA 


Flowers are formed as plants mature and reach a certain number of nodes. Warm 

temperatures accelerate growth and flowering, but temperatures above 80F 

(27C) should be avoided. Photoperiod has little effect on flowering. High temperatures 

and lack of water result in reduced stem length. 


Spacing: Space plants or thin seedlings to 6–9" (15–23 cm) centers. When 

using successive sowings, use dense spacings. The tighter the spacing, the greater 

the opportunity of obtaining large terminal flowers; however, the tighter the 

spacing, the greater the opportunity for disease. Use common sense. 

Planting time: Sow or transplant 3 or 4 times every 2–3 weeks early in the season 

for best fruit production. Hot summer temperatures will reduce stem 

length. The best pods are from the terminal flowers. Those from the laterals are 

smaller and less saleable; however, many growers clear cut the stems and still 

find an acceptable market for all the pods. 

Fertilization: Side dress with a granular fertilizer, such as 10-10-10 or 8-8-8, 

approximately 3 weeks after direct sowing or transplanting to the field. Soluble 

fertilization may also be used at the rate of 300–500 ppm N applied every week. 

Shading: In the South, shading (up to 30% shade) is useful: longer stems result. 


Temperature: Plants may be produced with cool temperatures of 55–60F (13– 

15C) and bright light. 

Scheduling: Seed sown in fall or early spring results in flowering plants approximately 

9–12 weeks later. 

Supplemental light: Use of HID (not incandescent) lights can greatly enhance 

stem strength and yield. 


Flowers: Harvest when the flowers are fully colored but before the petals have 

totally separated from the center. 

Seed pods: The correct stage of maturity of the pods is debatable. Some growers 

harvest pods when they begin to turn purple-bronze; however, Kate van Ummersen, 

an Oregon grower, emphatically takes bronze coloration to be a sign of 

tardy harvest and poor quality. She suggests that pods should be fully developed, 

slightly before the pod starts to split; this stage, she contends, results in the 

most vibrant green and purple colors. 

Postharvest 

Fresh: Flowers persist 7–10 days, particularly if a preservative is used and water 

is replaced often. Store at 36–41F (3–5C) only if necessary. Pods are also sold 

fresh.

NIGELLA DAMASCENA 431 

Dried: Flowers may be dried if harvested when fully open. Pods, harvested 

when they are green or purple, are air-dried and persist indefinitely. If harvested 

when fully developed, but still vibrant green, they dry well in the dark. This is also 

true for the pods of Nigella orientalis. Drying in the light causes bronzing. 

Removal of the finely divided foliage is usually not necessary. 

Cultivars 

These differ mainly in flower color; only a few show improvements in fruit size 

and color. 

‘Albion’ bears double white flowers and deep green-purple pods. 

‘Cramers’ Plum’ has plum-colored pods with no stripes. Useful both for fresh 

and dried sales. Plants averaged 11" (28 cm) long with 8 stems per plant in 

national trials (Dole 1998); according to its developer, Ralph Cramer, if sowing 

had been accomplished in the fall rather than the spring, stems would be closer 

to 22" (55 cm) long. 

‘Dwarf Moody Blue’ is only 6–9" (15–23 cm) tall with blue flowers. 

‘Miss Jekyll’ has semi-double flowers in sky blue. Also found in white (‘Miss 

Jekyll White’), as well as dark blue and rose. 

‘Mulberry Rose’ produces double pale pink flowers on 24" (60 cm) stems. 

‘Oxford Blue’ bears large double, dark blue flowers. 

Persian Jewels is a mixture of mauve, purple, and white flowers. 

‘Red Jewel’ produces deep rose flowers. 


Several additional species are available, mainly for the unusual pods they produce. 

Nigella arvensis bears pale mauve-blue flowers and ferny foliage. 

Nigella ciliaris ‘Pinwheel’ has yellow flowers followed by pinwheel-like pods. 

It resembles the better-known N. orientalis. 

Nigella hispanica (fennel flower) is about 2' (60 cm) tall and bears deep blue 

flowers with blood-red stamens. The 1–2" (2.5–5 cm) wide flowers are similar to 

those of N. damascena, except they don’t have the spider-like extensions (involucres) 

at the base. The lack of these spidery structures makes for a cleaner look, 

but some consumers may miss it—after all, that’s one reason love-in-a-mist is so 

misty. The fruit, which is not as inflated as N. damascena, is longer than wide and 

topped by a crown of 5 spreading styles, further helping to differentiate this species 

from N. damascena. ‘Curiosity’ grows 28–36" (70–90 cm) with violet-blue 

flowers and spider-like pods. ‘Exotic’ has velvety petals on single flowers and 

dark purple stamens. 

Nigella orientalis (Asian nigella) differs considerably, mainly by producing 

smaller yellow flowers with red spots. The “spiders” are also absent. The inflated 

fruit is united in the middle and divergent above. ‘Transformer’ bears yellow 

flowers and curious seed pods that are excellent for cutting and drying. Closely 

spaced plants result in unbranched 18–24" (45–60 cm) stems.

432 ORNITHOGALUM ARABICUM 

Nigella sativa has bluish white flowers and grows about 18" (45 cm) tall. The 

seeds of this species are the culinary spice black cumin. 


Damping off, aphids, and spider mites can be serious problems. 


“[I have] a tractor-mounted Planet Jr seeder. For Nigella damascena, I use the 

#12 hole (second-shallowest notch) and plant 4 rows per 4' bed, 4.7 oz/1000 ft 

(440 g/1000 m). For N. orientalis, I use the #23 hole (third-shallowest notch) and 

plant 4 rows per 4' bed, 4.0 oz/1000 ft (374 g/1000 m).” Kate van Ummersen, 

Sterling Flowers, Brooks, Ore. 

Reading 


10(1):1–33. 


Netherlands. 


Many thanks to Don Mitchell (first edition) and Ralph Cramer and Kate van 

Ummersen (second edition) for reviewing this section. 

Ornithogalum arabicum Arabian star flower Liliaceae 

bulb, Zones 8–10 Mediterranean white 18–24"/18" (45–60 cm/45 cm) 

Clusters of creamy white flowers with black centers are borne on long stems. 

Plants lack winter hardiness and have poor heat tolerance, so, although production 

is common in Mediterranean countries, it is limited to the West Coast 

in this country.The genus is bulging with many fine species, but cut flower production 

usually involves Ornithogalum arabicum and O. thyrsoides (chincherinchee); 

O. saundersiae has a small but useful market. Other species sometimes 

mentioned, such as O. nutans (nodding star-of-Bethlehem) and O. dubium 

(orange star flower) are more often used as garden plants and pot plants, respectively. 

Be careful, all parts of plant are poisonous. 


Photoperiod: No effects of photoperiod have been observed. 

Temperature: Temperature is important for flower and scape development. 

Under natural conditions, flower development occurs after the foliage has died 

down. Bulbs can be programmed for immediate flowering or treated with warm

Ornithogalum thyrsoides


temperatures to retard flowering in order to extend the harvest. Bulbs can either 

be programmed for immediate flowering or can be placed at 86–91F (30–33C) to 

retard development (Shimada et al. 1995). 

Bulb storage temperatures: Storage regimes for Ornithogalum arabicum vary; a few 

are provided here. 

1. 68F (20C) after harvest until 1 November, then hold at 55F (13C) for 30 days 

prior to planting (Shoub and Halevy 1971). 

2. 77F (25C) after harvest until 1 November, then hold at 63F (17C) for 30 days 

prior to planting (De Hertogh and Le Nard 1993). 

3. For fastest development, 86F (30C) for 12 weeks, then 68F (20C) for 4 weeks, 

then hold at 55F (13C) 8 weeks before flowering (Shimada et al. 1995). 

4. To retard flowering, store at 86–91F (30–33C) for several months (Shimada et 

al. 1995), follow with holding temperatures provided in scenario 1 or 2. 

Greenhouse forcing temperatures: After programming, a greenhouse cycle of 70/ 

50F (21/10C) day/night temperature requires about 21 weeks to flower (Dole 

and Wilkins 1999), 72/64F (22/18C) requires approximately 13–14 weeks, 79/ 

72F (26/22C). Highest quality flowers result from greenhouse temperatures of 

55–62F (13–17C). 


Bulb size: Large bulbs of 5½–6½" (14/16 cm) circumference yield the greatest 

percentage of flowering plants. Bulbs below 3" (8 cm) fail to flower, and only 

about 30% of 4½" (11 cm) circumference bulbs flower; the following table has 

additional details (Shoub and Halevy 1971). 

Bulb size and yield of Ornithogalum. 

Bulb weight Bulb circumference Stems per Flowers per 

(g) (cm) 100 bulbs inflorescence 

6–8 7–8 0 0 

8–13 8–9 5 13–19 

12–22 9–11 20–30 18–23 

20–60 11–15 70–95 22–26 

50–100 15–20 100–120 25–29 

Larger bulb sizes also result in increased flowers per inflorescence; however, very 

large bulbs tend to split and should be avoided. John LaSalle of Whately, Mass., 

gets good flowers from 16/18 cm bulbs and better flowers from larger bulbs; he 

also notes that the larger bulbs tend to flower faster. From 12/14 cm bulbs, he 

gets small flowers. 

Spacing: Place bulbs 6–9" (15–23 cm) apart and cover with 4" (10 cm) of soil. 

Longevity: Bulbs persist 1–2 years, depending on location. On the West Coast 

or in Mediterranean climates, they may be left in the ground for 2 years, but are

ORNITHOGALUM ARABICUM 435 

generally treated as annuals. If grown in the East, bulbs must be lifted each year 

and treated as annuals. Trials in Georgia were disappointing: the majority of 

bulbs failed to survive, and of those that did, flower production was poor. Plants 

are essentially xerophytic, and the cold winter temperatures in combination with 

rain in the winter and summer were likely to blame for the poor performance. 


Most production is under protection. Purchase prepared bulbs (see “Environmental 

Factors”) for winter and spring flowering. Place bulbs 6" (15 cm) apart in 

8–10" (20–25 cm) pots, bulb crates, or ground beds. The temperature and duration 

of storage has a direct influence on flowering time (see “Environmental Factors” 

and section on Ornithogalum thyrsoides). Fertilize with 75–100 ppm N from 

calcium nitrate after planting. Greenhouse temperatures vary, but temperatures 

of 68–70F (20–21C) for 3–4 weeks followed by 58–62F (14–17C) until flowering 

have been successful. Treat bulbs as annuals, digging them up every year, but be 

sure they’re dried down well before storing. Bulbs must have minimum storage 

temperature of 60F (15C) with good air movement. 

Provide the highest light possible, particularly in the winter, and plant in 

well-drained soils at approximately 5.5–6.0 pH. 






(%) 

N P K Ca Mg 

2.0 0.25 3.59 2.08 0.30 

(ppm) 

Fe Mn B Al Zn 

82 10 24 60 37 


If flowers are to be shipped long distances, harvest no later than when the first 

flower is open. Approximately ¼ of the flowers may be open for local sales. Place 

10 per bunch and hold them in water, if possible. 

Postharvest 

Fresh: Flowers have excellent vase life and persist over 2 weeks. Preservative is 

not necessary. Unopened flowers continue to open even in plain water.


Storage: Flowers of various species of Ornithogalum may be stored dry at 40F 

(4C) for 4–6 weeks in moisture-retentive boxes (Rees 1985). 

Dried: Flowering stems may be dried by desiccation. A equal mixture of borax 

and fine sand is best for drying. Place a thin layer of the borax/sand mixture in a 

container and lay the flowers on the layer. Gently pour desiccant over the stems, 

enough to cover them. Cover the container. Drying takes 4–10 days (Vaughan 

1988). 


Ornithogalum saundersiae bears 2–3' (0.6–0.9 m) stems that terminate in white 

flowers with dark eyes. A better choice for eastern growers than O. arabicum—it is 

far more tolerant of cold winters and hot summers. 

Ornithogalum thyrsoides (chincherinchee) is native to South Africa and bears 

12–30 pure white flowers on each 15–20" (38–51 cm) stem. As with O. arabicum, 

bulb storage regimes vary, depending on whether flowers are required immediately 

or delay of flowering is desired. Three possible scenarios follow. 

1. 86F (30C) for 8 weeks after bulb harvest, then hold at 63F (17C) for 30 days 

prior to planting (De Hertogh and Gallitano 1997). 

2. 41F (5C) for 14 weeks after bulb harvest and hold until planting (van Vuuren 

and Holtzhausen 1992). 

3. To retard flowering, 86–95F (30–35C) for several months. Follow with 41F 

(5C) for 6–14 weeks (length of storage decreases as length of heat retardation 

increases) prior to planting (Shoub and Halevy 1971, van Vuuren and Holtzhausen 

1992). 

For greenhouse production, 50–60F (10–15C) is used after planting. 

For outdoor planting, plant in February–March for flowering in early June. 

An average of 1.5 inflorescences are produced by 4–5 cm bulbs; 8–10 cm bulbs 

produced 4 inflorescences per bulb (Rees 1985). Flowers should be harvested 

when the first flower opens. Stems are pulled, not cut. Postharvest treatments are 

similar to Ornithogalum arabicum. Cultivars include double-flowered ‘Mount 

Blanc’ and ‘Mount Everest’. An excellent cut flower species. 

Ornithogalum umbellatum (star-of-Bethlehem) carries 10–20 star-shaped white 

flowers with green stripes on 12" (30 cm) stems. Bulbs spread rapidly and can be 

considered perennial in much of the Southeast. This is one of the few useful 

ornithogalums for the eastern half of the country. Unfortunately the common 

name, star-of-Bethlehem, is also used for O. arabicum. Do not confuse the pair 

when ordering bulbs; they are very different. 


Leaf spots occasionally detract from the foliage, and root rots may occur in wet 

soils. 

Ornithogalum mosaic virus results in finely mottled light and dark green 

foliage. More conspicuous mottling of gray and yellow occurs as the foliage

matures. The virus is spread by aphids and is best controlled by controlling the 

aphid population. 

Reading 

De Hertogh, A. A., and M. Le Nard. 1993. Ornithogalum. In Physiology of Flower 

Bulbs. A. A. De Hertogh and M. Le Nard, eds. Elsevier Press, Amsterdam. 

De Hertogh, A. A., and L. Gallitano. 1997. Basic forcing requirements for Israeligrown 

Ornithogalum dubium. Acta Hortic. 430:227–232. 



Rees, A. R. 1985. Ornithogalum. In The Handbook of Flowering. Vol. 1. A. H. Halevy, 


Shimada, Y., G. Mori, and H. Imanishi. 1995. Effect of temperature on the flowering 

of Ornithogalum arabicum L. J. Jap. Soc. Hort. Sci. 64: 617–623. 

Shoub, J., and A. H. Halevy. 1971. Studies in the developmental morphology 

and the thermoperiodic requirement for flower development in Ornithogalum 

arabicum L. Hortic. Res. 11:29–39. 

van Vuuren, P. J., and L. C. Holtzhausen. 1992. The influence of temperature on 

phenological dating of Ornithogalum thyrsoides Jacq. as a commercial flower. 

Acta Hortic. 325:119–128. 


Ore. 

Many thanks to John LaSalle for reviewing this section. 

PAEONIA HYBRIDS 437 

Paeonia hybrids peony Ranunculaceae 

perennial, Zones 2–7 China, Japan many colors 1 

2–3'/3' (60–90 cm/90 cm) 

Modern hybrid peonies are the result of persistent breeding and include both 

herbaceous (bush) peonies (the result of crossings between Paeonia lactiflora, P. 

officinalis, P. mollis, and others) and tree peonies (P. suffruticosa, P. lutea, etc.). Most 

cut flower production in this country involves the herbaceous forms; flowers of 

tree peonies are mainly harvested overseas. 

Herbaceous peonies have long enjoyed popularity for their cut flowers and 

were farmed on hundreds of acres in the Midwest during the 1930s. They are 

making a comeback. A minimum of 5 years is needed before peonies become 

profitable. Capital during the first 3 years is spent on plants, soil improvements, 

cultivating, and overhead expenses. Only during the following 2 years will plants 

produce sufficient stems to realize a profit. 

All growth originates from an underground crown. The stem buds or eyes 

are formed at the top of the crown and are the beginning of the next year’s 

growth. Single- and double-flowering cultivars, and early-, mid- and late-flowering 

cultivars are available.

Paeonia ‘Bowl of Beauty’ 

(Japanese pink lactiflora)

Propagation 


Plants are purchased as divided crowns and transplanted directly to the field. 

Five-eyed pieces are best, although 3-eyed pieces readily develop into flowering 

size (Stimart 1989). It takes propagators 3–5 years to produce transplants. Remove 

threadlike roots prior to planting. Planting is best done in the fall; early 

spring planting is appropriate if fall-harvested roots were cold stored during the 

winter. 


Photoperiod: Buds of peonies are vegetative in early summer; flower initiation 

commences in July and August, depending on cultivar. Both terminal and lateral 

buds are initiated by late fall, before the onset of dormancy. Peonies go dormant 

as early as late August, but most cultivars persist until late October. Short days 

do not trigger dormancy as in other perennials, and experiments have shown 

that plants go dormant regardless of photoperiod (Wilkins and Halevy 1985). 

Temperature: No exact data are available concerning optimum length of cold 

or temperature necessary to break dormancy. Although peonies flower in northern 

latitudes where freezing temperatures occur, they also perform well in central 

California and northern Georgia, where frost is not a constant guest in winter. 

From the authors’ point of view, however, the more persistent the winter cold, the 

better the production. This does not mean freezing temperatures are necessary, 

but persistent soil cold (

440 PAEONIA HYBRIDS 

Garden Flowers in western Washington plants peonies very shallow—with the 

pink buds just at the soil line, often showing a bit. She goes on to say that growers 

in eastern Washington plant the eyes much deeper. The difference is temperature: 

“On the western side of the state, deep plantings don’t get enough cold 

to promote flowering, but shallow plantings do. Many peonies here [western 

Washington] fail to bloom if planted too deep, and even after 10 years they have 

failed to adjust themselves to the correct depth to promote blooms.” 

Mulching: Mulch is often used to provide some winter protection, particularly 

in newly planted root divisions; however, cold is seldom an overwintering 

problem. Mulch also may help to keep roots cooler and delay flowering. In general, 

overzealous mulching will not hurt plants if done for a year or so; however, 

continuous mulching causes a buildup, reducing oxygen and water penetration 

to the roots, and soon the roots are buried too deeply. Some suggest 

that the roots will eventually find their own proper depth, but Bernie Van 

Essendelft, a peony grower in North Carolina, states that mulching or planting 

too deep causes the plant to move eye development from the crown up to the 

stem, especially on ‘Sarah Bernhardt’. The result is fewer blooms and weaker 

stems. He plants no deeper than 1" (2.5 cm). Most peony growers caution 

against mulch (especially bark), as too thick a mulch may reduce flowering and 

promote fungal disease. 

Spacing: Plants should be planted no closer than 18" (45 cm) apart; 24" (60 

cm) is not uncommon (Kneppers 2001). If row planting is used, 2–3' (60–90 cm) 

spacing between plants and 4' (1 m) wide rows are common (Stimart 1989). 

Closer spacing reduces longevity. 

Disbudding: Lateral flowers are often disbudded to increase the size of the primary 

flower and to provide longer stems; disbud approximately 3 weeks prior to 

blooming. Alternatively, terminal flower buds are removed, resulting in a spray 

of lateral flowers. The best time to disbud is when the buds are easy to reach and 

are the size of a small pea. According to Roy Snow of United Flower Growers in 

Burnaby, B.C., “All peonies sold through the Vancouver Flower Auction have to 

be disbudded or they are sold as second grade.” In 2000 the auction sold about 

90,000 stems of peonies, all disbudded. 

However, not everybody agrees that disbudding means better quality. As Ed 

Pincus, a Vermont grower, puts it,“The market demands it, so you disbud.” He 

also provides a contrary argument: “The side buds give the peony a different 

look that some prefer, and in any case they can be disbudded after sale. On some 

varieties the side buds will blossom on the cut stem, extending bloom time. On 

‘Ann Cousins’ and other varieties, the side buds are fairly long (12"), and if you 

are willing to give up the main bud, you can get 2 or 3 12" stems without cutting 

any of the plant’s foliage.” 

Longevity: Two- to 3-year-old transplants require an additional 2–4 years before 

any significant harvest occurs. Plants are kept in the field for 10–15 years, 

and 30-year longevity is not uncommon. Flower production peaks in the third 

through tenth year in the North. In southern areas, plants may have to be rotated 

a little earlier. Divide or replace plants when yield is significantly less than the 

previous year.


Shading: Peonies should be planted in full sun but will tolerate partial shade, 

particularly in the South. Reduction in flower number and size is indicative of 

too much shade. 

Fertilization: Side dress peonies (e.g., 8-8-8) in the fall and again in the spring, 

after stems have emerged. A pH of approximately 6.0 is recommended. 

Forcing: Flowering is advanced by covering the beds with plastic or tunnels in 

late winter. 

Failure to flower: Sometimes no buds appear at all, and sometimes buds appear 

but flowers do not develop. The reasons and possible solutions follow (American 

Peony Society 1995). 

No buds appear: 

1. Plants too young and immature. Allow them to mature. 

2. Planted too deep or too shallow. Examine, and if eyes are more than 

3" (8 cm) below ground, lift and 

replant. 

3. Clumps too large and too old. Divide the clump if it stops 

flowering (after 3–10 years), 

leaving 3 eyes per division. 

4. Too much nitrogen. Cut down on frequency or 

concentration of fertilizer. 

5. Moved and divided too often. If the clump is flowering well, it 

should not be moved. Clumps can 

remain in place well over 10 years. 

6. Too much shade. Move to sunny location. 

Buds appear but flowers do not develop: 

1. Buds killed by late frost. Better luck next year. Plant later 

cultivars. 

2. Buds killed by disease. They Spray fungicide as directed for 

usually turn black and die. botrytis. 

3. Buds attacked by thrips. They 

open partially, turn brown and 

fall. 

Spray as directed. 

4. Buds waterlogged due to Plant singles or Japanese forms. 

excessive rain. Bagging buds will help. 

5. Plants undernourished. Fertilize with 8-8-8 and bonemeal. 

6. Excessively hot weather. Plant early-flowering cultivars. 

Yield: Depending on cultivar, 8–12 flower stems/plant can be realized once 

plants are mature. Karen Gast at Kansas State University evaluated yield and 

vase life of dozens of cultivars over approximately 10 years. Cultivars that con-


sistently produced excellent yield are listed in the following table (Gast 1998). 

Karen notes that Kansas is on the southern end of peony production and 

believes that yields would be higher in cooler climates. 

Cultivar Stems/plant 

White Henry Sass 5.8 

Lois Kelsey 6.6 

Pink Edulis Superba 5.1 

Hermione 5.0 

Mrs. Franklin D. Roosevelt 5.6 

Reine Hortense 5.0 

Sarah Bernhardt 20.2 

Therese 6.6 

Walter Faxon 9.4 

Red David Harum 6.4 

Felix Supreme 13.4 

Grover Cleveland 5.0 

Karl Rosenfield 7.8 

Louis van Houtte 8.8 

Philippe Rivoire 7.6 

Richard Carvel 13.4 

Cut only ⅓ of the harvestable stems, and allow as much foliage to remain on the 

plant as possible (Post 1955). Leaving behind some stems is good for the health 

of the plant; removal of too much foliage reduces vigor and results in poorer 

production in subsequent years. Growers who do elect to cut all stems aggressively 

must replace plants more often. Stem length depends on cultivar and the 

duration of cold. Stem length in Fremont, Calif., averaged 10" (25 cm); in Pantego, 

N.C., 18" (45 cm); in the upper Midwest, 2–3' (60–90 cm) (Stimart 1989). 


Plants in which dormancy has been broken with cold temperatures can be forced 

in the greenhouse in 8 weeks at 60–65F (15–18C) night temperatures (Wilkins 

and Halevy 1985). Crowns dug from the field on 1 November in Minnesota were 

stored at 32–40F (0–4C) until the cold treatment had been satisfied (late December), 

then placed in a 65F (18C) greenhouse; shoots emerged and flowering 

occurred without problem. 

Since flowers initiate before the onset of dormancy, it is possible that plants 

simply must attain a certain size or leaf area to stimulate the formation of additional 

flower buds. Another possible environmental signal to force initiation of 

new buds may be the lessening of daylength, since peonies are generally vegetative 

in summer but have finished initiation of terminal and lateral buds by Sep-


tember (Wilkins and Halevy 1985). If additional flower buds were forced early, 

then plants would still likely require a dormant period and then a cold treatment 

to overcome the dormancy. Most forced peonies are replanted or discarded 

after flowering. 


Stage of harvest is tricky with peonies—all growers agree that skilled pickers are 

essential. As a general rule of thumb, flowers should be harvested when the first 

true color appears on top of the tight bud, but researchers have come up with 

bud maturity indices that offer more precision. ChaeKyu (1998) broke flower 

development into 3 stages: in stage 1 the margin of the calyx was showing color, 

in stage 2 the calyx had started to open and petals could be seen, and in stage 3 

the petals were obviously puffy. Harvesting in stage 2 was recommended. In 

2001, Gast et al. determined additional stages of development using 8 cultivars. 

Flowers were separated into grades based on firmness, amount of lifted petals, 

amount of center showing, color shift, angle of guard petals, bud length, and 

brightness of petal color. As expected, vase life varied by cultivar. 

Double-flowered types should be further developed than single forms, and 

red cultivars should be more developed than whites (Post 1955). 

Postharvest 

Fresh: Work by ChaeKyu (1998) showed that pulsing the cut stems in a 20% 

sucrose solution for 24 hours provided the best opening and longevity of the 

flower. Flowers may persist up to 10 days if harvested in the bud stage, but if 

already open, they persist only 5 days (Vaughan 1988). Fresh flowers are best 

maintained at 36–41F (3–5C) at all times. Gast (1999, 2000) measured vase life 

of numerous cultivars in water and the floral preservative Floralife at the rate 

of 4 tablespoons per gallon of water. In general, her results showed that floral 

preservative was not useful in all cases; however, it did result in larger flowers in 

the vase for some cultivars. Interestingly, the way in which the flowers declined 

differed too: in water, the petals fell off; in the preservative, they wilted. This 

study suggests that all preservatives should be trialed prior to widespread use. 

Dried: Flowers harvested when first showing color or at loose calyx stage may 

be stored dry at 32–34F (0–1C) for up to 4 weeks (Wilkins and Halevy 1985, 

Heuser and Evensen 1986). Lower leaves should be removed from the cut stem. 

Flowers may be air-dried, although they tend to shrink considerably. When flowers 

are almost dry, smooth out the outer petals until the flower regains its original 

shape (Bullivant 1989). Flowers may also be dried in a microwave. Cover 

with warm silica gel and microwave for 1–3½ minutes, depending on the fleshiness 

of the flowers. Freeze-drying of peonies has also been recommended. 

Storage: Flowers may be stored dry after being placed in water for 2–3 hours at 

36F (2C). Remove from the water and stand upright in 32–36F (0–2C) at 75–80% 

humidity. Storage of up to 4 weeks is reported (Stimart 1992, Gast 1999), but 

that is too long for most cultivars. However long they are held, flowers must be 

dry, or fungal growth sets in.


Cultivars 

Many cultivars and forms are available from specialist peony producers. The 

American Peony Society divides the flowers of herbaceous peonies into 4 different 

forms (American Peony Society 1995). 

Single Five or more petals are arranged around a center made 

up of stamens with pollen-bearing anthers. 

Japanese Really a double form, characterized by 5 or more petals 

around a center made up of stamens with non-pollenbearing 

anthers (staminodes). When the stamens in the 

center have been transformed into narrow petal-like 

structures (petaloids), the bloom is said to be anemoneflowered. 

Semi-double Five or more outer petals are arranged around a center 

consisting of broad petals and stamens with pollenbearing 

anthers. There may be a distinct center of 

stamens or they may occur in rings, intermixed among 

the petals. Either way, the stamens are always clearly 

visible and prominent. 

Double Five or more outer petals occur, but the bulk of the 

flower is the stamens, transformed into petals. Often no 

trace of the stamens remains; sometimes they may be 

present or partially petaloid. In double types, stamens 

are not a prominent part of the flower. 

As cut flowers, doubles enjoy the greatest market, followed by semi-doubles 

and then singles and Japanese. Without doubt, white is the favorite color of buyers 

and should be planted more heavily than others. Pink is the next most 

requested color, followed by red. Bicolors are useful but more of a fad than a 

mainstay. If growing fully doubles in the South, select early and midseason cultivars 

to reduce disease problems. 

According to Alice Vigliani, a peony grower in Massachusetts, factors that 

make a cultivar good for cut flower production include stem length and 

strength; number of side buds (ease of disbudding); hardness of bud when it 

can be cut (the harder the bud, the easier to ship wholesale without it opening 

too much before getting to the end user); number of harvestable stems per plant; 

vase life (doubles last longer than Japanese or singles); and disease resistance 

(botrytis). 

The following cultivars are recommended for cut flower production by Alice 

Vigliani (V) of Massachusetts, Paul Sansone (S) of Oregon, and Bernie Van Essendelft 

(E) of North Carolina. The color given is the predominant color in the 

flower, not necessarily the only color; some flowers are flecked, spotted, edged, or 

blushed with additional colors.


White ‘Bowl of Cream’ (double) (E), ‘Charlie’s White’ (double) 

(V, E), ‘Festiva Maxima’ (double) (V, S, E), ‘Henry Sass’ 

(double) (E), ‘Marie Lemoine’ (double) (S) 

Pink ‘Angel Cheeks’ (double) (V), ‘Cytherea’ (semi-double) (S), 

‘Duchesse d’Orléans’ (double) (S), ‘Honor’ (single) (S), 

‘James Pillow’ (double) (V), ‘Monsieur Jules Elie’ (double) 

(V, S, E), ‘Raspberry Sundae’ (double) (V), ‘Reine 

Hortense’ (double) (E), ‘Roselette’ (single) (S), ‘Sarah 

Bernhardt’ (double) (S, E) 

Red ‘Big Ben’ (double) (E), ‘Charm’ (Japanese) (V), ‘Felix 

Crousse’ (double) (S, E), ‘Felix Supreme’ (double) (V, E), 

‘Kansas’ (double) (E), ‘Nippon Beauty’ (Japanese) (S), 

‘Red Charm’ (double) (E), ‘Red Red Rose’ (semi-double) 

(S), ‘Richard Carvel’ (double) (V) 

Coral ‘Coral Charm’ (semi-double) (S) 

Lavender ‘Rivida’ (single) (S) 

Bicolor ‘Gay Paree’ (pink/white, Japanese) (V), ‘Largo’ (pink/ 

yellow, Japanese) (V), ‘Top Brass’ (white/pink/yellow, 

double) (V). 


Botrytis or gray mold (Botrytis paeoniae) affects flowers, particularly double forms, 

during periods of wet weather. Botrytis can infect the entire plant, causing it to 

turn black. Control by removing any infected parts in summer and fall. Apply 

preventative fungicides in early spring when leaves begin to unfurl; a second 

application may be applied 10–14 days later. If additional sprays are needed, 

apply at 10- to 14-day intervals. 

Leaf spots, caused by numerous fungal species, result in spots of varying sizes 

and colors. Red spots or measles (Cladosporium paeoniae) occur as small, circular, 

discolored spots that eventually run together. The undersurface becomes 

light brown, the upper, dark purple. Remove all infected tissue as soon as spots 

are visible. Apply general foliar fungicide as above. 

Root rots caused by soil-inhabiting fungi cause decay at the base of the plant. 

Stem rot (Sclerotinia sclerotiorum) results in sudden wilt and stem rot. The 

large, black sclerotia develop inside the infected stems. Remove and dispose of 

infected plants. 

Northern root-knot nematodes (Meloidogyne spp.) can be particularly destructive. 

Nematicides and soil fumigation are useful, but if infestation is severe, the 

only solutions may be to plant where peonies have never been grown or to relocate 

the nursery. 

Viral organisms can cause ringspot—circular areas consisting of concentric 

bands of alternating dark and light green. Unlike other viruses, plants are not


dwarfed. Dwarfing of plants is caused by leaf curl virus, Lemoine virus, and 

crown elongation virus. Control all viral diseases by removal and disposal of 

affected plants. 

Reading 

American Peony Society. 1995. Handbook of the Peony. 7th ed. American Peony 

Society. 

Aoki, N. 1992. Effects of pre- and post-budbreak temperature on the subsequent 

growth and cut-flower quality of forced tree peony. J. Jap. Soc. Hort. Sci. 61(1): 

127–133. 



ChaeKyu, S., C. Byeong-Jin, and K. JaeChul. 1998. Effects of sucrose pulsing on 

blooming and flower qualities according to flower bud stages in Paeonia lactiflora 

‘Eulsung Jaerae’. J. Korean Soc. Hort. Sci. 39(6):794–798. 

Gast, K. L. B. 1998. 1998 production and postharvest evaluations of fresh-cut 

peonies. Kansas State Univ. Agr. Exp. Sta. and Coop. Ext. Serv. Report 820. 

———. 1999. 1999 production and postharvest evaluations of fresh-cut 


———. 2000. 2000 production and postharvest evaluations of fresh-cut 


Gast, K., R. Kampjes, and J. McLauren. 2001. Identification of bud maturity indicators 

for fresh-cut peony flowers. Acta Hortic. 543:317–320. 

Heuser, C. W., and K. B. Evensen. 1986. Cut-flower longevity of peony. J. Amer. 

Soc. Hort. Sci. 111:896–899. 

Kneppers, D. 2001. A quick guide to cut Paeonia. FloraCulture International 11(12): 

20. 

Nehrling, A., and I. Nehrling. 1960. Peonies, Outdoors and In. Hearthside Press, 

New York. 


Stimart, D. P. 1989. Peonies. The Cut Flower Quarterly 1(4):5–7. 

———. 1992. Strategies of growing fresh cut flowers of Liatris and Paeonia. In 

Proc. 4th Natl. Conf. on Specialty Cut Flowers. Cleveland, Ohio. 


Ore. 

Wilkins, H. F., and A. H. Halevy. 1985. Paeonia. In The Handbook of Flowering. Vol. 


ZhiMin, G., W. Yan, and W. LianYing. 1999. Effects of substrate warming on the 

growth and development of tree peony. J. of Beijing Forestry Univ. 21(6):22–27. 

Many thanks to Dennis Stimart and Roy Klehm (first edition) and Karen Gast, 

Paul Sansone, Bernie Van Essendelft, and Alice Vigliani (second edition) for 

reviewing this section.

PAPAVER NUDICAULE 447 

Papaver nudicaule Iceland poppy Papaveraceae 

perennial, Zones 2–7 subarctic regions many colors 1 

1–2½'/1' (30–75 cm/30 cm) 

This northern species, grown for its colorful flowers, is becoming more popular 

in designs. Breeders have provided some outstanding cultivars with incredible 

colors, including white, pale yellow, burnt orange, raspberry, salmon, egg-yolkyellow, 

and apricot. 

Propagation 

All plants are grown from seed, yet germination is erratic (often less than 50%) 

and is a major limitation to the crop. When sown at 65–75F (18–24C), seeds germinate 

in 7–12 days (Nau 1999). Do not cover seeds. Some growers start plants 

in 392-cell trays the last 2 weeks of August, then bump them up to 72s, and plant 

around mid November, depending on latitude. It may be more profitable to purchase 

started plugs when available. 

Growing-on 

Transplant seedlings to containers in about 3 weeks from sowing, or when the 

seedlings can be handled. Plugs are available, and an intermediate transplant 

prior to placing in the field or greenhouse is recommended. Grow on at 45–55F 

(10–13C). 


Iceland poppies do poorly in temperatures above 70F (21C). Plants can be flowered 

at warm temperatures, but plant quality and flower size is reduced as temperatures 

rise. No photoperiodic effect is known. 


In the South (Zones 7 and 8), plant in late fall (October) for early spring production; 

to be safe, plant them out in an unheated greenhouse to avoid winter 

injury and death. In the North, plants will not do well if planted in the fall unless 

protected. In the spring, place in the field as soon as the ground can be worked. 

Plants generally produce 10–15 flower stems per plant before warm temperatures 

reduce their usefulness. Plants can be harvested as long as summer nights 

remain below 60F (15C). Stem length varies, 18–28" (45–70 cm). 


Plants are produced in greenhouse conditions for winter production when cool 

temperatures can be maintained. Propagate and grow on as just described. Production 

occurs in ground beds or 6" (15 cm) containers. Multiple plants per

448 PAPAVER NUDICAULE 

container can be used successfully. Temperature should be maintained below 

60F (15C) whenever possible. Crop time is 15–17 weeks from seed (Nau 1999). 

Supplemental lighting enhances growth and flowering, particularly at northern 

latitudes. 


Harvest flowers at colored bud stage (when fuzzy sheaths split open and color is 

showing). Some flowers fail to open if cut too early; it may be necessary to cut 

twice a day. Harvest stems by giving them a sharp tug to the side; some growers 

find this method reduces decay and crown rot. Scald stems in hot water to reduce 

latex flow each time they are cut (see “Grower Comments”). 

Postharvest 

Flowers persist 5–7 days (Vaughan 1988). Storage is not recommended; stems 

and petals are too thin. 

Cultivars 

‘Champagne Bubbles’ is an F1 hybrid with 3" (8 cm) wide flowers in white, 

orange, pink, and yellow shades. Stem length is about 15" (38 cm). 

‘Flamenco’ offers a mixture of flowers in pastel pink shades with white fluted 

edges. 

Highlight Mixed offers a wide range of early-flowering halo and pastel types. 

Kelmscott Strain is 12–18" (30–45 cm) tall and consists of mostly pastel 

colors. 

‘Meadow Pastels’ is a mix of both pastel and bright colors, in shades of rose, 

pink, white, yellow, orange, and cream and bicolors. Plants grow to 24" (60 cm). 

Monarch Mix bears flowers up to 2" (5 cm) wide in many bright colors. 

‘Party Fun’ produces sturdy upright stems with 4" (10 cm) wide flowers in a 

wide range of colors. Plants stand 12–15" (30–38 cm). 

‘Popsicle’ has 3–4" (8–10 cm) wide flowers in an assortment of colors. 

‘Red Sails’ bears 5" (13 cm) wide orange-scarlet flowers on 30" (75 cm) tall 

plants. 

San Remo Mix is a lesser-known variety, with red, orange, rose, yellow, and 

white flowers on 24" (60 cm) plants. 

‘Solar Fire Orange’ is especially useful as a cut flower, growing nearly 2' (60 

cm) tall. One of the few choices in a single color; the bright orange flowers are 

eye-catching. 

‘Summer Promise’ contains both solid and bicolor 2–3" (5–8 cm) wide flowers 


Temptress series provides long-stemmed flowers in numerous colors. A favorite 

among growers (see “Grower Comments”). 

Wonderland Mix is more compact than the type and bears flowers 2–3" (5–8 

cm) in diameter. ‘Wonderland Orange’ has bright orange flowers 3" (8 cm) wide.


PAPAVER NUDICAULE 449 

Papaver somniferum (opium poppy) is grown for the seed capsules, used in 

dried arrangements. Opium is made from the sap of the green seed capsules and 

was known by the Greeks and Egyptians several centuries before the birth of 

Christ. Cut flower growers have been producing opium poppy for the decorative 

pods for years. Laws about growing this plant are changing in the United States; 

since some states frown on fields of opium poppy, a fruitful discussion with 

local law enforcement prior to planting is a fine idea. 

Seeds can be direct sown in the fall or early spring. Flowers are beautiful, but 

their vase life is minimal and they are seldom harvested. Capsules are harvested 

green when an appropriate size is attained, then dried. Plants are less stringent 

in their need for cool temperatures, and capsules are harvested into the summer; 

however, warm temperatures result in decline of additional flowers. 

Select cultivars whose capsules are sufficiently large and whose stem length is 

long enough. ‘Black Cloud’ has almost 4" (10 cm) double, ruffled flowers in a 

rich dark purple red. ‘Hens and Chickens’ bears 3–4" (8–10 cm) lavender flowers, 

followed by many small seed pods; plants grow to 2' (60 cm) in height. ‘Oase’ has 

fringed double scarlet flowers with a contrasting white blotch. ‘The Giant’ bears 

lilac flowers followed by large 1–2" (2.5–5 cm) seed pods. ‘White Cloud’ is about 

36" (90 cm) tall and has 4" (10 cm) double, ruffled flowers. 


Southern blight (Sclerotinia) can be a problem, especially with over-wet conditions. 

It results in crown rot, which shows up as a fuzzy white fungus. 


“My best results with poppies is to cut just as the bud is starting to split. When 

you get them back to the barn, recut a tiny amount from the bottom of the stem, 

dip a half inch or so in boiling water for a few seconds, and plunge stems into several 

inches of cold water. Each time the stems are recut, the treatment needs to 

be repeated. On Icelandics we receive from New Zealand, the treatment appears 

to be the same. They are shipped dry with the sepals bursting and there is evidence 

of ‘cooked’ stems on the end centimeter or so.” Ray Gray, Sunset Flowers 

of New Zealand, Oregon City, Ore. 

“I grew Temptress poppies outside last year, and they did last better than 

other Iceland poppies. I tried them several times in the house, and they definitely 

lasted longer than other Icelands I’ve tried. Overall I do think they are the best 

cut flower poppies I’ve ever tried, and the price is fair.” Janet Foss, J. Foss Garden 

Flowers, Everett, Wash. 

“I grow [Papaver somniferum] for the pods, which I sell green. We sell in 12pod 

bunches. That might be 5–10 stems, depending on the branching. We don’t 

count little pods. The stems are about 3'. I grow Icelandic for the flowers. These 

are scalded and are about 12–28" long. . . . I love Temptress because I get 15–20"

450 PAPAVER NUDICAULE 

Papaver somniferum 

stems and great colors. Salmon is the most popular. Germination was poor, and 

next year I’m ordering plugs. I’ve grown ‘Champagne Bubbles’, and the blooms 

are bigger, but the stems aren’t as long. We treat every stem by scalding the bottom 

half inch for 20 seconds. I have been getting more than a week in the vase, 

but my farmhouse is cold. I planted mine in November and production started 

early March in my hoophouse. We cut twice a day when they open and put them 

in the cooler. They store there very well, although sometimes a few never open. 

With all this said, these flowers are still my favorite to grow in the winter/spring.” 

Bob Wollam, Wollam Gardens, Jeffersonton, Va.

PHLOX PANICULATA 451 

“I grow ‘Temptress’ poppies every year. I have also tried other varieties such as 

‘San Remo’ [and] ‘Meadow Pastels’ . . . but ‘Temptress’ is the best quality and 

most productive. We treat our cut stems in boiling water to stop sap flow. We 

stick the whole bunch in the water up to about 2" deep for 20 seconds. You will 

know you have done it long enough when you see a light grayish ring at the 

water level after treating. A flame can be used but is not really effective with large 

amounts. When we sell them, we tell our customers to flame the ends if they cut 

the stems to another length.” Frank Arnosky, Texas Specialty Cut Flowers, 

Blanco, Tex. 

Reading 



Ore. 

Phlox paniculata summer phlox Polemoniaceae 

perennial, Zones 3–8 North America many colors 1 

3–4'/3' (0.9–1.2 m/0.9 m) 

Phlox has long been used as a cut flower for its vigorous growth, wide selection 

of flower colors, and large inflorescences. It is a popular stem for fillers in bouquets, 

and the fragrance of the flowers only increases demand. Two major problems 

still plague summer phlox: the incidence of powdery mildew on many 

cultivars and the premature shattering of flowers after harvest. Less mildewsusceptible 

cultivars and species such as spotted phlox (Phlox maculata) are being 

incorporated into cut flower programs. 

Propagation 

Propagation is accomplished by perennial growers from root cuttings, stem cuttings, 

or division. For cut flower production, stem cuttings rooted in plug trays 

and 1- to 2-year-old transplants are most popular. Cuttings root in 2–3 weeks in 

well-drained medium and warm soil temperatures. Bare-root material is mainly 

used in the nursery business, although some cut flower growers also use this 

method of propagation. 

Growing-on 

Propagules are usually placed in the field directly, with little or no additional 

growing time necessary. If bare-rooted plants are received too early, they may be 

stored in moist sphagnum moss at 40F (4C). If potted plants are received too 

early, they may be placed in 45–55F (7–13C) greenhouses until ready to plant out. 

Planting in the fall is best for cut flower growers; planting in early spring is 

acceptable.

452 PHLOX PANICULATA 

Phlox paniculata 

‘Bright Eyes’ 


Temperature: Garner and Armitage (2000) worked with greenhouse forcing 

of ‘Ice Cap’ and ‘Red Eyes’. Plants were kept in a cooler for 0, 4, 8, or 12 weeks at 

40F (4C) with incandescent light inside the cooler for 12 hours. When they came 

out of the cooler, they were placed under long days using extended lighting or 

nightbreak lighting with incandescent lamps. Regardless of the kind of LD 

incandescent lighting they received, plants that were cooled flowered earlier, 

with longer stems and higher yields, than uncooled plants. The following table 

shows that as cooling increased, time to flower decreased and stem length and 

yield increased.

Weeks in Flowering time in gh* Stem Stems/ 

cooler using extended days length(in) z plant 

0 118 17 2 

4 98 18 3 

8 92 19 5 

12 87 22 6 

16 79 24 7 


* = greenhouse 

Similarly, in work with Phlox paniculata ‘Fairy’s Petticoat’, no cold treatment 

was necessary to break dormancy, but cold resulted in accelerated flower development 

and taller plants (Iversen 1989). In the field, cooling is provided by winter 

temperatures; in the greenhouse, a cooler or cold greenhouse is necessary. 

Photoperiod: Under normal growing conditions, summer phlox is a long day 

plant; the critical photoperiod is between 8 and 16 hours. All plants of ‘Fairy’s 

Petticoat’ flowered when provided with 16- and 24-hour days, but no flowering 

occurred under 8 hours, regardless of cold treatment (Iversen 1989, Runkle 

1998, Garner and Armitage 2000). In the field, photoperiods longer than 10 

hours initiate the flowering process. 

In the greenhouse, incandescent lamps are used to extend daylength or as 

nightbreak lighting. Extended day lighting using incandescent lighting was 

more effective than nightbreak lighting in increasing stem length, although 

yields and flowering time were similar, regardless of cooling. Regardless of the 

length of cooling, plants of ‘Ice Cap’ exposed to extended day lighting in the 

greenhouse flowered more quickly and had longer stems and usually a higher 

yield than those exposed to nightbreak lighting. 

High-intensity discharge (HID) lamps are another way to provide LD. Interestingly, 

if HID lighting (which provided far more cumulative light to the plants 

than incandescent light) was used, the high light substituted for cold and the 

effect of cooling was insignificant. As the following table shows, HID lights 

caused faster flowering, higher yields, and longer stems than either extended 

day or nightbreak lighting using incandescent lamps. 

Weeks in Flowering time in gh Stem Stems/ 

cooler using HID light length (in) z plant 

0 64 26 7 

4 61 35 8 

8 59 37 10 

12 62 37 11 

16 57 38 13 


PHLOX PANICULATA 453



Spacing: Space plants as close as 10 × 10" (25 × 25 cm) or as wide as 18" (45 cm) 

centers; these compute to 1.4 plants/ft 2 (15 plants/m 2 ) and 0.45 plants/ft 2 (5 

plants/m 2 ), respectively. Sufficient spacing promotes good air movement, a 

necessity for reducing the incidence of powdery mildew. European recommendations 

suggest a spacing of 1.5 plants/ft 2 (16 plants/m 2 ). 

Support: Use one or 2 layers of support. 

Yield: The first harvest, after fall planting, results in 3–6 stems/plant. Yield 

increases the second year to 5–10 stems, depending on cultivar. The following 

table provides data from consecutive harvests in Watsonville, Calif. 

Two-year yields and stem lengths of Phlox paniculata. 

Cultivar Year Stems/plant Stem length (in) z 

Amethyst 1 12 17 

2 10 44 

Bright Eyes 1 4 17 

2 6 38 

Lilac Time 1 5 27 

2 8 48 

Snowdrift 1 6 24 

2 8 45 


This table demonstrates the effect of maturity on Phlox. Summer phlox is a 

clump-forming species; as plants mature, the additional vigor is translated into 

longer and stronger stems, not necessarily significant additional yield. 


Greenhouse spacing is more dense than field spacing. We planted phlox in bulb 

crates, at a spacing of 2 plants/ft 2 (22 plants/m 2 ); European recommendations 

suggest a spacing as dense as 8 × 8" (20 × 20 cm), which works out to approximately 

2.2 plants/ft 2 (24 plants/m 2 ). 

Garner and Armitage (2000) found that flowering stems from rooted cuttings 

were generally longer than those from one-year-old transplants, although 

transplants yielded more stems over a given period of time than did cuttings. 

They found, however, that terminal shoots from vegetative cuttings could easily 

be rooted in about 3 weeks, and results suggested that an efficient programmed 

production could be developed using rooted terminal cuttings. Cuttings may 

also be placed at denser spacings, increasing yield efficiencies. For patented material, 

it makes sense to purchase rooted cuttings in plugs from a distributor. The

use of cutting or graded transplants provides more uniformity than bare-root 

material and is recommended for greenhouse forcing. 

If bare-root material is used, 2- to 3-year-old roots are best. Root divisions 

generally require 6–8 weeks to become established in the container or bed. Plants 

may be purchased or dug, but for more uniform flowering, the roots should 

always be cooled. If roots are dug on 15 August, cold storage can begin on 15 

October. After cooling roots and crown at 40F (4C), forcing can begin on 1 December 

by placing plants under long days (incandescent lamps at 20–50 fc). Use 

good ventilation and fungicides to reduce incidence of disease. At 60F (15C), 

plants flower in approximately 12–15 weeks (Iversen 1989). Fertilize with a complete 

fertilizer at 150–250 ppm N every irrigation or with 500 ppm N once a 

week. 


Harvest as early as when 2 flowers are open (Bartels 2000), or as late as when ½ 

the flowers are open on the inflorescence (Nowak and Rudnicki 1990). Flowers 

are sensitive to ethylene and must be stored where ethylene is not present. Normal 

recommendations call for the use of an anti-ethylene agent after harvest, 

although results have been inconsistent. An antibacterial agent is also recommended. 

Leave approximately 2" (5 cm) of stem behind to encourage regrowth. 

The next flush should occur in 10–12 weeks, depending on the environment. 

Postharvest 

Fresh: Flowers persist 5–7 days in floral preservative. 

Storage: Stems may be stored wet at 38F (3C) for 1–3 days (Nowak and Rudnicki 

1990). 


Cultivars 

PHLOX PANICULATA 455 

Pink 

‘Bright Eyes’, among the most popular cultivars, has pale pink flowers with a 

crimson eye. 

‘Dresden China’ produces pastel pink flowers with a deep rose-pink eye. 

‘Eva Cullum’ has large heads of clear pink flowers with a dark red eye. Plants 

are only 2–2½' (60–75 cm) tall. 

‘Fairest One’ has wonderful, full salmon-pink blooms with a red eye. 

‘Fairy’s Petticoat’ bears large heads of pale pink flowers with darker eyes. 

‘Miss Candy’ bears dark pink flowers with darker eyes. 

‘Miss Pepper’ has pink flowers with a white eye. More often recommended 

for landscape use. 

‘Rose Joy’ has rosy pink flowers and stands approximately 3' (90 cm) tall. 

‘Windsor’ produces deep pink flowers with a magenta eye.


Purple, lavender 

‘Amethyst’ bears purple flowers on 3–4' (0.9–1.2 m) stems. 

‘Ann’ is a late bloomer with large, lavender flower heads. 

‘Lilac Time’ has lilac flowers with a white eye on 3–4' (0.9–1.2 m) tall plants. 

‘Progress’ has pale violet blossoms with a darker eye. 

‘The King’ is approximately 3' (90 cm) tall and bears deep purple flowers. 

‘The Prince’ has light violet flowers. 

Salmon, red 

‘Othello’ has deep red flowers with a long blooming time. 

‘Sir John Falstaff’ bears large inflorescences of salmon-pink. 

‘Starfire’ has striking, cherry-red flowers. 

‘Tenor’ produces large, red flower heads. 

White 

‘Blue Ice’ is only 2½' (75 cm) tall and bears white flowers with a blue eye. 

‘David’ can grow to 4' (1.2 m) and is more mildew resistant than many. Not 

entirely resistant, however. 

‘Ice Cap’ has been an excellent performer with high yield and clean white 

flowers. 

‘Mount Fuji’ (‘Mt. Fujiyama’) bears large, pure white flower heads. Mildew 

sensitive. 

‘Prime Minister’ produces white flowers with a red eye and grows 3' (90 cm) 

tall. 

‘Snowdrift’ (‘Schneerausch’) bears white flowers on 3–4' (0.9–1.2 m) tall 

plants. 

‘White Admiral’ has large, clear, white flower heads. 


These may be better cut flower species for areas where mildew is a problem. 

Phlox ×arendsii (Arend’s phlox) is a hybrid between P. paniculata and P. divaricata 

(woodland phlox). Phlox divaricata is only 12–15" (30–38 cm) tall but is not 

as susceptible to mildew as P. paniculata is. Arend’s phlox may provide a robust 

plant with good disease resistance and is a potentially good hybrid for Midwest 

and southern growers. Cultivars include ‘Anja’ (red-purple), ‘Hilde’ (lavender), 

and ‘Suzanne’ (white with a red eye). 

Phlox maculata (spotted phlox) is rapidly gaining popularity as a cut flower. 

Plants are less susceptible to powdery mildew than P. paniculata but are not as 

vigorous or tall. Stems 2–3' (60–90 cm) tall may be harvested. Cultivars include 

‘Alpha’ (rose-pink with the hint of a darker eye), ‘Delta’ (white with a pink eye), 

‘Miss Lingard’ (white with a pale yellow eye), ‘Omega’ (white with a lilac eye), 

and ‘Rosalinde’ (dark pink).


PHYSALIS ALKEKENGI 457 

Leaf spots are caused by many different fungi. Dark brown, circular spots up to 

¼" (6 mm) in diameter with light gray centers occur, followed by leaves that dry 

up and die prematurely. Use of sulfur helps reduce the incidence of leaf spots. 

Powdery mildew (Erysiphe cichoracearum, Sphaerotheca humuli) occurs as a white 

coating on the foliage. The fungi do not cause permanent damage, but the leaves 

become terribly discolored. Use of fungicides is essential starting around mid 

June. 

Crown rot (Puccinia, Sclerotium, Thielaviopsis) can result in significant losses. 

Sterilizing soils inhibits these soil-borne fungi. 

Mites, thrips, and nematodes feed on phlox and may be controlled with 

appropriate spray materials. In the case of stem nematodes, plants should be 

discarded, soil disinfected, and crops rotated. 

Reading 


Garner, J. M., and A. M. Armitage. 2000. Greenhouse production of herbaceous 

perennials as cut flowers. The Cut Flower Quarterly 12(1):5–6. 

Iversen, R. 1989. Greenhouse forcing of herbaceous garden perennials. Ph.D. 

diss., Cornell Univ., Ithaca, N.Y. 



Runkle, E. S., R. D. Heins, A. C. Cameron, and W. H. Carlson. 1998. Flowering of 

Phlox paniculata is influenced by photoperiod and cold treatment. HortScience 

33(7):1172–1174. 

Physalis alkekengi Chinese lantern Solanaceae 

annual China, Japan orange fruit 12–15"/15" (30–38 cm/38 cm) 

Physalis consists of approximately 100 species, the best known of which is Physalis 

alkekengi (syn. P. franchetii, P. alkekengi var. franchetii; Chinese lantern), for the inflated, 

bright orange calyces that surround the fruit. When harvested and dried, 

the calyx persists for years. Plants may reseed themselves in many areas and act 

like perennials. 

Propagation 

Best germination occurs when seed is chilled 4–6 weeks at 40F (4C) then placed 

at 60–70F (15–21C). Approximately 0.12 oz (3.5 g) of seed yields 1000 seedlings 

(Nau 1999). Germination may require as little as 7 days and as many as 30. Fresh 

seed may be sown at 60–70F (15–21C) without stratification, but if stored for any 

length of time, moist stratification at 40F (4C) reduces germination time and 

increases uniformity.

458 PHYSALIS ALKEKENGI 

Growing-on 

Physalis alkekengi 

Transplant to 3–4" (8–10 cm) containers from the open seed pack approximately 

3 weeks from sowing. Grow seedlings in plug flats for 4–6 weeks at 55–60F (13– 

15C). Fertilize once or twice per week with 150–200 ppm N from a balanced fertilizer. 

Over-fertilization and warm temperatures result in leggy plants with poor 

stem strength. Transplant to the field 8–12 weeks after sowing. 


Chinese lanterns flower as plants mature. No evidence suggests that photoperiod 

is necessary for flower initiation. Warm temperatures and bright light

esult in faster flowering. Temperatures below 80F (27C) are best for production 

of largest fruit. Consistently high temperatures (above 80F, 27C) result in 

fewer flowers and small, poorly colored fruit. 


Spacing: Space on 1' (30 cm) centers or 12 × 18" (30 × 45 cm). Sufficient space 

allows for expansion of the fruit and proper coloration. 

Irrigation: Plants are heavy water users and should not be allowed to dry out, 

especially when fruit is being formed. 

Fertilization: Side dress in the spring with a balanced fertilizer (20-10-20, 10- 

10-10) and also when plants are in flower but before fruits have matured. 


Harvest when the fruit is fully colored. 

PHYSALIS ALKEKENGI 459 

Postharvest 

Fresh: If the fruit is used fresh, expect 12–20 days of vase life. 

Storage: Store stems bearing fruit in water at 36–41F (3–5C) if necessary. Recut 

the stems when first placed in storage. 

Dried: Strip leaves and hang stems containing fruit, or place fruit and stems 

horizontally in a box or other container. They are gourmet food for mice, so 

keep boxes sealed if mice are a problem. 

Cultivars 

‘Gigantea’ has larger fruit than the species but is not easy to locate. 


Several diseases occur on Chinese lanterns, but if grown in favorable environments, 

diseases are seldom serious. 

Bacterial wilt (Pseudomonas solanacearum) results in rapid deterioration of the 

foliage. Plants should be discarded and plant rotation practiced. 

Leaf spotting by various species of Phyllosticta may be controlled by general 

foliar fungicides at 10- to 14-day intervals. 

Skeletonizing of the fruit by various insects and fungi occurs if the fruit is left 

on the plant too long. The problem is worse in high-density plantings, where 

air circulation is poor, fruit remains wet, and light seldom penetrates. Using 

landscape fabric around the plants helps keep fruit off the ground. 

Reading 

Nau, J. 1999. Ball Culture Guide. 3rd ed. Ball Publishing, Batavia, Ill.

460 PHYSOSTEGIA VIRGINIANA 

Physostegia virginiana obedient plant Lamiaceae 

perennial, Zones 3–9 North America purple-pink 1 

3–4'/3' (0.9–1.2 m/0.9 m) 

Physostegia virginiana is a popular cut flower in Europe and Japan and in some 

North American markets. The whorled flowers are held in upright spikes above 

opposite, slightly toothed foliage, and the rhizomatous plants spread freely and 

rapidly, particularly in rich soil. Its common name is derived from the notion 

that flowers supposedly retain the position into which they are pushed, a useful 

characteristic for floral arrangers and decorators. Never, ever works for us. 

Propagation 

Seed: Germination is erratic and may take from 3 weeks to many months. For 

best uniformity, sow seed in moist seed flats or plugs and place at 35–40F (2–4C) 

for approximately 6 weeks. Remove from cold and place in 70–72F (21–22C) 

greenhouse. Germination occurs in 7–14 days; approximately 0.12 oz (3.5 g) of 

seed yields 1000 seedlings (Nau 1999). 

Division: The easiest method of propagation is to divide plants in the spring, 

retaining roots with each propagule. Plants may be divided after one year in the 

field. 

Cuttings: Stem cuttings may be rooted under warm substrate conditions. To 

increase the number of branches for cuttings, BA can be sprayed. Bessler (1995) 

suggested applications of 10 ppm 3 times weekly for 5 weeks. Root cuttings are 

also successful. 

Growing-on 

Large divisions may be transplanted directly to the field; small divisions should 

be placed in 4–5" (10–13 cm) pots for additional growth. Grow seedlings and 

divisions at 50–60F (10–15C) in cold frames or cool greenhouses until ready for 

transplant to the field. Plants grow more rapidly at 70F (21C), but internode 

elongation may occur. Fertilize sparingly with 100 ppm N using calcium nitrate 

and potassium nitrate. 


Temperature: Work with Physostegia virginiana ‘Alba’ demonstrated that cold is 

not necessary to break dormancy of the rhizome; however, the cold normally 

associated with winter temperatures seems to synchronize flower development. 

Plants given a 12-week cold treatment were taller than those provided with 6 

weeks of cold (Iversen 1989). 

Photoperiod: Physostegia is a long day plant, the critical daylength lying 

between 12 and 16 hours (Cantino 1982, Deneke and Beattie 1989). If provided 

with LD, plants flowered regardless of presence or absence of a cold treatment; 

however, when plants were provided with 12 weeks at 40F (4C), 80% flowered. 

This shows that cold can substitute for LD, an occurrence not uncommon in

Physostegia virginiana


LD plants. The critical photoperiod is probably shorter for ‘Alba’ than ‘Bouquet 

Rose’. ‘Alba’ flowers in late June and July in north Georgia, while ‘Bouquet Rose’ 

does not flower until late August and continues through mid September. 


Longevity: Obedient plant is long-lived and may be expected to produce well 

for 3–5 years. Plants become very dense after 2–3 years of production, however, 

and should then be divided and rejuvenated. 

Longevity of Physostegia virginiana ‘Alba’. Spacing 1' (30 cm). 

Year Stems/plant (in) z Stem length (in) z Stem width 

1 13 29.4 0.30 

2 26 30.9 0.30 

3 14 29.0 0.26 


Yield was significantly reduced in the third year for ‘Alba’, but not for ‘Bouquet 

Rose’. 

Longevity of Physostegia virginiana ‘Bouquet Rose’. 

Year Stems/plant (in) z Stem length (in) z Stem width 

1 12 40.2 0.34 

2 24 63.6 0.35 

3 30 76.2 0.35 


Stem lengths are considerably longer with ‘Bouquet Rose’ than ‘Alba’ at the same 

spacing. 

The effect of cultivar on stem length. Spacing 2' (60 cm). 


Cultivar Stem length (in) z 3' 

Alba 30.9 11.6 54.1 34.3 

Bouquet Rose 63.6 0.4 1.9 97.7 


y = multiply (ft) by 30 to obtain (cm)

Various cultivars of Physostegia virginiana were trialed in Watsonville, Calif.; 

the results follow. 

Yield and stem length of Physostegia virginiana. 

Cultivar Year Stems/plant Stem length (in) z 

Bouquet Rose 1 17 33 

2 25 54 

Summer Snow 1 10 22 

2 16 46 

Summer Spire 1 18 27 

2 20 52 


In general, yield and stem length were excellent, but less so in California than in 

Georgia. 

Spacing: Plants may be spaced 1 × 1' (30 × 30 cm), but because plants fill in rapidly, 

yield declines after 3 years. Spacing at 18–24" (45–60 cm) centers is best for 

tall cultivars such as ‘Bouquet Rose’ and ‘Summer Snow’, but ‘Alba’ may be 

planted on 12" (30 cm) centers to increase yield. 

The effect of spacing on yield and stem quality of Physostegia 

virginiana ‘Alba’. Second season in production. 

Spacing (in) z Stems/plant Stems/ft 2y Stem length (in) z 

12 26 26 37.4 

24 43 10 35.6 

36 50 6 33.9 



PHYSOSTEGIA VIRGINIANA 463 

Spacing also affected the distribution of stem lengths: spacing plants greater 

than 2' (60 cm) apart resulted in fewer long stems. 


For more uniform flowering, plugs or bare root plants should be provided with 

6 weeks at 40F (4C). Cold is not necessary if uniformity is of little importance. 

Space rhizomes in 6–8" (15–20 cm) pots or a 9 × 12" (23 × 30 cm) spacing in 

greenhouse beds. Provide 16-hour LD and 60F (15C) average temperature once 

cooled rhizomes are in the greenhouse. In Pennsylvania (Beattie et al. 1989), 

‘Summer Snow’ flowered in 10 weeks, ‘Vivid’ in 15 weeks under 75/62F (24/17C)


day/night temperatures. Under New York conditions, flowering will begin in 

approximately 12 weeks (Iversen 1989). Work conducted in the winter in Finland 

showed that 16 weeks was required (Sarkka 1991). 






‘Alba’ 

(%) 

N P K Ca Mg 

2.72 0.32 1.25 1.00 0.37 

(ppm) 

Fe Mn B Al Zn 

242 66 27 50 198 


Flowers may be cut when the spikes are fully elongated but before individual 

flowers are open, although allowing 3 or 4 flowers to open does not reduce shelf 

life significantly. Harvesting when more basal flowers are already declining 

reduces shelf life by 3–4 days. Pink flowers have better shelf life than white flowers: 

the white flowers turn brown as they decline and become unsightly; pink 

flowers abscise in the same manner, but the browning is significantly less visible. 

Postharvest 

Fresh: Even though stems appear relatively resilient, they should go into preservative 

immediately; plunge them in preservative in the field to increase longevity. 

Place stems in cooler at around 40F (4C) as soon as possible. The use of 

pulses of silver thiosulfate (STS) and 5% sucrose reduces shattering significantly. 

Too much STS (>2 mM) results in browning of petals and leaf margins. Flowers 

persist about 6 days without preservative or STS treatment, but with proper 

treatment (STS, preservative, sugar) a vase life of 14 days is realistic. Work with 

Physostegia purpurea showed that flowers stored dry for one week at 32F (0C) and 

treated with preservative and STS persisted 8 days compared with a 4-day vase 

life when stems were not treated once removed from cold storage (Kelly and 

Starman 1990). The same study showed that if flowers were held dry at relatively 

warm temperatures (72F, 22C), vase life was not affected unless flowers remained 

warm and dry for up to 8 hours. 

Dried: Flowers do not dry well.

Cultivars 

PHYSOSTEGIA VIRGINIANA 465 

‘Alba’ (var. alba) has milky white flowers on 2' (0.6 m) stems. Flowers are produced 

4–6 weeks earlier than pink cultivars. 

‘Bouquet Rose’ (‘Rose Bouquet’) has rose-pink flowers on 3–5' (0.9–1.5 m) 

stems. 

‘Miss Manners’, a dwarf form, stands about 16" (40 cm) tall. It is less invasive 

than other varieties. 

‘Red Beauty’ has rose-lavender flowers. 

‘Rosea’ flowers a little earlier than ‘Bouquet Rose’ and bears rose-pink flowers 


‘Summer Snow’ is the most popular white-flowered form with 3–4' (0.9–1.2 

m) tall, white spikes in early to late summer. Flowers appear about the same time 

as pink cultivars and are taller than var. alba. 

‘Summer Spire’ has pink-red flowers on 3–3½' (0.9–1.1 m) stems. 

‘Vivid’ is the most popular garden form with 12–15" (30–38 cm) stems and 

vivid purple flowers. The short stems make it more difficult to market, however. 


Physostegia purpurea, which bears purple-magenta flowers, is native to the 

southwestern United States and has become naturalized across the southern 

states. May have potential for its relatively early flowering: in South Carolina, 

flowers are harvested in late April and May. Combining P. purpurea and P. virginiana 

allows for a longer harvest of flowers. 


Crown rot (Pellicularia rolfsii, Sclerotinia spp.) invades through roots or lower stem 

wounds and causes rapid wilting. Sterilizing soil prior to planting offers the best 

control. Rust (Puccinia), downy mildew (Plasmopara), and stem rot (Sclerotinia) 

also occur (Perry 1998). 

Reading 

Beattie, D. J., C. F. Deneke, E. J. Holcomb, and J. W. White. 1989. The effects of 

photoperiod and temperature on flowering of Physostegia virginiana ‘Summer 

Snow’ and ‘Vivid’ as potted plants. Acta Hortic. 252:227–233. 

Bessler, B. 1995. Cytokinin-induced branching of perennials. Gartenbauwissenschaft 

60(5):218–223. 

Cantino, P. D. 1982. A monograph of the genus Physostegia (Labiatae). Contributions 

From the Gray Herbarium 211:1–105. 

Deneke, C. F., and D. J. Beattie. 1989. Adaptation of Physostegia virginiana to 

greenhouse production as a flowering potted plant. Alabama Agr. Exp. Sta 

Research Report Ser. 6:13–14, 16. 


diss., Cornell Univ., Ithaca, N.Y.

466 PLATYCODON GRANDIFLORUS 

Kelly, J. W., and T. W. Starman. 1990. Postharvest handling of Physostegia purpurea 

cut flowers. HortScience 25:552–553. 




Sarkka, L. 1991. Wintertime production of Achillea and Physostegia with supplemental 

lighting and supplemental CO2 enrichment. Abstr. presented at 2nd 

International Symposium on Development of New Floricultural Crops. 17–21 September 

1991, Baltimore, Md. 

Many thanks to John Kelley for reviewing this section. 

Platycodon grandiflorus balloonflower Campanulaceae 

perennial, Zones 3–8 China, Japan blue 2½–3'/2' (75–90 cm/60 cm) 

Balloonflower has never become a mainstream cut flower crop, perhaps because 

of the time required to establish the plants, the height of the mature plant, or the 

tendency of the foliage to yellow. The unique bulging flower buds and lovely 

blue flowers have gained plants their followers as cut flowers, however. Starman 

et al. (1995) studied field production of balloonflower and concluded that mature 

plants, combining high yield with long stems, could be highly profitable. 

Propagation 

Seed: Most material grown for cut flowers is still seed-propagated. Approximately 

0.06 oz (2 g) of seed yields 1000 plants. Seed sown at 68–70F (20–21C) 

germinates in 1–2 weeks, and seedlings can be transplanted approximately 2 

weeks later (Nau 1999). 

Division: Plants have long tap roots and do not divide well. The crown may be 

carefully divided as long as sufficient root is taken with the section; if replanted 

immediately, few problems occur. Division may be accomplished in the spring 

after the foliage has emerged. Do not divide more than once every 3 years. 

Growing-on 

Three to 5 weeks are needed to transplant to final container from sowing, depending 

on whether seedlings are in open trays or plugs. Temperatures of 62– 

68F (17–20C) are recommended for growing-on. Temperatures below 55F (13C) 

may result in leaf yellowing and unacceptable slow growth. Plants may be 

planted out to the field in 10–13 weeks, or when the roots reach the bottom of 

the container. Planting in the fall or early spring is recommended. 


Temperature: Plants grown from seed require no cold treatment to flower; 

plants that have been divided require a cold treatment to break crown dormancy

PLATYCODON GRANDIFLORUS 467 

Platycodon grandiflorus 

(Iversen 1989). At least 6 weeks at 40F (4C) are necessary; 12 weeks result in more 

rapid flowering. Goi et al. (1994) stored quiescent crowns for up to 30 weeks as 

low as 32F (0C) and were able to have flowering plants all season. 

Research with ‘Astra Blue’ and other pot plant cultivars suggests that greenhouse 

temperatures of 68–72F (20–22C) result in rapid flowering and excellent 

branching; however, fresh weight and leaf area at flowering increased with 

decreasing temperatures (Park et al. 1998). Plants of ‘Sentimental Blue’, another

468 PLATYCODON GRANDIFLORUS 

pot cultivar, flowered 133–149 days from sowing at 62/60F (17/15C) day/night. 

Supplemental light and LD did not influence the number of days to flower but 

increased the number of shoots and flowers (Song et al. 1993). 

In the field, plants tolerate outdoor temperatures as far south as north Florida 

and north to New England. 

Photoperiod: Plants are day neutral (Iversen 1989), but a 4-hour night interruption 

during the forcing phase may result in flowering one week earlier. In 

the field, photoperiod is not used. 


Spacing: Space plants as wide as 12" (30 cm) centers to as dense as 9" (23 cm) 

centers. This is equal to 100 plants/100 ft2 (1080 plants/100 m2 ) and 180 plants/ 

100 ft2 (1750 plants/100 m2 ), respectively. Plants will form large clumps within 

3 years. 

Yield: Approximately 5 flower stems are formed after the first winter, up to 

15 stems on mature, well-developed specimens. Flowering occurs in mid to late 

summer and continues for about 4 weeks. Plants will rebloom on side shoots 

after cutting but with shorter stem lengths. 

Longevity: Plants are long lived and should remain productive 5–8 years. 

Support: Stems of the species and other tall cultivars require support. This is 

a necessity in the South and recommended in the North. 

Weed control: Because balloonflower is so late in emerging, herbicides such as 

Roundup can be applied in the spring (before emergence) to control overwintering 

and early spring weeds. 


If forcing bare-root material, plant one-year-old roots in ground beds (12", 30 

cm centers) or in deep pots, 6–7" (15–18 cm) in diameter. Provide 6 weeks of 

40F (4C) cold treatment; be sure that the medium remains moist. The cold treatment 

may be given in an unheated greenhouse, cold frame, or cold storage chamber. 

After 6 weeks, plants should be placed in 60F (15C) houses. Balloonflower is 

notoriously slow to emerge in the field or greenhouse; don’t give up too early: 

stem emergence will occur in about 4 weeks (Iversen and Weiler 1994). An additional 

9 weeks are necessary for flowering. 

If growing from seed, no cold treatment is necessary. Transplant seedlings in 

ground beds or final containers. Natural photoperiod is sufficient, although LD 

(nightbreak lighting or extended days) may result in slightly faster flowering. 

Supplemental lighting with HID lamps during low light months will improve 

quality but may not be economical. Keep temperatures warm; below 55F (13C), 

leaves will turn yellow, and plants will be stunted. Work with pot plant cultivars 

suggested 12–13 weeks at 64F (18C), 10–11 weeks at 70F (21C), and 9–10 weeks 

at 75F (24C). Expect an additional 2–3 weeks for cut flower cultivars. Approximately 

30 days are necessary between visible flower bud and open flower (Iversen 

1989).


Harvest when 2–3 flowers are open on the flower stem (Nowak and Rudnicki 

1990). 

Postharvest 

Flowers persist 5–8 days in preservative. 

PLATYCODON GRANDIFLORUS 469 

Cultivars 

‘Albus’ has white flowers with yellow veins on 3' (90 cm) stems. 

‘Double Blue’ bears deep double flowers on 2' (60 cm) tall plants, but who 

wants double balloonflowers? 

Florists series, available in dark blue, pink, and white, was developed for the 

specialty cut flower trade. 

Fuji series is a seed-propagated strain bred for cut flowers. Flowers are available 

in pink, white, and blue. Plants grow 2–3' (60–90 cm) tall. 

‘Hakone Double Blue’, a tall double-flowered form, is also available from seed. 

‘Komachi’ is a flowerless flower: the buds swell but never open. Interesting 

enough and may find a following, but don’t bet the farm on it. A white form is also 

available, and likely other cultivars with similar flower habit will be developed. 

‘Misato Purple’ grows 15–18" (38–45 cm) tall and provides dark purple 

flowers. 

‘Shell Pink’ may be grown from seed and bears shell-pink flowers on 2–2½' 

(60–75 cm) stems. 


Aphids and whiteflies can be a problem, as can earwigs, who chew through the 

bud and live within. 

Reading 

Goi, M., Y. Nagayama, A. Hasegawa, and M. Tanaka. 1994. Year-round production 

of Platycodon grandiflorus A. D.C. Tech. Bul. Fac. Agric. Kagawa Univ. 46(2): 

87–92. 


diss., Cornell Univ., Ithaca, N.Y. 

Iversen, R., and T. Weiler. 1994. Strategies to force flowering of six herbaceous 

garden perennials. HortTechnology 4(1):61–65. 



Storage Greens, and Potted Plants. Timber Press, Portland, Ore. 

Park, B. H., N. Oliveira, and S. Pearson. 1998. Temperature affects growth and 

flowering of the balloonflower (Platycodon grandiflorus (Jacq.) A. DC cv. Astra 

Blue). HortScience 33(2):233–236.

470 POLIANTHES TUBEROSA 

Song, C. Y., M. S. Roh, S. K. Chung, and R. H. Lawson. 1993. Effect of temperature 

and light on growth and flowering of potted plant production of Platycodon 

grandiflorus. J. Korean Soc. Hort. Sci. 34(6):446–453. 

Starman, T., T. A. Cerny, and A. J. MacKenzie. 1995. Productivity and profitability 

of some field-grown specialty cut flowers. HortScience 30(6):1217– 

1220. 

Many thanks to Dave Dowling for reviewing this section. 

Polianthes tuberosa tuberose Agavaceae 

bulb, Zones 7–10 Mexico white 2–4'/2' (0.6–1.2 m/0.6 m) 

Tuberoses have been cultivated for years and are well known for their sweet, 

heavy fragrance. The fragrance is sometimes considered too overpowering for 

use in confined areas, although historically, flowers were forced in European 

hothouses and used to decorate churches. The oil in tuberose is extracted for 

use in perfumery; approximately 1150 grams of flowers yield 1 gram of oil 

(Royal Horticultural Society 1992). The species itself no longer exists and is 

found only as a cultigen, that is, a plant solely represented by a cultivar(s), in 

this case, with single or double flowers. Up to 24 waxy-white, 2½" (6 cm) long 

flowers occur along an erect, open spike. Rootstalks consist of tender bulb-like 

tubers and must be lifted north of Zone 7b (north Georgia), although if adequate 

mulch is employed, growers in Zone 7a may leave bulbs in the ground. If 

tubers are lifted in the fall, store around 45F (7C) in a dry area and replant in 

spring after danger of frost is passed. Growers in the Northwest and coastal 

California may also leave bulbs in the ground. Since they don’t ship particularly 

well, tuberoses have become desirable local items, particularly popular for farmers’ 

markets. 

Propagation 

Tubers come in all sizes, including singles and clumps—that is simply the nature 

of the beast. They may be split after flowering and separated by size. They are also 

split and graded by the distributor, or the grower may split them after receiving 

from the distributor. Tuberoses increase naturally, and large offsets may flower 

the following year. Smaller ones can be placed together in nursery rows for an 

additional year if they overwinter, but this is hardly worth the time if they are 

dug every year. 


Photoperiod: No photoperiodic effects have been reported. 

Temperature: Tuberoses grow best at a minimum temperature of 68F (20C). 

They do continue to flower even when air temperatures fall below 50F (10C);

Polianthes tuberosa 

‘The Pearl’


however, warm temperatures are necessary for flower bud initiation, continued 

differentiation, and development (Kosugi and Kimura 1961). For growers in the 

North (Zone 5 and colder), the use of polyhouses to build up heat earlier may be 

essential. Tuberoses perform best under hot summers; 90F (32C) is not too 

warm for this crop. 


Tuber size: A great diversity in tuber size is available. The smaller sizes may 

flower in the southern United States but are of little use in the North. Large 

tubers emerge slower but flower faster than smaller ones. In general, 10+ cm 

bulbs will flower the first year. Plant 9–12" (23–30 cm) apart and cover with 2–3" 

(5–8 cm) of soil. They may be planted as clumps, in which case tubers may be 

placed almost cheek by jowl. 

Planting time: Tubers must be planted after danger of frost, in northern areas 

usually around late April, and can be planted all season. In areas of mild winters, 

they may be planted in the fall or early winter. In the North, there is no reason 

why tubers can’t be started early in moveable polyhouses or tunnels; this may 

help to bring in flowers significantly earlier. 

To be on the safe side, plant no earlier than February, even in mild climates, 

if no protection is provided. Once established, bulbs can tolerate occasional 

freezing temperatures in the winter. The effect of different planting times in 

Zone 7b, Athens, Ga., is shown in the following table (Armitage and Laushman 

1990). 

The effect of planting date on tuberose cultivars. 

Harvest Stem Stem 

Month Flw/ First duration length diameter 

planted tuber harvest (days) (in) z (mm) y 

‘Mexican Single’ 

Feb 0.8 2 Jul 87 43.7 8.3 

Mar 

‘The Pearl’ 

1.1 22 Jul 67 36.9 7.4 

Feb 0.9 16 Jul 73 33.2 8.9 

Mar 1.1 1 Aug 58 35.0 9.3 



Notice the duration of harvest: well over 8 weeks. Carolyne Anderson of Clark, 

Mo. (Zone 5–6), plants at 2-week intervals from April through July and harvests 

flowers from 15 July through frost. In northerly climates, earlier planting (e.g., 

March) is possible, but beds may require frost covers for the first 6–8 weeks.

POLIANTHES TUBEROSA 473 

Longevity: If tubers remain in the ground (assuming they are hardy for the 

area), tuberoses may be harvested for at least 3 years without division. The dead 

foliage may be used as a mulch in the winter. Remove mulch as soon as possible 

in the spring. Yield does not decline until the fourth year; therefore, lifting and 

dividing should be accomplished during the third or fourth year. Stem length 

may decline after the first year. 

Nutrition: Tuberoses are heavy feeders, and side dressing of a complete fertilizer 

is recommended. 


Warm temperatures around 68–75F (20–24C) are necessary to force tubers, 

which should be planted in ground beds. In one report, tubers of single-flowered 

cultivars planted on 1 April flowered on 10 August, 132 days from planting, 

when the average temperature was approximately 68F (20C) (Kosugi and Kimura 

1961). Double forms are generally 3–4 weeks earlier under greenhouse 

conditions than the singles. Check with the bulb supplier for the availability of 

bulbs for winter forcing. Although bulbs received in the spring may be dry-stored 

at 40–50F (4–10C) until ready to plant, properly stored bulbs should be received 

at the appropriate time from the supplier. 


Harvest when 2–3 flowers are open on the flower stalk and others are showing 

color. If necessary, stems may be cut with as many as ½ to ¾ of the flowers open, 

but the bottom flowers must not have started to fade. 

Postharvest 

Fresh: Fresh flowers have a vase life of about 9 days, during which time 44% of 

the buds open (Reid and Dodge 1997). Storage reduces vase life significantly. 

Faded flowers should be removed and stems recut as necessary. A flower preservative 

is useful for additional postharvest life. High concentrations of ethylene 

are deleterious, but treatment with an anti-ethylene agent is likely not warranted. 

Single flowers appear to persist longer than doubles because the inner row of 

petals on double flowers darkens rapidly, thus discoloring the whole flower. Petals 

of single flowers also discolor but not as quickly. 

Dried: Single flowers do not dry well, doubles are only slightly better. 

Storage: Optimal temperature to store cut tuberose is 32–41F (0–5C), but storage 

of flowers is not recommended. Reid and Dodge (1997) found that the vase 

life of flowers stored wet (stems in a solution of 250 ppm 8-HQC and 2% sucrose) 

was no better than dry stored flowers (wrapped in newsprint and polyethylene to 

reduce water loss); when they expanded their research to determine if dry storage 

at 35F (2C) could be used in combination with different pretreatments, storage 

duration, and vase solutions, the results were quite interesting.


The effect of vase solutions, dry storage at 35F (2C), and chemical 

pretreatments on keeping quality of cut tuberose flowers. 

Dry storage Vase Open florets Vase life 

Pretreatment (days) solution (%) (days) 

none 0 HQC 250 ppm 34.3 b z 6 c 

none 0 HQC + 2% sucr. 50.5 a 9 b 

20% sucrose 0 HQC + 2% sucr. 57.5 a 11 a 

1 umol STS 0 HQC + 2% sucr. 39.5 b 8 b 

none 6 HQC + 2% sucr. 19.0 c 5 c 

1 umol STS 6 HQC + 2% sucr. 33.3 b 6 c 

20% sucrose 6 HQC + 2% sucr. 50.1 a 11 c 

z = means with the same letter are not significantly different using Duncan’s 

Multiple Range Test (5%) 

The table shows that STS actually decreases vase life of tuberose; however, a pretreatment 

of 20% sucrose enhanced vase life regardless of storage methods. And 

for growers and shippers, a 20% sucrose pretreatment essentially overcame the 

negative effects of 6 days of cold storage. Most important, the work shows the 

importance of using a proper preservative when florists are unboxing the stems. 

Storage of tubers must be attended to carefully. They must be dried before 

storage, or stored in a well-ventilated area to allow for drying. Temperatures of 

70–80F (21–27C) will speed the process of drying before storing at 45–50F (7– 

10C). 

Cultivars 

‘Chula’, a recent offering, is a single white form, but there does not appear to 

be a great deal of difference between it and ‘Mexican Single’. 

‘Mexican Single’, the old standby, has waxy-white single flowers closely spaced 

on the flower stalk. An excellent cut flower. 

‘The Pearl’ is the most popular double-flowered form, with twice the number 

of petals as singles. 


Few problems affect tuberose, but that doesn’t mean there aren’t some sad tales 

out there. If conditions are too wet, especially when flowers are forming or opening, 

then flowers may be speckled with brown spots, probably the result of botrytis. 

Begin spraying with a fungicide as buds swell. Thrips can be a major problem 

in open flowers, causing damage with their sucking mouth parts. If field conditions 

are too wet, tubers disintegrate over the winter; therefore, good drainage is 

important.

Reading 

RANUNCULUS ASIATICUS 475 



Kosugi, K., and Y. Kimura. 1961. On the flower bud differentiation and flower 

bud development in Polianthes tuberosa L. Tech. Bul. Fac. Agric. Kagawa Univ. 12: 

230–234. 

Reid, M., and L. Dodge. 1997. Postharvest handling recommendations for cut 

tuberose. The Cut Flower Quarterly 9(1):13–14. 

Royal Horticultural Society. 1992. The New Royal Horticultural Society Dictionary of 

Gardening. Vol. 3. Macmillan Press, New York. 

Many thanks to Carolyne Anderson and Craig Schaafsma for reviewing this 

section. 

Ranunculus asiaticus Ranunculaceae 

bulb, Zones 8–10 Mediterranean many colors 1–2'/9" (30–60 cm/23 cm) 

Many species of buttercups are found in gardens and along roadsides, but this 

is the species that provides the color in bouquets from Saskatchewan to Singapore. 

Shyness is not one of its qualities, and its bold colors brighten up any 

arrangement. Plants do have one drawback: they are intolerant of extremes of 

heat or cold and can be grown outdoors only in areas with a Mediterranean climate, 

such as southern and central coastal California. Some southern growers 

have had moderate success with it as a winter crop; however, winter rains result 

in a high incidence of rotted tubers, especially where drainage is not sufficient. 

Flowering generally takes place from late September and continues through 

March, depending on prevailing temperatures. Most stems emanate from winter 

greenhouses, where production can take place anywhere cool temperatures 

and bright light occur. Ranunculus is a good companion crop for carnations or 

Anemone coronaria in the greenhouse. 

Propagation 

Tubers: Tubers may be purchased from bulb suppliers. Yield is directly proportional 

to tuber size; however, the start of flowering and full bloom occur at 

the same time regardless of tuber size. Also, as expected, tuber yields per mother 

tuber were highest from the largest mother tubers (Piskornik 1997). In general, 

tubers smaller than 3/5 cm will not flower adequately. 

Tuber viability is always a question when purchasing tubers. Umiel et al. 

(1992) developed a viability test for tubers anyone can do. Immerse dry tubers in 

running tap water for 2–12 hours (6 hours is sufficient), and follow this with a 

20-minute soak in an aqueous solution of Captan (0.25%). Plant the swollen 

tubers in a tray containing wet vermiculite (5:1 vermiculite:water, by volume) 

and incubate for 2 weeks at 62F (17C). After this, remove the tubers from the 

tray. Those that have produced roots and shoots are viable.

Ranunculus asiaticus ‘Tecolote’


Soaking tubers: Traditional wisdom has been to soak tuber for 2–4 hours to 

hasten germination and rooting, but Mike Mellano Sr. of Mellano & Company 

has a better method. He spreads the tubers out on a screen and mists them, soaking 

them but allowing the water to pass through the screen to a trough below. 

This minimizes the risk of spreading bacteria or fungi from infected tubers to 

healthy ones. He cautions that the screen must be high enough so that no water 

splashes back up from the trough. He suggests doing the same with any kind of 

preplant soak, including fungicides. 

Seed: Seed, if sown at 50–60F (10–15C), will germinate in 15–20 days. For the 

commercial flower grower, purchasing plugs from specialist plug growers is 

more sensible. Plugs may be planted immediately or grown on in a 45–55F (7– 

13C) greenhouse until ready for planting. 


Temperature: As for freesia and alstroemeria, soil temperature is very important, 

particularly in the Southeast and Southwest, where warm temperatures 

are the norm. Ranunculus are cool-loving plants and perform poorly if temperatures 

exceed 60F (15C) for any length of time. Night temperatures of 45–50F 

(7–10C) are preferable (Horovitz 1985). Cold temperatures of 34–36F (1–2C) 

have been used on presprouted tubers (tubers soaked in water for 24 hours) to 

accelerate flowering. Research in France showed that when soaked tubers were 

given a 14-day treatment of 36F (2C), the time between planting and the production 

of the first 3 flowers was shortened by 4 weeks (Horovitz 1985). More 

recent work in Italy found that storing tubers for 30 days at 50F (10C) resulted 

in faster flowering (126 days from planting tubers), compared with those stored 

at 36F (2C) (170 days) or those not cooled at all (190 days) (Guda and Scordo 

1989). Frank Arnosky suggests that 10 days is the maximum storage time for 

his operation; longer than that, and tubers begin to rot. 

Before exposing tubers to cool temperatures, they should first be stored at 

55–60F (13–15C) for 8–10 days. Frank has been growing ranunculus for years in 

Blanco County, Tex., hardly a “normal” location for these cold-loving plants. 

He has found that soil temperatures must be below 70F (21C), or prechilled 

tubers will go dormant and begin to rot. For him, patience is important: tubers 

are not normally planted until late October or November. 

Photoperiod: The highest percentage of tubers flower when placed under short 

day treatments (12 hours or less). Although long day treatments (>12 hours) 

accelerate flowering and flower quality, yields may not be as high. Long days also 

result in greater tuberization. If plants are placed under 14-hour days or longer, 

all the plants produce tubers but fewer than 40% produce flowers (Horovitz 

1985). 


Tuber size: Best results occur with 5/6 cm tubers, although 3/5 cm tubers will 

flower. In ranunculus, bigger is better; buying smaller tubers is a false economy.

478 RANUNCULUS ASIATICUS 

As Mike Mellano Sr. says, “If you figure your bulb cost relative to flower production 

and quality, the bigger bulbs are better.” 

Planting depth: Plant tubers with eyes up, approximately 1–2" (2.5–5 cm) below 

soil surface. The claw-like appendages should be on the bottom. Increasing 

planting depth delayed emergence and reduced the percentage of emerging 

plants. The number of developing shoots, leaves, and flowering stems were negatively 

correlated with planting depth. Tubers of ranunculus, when planted 

deeply, formed new tubers above the deep planting depth closer to the ground 

surface (Hagiladi et al. 1992). 

Spacing: It is better to be conservative on spacing; crowding tubers invariably 

results in botrytis and tuber rot. If using 3/5 cm tubers, plant approximately 5 

tubers/ft 2 (54 tubers/m 2 ) or approximately 4" (10 cm) apart. The largest tubers 

should be planted about 8" (20 cm) apart (De Hertogh 1996). 

Yield: Depending on cultivar and tuber size, 3–5 marketable stems per tuber 

is not uncommon. For the Victoria series, 4–6 stems/tuber were obtained the 

first year from plugs. 

Longevity: Tubers are inexpensive and are usually treated as annuals. If grown 

from seed, they are always treated as annuals. 


Ranunculus are usually produced in greenhouses or clear plastic houses but can 

also be forced in unheated cold frames in the South. Plant tubers (or plugs) in a 

very well-drained soil in a raised bed. Planting can be started when soil temperatures 

are below 70F (21C) (September–November) and continued until January. 

Maintain 45–50F (7–10C) night, 60F (15C) day temperatures and provide as 

much light as possible. Do not allow temperatures to exceed 60F (15C) for any 

length of time. If plants are grown too warm or if they dry out excessively, leaves 

are yellow and short-stemmed, and flowers are smaller in diameter. Soil-cooling 

equipment may prove to be cost beneficial. Maintain plants under natural 

photoperiod or as little as 8 hours of light. Avoid long days caused by light drift 

in the winter. 

Plants and even flower buds can endure freezing temperatures, probably as 

low as 23F ( −5C). In the South, when plants are forced in unheated cold frames, 

a floating row cover provides adequate protection from harsh weather. 

Fertilize plants weekly with approximately 200 ppm N and leach often to 

reduce soluble salts (Horovitz 1985). Application of 50 or 100 ppm gibberellic 

acid 2 months after planting, and again 3 weeks later, advanced flowering and 

the number of flowers produced (Pascale and Scognamiglio 1998). Drip irrigation 

reduces disease on foliage and tubers; avoid overhead irrigation. 

Tubers flower 60–90 days from planting, depending on whether they have 

been soaked and/or vernalized prior to planting. Seed-grown plants flower 4–6 

months from sowing. The lengthy time required for flowering from seed often 

dictates that seed cultivars be purchased as plugs.



Cut flowers when buds show color and are about to open (Nowak and Rudnicki 

1990). For local markets, flowers can be allowed to fully open. 

Postharvest 

Fresh: Flowers persist in preservative for 7–10 days at cool room temperatures 

around 60F (15C). Work by Kenza et al. (2000) found that flower quality was 

not improved by treatments with aminooxyacetic acid (AOA) or silver thiosulfate 

(STS). This indicates that ethylene is not an important regulator of senescence 

in cut ranunculus and that no special precautions are needed to keep the 

flowers from contact with ethylene. 

Dried: Flowers may be air-dried by first stripping leaves and hanging upside 

down in small bunches. Drying by microwave is also practiced (Vaughan 1988). 

Storage: Flowers should be stored only if necessary at 34–36F (1–2C) in 

water/preservative (Vaughan 1988). They do not store well dry. 

Cultivars 

La Bella series has been highly successful, producing fully double flowers in 

many colors. Arnosky harvests 10 and more flowers per tuber. 

‘Tecolote’ has been used for cutting for many years. Plants bear double flowers 

3–4" (8–10 cm) wide, and some singles, in a range of colors. 

Victoria series is an F1 hybrid strain with excellent uniformity and flower 

shades. Available from seed or plugs. 


Crown rot (Botrytis) affects tubers. Provide good ventilation and do not plant 

too closely or use overhead irrigation. 

Southern blight (Sclerotium) can be a serious disease, particularly in dark, 

moist conditions. Older leaves develop fuzzy white growth that moves into the 

crown. Good airflow and removal of infected leaves is essential. 

Various water molds, such as Pythium and Phytophthora, result from poor 

drainage. Tubers and roots are susceptible to these fungi. Be sure soils are exceptionally 

well drained. 

Reading 



Guda, C. D., and E. Scordo. 1989. Hybrid Ranunculus response to cold treatments 

on corm sprouts. Herbertia 45:56–60. 



of some geophytic plants. Acta Hortic. 325:131–137.

480 SALIX 

Horovitz, A. 1985. Ranunculus. In The Handbook of Flowering. Vol. 4. A. H. Halevy, 


Kenza, M., N. Umiel, and A. Borochov. 2000. The involvement of ethylene in the 

senescence of ranunculus cut flowers. Postharvest Biology and Technology 19(3): 

287–290. 



Pascale, S. de, and D. Scognamiglio. 1998. Effects of photoperiod and gibberellic 

acid on Ranunculus asiaticus. Colture Protette 27(9):107–110. 

Piskornik, M. 1997. Effect of tuber weight on flower and tuber yields of Persian 

ranunculus (Ranunculus asiaticus L.). Zeszyty Problemowe Postepów Nauk Rolniczych 

449:153–160. 

Umiel, N., A. Hagiladi, Y. Ozeri, R. Elyasi, S. Abramsky, and M. Kenza. 1992. A 

standard viability test for corms of Anemone coronaria and Ranunculus asiaticus. 

Acta Hortic. 325:333–340. 


Ore. 

Many thanks to Bob Pollioni (first edition) and Frank Arnosky and Mike Mellano 

Sr. (second edition) for reviewing this section. 

Salix willow Salicaceae 

woody, Zones 3–8 worldwide contorted, colorful stems 1 

6–20'/20' (1.8–6 m/6 m) 

Willows, among the most common cut woody stems, are easy to propagate and 

fill an important niche in the cut branch market. They are grown for their contorted 

stems (Salix matsudana ‘Tortuosa’), flattened stems (S. sachalinensis ‘Sekka’, 

the fantail willow much sought after by arrangers), and colored stems (S. alba 

‘Britzensis’, ‘Vitellina’)—or a combination of these (S. ×erythroflexuosa ‘Golden 

Curls’, ‘Scarlet Curls’). Stem colors range from red to yellow, and several fastgrowing 

species and cultivars with twisted stem shapes are now available. 

They are also grown for their male catkins (pussy willows), but Mel Heath of 

Bridge Farm Nursery in Maryland, who has been growing salix for about 6 years, 

says pussy willows may not be worth the space, attention, water, fertilizer, and 

labor required, particularly on a small scale. He has found that prices are low, volumes 

for individual customers are low, and plants take up a lot of space. He 

makes the excellent point, however, that those same arguments could be applied 

to any plant in this book, so listen to Mel and choose your crops wisely. 

Propagation 

Cuttings: Easily propagated by soft and hardwood cuttings any time of year. 

Cut and stick.

Seed: Seed has no dormancy and germinates in 12–24 hours if provided with 

a moist environment (Dirr 1998). 

Growing-on 

After rooting, transplant to a 6" (15 cm) pot or 1 gallon (4 l) container until 

plants are large enough to transplant to the field. 


Stems are most contorted and colored forms most colorful when young. Cool 

temperatures in late fall and winter and high light intensity result in more colorful 

stems. 


All species grown for colored stems need to be cut back hard in late winter and 

early spring for best form and color in the fall and winter. 


Harvest leafless stems at peak of color. 

Postharvest 

When stems are cut, place immediately in water. Remove foliage. Stems may be 

stored dry at 30F ( −1C). Plunge pussy willow stems in water upon harvesting 

and store in a 35–40F (2–4C) cooler. 


SALIX 481 

Species grown for male catkins (pussy willows) 

Salix caprea (goat willow) and S. discolor, the true pussy willow, are closely 

related and often confused with each other. Salix discolor has brown branches 

and almost white lower leaf surfaces. The catkins of S. caprea, a 15–25' (4.5–7.5 

m) tall tree, are 1–2" (2.5–5 cm) long and appear in March and early April. It is a 

better species for catkins than S. discolor because of the latter species’ susceptibility 

to canker. Neither species is long lasting in the field. 

Salix chaenomeloides (Japanese pussy willow) grows 10' (3 m) tall in a couple of 

years. The large red flower buds are the best part of the plant, even better than the 

pink to rosy catkins. Vigorous, well worth a try. 

Salix gracilistyla (rosegold pussy willow) has rosy catkins. 

Salix melanostachys (black pussy willow) is an interesting 10' (3 m) tall shrub. 

In winter, the stems take on a purplish hue, and in the spring the catkins are

Salix chaenomeloides

SALIX 483 

purple-black, finally showing off red stamens, which later turn yellow. The stems 

and catkins are beautiful, but production of useable stems has been inconsistent 

due to inconsistent spacing of the catkins. 

Species grown for contorted and/or colorful stems 

Salix alba (white willow), a common landscape plant, is of little value as a cut 

stem. But its colored-stem forms, particularly ‘Britzensis’ (coral bark willow) 

and ‘Vitellina’ (yellow bark willow), are quite beautiful and highly functional 

for cut stems in late fall and winter. 

Salix ×erythroflexuosa ‘Golden Curls’ is a cross between S. alba ‘Tristis’ and S. 

matsudana ‘Tortuosa’; its stems are slightly contorted and golden-yellow in the 

winter. ‘Scarlet Curls’ is similar but with red winter stems. 

Salix matsudana (Hankow willow) is best known for the cultivar ‘Tortuosa’, 

the common contorted willow harvested by the truckload. Short-lived in the 

heat but an effective persistent plant elsewhere. 


All willows are fast-growing and short-lived. The wood is weak, and maintenance 

and upkeep are necessary to keep plants productive. 


The biggest complaint we hear about growing pussy willows is the inconsistent 

spacing of the buds (later the catkins). In some stems, they are equally spaced 

along the entire length; in others, half the stem will have no buds at all. This is 

likely attributable to changes in soil moisture, fertility, or temperatures while the 

buds are forming in the summer and fall. Very difficult to forecast. 


“Black pussy willow (Salix melanostachys) grew slower than most salix but are now 

fully growing together in rows and are 4' tall (after being cut back to about 18" 

each winter). We’ve had very dry years recently, and the plants just haven’t made 

very good cuts. When you cut them they are branched, and the catkin is beautiful—black 

with a red fuzzy end—on reddish stems. But so few of my stems have 

been really nice. Also, in the few years when I did have good stems I found only 

very special florists knew how to design with them.” Bob Wollam, Wollam Gardens, 

Jeffersonton, Va. 

“We have black pussy willow on the farm. The market potential is very promising, 

but they are too short and have too many twigs without the black buds 

(look like red dogwood.). We found out that with willows, if you cut it to the 

ground (6–12") you get very heavy twigs in the next season and very tall ones—we 

got 8–10'. If you cut it just about 2–3' at pruning, you will get many more twigs 

that are not as heavy as the first ones, and about 4–6' in length.” Shlomo Danieli, 

Blooming of Beloit, Beloit, Wis.

484 SALVIA 

Reading 



Many thanks to Mel Heath for reviewing this section. 

Salvia sage Lamiaceae 


Hundreds of species of sage have been grown over the years by gardeners, landscapers, 

greenhouse operators, and nurserymen, but only a few have been used 

in the cut flower trade. Some reasons for their general exclusion are obvious: 

lack of sufficient stem length, flower shatter, malodorous foliage, and poor yield; 

however, many salvia species have cut flower potential for bouquet work as well 

as bunches and arrangements. A few are perennial, some are obvious annuals, 

and others are “temperennials,” depending on the latitude. Their ornamental 

properties are waiting to be exploited. 

Salvia leucantha Mexican bush sage, velvet sage Lamiaceae 

annual Mexico purple, white 2–4'/3' (0.6–1.2 m/0.9 m) 

This species is among the most useful salvias for cut flower production. Plants 

are relatively easy to grow in both field and greenhouse, the foliage is handsome, 

and flower production is excellent—a high-impact show. Flowers are seldom 

seen from overseas growers. 

Propagation 

Velvet sage is easily propagated by terminal cuttings taken before flower buds 

have formed. Approximately 2–3" (5–8 cm) long cuttings may be rooted in a 1:2 

ratio of a peat/perlite mix in 7–10 days if placed at 70–75F (21–24C) and humid 

conditions. A sweat tent or similar means of maintaining high humidity is better 

than intermittent mist. Plants may also be dug out of the field in the fall and 

overwintered in cool (40F, 4C) greenhouses (Wollam 1997). Cuttings may be 

taken from these plants in late winter and spring. If overwintering for stock 

plant use, provide long days to inhibit flower initiation. 

Growing-on 

Once plants are rooted, they may be transplanted to small containers prior to 

planting out in the field. Place plants at 55–62F (13–17C) under long days (>12 

hours) and fertilize with 150–200 ppm N once or twice a week. If roots are well 

formed, plants may be transplanted to the field immediately once the threat of 

frost has passed.


Photoperiod: Velvet sage is a short day plant, which helps to explain why flowers 

occur in the fall. Long days result in vegetative development and long stems; 

short days are necessary for both flower initiation and development (Armitage 

1989). This plant was in full flower in December in Quito, Ecuador, where 

photoperiod is essentially 12 hours year-round, suggesting that the length of 

the dark period need not be greater than 12 hours. In areas of early frosts, such 

as the Northeast, there may be insufficient time for flower development. 

Temperature: Warm temperatures are best for flower development. Plants are 

particularly vigorous in warm summers. Cool temperatures in late summer 

result in fewer flowers on smaller plants. 


Spacing: Velvet sage is a large, vigorous plant; therefore, spacing less than 15" 

(38 cm) apart should be avoided, as should spacing greater than 3' (90 cm) centers, 

not only because yield/ft2 is reduced, but also because the brittle stems need 

surrounding plants for support. Bob Wollam grows his on 2' (60 cm) spacing in 

2 rows on a 3½' (1.1 m) bed. Work at the University of Georgia showed that wide 

spacing resulted in more stems/plant than close spacing, but stems/ft2 decreased 

(Armitage 1987). 

The effect of spacing on yield of Salvia leucantha. 

Spacing (in) z Stems/plant Stems/ft 2y 

24 125 32 

36 180 20 

48 180 12 



SALVIA LEUCANTHA 485 

Lateral stems: Lateral stems form after the terminal has been harvested. Harvesting 

the entire stem (laterals and all) at once is easier and less expensive, and 

provides the greatest stem length; however, if stem length is not a major issue, 

harvesting the terminal stem about halfway down and then allowing the laterals 

to flower will provide significantly higher yield. It’s your choice. 

Support: Plants are woody at the base and can grow to 5' (1.5 m) tall and almost 

as wide. The main stems are sufficiently strong without support, but the 

secondary flower stems are brittle. Netting can be used, but cutting would be 

time consuming and unacceptable breakage of stems might occur. Wind damage 

can be a problem, and planting a windbreak makes sense (Wollam 1997). 

Plants eventually fall on themselves, acting as their own support system. 

Flowering time: Velvet sage is a fall-flowering salvia, and unless lights are employed 

outdoors, plants flower in September and October, regardless of planting

486 SALVIA LEUCANTHA 

date. This can be a serious limitation to growers in the North, particularly those 

north of Zone 6. Early frosts can be painful, and Bob Wollam (1997) suggests 

overnight water sprays to reduce frost injury. 


Salvia leucantha is an excellent plant for greenhouse production. Flowering is 

easy to control, and forcing may take place year-round using a chrysanthemum 

schedule. 

Space rooted cuttings 12 × 12" (25 × 25 cm) or 12 × 18" (25 × 45 cm) apart in 

ground beds or in large containers. Closer spacing may be used, but air movement 

is reduced. Place cuttings under long days (>14 hours) and fertilize with 

200 ppm N of a balanced fertilizer, such as 20-10-20. Calcium nitrate and potassium 

nitrate should be rotated in the winter. For the first crop, a single pinch 

when the shoots are about 4" (10 cm) long is useful but not necessary. Once the 

new shoots are 4–6" (10–15 cm) long, place plants under short days (12 hours) 

until the flower buds are colored. Short days must be maintained until flower 

buds have colored; long days interrupt the development of the flowers (Armitage 

1989). Maintain 60–63F (15–17C) night temperatures and 70–75F (21–24C) day 

temperatures. Reduce night temperatures to 55F (13C) about one week prior to 

harvesting (when flower buds are colored). 

Harvest all stems from a single planting over a period of one week; do not 

wait for laterals to form as in the field. Yield is reduced compared to the field, but 

harvesting is easier and subsequent plantings allow for extended harvests 

throughout the season. Place stems immediately in water with floral preservative. 

The leaves wilt readily and must be protected from heat and stress. 

Crop time is 11–15 weeks from planting. This includes 3–5 weeks LD and 

8–10 weeks SD until harvest. These times vary with season and location. 


Flowers should be harvested when the white petals (corolla) emerge from the 

purple sepals (calyx) on the first 3 or 4 basal flowers. This generally occurs outdoors 

any time from the first 2 weeks of September to the last 2 weeks in October. 

Postharvest 

Fresh: Hydrate immediately in the field. Recut once indoors. Flowers persist 

approximately 7 days in water (Gast and Inch 2000). The flowers tend to shatter, 

particularly if stems are out of water for any length of time. Using STS, if available, 

as a 30-minute pulse prior to placing in preservative solution adds an additional 

3–4 days. 

Storage: Stems do not store well dry; the foliage declines more rapidly than 

the flowers. They may be stored wet for 3–4 days at 35–40F (2–4C). 

Dried: Flowers are air-dried and make good dried flowers. The application of 

silica gel or glycerine may be useful.

Cultivars 

‘Midnight’, the name of choice for the cultivar with entirely purple flowers, is 

also known as ‘Blue on Blue’ and ‘Purple on Purple’. 

‘Santa Barbara’ is a dwarf form, growing only about ½ as tall as the species 

itself. May be useful if shorter stems are desired. 


SALVIA LEUCANTHA 487 

Salvia farinacea (mealy-cup sage) bears Wedgwood-blue flowers on 2' (60 cm) 

stems. Seed germinates in 2–3 weeks at 70–72F (21–22C). Numerous colors have 

been bred; all are useful for cuts, but none have outstanding stem length or stem 

strength. ‘Argent’ (‘Silver’), an older form with silver-white flowers, does not 

stand out from other plantings as well as the blue and violet forms; in national 

field trials, 14 stems/plant with an average stem length of 15" (38 cm) were produced 

(Dole 1998). ‘Blue Bedder’ is one of the standards in the industry; plants 

are productive and sufficiently tall, and provide handsome dark blue flowers. 

‘Cirrus’ is about 15" (38 cm) tall with white flowers on silver-white flower stems; 

more compact and slightly whiter flowers than ‘Argent’. ‘Rhea’ is a 12" (25 cm) 

compact form with dark blue to violet flowers. ‘Strata’ can be an interesting addition 

to the garden, bearing bicolored blue and white flowers. It comes off as 

rather washed-out, not knowing whether it wants to be blue or white, and being 

neither; all the same, this cultivar was honored with Europe’s Fleuroselect award 

and was a 1996 All-American Selection in the United States. ‘Victoria’ is by far the 

most common cultivar, with large intense violet-blue flowers. Bigger and more 

vivid than ‘Rhea’, ‘Victoria’ produces deep violet-blue flowers that are useful fresh 

or dried. In national field trials, 8 stems per plant with an average stem length of 

15" (38 cm) were produced (Dole 1998). Recommended: most mealy-cup sage cut 

in this country is either ‘Victoria’ or ‘Blue Bedder’. ‘Reference’ has bicolor flowers, 

similar but not as well known as ‘Strata’; in national field trials, 7 stems/plant 

with an average stem length of 15" (38 cm) were produced (Dole 1997). 

Salvia guaranitica (anise-scented sage) grows 3' (90 cm) tall and bears dozens 

of dark blue flowers. Untested but has potential. This outstanding sage begins to 

flower in early to mid summer and continues all season. The dark green leaves 

are 4–6" (10–15 cm) long and sparsely hairy. They don’t have much smell when 

crushed, and do not smell like anise. Flowers are held in whorls of 3–8; the 

corolla (the petals) can be up to 3" (8 cm) long, and the calyx (sepals) may be a 

different color. Hardy to Zone 6. ‘Argentina Skies’ has flowers of pastel blue, 

much more muted than those of the species; beautiful but not quite as floriferous 

as the type. ‘Black and Blue’ is a huge subshrub with hairy leaves and large 

dark blue flowers with almost black sepals; plants often reach 5–6' (1.5–1.8 m) in 

height. ‘Blue Ensign’ has large light blue petals with green sepals. ‘Costa Rica 

Blue’ may be the same as ‘Black and Blue’, which may be the same as ‘Late Blooming 

Giant’. They are all big, flower later than the species, and have darker calyces 

than the corollas. ‘Purple Majesty’, a hybrid between S. guaranitica and S. gesneraeflora 

(a red-flowered Mexican species) is at least 5' (1.8 m) tall and 3' (90 cm)

488 SALVIA LEUCANTHA 

wide with deep purple flowers. Hardy to Zone 7b. ‘Purple Splendor’ is smaller 

than ‘Purple Majesty’; it too has dark violet-blue sepals, but its leaves are smooth. 

Salvia ‘Indigo Spires’, a tall-growing blue-flowering sage, is among the most 

vigorous and floriferous hybrids (Salvia farinacea × S. longispicata) available. In 

flower, plants easily grow 3–4' (0.9–1.2 m) tall and bloom for many months; as 

fall settles in, the flower color becomes more intense, and the spires live up to 

their name. Unfortunately for northern growers, it is hardy only to about Zone 

7b, but for those who grow it, the best advice is to plant and get out of the way. 

Cut the flowers back occasionally for repeat bloom. Flowers for months at a 

time, and is perennial to Zone 7. 

Salvia splendens (annual sage) is occasionally used. Colors include white, 

salmon, and purple, but red is the predominant color. Propagate by seed. Dozens 

of cultivars—taller ones include ‘Bonfire’, with 26" (66 cm) stems, and ‘Flare’, 

18" (45 cm). A new selection, ‘Faye Chappell’ (syn. S. splendens subsp. van houttei), 

has bright scarlet flowers held on 2–3' (60–90 cm) stems. Quite outstanding. 

Salvia ×superba (perennial hybrid sage) produces dozens of 18–24" (45–60 

cm) long, blue to violet-blue flowers. ‘Blue Queen’ (violet-blue), ‘Lubecca’ (purple), 

and ‘May Night’ (indigo) are useful for cutting. Propagate cultivars by terminal 

cuttings; seed is available for S. ×superba. Very closely related to S. nemorosa, 

another species worth a try for its straight thick stems. 

Salvia viridis (green sage, clary; not to be confused with S. sclarea, clary sage) is 

the namesake of all salvias in the Greek language: until the early 1980s, it was 

known as S. horminum, and horminum is ancient Greek for sage. Plants have 

brightly colored, veined bracts and dry well. Harvest when the bracts feel firm 

and papery, remove large leaves, and hang upside down. Quite different from 

other large-flowered forms, simple to raise and grow, and worth trying, for the 

interest alone; however, stems are only 12–15" (30–38 cm) long. Plants are native 

to the Mediterranean and do not tolerate extremes of temperature or humidity. 

Better in the North than in the South. Many cultivars available, all raised from 

seed. ‘Alba’ has white bracts. ‘Bluebeard’ produces pale violet bracts with darker 

veins. ‘Claryssa’ is a dwarf form with a mix of purple, pink, and white bracts. 

Marble Arch series is available in blue, rose, and white. In national field trials, 

‘Marble Arch Blue’ produced 18 stems/plant with an average stem length of 14" 

(36 cm); the rose and white form produced 19 and 20 stems per plant with 

lengths of 18" (45 cm) and 14" (36 cm), respectively (Dole 2000). ‘Oxford Blue’ 

bears blue-purple bracts. ‘Pink Sundae’ has rosy carmine bracts with darker 

veins; similar to ‘Purpurea’. ‘Purpurea’ is quite common and has rosy red to purple 

bracts. ‘Rose Bouquet’ has pink bracts. ‘Violacea’ bears violet bracts with 

darker veins. ‘White Swan’, with clean white bracts, is essentially the same as 

‘Alba’. 


Few pests and diseases occur on velvet sage. Aphids can be a problem. Perennial 

sages grown north of Zone 7 are seldom troubled with disease; however, if grown 

in areas of hot, humid summers, root rot may be common.


“Salvia leucantha is marginally hardy for me in Zone 7b. I have taken cuttings as 

late as early June and had good-sized plants to cut in September–October.” Alex 

Hitt, Peregrine Farm, Graham, N.C. 

“I have tried many [Salvia farinacea] cultivars, and the only ones I grow are 

‘Victoria’ (it’s productive, very blue, and tall enough for use in small bouquet 

work) and ‘Blue Bedder’ (which is tall and the industry standard in the salvia 

department).” Bob Wollam, Wollam Gardens, Jeffersonton, Va. 

Reading 



———. 1989. Photoperiodic control of flowering of Salvia leucantha. J. Amer. Soc. 

Hort. Sci. 114:755–758. 


9(1):31–37. 


10(1):1–33. 

———. 2000. 1999 ASCFG National Seed Trials. The Cut Flower Quarterly 12(1): 

1–19. 

Gast, K. L. B., and R. J. Inch. 2000. 2000 evaluation of postharvest life of selected 

fresh-cut flowers and greenery. Kansas State Univ. Agr. Exp. Sta. and Coop. Ext. 

Serv. Report 859. 

Wollam, B. 1997. Salvia leucantha. The Cut Flower Quarterly 9(3):11 

Many thanks to Bob Wollam for reviewing this section. 

SCABIOSA 489 

Scabiosa pincushion flower Dipsacaceae 


Both annual and perennial species of the genus are used as cut flowers, nearly all 

field-grown. The annual forms are more often seen in mixed bouquets and as 

fillers; their range of flower colors adds diversity on a season-long schedule. Perennial 

cultivars usually bear larger flowers but are available in limited color selection 

only. 

Scabiosa atropurpurea pincushion flower Dipsacaceae 

annual southern Europe blue 2–3'/2' (60–90 cm/60 cm) 

The tufted appearance of this species’ flower heads recalls a velvet pincushion, 

and the flowers’ dark color also signifies death, accounting for another of its 

common names, mournful widow. According to Joan Thorndike of Ashland,

490 SCABIOSA ATROPURPUREA 

Ore., plants with purple flowers are known as la viuda (“the widow”). The erect 

branched stems stand upright, without need of support. The fully double flowers 

are sweetly fragrant; they form in late spring and continue through the summer. 

They are borne singly on long flower stems, and are purple to crimson, but 

other colors have been bred. At the base of the flowers are the whitish overlapping 

bracts, one of the ways to distinguish the genus from others in the family. 

Compared to the more common perennial forms of Scabiosa, particularly Scabiosa 

caucasica, some cultivars of this annual are more tolerant of heat and can be 

grown further south. Scabiosa atropurpurea may not be a big money maker, but 

it’s terrific for wedding work (including boutonnieres) and other specialized 

functions. 

Propagation 

Seed: Seed is often direct sown to the field after the threat of frost has disappeared. 

Sow 0.5 oz per 100' (50 g per 100 m) (Kieft 1996); if transplants are used, 

0.5 oz (14 g) of seed yields 1000 seedlings (Nau 1999). Seed should be covered 

lightly, if at all, because light enhances germination. Seed germinates in 10–12 

days at 65–70F (18–21C). 

Growing-on 

If sown in the greenhouse, grow plugs or trays at 50–55F (10–13C) for 10–12 

weeks from seeding. Warmer temperatures accelerate growth, but plants tend to 

stretch. Fertilize lightly (50–100 ppm N) with potassium and calcium nitrate. 


Photoperiod: Scabiosa atropurpurea is a long day plant. Flowering during the 

winter is enhanced with incandescent lights, either by daylength extension or 

by nightbreak lighting (Wilkins and Halevy 1985). 

Temperature: Temperatures below 55F (13C) are best for plant growth. The 

combination of cool growing temperatures and LD significantly reduces flowering 

time. Well-rosetted (i.e., older) plants are more responsive to cool/LD conditions 

than seedlings (Wilkins and Halevy 1985). 


Seed or transplant on 9–15" (23–38 cm) centers in full sun (Post 1955). The yield 

in trials at Athens, Ga., was 14 stems/plant with an average stem length of 27.8" 

(70 cm) from 3 to 20 July. Many more flowers were produced after that time, but 

stem length averaged only 15" (38 cm). Plants can reach 4' (1.2 m) in height. 

Successive plantings (every 2–4 weeks until mid summer) are necessary for optimum 

stem length and flower quality. Flowering occurs as days lengthen and 

temperatures increase. Netting should be used to avoid flopping and bent stems;

once the netting is up, harvesting becomes more labor intensive. Plants are generally 

low in maintenance, hardly affected by fertility or insects and diseases, 

and they keep producing generously all season long. 

Plants can be overwintered, but they should be replanted every year. Self-sown 

seedlings are generally haphazard in performance and color; however, if seeds are 

collected, germination is good, and the random hybridization that results can 

yield some very different offspring, some outstanding. 


Scabiosa atropurpurea is seldom greenhouse-grown: quality is poor under warm 

conditions and so too is financial return. For an early spring crop, seedlings 

may be grown at 55–60F (13–15C) until rosettes have formed (10–12 weeks after 

sowing). Reduce night temperature to 50F (10C) and keep days as cool as possible. 

Long days (>16 hours) using 10–20 fc of incandescent light should be used 

throughout the crop cycle. Warmer temperatures result in thin stems. Flowering 

occurs approximately 4 months from sowing. 


Harvest the flower when the center has just started to unfurl. 

SCABIOSA ATROPURPUREA 491 

Postharvest 

Fresh: Flowers persist 5–7 days in water, an additional 3–5 days with flower 

preservative. 

Cultivars 

‘Ace of Spades’ is a terrific plant, with dark purple to almost black, honeyfragrant 

blooms. About 2½' (75 cm) tall. Everyone enjoys this one. 

Double Giant Mixture has 2" (5 cm) double flowers in pink, white, lilac, red, 

and blue. 

‘Imperial Giants’ comes in a mixture of colors and grows 2–3' (60–90 cm) 

tall. Some people detect a fragrance, but that is very subjective. 

‘Perfect Lilac’ and ‘Perfect White’ both grow to about 2' (60 cm). 

QIS Formula series is available in separate colors (dark blue, salmon-pink, 

scarlet, and burgundy-red) and as a mix. Plants are 3' (90 cm) tall. The upright 

growth and uniformity of flowering are most useful for cut flower growers. Stem 

yield in national trials of QIS Formula Mix averaged 17 stems/plant with 19" 

(48 cm) stem length; many growers loved them and sold all they produced, others 

found problems with lodging after rain or wind, and crooked stems (Dole 

2000).

492 SCABIOSA CAUCASICA 

Scabiosa caucasica perennial scabious Dipsacaceae 

perennial, Zones 3–7 Caucasus blue, white 2–2½'/2' (60–75 cm/60 cm) 

This species is the most popular scabious used for cut flowers. 

Propagation 

Seed: Seed sown at 65–70F (18–21C) under intermittent mist or sweat tents 

germinates in 10–18 days. Approximately 1 oz (28 g) of seed yield 1000 seedlings 

(Nau 1999). Seed is not direct sown. 

Division: Plants may be divided after 2–3 years in the field. 

Growing-on 

Transplant to flats (50–96 cells per tray) in the greenhouse 3–4 weeks after sowing. 

Fertilize with 75–100 ppm N for the first 2 weeks, then raise to 125 ppm N 

with a complete fertilizer. Grow on at 55–58F (13–14C) until ready to transplant 

to the field. Plants are ready to transplant as soon as they can be put in the 

ground without damage, approximately 6–10 weeks from sowing. Plants that 

have been divided may be moved immediately to 4" (10 cm) pots for 2–3 weeks 

prior to planting in the field, or planted directly. 


Temperature: Scabiosa caucasica appears to have a critical temperature and photoperiod 

for flowering. Under winter and SD conditions, temperatures above 

65F (18C) inhibit stem elongation (Post 1955). This species requires some cooling 

at temperatures below 40–45F (4–7C), whereas the annual S. atropurpurea 

(which see) does not. 

Photoperiod: Flowering occurs more rapidly under LD. Larger plants are more 

responsive to LD treatments than seedlings. 


Plants produce more flowers of higher quality in areas of cool summers and cold 

winters. Quality of the cut flowers declines south of Zone 7, although precooled 

plants may be used for winter production in Florida. 

Spacing: Space plants 18 × 18" (45 × 45 cm) or 12 × 12" (30 × 30 cm). Spacing 

as wide as 2' (60 cm) centers has also been used. 

Yield: In Burlington, Vt., 13 stems/plant were harvested from 2-year-old plants 

of Scabiosa caucasica ‘Fama’ spaced 2' (60 cm) apart (Perry 1989). The average 

stem length was 27" (67 cm). Plants of ‘Fama’ trialed nationally averaged 26 

stems/plant with a stem length 18" (45 cm) in its first year (Dole 1997), but 

longer stem length would be expected the second year. 

Longevity: Plants are productive for 3–5 years, but 2–3 years are normal. 

Shading: Not necessary.

Scabiosa caucasica ‘Alba’

494 SCABIOSA CAUCASICA 

Forcing: Field plants covered with clear single plastic were forced earlier than 

uncovered plants. Night temperatures of 40–43F (4–6C) were provided (Plomacher 

1980). 


Plants forced for winter production should be sown in July and August and 

grown under SD at 50–55F (10–13C) for 4–6 weeks. Long days (>14 hours), by 

day extension or nightbreak lighting with 4 hours of incandescent lights, should 

then be provided. Flowering occurs 8–12 weeks after the beginning of LD treatment. 

Night temperatures below 55F (13C) must be maintained; otherwise, weak 

stems result. 






‘Fama’ 

(%) 

N P K Ca Mg 

2.81 0.22 2.11 0.20 0.36 

(ppm) 

Fe Mn B Al Zn 

400 116 27 332 19 


Flowers may be harvested as soon as flower color is visible. 

Postharvest 

Fresh: Fresh flowers remain viable for 5–8 days. 

Storage: Flowers may be held wet at 36–41F (3–5C). 


Cultivars 

White forms tend to have thinner stems than the blue forms. 

‘Alba’, a white-flowered form, comes true from seed but is otherwise similar to 

the species. Does not continue to produce flowers as long as ‘Fama’.

SCABIOSA CAUCASICA 495 

‘Blue Perfection’ (‘Perfecta Blue’) has fringed, lavender-blue flowers and 

stands 2' (60 cm) tall. A selection of var. perfecta (‘Perfecta’), which has large 

fringed flowers in shades of blue. 

‘Bressingham White’, with 3–4" (8–10 cm) wide flowers of clear white on 3' 

(90 cm) stems, has effectively replaced ‘Miss Willmott’, an older white cultivar. 

‘Compliment’ (‘Kompliment’) is 20–24" (50–60 cm) tall with dark lavender 

flowers. 

‘Fama’ has large dark, lavender-blue flowers with a silver center on 18" (45 

cm) stems. The flower color and plant habit are excellent. Most popular as a cut 

flower (see comments by Thorndike). 

‘House Hybrids’ (‘Isaac House Hybrids’) is a mixture of blue and white shades. 

They arose from selections made at Isaac House in Bristol, England, and are parents 

to many of the more recent selections. 

‘Miss Willmott’ has white flowers on 2–2½' (60–75 cm) stems. 

‘Moerheim Blue’ has large blue flowers, darker than the species. 

‘Perfecta’ has lavender-blue flowers on 2–3' (60–90 cm) stems; ‘Perfecta Alba’ 

has cream-white flowers, larger than ‘Alba’, with fringed petals; ‘Perfecta Lilac’ 

has 2–3" (5–8 cm) lilac flowers on 20" (50 cm) stems. 

‘Stafa’ bears dark blue flowers on 2–2½' (60–75 cm) stems. 


Scabiosa columbaria differs from S. caucasica by being shorter but more than 

makes up for the lack of height in early and persistent flowering. The best selection 

is ‘Butterfly Blue’, whose lavender-blue flowers begin in late spring and continue 

for months. ‘Pink Mist’ has lavender-pink flowers, quite respectable but 

not as good a performer. Neither has the stem length needed to impress the florist, 

but yield is outstanding. 

Scabiosa lucida has 1–1½" (2.5–4 cm) wide rosy lilac flowers that appear in late 

spring and flower for 6–8 weeks. Plants are only 1–2' (30–60 cm) tall. 

Scabiosa ochroleuca (cream scabious) has creamy yellow flowers and makes a 

good, although short-lived, species for cut flower production. Under proper conditions, 

plants grow 4' (1.2 m) tall. 

Scabiosa prolifera (Carmel daisy) is an annual occasionally used as a cut flower. 

Plants grow about 2' (60 cm) tall with 2" (5 cm) wide creamy white flowers, 

sometimes blushed with lilac. The seed heads are also ornamental. Useful dried 

and fresh. 

Scabiosa stellata (drumstick plant) is grown for its seed heads, which may be 

dried. An interesting novelty item. Direct seed at 0.2 oz per 100' (20 g per 100 m) 

(Kieft 1996). ‘Ping Pong’ has 2" (5 cm) white flowers that develop into starshaped 

heads. 


Powdery mildew (Erysiphe polygoni), root rot (Phymatotrichum omnivorum), and 

stem rot (Sclerotinia sclerotiorum) are fungal diseases that infect scabious. Fungal 

sprays and sterilized soils offer some protection.

496 SOLIDAGO HYBRIDS, ×SOLIDASTER 

Beet curly top virus results in foliar deformation. Dispose of plants at first 

sign of infection. 


“‘Fama’ I call my queen. She is tireless! Once she starts blooming, she just gets 

completely into the task at hand and will not quit, even after frost has hit the 

field and we are all tired of looking at her, picking her, and trying to find a companion 

flower for her! The flower comes in variations of lavender; the stem is 

strong, though not always straight (which provides just the right amount of 

character), and seems to thrive on being cut. We can’t sell it for all that much 

money, but the demand is steady throughout the whole picking season.” Joan 

Thorndike, Le Mera Gardens, Ashland, Ore. 

Reading 


9(1):31–37. 

———. 2000. 1999 ASCFG National Seed Trials. The Cut Flower Quarterly 12(1): 

1–19. 


Netherlands. 



Athens, Ga. 

Plomacher, H. 1980. Plants grown under plastic for cutting: Scabiosa caucasica. 

Zierpflanzenbau 80:17. 


Wilkins, H. F., and A. H. Halevy. 1985. Scabiosa. In The Handbook of Flowering. Vol. 


Many thanks to Mary Ellen Schultz and Joan Thorndike for reviewing this 

section. 

Solidago hybrids, ×Solidaster goldenrod, golden aster Asteraceae 

perennial, Zones 3–8 North America yellow 2–3'/3' (60–90 cm/90 cm) 

The entry in the first edition of this book began like this: “To refer to Solidago as 

a useful plant 5 years ago would bring chuckles at best, or outright derision. . . . 

Market resistance to goldenrod is declining, albeit slowly, and sales potential is 

strengthening.” Goldenrod is now a mainstream cut flower, produced in the 

field and the greenhouse, wherever cut flowers are grown. Florists and designers 

incorporate them in mixed bouquets and arrangements. Plants exhibit ease of 

culture, high yield, and excellent vase life. 

×Solidaster (golden aster; the × is silent) is an intergeneric cross between Solidago 

and Aster. Some field production of ×Solidaster luteus took place; however,

SOLIDAGO HYBRIDS, ×SOLIDASTER 497 

Solidago ‘Baby Gold’ 

the exceptional breeding with Solidago has virtually eliminated ×Solidaster as a 

cut flower. Its only cultivar is ‘Lemore’, bred in 1948, with light yellow to lemonyellow 

flowers. The information provided here refers to both genera. 

Propagation 

At least 90% of the world’s production involves hybrids propagated from cuttings 

or through tissue culture. All popular cultivars are available as plugs. Renewal 

in the field and greenhouse should occur after 2–3 years.


Seed: Seeds of numerous taxa (not hybrids) may be sown at 68–72F (20–22C) 

and germinate in 2–3 weeks. Seed is small; approximately 1/50 oz (0.6 g) of seed 

is needed for 1000 seedlings, depending on species (Kieft 1996). With seed of 

Solidago petiolaris, a goldenrod native to Oklahoma, 10 weeks of stratification at 

41F (5C) significantly enhanced germination (Bratcher et al. 1993). 

Cuttings: Terminal cuttings may be rooted any time but preferably prior to 

flower initiation. 

Division: Field-grown plants may be divided after 2–3 years. 

Growing-on 

During the vegetative period (seedlings or small plugs), grow at 55–60F (13–15C) 

night and 60–65F (15–18C) day temperature with 100 ppm N using a complete 

fertilizer. Plants should be grown in LD (>14 hours). Plugs and divisions may be 

placed in 4" (10 cm) pots and grown for 2–3 weeks under LD prior to planting 

out. Plants may be field planted when green in the fall or early spring. For 

pinched plant production, pinch after about 3 weeks growth in the greenhouse. 


Temperature: No cool treatment is necessary for flowering. 

Photoperiod: Solidago in general and the hybrids specifically are sensitive to 

photoperiod. Paradoxically, although they require about 14 hours of light for 

flower production, they are nevertheless referred to as short day plants. This is 

because, as shown by research on Solidago canadensis, one of the parents of the 

hybrids, even though flowers initiate when plants are provided with 14 hours 

of light, they remain vegetative under 16-hour photoperiods, resulting in them 

being categorized as SD plants; very short photoperiods (8 hours) result in flower 

abortion and dormancy, while 12-hour photoperiods result in poorly developed 

inflorescences (Schwabe 1986). Thus, in the field in the annual cycle of changing 

daylengths, vegetative growth and shoot elongation are promoted by LD; then 

as days shorten in late summer, flowering occurs; and finally as autumnal equinox 

is approached and passed, dormancy ensues. Plants grow taller under LD; 

application of SD inhibits stem extension. For the cut flower hybrids, if daylength 

is regulated when appropriate, year-round production is possible, assuming 

light intensity during the day is sufficient. In the vegetative growing period, 

long days of at least 16 hours are recommended (Bartels 2001). 

Different species may exhibit somewhat differing responses to photoperiod. 

Roncancio et al. (1996) showed that floral induction of ×Solidaster luteus was 

more rapid and prolific in photoperiods of 16 hours or more, suggesting that 

this species should be classified as quantitative LD plants. Observing plants in 

outdoor situations will suggest whether plants will benefit from LD or SD treatment. 

Those that flower in the fall (e.g., Solidago canadensis) are likely SD plants; 

those that flower in summer may be LD or day neutral.


Large acreages of goldenrod are field-produced, usually with subirrigation and 

support systems. Production time is approximately 3 months from planting to 

harvesting. 

Spacing: Grow plants on 8 or 10" (20 or 25 cm) centers, which results in 144– 

225 plants/100 ft 2 (15–24 plants/m 2 ) if growing a pinched crop. Closer spacing 

may be employed for unpinched plants; however, disease susceptibility caused by 

decreased air movement must be taken into account. 

Longevity: To maintain quality, replant crop every 2–3 years. 

Pinch: Both pinched and unpinched crops are possible. Pinching is more common 

under natural field conditions, where lighting is not used. If pinching is to 

be done, it should be accomplished 3–4 weeks after planting in the field or the 

greenhouse. Leave at least 4–8 leaves on the plant. Pinch a whole block at once to 

get uniform regrowth. Spacing should be increased if plants are pinched. Pinching 

and pruning (removing thin stems) are recommended after the first year in 

the field. 

Lighting: Lighting for photoperiodic response is generally done under greenhouse 

conditions; however, lights may be used in the field as well (see “Greenhouse 

Performance”). 

Support: Not necessary the first year but recommended for taller cultivars in 

subsequent years. 

Yield: Dutch production suggests yields of approximately 37 stems per 100 ft 2 

or 350 per 100 m 2 (Anon. 1998b). The following table provides consecutive yields 

of Solidago ‘Strahlenkrone’ from Athens, Ga., and Watsonville, Calif. 

Yields and stem quality of Solidago ‘Strahlenkrone’. 

Stems/ Stem Stem 

plant length (in) z width (mm) y 

Year 1 

Georgia 7 17.5 4.7 

California 

Year 2 

5 27.0 5.0 

Georgia only 

Year 3 

44 19.6 4.5 

Georgia only 17 20.3 4.3 




Shade: Shading results in higher incidence of disease and lower yield, and does 

not benefit stem length or diameter. Second-year data with ‘Strahlenkrone’ 

showed that shade resulted in 22 stems/plant (44 stems in sun) and average stem


length of 16.9" (42 cm). In the sun, stems lengths were 19.6" (49 cm), and no difference 

in stem widths occurred. Obviously, shade is not recommended. 


In the greenhouse or under protected culture, flowers can be forced in the winter 

and spring by manipulating temperature and photoperiod lighting. Use at 

least 2 layers of support. 

Temperature: Grow at 55–60F (13–15C) night and 60–65F (15–18C) day temperature. 

If grown too warm (>80F, 27C), flowering is delayed and quality is 

reduced. ‘Tara’ may be more heat tolerant than ‘Toto’ or ‘Yellow Submarine’ 

(Anon. 1998a). 

Spacing: In general, plants are not pinched in the greenhouse and can be 

spaced as close as 5" (13 cm) centers, 5½ plants/ft2 (60 plants/m2 ) or as wide as 

6" (15 cm) centers, 4 plants/ft2 (45 plants/m2 ). More space is given for pinched 

crops: 1½–2 plants/ft2 (16–21 plants/m2 ). Spacing is determined by yield, air 

movement, and disease control measures. 

Fertilization: Cuttings may be grown at 65F (18C) and fertilized with 100 

ppm N. 

Lighting: Long days (>16 hours) should initially be applied for approximately 

5 weeks to extend stem length and delay flowering. Cyclic lighting (at least 6 

minutes per half hour) or daylength extension can be used. This should be done 

until the plants reach a height of at least 12–15" (30–38 cm). After lighting, 

plants will begin to set flowers. Crop time is 10–14 weeks from planting of cuttings, 

depending on temperature and cultivar. Under this system, 3 flushes of 

flowers may be possible. If pinching, allow approximately 2 weeks additional 

time. 


At field trials, Athens, Ga., and Watsonville, Calif., foliage was sampled from vigorously 

growing healthy plants when flower buds were visible but prior to flower 

opening. These are guidelines only and should not be considered absolute standards. 


‘Strahlenkrone’ (Ga.) 

(%) 

N P K Ca Mg 

3.6 0.46 3.82 0.87 0.30 

(ppm) 

Fe Mn B Al Zn 

202 115 24 43 68

‘Super’ (Calif.) 


(%) 

N P K Ca Mg 

2.7 0.27 4.71 1.23 0.43 

(ppm) 

Fe Mn B Al Zn 

200 282 30 43 25 

Although nitrogen and phosphorus were relatively low for ‘Super’ in California 

trials, the resulting stems were of excellent quality. 

Magnesium deficiency has been shown to produce yellow leaves and poorquality 

stems. This may occur when under conditions of high soil pH and high 

calcium: the calcium can take the place of the Mg in the soil, and the available 

Mg will not be available. 


Harvest the inflorescence when ½ the flowers are open (Nowak and Rudnicki 

1990) or as early as when about ¼ of the flowers have opened (Bartels 2001). 

After harvesting, all plants should be cut back to just above ground level. Harvest 

time for the entire crop should be completed in about a week. 

Postharvest 

Fresh: The most important consideration is to place cut stems immediately in 

a rehydrating solution containing a bactericide. Stems will persist 5–6 days in 

water, significantly longer with various preservatives. Research has shown considerable 

enhancement of vase life with 0.5 mM cobalt sulfate + 2% sucrose (Patil 

and Reddy 1997) or 0.4% aluminum sulfate (Ryagi et al. 1996). Leaf yellowing 

was retarded by pulsing with 45 mM of a formulation of soluble benzyladenine 

(Philosoph-Hadas et al. 1997). 

Storage: Flowers may be stored dry for up to 5 days at 36–41F (3–5C) (Vaughan 

1988). 

Dried: Cut when flowers are fully open, then dry standing up (Bullivant 1989). 

Cultivars 

‘Baby Gold’, a dwarf form, is more often used as a garden plant than a cut 

flower. The flower color is excellent, however, and the flowers hold up well. 

Research in Burlington, Vt., on 2-year-old plants showed 21 stems/plant (spacing 

2 × 2', 60 × 60 cm) with an average stem length of 24" (60 cm) (Perry 1989). 

‘Golden Gate’ has dark yellow flowers. 

‘Golden Lime’ has a free branching habit and numerous side branches.


‘Praecox’, a selection of Solidago virgaurea, bears bright yellow flowers. Early 

summer and fall flowering occur. Popular in Europe. 

‘Strahlenkrone’, an exceptional yellow cultivar, grows about 2–2½' (60–75 

cm) tall. 

‘Super’ has lemon-yellow flowers on 2–3' (60–90 cm) stems. This is one of the 

most handsome goldenrods we have seen, but, unfortunately, is highly susceptible 

to rust and intolerant of poor drainage. Losses in our trials were close to 

100%. 

‘Tara’ has mid-yellow plume-shaped flowers and robust habit. 

‘Tara Gold’ has golden-yellow flowers. 

‘Toto’ produces deep yellow flowers. 

‘Yellow Submarine’ bears lemon-yellow, open, spreading blooms. Excellent 

performer. 


Solidago caesia (wreath goldenrod) has dark yellow flowers with 3' (90 cm) 

tall bluish wiry stems. Flowers occur in the fall and may be used to extend goldenrod 

flowering time. This unusual goldenrod may find a niche in the cut flower 

market. 

Solidago odora (sweet goldenrod) has yellow flowers on 3' (90 cm) stems. The 

benefit of this species is its fragrant foliage, which smells like anise when crushed. 

Solidago rugosa ‘Fireworks’ and S. sphacelata ‘Golden Fleece’ are exceptional yet 

underused goldenrods. ‘Fireworks’ performed very well in trials as a garden plant 

(Hawke 2000). 


Powdery mildew (Erysiphe polygoni) is a white fungus on the undersides of the 

leaves and the stems. Downy mildew can also be a severe problem. Work done by 

Hawke (2000) at the Chicago Botanic Garden with different goldenrod taxa suggested 

that Solidago caesia, S. flexicaulis, S. graminifolia, S. sphacelata ‘Golden Fleece’, 

and S. ‘Peter Pan’ were less susceptible to powdery mildew than others tested. 

These data may be useful for breeding some disease resistance into the hybrid cut 

flower forms. 

Rust (Coleosporium asterum) is the most serious disease of goldenrod. Rustcolored 

pustules cover the foliage and stems in late summer. Because pine trees 

act as an intermediate host, plant well away from stands of pine trees. No effective 

control is known, although spraying with zinc-based fungicides appears to 

provide some control. 

Leafminers, whiteflies, and spider mites are pests of Solidago. 

Leaf yellowing is not uncommon and may be related to high pH, low soil temperatures, 

or mineral imbalance. An application of 1.8–2.0% zinc sprayed every 

10 days has been shown to reduce leaf yellowing (Bartels 2001).

Reading 

Anon. 1998a. Solidago market grows. FloraCulture International (March, 98):35 

Anon. 1998b. Solidago. GMPRO 18(6):8. 


Bratcher, C. B., J. M. Dole, and J. C. Cole. 1993. Stratification improves seed germination 

of five native wildflower species. HortScience 28(9):899–901. 



Hawke, R. G. 2000. Plant evaluation notes: an evaluation report of goldenrods 

for the garden. Chicago Botanic Garden 15:1–4. 


Netherlands. 

Nowak, J., and R. M. Rudnicki. 1990. Postharvest handling and storage of cut 

flowers, storage greens and potted plants. Timber Press, Portland, Ore. 

Patil, S. R., and B. S. Reddy. 1997. Effect of cobalt sulfate and sucrose on postharvest 

physiology of golden rod (Solidago canadensis L.) cut flower. Karnataka 

J. Agr. Sci. 10(2):591–594. 


Athens, Ga. 

Philosoph-Hadas, S., R. Michaeli, Y. Reuveni, and S. Meir. 1997. Benzyladenine 

pulsing retards leaf yellowing and improves quality of goldenrod (Solidago 

canadensis) cut flowers. Postharvest Bio. and Tech. 9(1):65–73. 

Roncancio, V. J. F., L. E. Peres, L. B. P. Zaidar, and M. de F. A. Pereira. 1996. Influence 

of interaction between photoperiod and temperature on development of 

Solidaster luteus plants. Revista Brasileira de Fisiologia Vegetal. 8(2):131–138. 

Ryagi, Y. H., U. G. Nalawadi, M. B. Chetty, and P. A. Sarangamath. 1996. Effect 

of different chemical treatments on vase life of goldenrod. Karnataka J. Agr. Sci. 

9(1):177–178. 

Schwabe, W. W. 1986. Solidago. In The Handbook of Flowering. Vol. 5. A. H. Halevy, 



Ore. 

Many thanks to Jeff McGrew for reviewing this section. 

THALICTRUM 503 

Thalictrum meadow-rue Ranunculaceae 

perennial, Zones 3–7 western China white/mauve 1 

3–6'/3' (0.9–1.8 m/0.9 m) 

Plants bear small but delicate flowers that are useful as fillers and are occasionally 

substituted for baby’s breath. Flowers of all meadow-rue consist mainly of 

stamens and tend to shatter; double-flowered forms reduce the problem. 

Several species are useful for cut flowers, the most common being Yunnan 

meadow-rue (Thalictrum delavayi) and columbine meadow-rue (T. aquilegifolium),

504 THALICTRUM 

Thalictrum delavayi 

although lavender mist (T. rochebruneanum) has its followers. Thalictrum delavayi 

has fern-like foliage and lilac flowers on thin-stemmed plants that are usually at 

least 3' (90 cm) tall; the flowers consist of lilac sepals and hundreds of yellow 

stamens. A fair amount of research has been conducted on this species, particularly 

on ‘Hewitt’s Double’, a double-flowered cultivar that is much less prone to 

shatter. With fuller flowers in purple and white, T. aquilegifolium is common in 

cut flower markets and an excellent species for the South; seed and plants are easier 

to obtain than those of T. delavayi.

Propagation 

Seed: Seeds benefit from chilling at approximately 40F (4C) for at least 2 

weeks. Seeds of Thalictrum aquilegifolium germinated at 74–93% compared with 

16% of unchilled seeds (YongGu et al. 1996). After chilling, sow thinly on fine 

medium at 60–65F (15–18C); seeds normally germinate within 2–3 weeks. Approximately 

0.33 (10 g) of seed yields 1000 seedlings (Kieft 1996). 

Division: The storage organ for Thalictrum is the crown, and plants may be 

divided every 2–3 years. 

Growing-on 

Transplant seedlings when they are large enough to handle. In general, 2-yearold 

crowns are used. Divisions and seedlings should be grown at 55F (13C) for 

6–8 weeks before placing in the field. Fertilize with 100 ppm N using a complete 

fertilizer. Larger divisions may be planted immediately in the field. 


Crowns of ‘Hewitt’s Double’ benefit from a cooling period. Plants were cooled 

for up to 15 weeks at 45F (8C), and sufficient cooling was obtained after 6 weeks; 

however, when removed from storage, the time to flower on the bench was 

reduced for each storage time (Huang et al. 1999). 

Weeks of cooling Days to flower after removal 

0 190 

3 175 

6 140 

9 130 

12 120 

15 115 

THALICTRUM 505 

Plants respond to LD (11–13.5 hours); incandescent lights result in decreased 

time to flower. 


The earliest meadow-rue to flower is Thalictrum aquilegifolium (early spring), the 

latest is T. rochebruneanum (as late as mid summer). Limited data are available on 

field performance; however, nylon or wire mesh must be used to separate the 

flowers from each other, otherwise they can become terribly entangled and damage 

occurs to flowers and to those trying to extricate them. To discourage tangling, 

do not space plants closer than 15 × 15" (38 × 38 cm). Harvest flowers 

after one full winter in the field. Crop time from sowing to harvest is approxi-

506 THALICTRUM 

mately 18 months. Crowns planted in the fall will flower the first season, but 

yield may be disappointing. Yield increases the second year. 


Harvest flowers when most are open. Unopened flowers do not develop well if 

cut in bud stage. 

Postharvest 

Fresh: Since flowers consist mainly of sepals, they tend to shatter rapidly. 

Flowers are sensitive to ethylene, and STS products enhance the vase life. Pulsing 

with 0.2 mM silver increased vase life of ‘Hewitt’s Double’ from about 4 days 

in water to 11 days in STS (Hansen et al. 1996). Thalictrum is recommended as 

a local item. 

Storage: Storage is not recommended. If necessary, store at 36–41F (3–5C) for 

up to one week (Vaughan 1988). 

Dried: Harvest in full flower, strip foliage, and dry standing up to maintain 

shape. Flowers retain their color for only a few months, but they are useful fillers 

for large arrangements. Stems may also be hung upside down to dry (Bullivant 

1989). 

Cultivars 

Thalictrum aquilegifolium 

‘Atropurpureum’ has dark purple stems and stamens. The variety listed as 

‘Purpureum’ is likely the same; however, the stems are not as highly colored. 

‘Roseum’ bears handsome light pink to pale rose flowers. 

‘Thundercloud’ has deep purple flowers and larger flower heads than the type. 

‘White Cloud’ is the best of the white-flowered forms, with large, white flowers. 

Thalictrum delavayi 

‘Hewitt’s Double’ bears flowers that consist of lilac sepals and creamy yellow 

stamens produced in a 2–3' (60–90 cm) long inflorescence (panicle). 


Thalictrum dipterocarpum (also known as Yunnan meadow-rue) is so similar 

to T. delavayi that plants are often offered under this name. Field culture is the 

same for both. 

Thalictrum flavum (yellow meadow-rue) grows aggressively to about 5' (1.5 m) 

and produces balls of yellow flowers. Some people find that the color is not 

bright enough and that the smell is disagreeable. ‘Glaucum’ has blue-green 

foliage. 

Thalictrum rochebruneanum (lavender mist) grows 6–7' (1.8–2.1 m) tall with 

deep blue flowers in early to mid summer held on strong self-supporting stems.

TRACHELIUM CAERULEUM 507 

Excellent potential as a local product for a filler or bouquets. Susan Minnich 

produces lavender mist in Massachusetts, where it grows 7' (2.1 m) or more 

without support netting. She grows them about 2' (60 cm) apart in damp soil 

under partly shady conditions, and fertilizes plants in spring and again later in 

the season. She has no problems with tangling when growing or cutting it, but 

keeps stems separated at market to avoid tangling. She sells only direct to consumer. 

It sells like crazy at markets—people either love it or hate it. Plants are 

slow-growing, one reason they are not seen as often as others. 


“The biggest problem with thalictrum is the bloom time, especially when cutting 

is very short; some types we harvest for less than a week (these are the ones that 

seem the best for cutting!).” Janet Foss, J. Foss Garden Flowers, Everett, Wash. 

Reading 



Hansen, L. N., K. A. Funnell, and B. R. Mackay. 1996. Silver thiosulphate reduces 

ethylene-induced flower shattering in Thalictrum delavayi. New Zealand J. of 

Crop and Hort. Sci. 24(2):203–204. 

Huang, N., K. A. Funnell, and B. R. Mackay. 1999. Vernalization and growing 

degree-day requirements for flowering of Thalictrum delavayi ‘Hewitt’s Double’. 



Netherlands. 


Ore. 

YongGu, S., H. YounYol, S. InKyu, K. TaeYoung, J. JaeSik, Y. JaeTak, and C. Boo- 

Sull. 1996. Influence of GA3 and chilling treatment on seed germination in 

several native plants. RDA J. Agr. Sci., Hort. 38(1):700–704. 

Many thanks to Susan Minnich and Ralph Thurston for reviewing this section. 

Trachelium caeruleum throatwort Campanulaceae 

annual Mediterranean blue, white 2–3'/2' (60–90 cm/60 cm) 

The generic name comes from trachelos (“neck”), for these plants were supposed 

to be useful against diseases of the throat; perhaps more soothing treatments, 

like a cup of homemade soup, are to be recommended before chewing on trachelium 

leaves. A much preferable common name is veil of flowers. Plants are 

grown by the acre in greenhouses in the United States, Holland, and South 

America, and in the field in coastal California. They are widely branched toward 

the top of the plant and bear lavender, dark blue, or white terminal flower clus-

508 TRACHELIUM CAERULEUM 

ters consisting of dozens of small tubular flowers, each measuring less than ¼" 

(6 mm) across. Plants are excellent subjects for cut flowers and will overwinter in 

areas of Florida, the Gulf Coast, and California. 

Propagation 

Always propagated from seed, and although raw seed is available, it is very tiny 

and seldom used. Pelleted seed is available, by seed count, and is recommended. 

Sown under intermittent mist in the greenhouse at 62–70F (17–21C), seed germinates 

in 14–21 days. Do not bury deeply, as light promotes germination. If 

sowing in open flats in the greenhouse, seedlings may be transplanted to plug 

trays (up to 200 cells) after the first set of true leaves are visible. Alternatively, seed 

may be sown in plug trays. In general, because approximately 10–12 weeks are 

needed between sowing and transplanting to plugs, most growers purchase 

plugs from commercial propagators. Direct sowing to the field is seldom practiced, 

due to inconsistent germination. 

Growing-on 

Grow seedlings in plugs or pots at 55/60F (13/15C) night/days. Fertilize with 

50–100 ppm N solution of a complete fertilizer when 2 true leaves have 

expanded. Raise temperatures gradually but no higher than 75F (24C). Increase 

fertilizer to 200 ppm N every other watering. As plants reach 3 or 4 leaves, reduce 

greenhouse temperature to 60–62F (15–17C). Plants may be transplanted when 

large enough to handle. 


Photoperiod: Plants flower faster under long days of at least 14 hours (Armitage 

1988). Short days inhibit flowering. 

Temperature: Plants are Mediterranean in origin and do not respond well to 

large fluctuations in seasonal temperature. During greenhouse growing, temperatures 

of 60–70F (15–21C) appear to be optimum. Field production is best in 

areas of cool nights and warm days. 


Plants may be field-grown in the summer in the Northwest and coastal California, 

but they do poorly in high heat, and therefore suffer in summers in the 

southern half of the country and in many areas of the Midwest. Performance in 

the fall, winter, and early spring is excellent in south Georgia and Florida. 

Spacing: Space plants 9–18" (23–45 cm) apart; the wider the spacing, the more 

breaks and the greater the yield/plant. 

Support: Two tiers of support netting may be useful, however, netting is 

mainly recommended where high winds are a factor. 

Overwintering: Plants should be considered annual in most of the country, 

and even in “mild” winters, overwintering in the field is questionable at best.

Trachelium caeruleum 

‘Lake Sunset Improved’


Overwintering depends on more than low temperatures, such as duration of 

cold, humidity, wind, and snow cover. Temperatures of 28F ( − 2C) for a single 

night are sufficient to damage mature plants and to kill plugs. At 20–25F 

( − 7– − 4C), most plants are killed. Even plants that survive mild winters will likely 

have to be cut back to the ground in the spring. 


Most production is under protection; comparatively little is accomplished in 

the open field. 

Temperature: Plants should be grown cool initially for good root development. 

Grow seedlings in plugs or pots at 55/60F (13/15C) night/days. Raise temperatures 

gradually but no higher than 75F (24C). 

Spacing: Fertilize with 50–100 ppm N solution of a complete fertilizer when 2 

true leaves have expanded. Grow plants in ground beds, 12" (30 cm) or as little as 

9" (23 cm) apart. Some production occurs in 6" (15 cm) pots, spaced pot to pot. 

Fertilization: Fertilize with 100–200 ppm N during the fall and winter. 

Light and temperature: Grow with bright light and 55–60F (13–15C) night temperatures 

and 65–70F (18–21C) day temperatures. Warmer temperatures result 

in faster growth and flowering but also cause thinner stems and more open inflorescences. 

Work in Spain showed that heating the greenhouse to 55F (13C) with 

18-hour days and continuous fertilization resulted in flowering 8 weeks earlier 

and a significant increase in stem quality, compared with unheated houses under 

natural photoperiods (Lopez et al. 1996). 

Supplemental light: Supplemental light (sodium or metal halide) accelerates 

growth and flowering if used during the day and is highly recommended 

(Armitage 1988). Place plants under 14- to 20-hour day conditions. Use either 

HID lamps (350–450 fc) or fluorescent lamps, depending on latitude. In northern 

latitudes, HID lamps may be necessary because natural light is too low for 

good-quality plants. If light intensity is sufficient but daylength too low, mum 

lighting (10–20 fc) can be used. Lighting generally starts about 3 weeks after 

transplanting (van Hee 1994). 

Incandescent lamps are the most inefficient means of producing light; fluorescent 

lights are far more efficient. Costs of installation, however, are quite different. 

Ben-Tal and Wallerstein (1999) studied the use of fluorescent lamps to 

provide 16-hour days and concluded that they were 44% cheaper and accelerated 

flowering equally with incandescent light. Although the fixtures cost 16 

times more, they lasted 10 times longer. 

Carbon dioxide: Elevating CO2 has positive effects on flowering. Reekie et al. 

(1994) found that raising CO2 to 1000 ppm advanced flower opening by affecting 

flower initiation. Plant size was also increased. 

Support: One to 2 tiers should be used with greenhouse-grown crops. Plants 

require 5–7 months to flower from seed. 

Scheduling: Transplanting from September to January would provide flowers 

after 14–18 weeks; in February to May, after 12–13 weeks, and during June to August, 

as low as 10–12 weeks in a sunny area (southern California).


TRACHELIUM CAERULEUM 511 

Harvest the stem when ¼ to ⅓ of the flowers are open (Bredmose 1987). If harvested 

too early, the flowers will not open (van Hee 1994). Most growers prefer to 

harvest the entire stem at once (called untopped), including the main flower and 

laterals, whereas others prefer to top off the main stem and harvest laterals later. 

With the former method, associated labor costs are lower and stems are longer 

and of a higher quality; however, yield is markedly reduced. Dirks (1996) studied 

the economics of both systems and found that costs per stem in the untopped 

harvest was higher, because of lower yields, but that the topped system resulted 

in many thinner, poorer quality stems. We recommend cutting everything at 

once. 

Postharvest 

Fresh: Fresh flowers, if harvested at the proper stage, persist approximately 2 

weeks in water. The addition of STS resulted in an additional 1–2 days but is 

not mandatory (Bredmose 1987). 

Storage: Store in water at 40F (4C) for approximately 24 hours. 

Shipping: If properly precooled and if temperatures are maintained at 36–40F 

(2–4C) during shipping, flowers may be shipped dry with excellent results. 

Dried: Flowers may be air-dried but lose much of their color. 

Cultivars 

Many available cultivars, but they don’t offer a great deal of diversity. 

‘Blue Wonder’ is a spring-flowering selection with mid-blue flowers. 

Devotion series comes in blue, white, and purple. Plants are naturally 30–36" 

(75–90 cm) tall, but because they respond well to growth regulator application, 

they have been mainly used for pots and large containers. 

Hamer series was bred especially for cut flower production. ‘Hamer Blue Umbrella’ 

is a dark blue, green-leaved standard variety. ‘Hamer Dafne’ bears flat 

umbels of dark pink flowers. ‘Hamer Eris’ produces silvery blue flowers. ‘Hamer 

Helios’ bears pure white flowers. ‘Hamer Pallas’ is an improved ‘Blue Umbrella’ 

and is said to have a short harvest period. ‘Hamer Pandora’ has purple flowers 

and dark stems. 

Lake series produces plants that grow to 28–40" (70–100 cm) with white or 

lavender to purple flowers. ‘Lake Avalon’ is a somewhat washed-out pink. ‘Lake 

Forest’ (mid-blue) is an excellent later-flowering form, flowering from fall into 

spring. ‘Lake Powell Improved’ has white flowers; white tends to discolor earlier 

than darker colors and has limited market appeal. Plants are about 2 weeks earlier 

to flower than its predecessor. ‘Lake Sunset Improved’ is burgundy-red and 

seems to flower almost year-round. ‘Lake Sunset’ (prior to being “improved”) 

was slightly earlier than other Lakes. Best under some protection; in national 

field trials, ‘Lake Sunset’ produced 4 flowers per stem when planted outdoors 

(Dole 2001). ‘Lake Superior Improved’ has darker purple flowers, stems, and 

leaves. A favorite in some markets.


‘Merii Blue’ has mid-blue flowers. 

‘Midnight Blue’ is said to be heat and stress tolerant and quite uniform. 

‘Summer Blue Wonder’ produces light blue umbels in the summer. 

‘Summer Lake Superior’ also flowers in the summer but with darker blue 

flowers. The Summer series was bred for optimal performance under high light 

and high temperature. 

‘Umbrella Blue’ has lavender-blue flowers and is similar to the species, perhaps 

a little more compact. 

‘Umbrella White’ bears creamy white flowers. The flowers decline more readily 

than the blue forms, showing petal blackening. 


A tospovirus, transmitted by western flower thrips, causes leaf scorch and blackening 

of stems. Whiteflies can also be an occasional pest. Many problems are 

caused by hot temperatures and high humidity, resulting in premature flowering 

and botrytis, respectively. Susceptibility to root nematodes, particularly Paratylenchus 

bukowinensis, has also been noted (Brinkman et al. 1995). 

Reading 

Armitage, A. M. 1988. Effects of photoperiod, supplemental light, and growth 

regulators on growth and flowering of Trachelium caeruleum. J. Hort. Sci. 63: 

667–674. 

Ben-Tal, Y., and I. Wallerstein. 1999. Saving energy in commercial growing of 

cut flowers. Acta Hortic. 482:387–391. 

Bredmose, N. 1987. Postharvest ability of some new cut flowers. Acta Hortic. 205: 

187–194. 

Brinkman, H., H. N. Cevat, and C. H. M. Peters. 1995. Research into the susceptibility 

of the cut flower crop Trachelium and of celery to the free-living root 

nematode Paratylenchus bukowinensis and their susceptibility as host plants. 

Gewasbescherming 26(2):43–46. 

Dirks, I. 1996. Trimmed Trachelium comes off better per stem. Gartenbau 5(5): 

44–45. 

Dole, J. 2001. 2000 ASCFG National Cut Flower Seed Trials. The Cut Flower Quarterly 

13(1):1–10, 12–19. 

Lopez, D., P. Cabot, and R. Molina. 1996. Trachelium, Limonium, and Lisianthius: 

study on the advancement of flowering. Horticultura, Revista d’Agricultura de 

Hortalizas, Flores y Plantas Ornamentales 116:118–120. 

Reekie, J. Y., P. R. Hicklenton, and E. G. Reekie. 1994. Effects of elevated CO2 on 

time of flowering in four short-day and four long-day species. Can. J. Bot. 

72(4):533–538. 

van Hee, F. 1994. The greenhouse production of Trachelium caeruleum. In Proc. 7th 

Natl. Conf. on Specialty Cut Flowers. San Jose, Calif. 

Many thanks to Philip Katz, Jeroen Ravensbergen, and Jim Rider for reviewing 

this section.

TRITELEIA 513 

Triteleia brodiaea Liliaceae 

bulb, Zones 6–9 California blue 9–15"/6" (23–38 cm/15 cm) 

Although the species commonly used for cut flowers were recently transferred 

from Brodiaea to the genus Triteleia, flowers and corms are often still sold as brodiaeas. 

The flip-flop of botanical names has occurred with Chrysanthemum and 

many other genera, and we will get used to it. Triteleia laxa, the species of choice 

and by far the most common, bears the largest inflorescences of the genus. The 

2–5" (5–13 cm) wide inflorescence consists of 15–25 deep blue tubular flowers. 

The individual flowers are up to 1½" (4 cm) across, about 1" (2.5 cm) long, and 

carried on 2–3" (5–8 cm) long pedicels. 

Flowers of brodiaea are easy to grow, inexpensive, and have reasonable vase 

life, but they are not often seen at local florists; their diminutive size and lack of 

easy availability perhaps contributes to this lack of visibility. Also, as Jan Roozen 

of Choice Bulb Farm in Mount Vernon, Wash., notes, his part of the country is 

“lousy with agapanthus at that time of year.” And agapanthus provide the same 

color with bigger, more showy flowers. 

Propagation 

One- to 2-year-old corms can be purchased from reliable bulb suppliers. Seed 

can be purchased but requires 2 years to reach flowering size. 

Growing-on 

Corms should be immediately planted in the field. Seedlings may be grown on in 

beds, pans, or 4–5" (10–13 cm) pots in the greenhouse or propagation field. In 

favorable environments (e.g., Northwest), they multiply rapidly, increasing 

threefold in 2–3 years. If propagating from corms, treat like gladioli and discard 

the mother corm. 


Growth is affected by soil temperature. A sunny location where the soil warms 

up quickly in the spring is best. Photoperiod has little effect on flowering. 

Treatment of corms with 20 ppm ethylene for 7 days resulted in reduction of 

time to sprouting and first flowering. The treatment also increased the number 

of flowers per inflorescence and the fresh weight of daughter corms. The length 

of the scape, however, was not affected (Han et al. 1990). 


Corm size: Corms 5/6 or 7/8 cm in circumference are recommended (De Hertogh 

1996). 

Spacing: Space corms 3–6" (8–15 cm) apart and 4–5" (10–13 cm) below the 

surface.

514 TRITELEIA 

Planting time: Corms may be planted in early spring north of Zone 6, in the fall 

south of Zone 6. Ruth Merrett of New Brunswick (Zone 4b) has had excellent 

stem lengths for 4 years in a row; she plants early and then covers crop with Remay 

to maintain corms above freezing. 

In Zone 7b (Athens, Ga.), no difference in yield of corms planted after November 

was found. Few growth and flower differences occurred for any date, although 

yield was slightly reduced when planted as early as November. As the 

following table shows, planting time did not affect initial harvest date (Armitage 

and Laushman 1990). 

The effect of planting date on Triteleia laxa. 

Month Flw/ First Harvest Stem Stem 

planted corm harvest duration (days) length (in) z width (mm) y 

Nov 0.8 27 May 7 8.7 4.7 

Dec 1.4 21 May 13 12.0 3.9 

Jan 1.0 29 May 8 9.9 2.7 

Feb 1.3 27 May 13 11.7 3.1 



Northern growers must wait until the ground thaws prior to planting. Corms 

may be lifted, cleaned, and sorted to size after the foliage has disappeared or in 

the fall after the first freeze. 

Longevity: In field tests in Georgia, corms persisted 2 years; summer temperatures 

in north Georgia, combined with evening rainstorms, likely reduced corm 

numbers in the third year. Triteleias should be treated as a 1- or 2-year crop east 

of the Rocky Mountains. Corms are sufficiently inexpensive to make annual 

renewal an option. 

Planting zones: Corms overwintered as far north as Nova Scotia (Zone 5) but 

are not normally overwintered north of Zone 6 (De Hertogh 1996). Flowering 

time and stem lengths were 20 July/16" (40 cm) in Nova Scotia (Zone 5), 25 

June/14" (36 cm) in East Lansing, Mich. (Zone 5), 20 June/14" (36 cm) in Washington, 

D.C. (Zone 7), and 2 May/10" (25 cm) in Baton Rouge, La. (Zone 9). 


Data from California for flowers forced in greenhouses at 65/40F (18/4C) 

day/night temperatures are of interest. Without any ethylene treatment, corms 

required 104 days to sprout and 274 days to flower; with 20 ppm ethylene treatment 

for 7 days, corms sprouted in 78 days and flowered in 228 days (Han et al. 

1990). Drip irrigation, starting when the stems are 4" (10 cm) tall and continuing 

until buds form, usually results in taller stems and larger flowers.


TRITELEIA 515 

Some growers harvest when only one flower is open; however, 4–6 flowers can be 

open with no loss in quality. If insect pollination can be avoided (e.g., if plants are 

greenhouse-grown), allow approximately 15 flowers to open prior to harvesting 

for local sales (Nowak and Rudnicki 1990). Harvesting in bud stage and cold 

storage are not recommended. 

Postharvest 

Fresh: Flowers persist 10–14 days in water (Vaughan 1988), 1–2 additional 

days if preservative is used. Stems must be recut at each step of the postharvest 

chain. The bottom white portion of the stem should be removed. Stems may be 

stored dry for up to 4 days at 36–41F (3–5C) if necessary, although if stems are in 

water, they can be stored significantly longer without significant loss in vase life. 



Triteleia californica (syn. Brodiaea californica) bears dark blue to mid-blue flowers. 

Plants are only 12–15" (30–38 cm) tall. Stems and flowers enjoy an excellent 

vase life. 

Triteleia ‘Corrina’ is 20–26" (50–66 cm) tall and has purplish flowers. 

Triteleia hyacinthina has pale blue, almost ghost-like flowers. ‘Royal Blue’ has 

double lilac flowers. 

Triteleia laxa (Ithuriel’s sword), the most common species, is as good as any 

cultivar and probably better. It is taller than most cultivars and bears more and 

larger flowers. Unfortunately, this species has been around for so long that some 

of the stock has weakened. ‘Alba’ produces white flowers. 

Triteleia ‘Queen Fabiola’, a probable hybrid between Triteleia laxa and T. peduncularis, 

is properly classified as T. ×tubergenii. Regardless of its taxonomic niche, 

it bears excellent dark blue flowers and is the principal cultivar available. The 

blue color is most intense in cool climates but fades as temperatures increase. 

Stems are 14–20" (36–50 cm) tall. 


Plants (corms) require excellent drainage or root and corm rots occur. Application 

of soil fungicide 1–2 weeks prior to planting reduces incidence of rot organisms. 

Reading 



Science 25:1236–1238.

516 TULIPA 



Han, S., A. H. Halevy, and M. S. Reid. 1990. Postharvest handling of brodiaea 

flowers. HortScience 25:1268–1270. 




Ore. 

Many thanks to Ruth Merrett and Jan Roozen for reviewing this section. 

Tulipa tulip Liliaceae 

bulb, Zones 3–7 Asia Minor many colors 12–30"/12" (30–75 cm/30 cm) 

The origin of the modern tulip is not known, although a long period of cultivation 

and selection occurred in Turkey and Iran prior to its introduction to 

Europe in the 16th century. Garden tulips have been divided into many different 

classes, based on parentage, flowering time (early, late), and flower form (single, 

double, lily-flowered, parrot). Major forms of tulips used for cut flowers include 

Darwin, Triumph, Rembrandt, Double, and Peony- and Lily-flowered. Essentially 

all bulbs come from Holland, and many flowers are also produced there. 

Flowers are produced mainly for the early spring market (outdoor production) 

or in early January under greenhouse conditions. Greenhouse production generally 

requires controlled-temperature forcing chambers, and, while all pregreenhouse 

treatment may be accomplished outside in cold frames, controlledtemperature 

facilities are necessary to meet a particular marketing period. A 

recent trend in bulb production, particularly tulips, is hydroponic production; 

and at least for the near future, this is how much of the greenhouse forcing will 

be accomplished. For forcers growing bulbs in outdoor beds, the market may be 

affected slightly by cultural techniques, but the market date and flower quality 

essentially are under control of prevailing temperatures. 


Like daffodils, tulips require an annual warm–cool–warm temperature sequence. 

In the field, this begins with warm summer temperatures, with winter and spring 

completing the sequence. The initial warm temperatures result in leaf differentiation 

and flower initiation. The cool treatment (13–20 weeks) causes acceleration 

of flowering, uniformity of flowering within the population, and sufficiently 

long flower stems (Rees 1985). The final warm treatment is necessary to force the 

flower to elongate and open. Research has been conducted on many cultivars, 

and optimal cooling and greenhouse forcing times have been determined for 

greenhouse-forced bulbs (De Hertogh 1996). In general, the optimum greenhouse 

temperatures are 63–68F (17–20C) (Rees 1985).

Tulipa ‘Fantasy’ 

(parrot form)

518 TULIPA 


Bulb size: The only factor that is unequivocally related to flowering is bulb circumference. 

Bulbs below a critical size (depending on cultivar) will form only a 

single leaf and will not flower until the following year. Use 10/11 to 12+ cm circumference 

bulbs, depending on cultivar (De Hertogh 1996). 

Planting: Place bulbs with 5–6" (13–15 cm) of media above the nose. Plant 

approximately 6" (15 cm) apart. 

Planting time: In most areas of the country, non-precooled bulbs should be 

planted in the fall. In the South (Zones 6 and 7b, e.g., north Georgia), plant in 

October to November; in the North (Zone 6 and lower) in September and early 

October. In the Deep South (e.g., Florida, south Texas, southern California), 

bulbs must be precooled (8–10 weeks at 40–45F, 4–7C) and planted in late November 

through December. 

Longevity: In all but the most northern states and provinces (Zone 4 and 

lower), tulips should be treated as annuals, although perhaps a couple of years’ 

production may be realized. In more northern areas, Darwin, Scheepers, and 

Fosteriana hybrids provide some perennial performance. 

Timing: The length of time tulips may be harvested depends on the use of 

early-, mid- and late-season cultivars. Also important is the length of winter temperatures 

below 45F (7C) and the rate of spring warming. If temperatures rise 

quickly in the spring, harvest time is shorter. Trials conducted in different areas 

of the country provided the following results (De Hertogh 1996). 

Average of 4-year cut tulip trials in various areas. 

Earliest harvest Harvest duration 

Location (Zone) date (days) 

College Station, Tex. (8) 18 Feb 48 

Pomona, Calif. (9) 26 Feb 64 

Corvallis, Ore. (9) 12 Mar 64 

Clemson, S.C. (7) 14 Mar 38 

Ames, Iowa (5) 10 Apr 40 

East Lansing, Mich. (5) 15 Apr 40 

St. Paul, Minn. (4) 27 Apr 30 

Hamilton, Ont. (5) 1 May 32 

Edmonton, Alb. (3) 15 May 33 

Notice that the duration of harvest is greatest in areas where less variation in 

temperatures occur (Northwest). In areas with “short springs,” harvest time is 

shortest. The beginning of harvest coincides with spring warming. 

Stem length: Cold is necessary for stem extension, therefore less cold equals 

shorter stems. Stems are shorter in warmer areas than in areas with cold winters 

(i.e., longer in the North than the South).


TULIPA 519 

Maturity of bulbs: Tulips go through well-defined stages of maturation; prior to 

cooling, the dry bulb develops 4 vegetative leaves, then the petals, stamens, and 

finally the female organs (gynoecium). At this point, the bulb is said to have 

reached stage G. It is imperative that the bulbs have reached stage G before bulb 

cooling commences. For early forcing, a random sample of bulbs should be dissected 

to determine that the G stage has been reached. For the early-flowering 

periods (prior to Valentine’s Day), bulbs should be stored at 63F (17C) for 1–5 

weeks prior to rooting in cold temperatures (De Hertogh and Le Nard 1993). 

In most cases, bulbs may be planted immediately upon arrival and stored in 

controlled facilities for the appropriate number of cold weeks for the cultivar 

used. For the Valentine’s Day market, bulbs are usually panned in October, 

stored at 48F (9C) until roots are visible through the drainage holes, transferred 

to 41F (5C) until shoots are 1–2" (2.5–5 cm) tall, and then placed at 33–35F (1– 

2C) until they are moved to the greenhouse bench. The total amount of time in 

the cooler depends on cultivar; 16–17 weeks are optimum for most, 15 is minimum, 

and 20–22 weeks is maximum (De Hertogh 1996). The greenhouse temperature 

and time in greenhouse (2–3 weeks) also depend on cultivar, locale, 

and time of year. For market times before Valentine’s, precooled bulbs must be 

used. For those interested in forcing in the greenhouse, the Holland Bulb Forcer’s 

Guide by Gus De Hertogh (1996) provides specifics on cultivars and is essential 

reading. 

One of the limitations to greenhouse forcing is the need for cooler space for 

bulbs. Dole (1996) suggested a delayed potting method in which the bulbs are 

cooled dry for the first 8 weeks, then potted up as normal for the last 6 weeks of 

cooling time. Cooler space needed for the dry bulbs is minimal, and when pots 

are removed for greenhouse forcing, additional dry cooled bulbs may be potted 

to take their place. In this method, the cooler should remain at 41F (5C) for the 

entire time that dry bulbs are present in the cooler. 


Harvest Darwin tulips when 50% of the flower is colored; others should be cut 

when nearly the entire flower is colored. Tulips must be harvested several times 

a day for optimum postharvest life. They are usually wrapped in 10-stem 

bunches. 

Postharvest 

Fresh: Sexton et al. (2000) concluded that tulip senescence does not involve 

primary regulation by ethylene. Neither addition of silver thiosulfate nor aminoethoxyvinylglycine 

(AVG) delayed the time to abscission. Flowers persist 3–4 

days in the opening stage, and a further week after they open (Vaughan 1988). 

Storage: Growers must wrap bunches after grading. If they are shipped immediately, 

they may be placed vertically in water. Cevallos and Reid (2001) found no

520 TULIPA 

significant differences between the vase life of flowers stored dry and flowers 

stored in water when storage temperatures were 32–50F (0–10C); however, the 

vase life after wet storage at temperatures of 54F (12C) and greater was significantly 

higher than vase life after dry storage at those temperatures. 

Stem stretch: Stems continue to grow for the first 24 hours in water, and flowers 

bend toward the light. Growth regulators have been effective in reducing 

growth and bending after harvest. The addition of 20 or 50 mg GA3/l to a preservative 

solution containing 8-hydroxyquinoline citrate and sucrose significantly 

prolonged the vase life of tulip cultivars. GA3 also reduced the excessive 

stem elongation that occurs in cut tulips kept in water. The addition of 25 or 50 

mg Ethrel (ethephon)/l to the preservative solution containing GA3 completely 

inhibited stem elongation during vase life and had no effect on flower 

longevity (Pisulewski et al. 1989). 

Wholesalers should store tightly wrapped stems horizontally at 32–35F (0– 

2C) (De Hertogh 1996). If placed in water, recut about ¼" (6 mm) of the stem 

base and place in 6–8" (15–20 cm) of cooled water. If flowers arrive bent, they 

may be straightened by wrapping them in wet paper and placing in water with 

light directly above (Vaughan 1988). 

Do not place tulips with daffodils. Daffodils exude a mucous substance that 

is toxic to many other species (Doorn 1998). Tulips and daffodils may be mixed 

if daffodils have been allowed to stand in water in separate containers for 24 

hours (see Narcissus). 

Cultivars 

Many, many are used. Contact your bulb distributor for up-to-date cultivar listings 

and availability. Roy Snow of the United Flower Growers auction in Burnaby, 

B.C., shares these most popular cultivars: ‘Angelique’ (double pink), ‘Apricot 

Beauty’ (apricot), ‘Bastogne’ (red), ‘Blenda’ (pink and white), ‘Christmas 

Marvel’ (hot pink), ‘Don Quichottee’ (hot pink), ‘Gander’ (hot pink), ‘Gander’s 

Rhapsody’ (light pink), ‘Ile de France’ (red), ‘Inzel’ (white), ‘Leen van der Mark’ 

(red and yellow), ‘Monte Carlo’ (double yellow), ‘Negrita’ (purple), ‘Upstar’ (double 

pink and white), ‘White Dream’ (white), and ‘Yokohama’ (yellow). 

Roy also mentions some interesting newer varieties: ‘Double Price’ (extremely 

double purple), ‘Jan Reus’ (burgundy), ‘Orange Monarch’ (orange), ‘Princess 

Irene’ (orange with red stripes), ‘Purple Prince’ (purple), ‘Rocco’ (parrot red), 

‘Top Parrot’ (parrot red), ‘Washington’ (red and yellow), ‘Weber’s Parrot’ (parrot 

pink and green), ‘Winterberg’ (cream), and ‘Zurel’ (purple and white striped). 


Sterilize beds whenever possible to reduce incidence of soil-borne diseases, such 

as those caused by Rhizoctonia and Pythium. 

Gray mold (Botrytis) affects flower petals and stems. Crop rotation and use 

of fungicides help combat the problem. Avoid overhead irrigation. 

Basal rot (Fusarium oxysporum) results in red foliage, few roots, and rotted

TULIPA 521 

bulbs. This problem must be controlled by the bulb grower and should never 

enter the grower’s field. Always check bulbs on arrival for a whitish mold and a 

foul smell. Infected bulbs feel soft beneath the outer covering, and some may 

feel very light. If more than 10% of the bulbs are infected, the whole lot may have 

to be discarded. 

Blue mold (Penicillium) is generally not serious, but bulbs should be dusted 

with a fungicide if placed in dry storage or drenched if immediately planted (De 


Flower rot often occurs on double-flowered forms that have been watered 

overhead and have not dried out. Provide good ventilation, particularly for double 

flowers. 


Flower abortion during early stages of development can be caused by excessively 

high temperatures during transportation of the bulbs from Holland or ethylene 

exposure at any point during forcing (Charles-Edwards and Rees 1975). Fusarium 

will induce concentrations of ethylene sufficient to result in flower abortion 

or malformation (De Hertogh and Le Nard 1993). Stem topple (the stem 

collapses slightly below the base of the flower) may be related to a calcium deficiency, 

excessively cold-treated bulbs, or forcing at a very high temperature (De 


Reading 

Cevallos, J. C., and M. S. Reid. 2001. Effect of dry and wet storage at different 

temperatures on the vase life of cut flowers. HortTechnology 11(2):199–202. 

Charles-Edwards, D. A., and A. R. Rees. 1975. An analysis of the growth of forced 

tulips. Part 2: effects of low temperature treatments during development on 

plant structure at anthesis. Sci. Hortic. 3:373–381. 



De Hertogh, A. A., and M. Le Nard, eds. 1993. Physiology of Flower Bulbs. Elsevier 

Press, Amsterdam. 

Dole, J. M. 1996. Spring bulb production: the delayed potting method. Ohio Florists 

Assoc. Bul. 806:1, 3–4. 

Doorn, W. G. van. 1998. Effects of daffodil flowers on the water relations and 

vase life of roses and tulips. J. Am. Soc. Hort. Sci. 123(1):146–149. 

Pisulewski, T., D. Goszczyska, and R. M. Rudnicki. 1989. The influence of gibberellic 

acid and ethrel on cut tulips. Acta Hortic. 251:115–118. 

Rees, A. R. 1985. Tulipa. In The Handbook of Flowering. Vol. 1. A. H. Halevy, ed. 


Sexton, R., G. Laird, and W. G. van Doorn. 2000. Lack of ethylene involvement in 

tulip tepal abscission. Physiologia Plantarum 108(3):321–329. 


Ore.

522 TWEEDIA CAERULEA 

Many thanks to Brent Heath (first edition) and Roy Snow (second edition) for 


Tweedia caerulea Asclepiadaceae 

annual Argentina blue 12–20"/12" (30–50 cm/30 cm) 

In the first edition of the book, Tweedia caerulea (syn. Oxypetalum caeruleum) was 

described as “a plant with exciting potential as a cut flower or a pot plant” and, 

although its gains in popularity at Dutch auctions were noted, it was judged 

“relatively unknown in the American market.” Boy, was that statement right on! 

Is anybody growing even a single plant of this stuff? Perhaps the negatives mentioned 

in the first edition, such as the milky sap, unappealing foliar fragrance, 

and twining habit, did not endear this species to growers, but that does not 

change the unique sky-blue color of the starlike flowers. Still, for the hard-core 

specialists, we decided to keep the plant with the wonderful name in this edition 

as well. Plants may be grown in the greenhouse or under protection outdoors. 

The botanical name was recently changed from Oxypetalum to Tweedia, commemorating 

the Scotsman James Tweedie (1775–1862). He was the head gardener 

at the Royal Botanic Garden in Edinburgh and later emigrated to South 

America, where he kept a small shop in Buenos Aires. He botanized throughout 

the continent, sending material back to Scotland for study. 

Propagation 

Propagate by sowing seed in plugs or open seed trays at 68–72F (20–22C) under 

high humidity. Approximately 0.25 oz (7 g) of seed yields 1000 plants (Nau 

1999). A significantly longer time is needed to germinate seed that is direct sown. 

Two to 3" (5–8 cm) terminal shoot cuttings may be rooted if seed supply is 

inconsistent. 

Growing-on 

Fertilize newly emerged seedlings or rooted cuttings with 50–75 ppm N from 

potassium nitrate and transplant to field when the root system fills a 3½" (9 cm) 

pot or plug. Grow at approximately 70F (21C). 


Temperature: Temperature has the greatest effect on growth and flowering of 

tweedia. Temperatures above 60F (15C) are necessary for optimum growth, but 

temperatures above 86F (30C) result in long, lanky stems, aborted flowers, and 

poor flower color. If plants are consistently grown below 60F (15C), growth is 

significantly slowed and flowering delayed; the following table summarizes the 

influence of temperature on tweedia (Armitage et al. 1990).

TWEEDIA CAERULEA 523 

Tweedia caerulea 

The effect of temperature on flowering and growth of tweedia at 

first harvest. 

Days to Stem length Aborted flowers 

Temperature flower z (in) y (%) 

57F (14C) 115 18.0 10 

70F (21C) 38 20.0 4 

86F (30C) 32 24.8 20 

z = time between placing 8-week-old plants at specific temperature to 

harvesting of 3 flower stems 

y = multiply (in) by 2.54 to obtain (cm)

524 TWEEDIA CAERULEA 

Light: High light intensity is best for flowering; low light levels cause stretching 

and thinning of flower stems. Provide shade in high light areas to increase 

stem length. 

Photoperiod: No photoperiodic effects on time to flower occur, but long days 

(>12 hours) result in extended internodes and therefore longer stems. Also, less 

flower abortion occurs on plants subjected to LD, and higher-quality flowering 

stems are formed. 


Flowers are susceptible to weather damage, particularly rain and wind. Greenhouse 

production is recommended, but field production is possible if protection 

from the elements is provided. Support of plants is necessary in the South but 

not in the Northwest. 

Yield in outdoor production is 5–10 stems/plant the first year and may be 

doubled if plants can be overwintered. Stem length is longest and stems are 

strongest if plants are well fertilized, temperatures of at least 65F (18C) are provided, 

and some shading is present. 

Fertilize with side dressing of N or with liquid fertility of 300–500 ppm N 

once a week. 


Tweedia is well suited for greenhouse production. Space plants 6–9" (15–23 cm) 

apart and fertilize consistently with liquid or slow-release fertilizer. Plants may 

be grown in containers or ground beds. If temperatures are above 70F (21C), 

support may be necessary. 


Flowers are indeterminate: flowers occur in the nodes of the stems, and the stems 

continue to produce additional leaves and flowers. Groups of 2–4 flowers 

(cymes) occur in each node. Long seed pods form from the flowers, which some 

designers find useful. To each his own! 

Harvest when approximately 6 cymes are present. The first 1 or 2 should be 

open, the last showing color. 

Postharvest 

Flowers persist 6–10 days, depending on temperature and light. The stems exude 

a milky sap that, although messy, does not seem to reduce the vase life. Studies 

with various solvents, such as alcohol and hot water, showed that removal of 

the sap did not affect vase life. Use of silver thiosulfate did not significantly 

extend vase life.

Cultivars 

‘Heavenborn’ bears deeper blue flowers. This selection has been successful in 

Dutch greenhouses. 


VERBENA BONARIENSIS 525 

Root rots under conditions of poor drainage and hot weather are not uncommon. 

Aphids, in particular, relish the plants. Otherwise, few pests bother them. 


“I picked up a 4" pot at a local nursery just by chance one spring. It got about 2' 

tall and bloomed very well that summer—a pale iridescent clear blue with slightly 

fuzzy leaves. No problems at all. It made tons of milkweed-type seed pods with 

a lot of viable seeds and reseeded some in the bed. It’s a tender perennial in Louisiana 

and probably well worth fooling with, though stems are a little short.” 

Denyse Cummins, Lafayette, La. 

Reading 

Armitage, A. M., N. G. Seager, I. J. Warrington, and D. H. Greer. 1990. Response 

of Oxypetalum caeruleum to light, temperature, and photoperiod. J. Amer. Soc. 

Hort. Sci. 115:910–915. 


Verbena bonariensis 

South American verbena, tall verbena Verbenaceae 

perennial, Zones 6–9 South America rose-violet 1 

3–4'/3' (0.9–1.2 m/0.9 m) 

Of all the verbenas, this is among the taller species and particularly effective as 

a filler. Named for the city of Buenos Aires, where it was first discovered, it has 

since become naturalized in the United States from South Carolina to Texas. 

The wiry stems are roughly hairy and conspicuously 4-angled. The individual 

flowers measure only about ¼" (6 mm) across but the entire inflorescence is 2–4" 

(5–13 cm) wide. 

Propagation 

Seed germination is inconsistent at best; conventional sowing can result in yields 

as low as 30% (Nau 1999). Stratifying seed has provided benefit occasionally; 

sow in moist media and place the tray at 40F (4C) for 3–4 weeks, after which 

time the tray may be moved to 70–75F (21–24C). Germination is erratic, and 

seedlings appear over 3–5 weeks.

526 VERBENA BONARIENSIS 

Two to 3" (5–8 cm) terminal cuttings of new spring growth may be rooted 

and transplanted 3–5 weeks later. Root cuttings, taken in the spring, may also be 

used. 

Growing-on 

Grow on at 55–62F (13–17C) in a minimum pot size of 4" (10 cm). Plants should 

remain in the greenhouse for as short a time as possible. Cutting back the plant 

results in a many-branched specimen with a shrub-like habit. 


Plants flower all season, from early spring until frost, indicating little or no 

photoperiodic response. Plants flower the first year from seed, suggesting that 

neither is a cold treatment necessary. Likely flower initiation is a function of 

node number (maturity). 


Yield: Ten to 12 stems per plant is obtainable. Plants do not branch much on 

their own; however, a single pinch yields additional stems. 

Spacing: Plants are taller than they are wide, and spacing can be dense. Plants 

can be spaced as closely as 12" (30 cm) apart; however, powdery mildew is a 

problem, and more open spacing (18–20", 45–50 cm) is recommended for air 

movement. 

Longevity: Plants can be treated as annuals. If planted early in the spring, they 

will be no more productive in subsequent years, even if they overwinter. Plants 

will reseed, but it has been our experience that the volunteers are not as vigorous 

as when started anew. 


Harvest when most flowers are open. The stems can become tangled, and harvesting 

individual stems can be difficult; some growers cut an entire row at one 

time. If using this method, stems must be graded to cull those that have been 

harvested too early or too late. 

Postharvest 

Flowers tend to shatter, which can be a problem, particularly for customers who 

like the neat-and-tidy look. Susan O’Connell of Hartwick, Vt., states, “I find it 

sheds a lot of blooms immediately after cutting, no matter what postharvest 

treatment I try. It continues to shed some after that, but not copious amounts, 

and I make sure I have shaken out any dead florets before it gets to market. But 

flowers are alive, and life is not static, it is constantly changing. So I try to make

VERBENA BONARIENSIS 527 

sure my customers are aware that it will be messy, and show them all the buds 

that continue to open. Most appreciate it and enjoy that gorgeous purple!” 

Flowers can be stored at 36–41F (2–5C). 


Verbena rigida (rigid verbena) is similar to V. bonariensis in all respects except 

size: V. rigida is only 1–2' (30–60 cm) tall. The flowers are similar, the square 

stems are also coarse, and the color is similar, perhaps a little darker. We recommend 

V. rigida as a short-stemmed annual; however, plants are winter hardy only 

to Zone 7. 


Powdery mildew is the biggest problem with verbenas in general, and the cut 

flower forms are no exception. Spray fungicides beginning in early summer. 


“I gave up trying to cut individual stems, and just started clear-cutting all the 

large stems without looking at the heads, putting them in 30-stem bunches. I 

actually sold to the wholesaler this way, and at home it’s easy enough to throw 

out the unbloomed heads as we make bouquets.” Ralph Thurston, Bindweed 

Farm, Blackfoot, Idaho. 

“I grew Verbena bonariensis last year and it bloomed forever. Because it was 

such a pain to cut, I didn’t grow it this year. All my customers kept asking for it, 

so I am going to try it again next year. I will make sure to wear gloves when I 

strip the foliage and also leave a little more space between plants, so I can see 

where the individual stems are. It is easy to grow from seed, and I got a few volunteers 

this year even though I tilled the area very well and applied 2" of compost 

on top of the soil.” Kate Sparks, Lilies and Lavender, Doylestown, Pa. 

“When the verbena blooms start looking ratty, I take the brush hog on my 

tractor set high and mow it all down. It reblooms in a few weeks with fresh flowers.” 

Mary Vanderslice, Laughing Flowers Farm, Maypearl, Tex. 

“I wish I had some verbena planted this season. I gave up on this stuff due to 

my personal dislike of the flower’s tendency to shatter. Not a week goes without 

a few customers asking when the verbena will be ready.” Paul Shumaker, Never 

Should Have Started Farm, Bangor, Pa. 

“It is an invaluable cut for me, and I can’t make a bouquet without reaching 

for some verbena as a final touch. Mixed with sunflowers and amaranth, or crocosmia, 

or red yarrow, it is a winning combination. I let the flower heads get 

fairly large before cutting. After it has stretched out and has the side stems 

blooming as well, it is perfect for my bouquet needs.” Susan O’Connell, Fertile 

Crescent Farm, Hardwick, Vt.

528 VERONICA 

Reading 


Veronica speedwell Scrophulariaceae 

perennial, Zones 4–8 Europe, Asia blue 2–3'/2' (60–90 cm/60 cm) 

This genus has enjoyed steady increases in cut flower production, particularly in 

Europe and in the United States, although it is still considered a minor crop by 

most growers. Much of the increase may be attributed to the improved vase life 

of newer cultivars. If treated properly, veronica can be shipped significant distances, 

but it is still recommended for local sales. Fresh local material will always 

be better than material shipped in from other parts of the country or other parts 

of the world. This can be said for many crops but is especially true for veronica. 

Several Veronica species are available from perennial plant growers, but longleaf 

veronica (Veronica longifolia) is the most suitable for the cut flower trade. 

Plants are robust and relatively winter hardy and tolerate warm summers well. 

Many more choices for flower color are available with spiked speedwell (V. spicata), 

but stem length is shorter on cultivars, unless selected for cut flower use. 

‘Sunny Border Blue’ and other hybrids are important landscape plants but are 

seldom used as cut flowers. The main problem with veronica as a cut flower is 

that flowers on the bottom of the inflorescence decline before the top flowers are 

open. The stage of harvest and postharvest procedures become particularly 

important with these plants. 

Propagation 

Most cultivars are propagated by division or terminal cuttings; however, the species 

and a few cultivars may be seed-propagated. The small seeds should be 

lightly covered and placed at 68–72F (20–22C). Germination occurs in 10–14 

days. Approximately 1/128 oz (221 mg) of seed yields 1000 seedlings (Nau 1999). 

Growing-on 

If small propagules are received or seedlings are being grown prior to planting in 

the field, initially place at 58–65F (14–18C) and lower the temperature 2–4 

degrees F (1–2 degrees C) after 2–3 weeks of growth. Fertilize sparingly (75–100 

ppm N once a week) until plants are large enough to plant to the field. 


Temperature: Little is known about the effects of cooling, but it is likely beneficial, 

if not necessary, for all species. Cooling is not necessary for those cultivars 

that flower the first year from seed. The hybrid ‘Sunny Border Blue’ requires 6 

weeks of cooling at 41F (5C) for flowering; 10 weeks provides even more rapid 

flowering under greenhouse forcing conditions (Runkle et al. 2000). Yields of

Veronica longifolia ‘Blauriesin’

530 VERONICA 

field-grown plants are lower the first year (after a winter) than in 2-year-old 

plants, but this is probably more to do with the plants’ maturing than to cooling. 

Plants tolerate hot summer temperatures, and they perform well in the Northeast 

and the West. 

Photoperiod: Plants begin flowering naturally in late spring in the South, early 

summer in the North, and flower sporadically all summer. Photoperiod appears 

to be of little importance, but LD may play a role in forcing greenhouse plants. 

In forcing ‘Sunny Border Blue’, researchers found that if plants received a sufficient 

cold period, they flowered regardless of photoperiod (Runkle et al. 2000). 


For cultivars of Veronica longifolia, no cooling or photoperiod appears to be 

needed; harvest times are 12–16 weeks after planting, and successive harvests 

are about 12 weeks later, depending on temperatures. Second-year yield will 

always be better than first-year yield. 

Spacing: Space plants on 9–12" (23–30 cm) or as wide as 15" (38 cm) centers. 

Pinching: Pinching is recommended for field growing, but may not be necessary 

for greenhouse forcing. Pinch plants about 3 weeks after receiving plugs or 

when 3–4 leaves can be left on the plant. Pinching out the center flower (disbudding) 

provides later harvests and a fuller flower head. 

Yield: Longevity of plants in the field is at least 5 years, although plants may be 

renewed as often as every 3 years. Field studies at Georgia on Veronica longifolia 

‘Schneeriesin’, an excellent white-flowered cultivar, are shown in the following 

table. 

Longevity of Veronica longifolia ‘Schneeriesin’. Spacing 15" (38 cm) 

centers. 

Stems/ Stem length Stem width 

Year plant (in) z (mm) y 

1 50 16.8 3.0 

2 84 21.4 3.3 

2 (shade) 26 30.0 3.9 

3 30 28.7 5.0 



Second-year yield for ‘Blauriesin’, a blue-flowered cultivar, was 31 stems/plant 

with an average stem length of 20" (51 cm). Stems are longer in cooler climates. 

Ed Pincus in Vermont finds that through selection of taller plants and continual 

division, stem length of his plants has increased to 32–42" (0.8–1.1 m). 

Shade: Shade cannot be recommended. Although the previous table shows 

that stem length and diameter benefitted from the presence of 55% shade cloth,

yield was much reduced. One reason for the large difference in yield between 

sun and shade was because of the longer harvest time for plants in full sun. 

Those in shade were harvested from 14 May to 3 July, whereas those in full sun 

were harvested well into October. If the additional late summer harvests were not 

counted, then full-sun plants yielded 40 stems/plant in the same time as shade 

plants produced 26 stems. 


For Veronica longifolia, seed-propagated cultivars are popular and may be obtained 

as plugs. No cooling or photoperiod appears to be needed; initial harvest 

time is 12–16 weeks after planting, and successive harvest is about 12 weeks later. 

Provide as much light as possible if forcing plants during the winter. 

Although cooling does not appear to be necessary for many cultivars of Veronica 

longifolia, it is needed for ‘Sunny Border Blue’, even in the field. 

For all species and cultivars, natural days are sufficient, regardless of cold. 

Temperatures of 60/70F (15/21C) night/day are recommended, although lower 

temperatures (50–55F, 10–13C) may be used. 






‘Schneeriesin’ 

(%) 

N P K Ca Mg 

2.9 0.35 1.20 0.58 0.23 

(ppm) 

Fe Mn B Al Zn 

82 30 11 30 57 

VERONICA 531 


Harvest when ⅓ to ½ of the flowers on the inflorescence are open (Nowak and 

Rudnicki 1990). Place immediately in preservative in the field. The inflorescences 

decline rapidly if too many flowers are already open. According to Ed Pincus, 

flower droop after harvest can be a problem; he finds that afternoon or morning 

shade lessens flower droop (harvesting before sunrise or after sunset achieves 

the same result). Sometimes drooped flowers recover in the cooler. Store at 36– 

41F (3–5C) and keep away from fresh fruit, etc., as flowers are ethylene sensitive.

532 VERONICA 

Postharvest 

Fresh: Flowers are sensitive to ethylene and should be treated with STS, if 

available. Bacteria can also significantly reduce water uptake, so treat with a preservative 

containing a bactericide. If plants are harvested at the proper stage of 

development, they persist about 7 days. Recut the stems prior to shipping and 

instruct buyers to do the same. 

Storage: Storage is not recommended; if necessary, stems may be kept at 36– 

41F (3–5C) (Vaughan 1988), and storage for up to a week at 33F (1C) is sometimes 

practiced. Be sure the cooler doesn’t fall a few degrees. 


Cultivars (Veronica longifolia) 

‘Anna’ has rose-red flowers and an improved vase life compared to ‘Blauriesin’ 

and other older cultivars. From cuttings. 

‘Blauriesin’ bears lavender-blue flowers on 2–2½' (60–75 cm) stems. Common 

and excellent. From seed or cuttings. 

‘Caya’ provides clean white flowers. 

‘Foerster’s Blue’ is about 2' (60 cm) tall and bears deep blue flowers. 

‘Leonie’ has pink flowers. From cuttings. 

‘Martje’ consists of flowers in blue and purple (‘Dark Martje’). They are the 

standard cultivars in Holland. 

‘Rosalinde’ is a hybrid with handsome rose-pink flowers on upright stems. 

‘Schneeriesin’ is an exceptional performer, flowering the first year from seed. 

Flowers are fairly clean; still, as with all white forms, its flowers appear to decline 

more rapidly than the flowers of blue-flowered forms. 

var. subsessilis, sometimes sold as Veronica subsessilis, is an excellent form for cut 

flowers. Plants are 2–3' (60–90 cm) tall and bear lilac-blue flowers. 


Veronica spicata is generally too short and compact for use as a cut flower, but 

its selection ‘Blue Charm’, with lavender-blue flowers, is sufficiently tall, up to 3' 

(90 cm). ‘Sightseeing’, a seed-propagated mix of white, pink, and blue flowers 

on 24" (60 cm) stems, is also highly useful as a cut (see “Grower Comments”). 

Veronica virginica (culver’s root) is properly known as Veronicastrum virginicum, 

which see. 


Aphids and thrips are the major pests. Leaf spots, caused by Septoria veronicae as 

well as other fungi (Sclerotinia), can result in ragged-looking leaves. Control with 

fungicidal sprays; start the spray program in early June and continue once every 

3 weeks with a general fungicide. Powdery mildew can also be a problem.


VERONICASTRUM VIRGINICUM 533 

“I planted the ‘Sightseeing’ mix in the spring of 1999; it bloomed a little in the 

fall (short stems), but this spring it is fabulous! I’m Zone 7 and I’m expecting it 

to be a perennial. My only complaint is that my mix turned out to be only blue 

with a few whites, so I’m going to plant some more with hopes to get a few pinks 

too.” Kathy York, Scarborough Farm, Mechanicsville, Md. 

“My ‘Sightseeing’ is like the Eveready bunny. It keeps going and going and 

going. It is about 4 years old and gets better every year.” Eileen Stephens, Green 

and Gold, Earlysville, Va. 

Reading 


Nowak, J., and R. M. Rudnicki. 1990. Postharvest handling and storage of cut 

flowers, storage greens and potted plants. Timber Press, Portland, Ore. 

Runkle, E. S., R. D. Heins, A. Cameron, and W. Carlson. 2000. Forcing perennials, 

Veronica longifolia ‘Sunny Border Blue’. Greenhouse Grower Special Pub., 

2000. 


Ore. 

Many thanks to Ed Pincus and Roxana Whitt for reviewing this section. 

Veronicastrum virginicum culver’s root Scrophulariaceae 

perennial, Zones 3–8 eastern United States light blue 1 

3–4'/2' (0.9–1.2 m/0.6 m) 

Often referred to as Veronica virginica, culver’s root is closely related to Veronica 

(the suffix astrum means “resembling”). Flowers of the species are light blue, but 

the white-flowered var. album is the best form for cut flowers. And Betsy Hitt 

from North Carolina adds something that may be important to many growers: 

“Veronicastrum seems to be of no interest to white-tailed deer.” 

Propagation 

Seed: Seeds germinate in 2–3 weeks if placed at 65–70F (18–21C) under mist. 

Approximately 0.02 oz (0.6 g) of seed yields 1000 seedlings (Kieft 1996). Most 

plants are divided or grown from cuttings. 

Division: Divide plants after 2–3 years. 

Cuttings: Terminal cuttings, about 2–3" (5–8 cm) long, should be taken in 

early summer or fall. Roots form in 2–3 weeks.

Veronicastrum virginicum

Growing-on 

Grow plants in cell packs or 4" (10 cm) pots at 55–65F (13–18C). Fertilize with 

75–100 ppm N using potassium nitrate or calcium nitrate. Plant in field in early 

fall or early spring. 


No photoperiodic responses have been shown with Veronicastrum, but its close 

relationship with Veronica suggests the genera would respond similarly. Plants 

must attain a certain leaf area or maturity prior to flowering; they tolerate warm 

temperatures, but stem strength is better in areas where summer nights fall 

below 70F (21C). 


Spacing: Space plants 12 × 18" (30 × 45 cm) or 12 × 12" (30 × 30 cm). Stems 

branch considerably, particularly near the top; therefore, avoid high-density 

spacing (

536 ZANTEDESCHIA 

Shade: Shading is not recommended. Second-year harvests of plants grown in 

full sun compared with those under 55% shade at the University of Georgia resulted 

in longer stems but reduced yield of plants grown under shade. 


For higher-quality stems, remove the terminal flowers as they form. This is labor 

intensive and may not be feasible; however, all the axillary flowers will open at the 

same time, resulting in a fuller flower head and more “flower power.” Stems 

should be cut when the inflorescence is approximately ⅓ open. This occurs when 

fewer than 10 flowers on the inflorescence are open. If cut too early, the foliage 

will decline before all the flowers open. 

Postharvest 

Flowers persist 7–10 days in floral preservative. One of the problems with veronicastrum 

is the incidence of marginal leaf browning. In work conducted at the 

University of Georgia, flowers cut at early bud stage persisted for 10 days in a 

flower preservative but only 4–5 days in water. Leaf browning was also significantly 

reduced. The use of sugar solutions (2.5–5%) also reduced the incidence of 

leaf browning. 

Cultivars 

var. album (‘Album’) has creamy white (often with a tinge of pink) flowers and 

a much-branched inflorescence. This is the cultivar of choice. 


Downy mildew (Peronospora grisea) results in pale spots on the top of the foliage. 

The undersides are covered with a grayish mildew. 

Leaf spots (Septoria veronicae) occur as small violet to brown circular spots of 

varying sizes on the top of the foliage. The spots may run together, resulting in 

a scorched appearance. Use a general-purpose fungicide. 

Reading 


Netherlands. 

Zantedeschia calla lily Araceae 

bulb, Zones 7–10 South Africa many colors 1 

2–4'/2–3' (0.6–1.2 m/0.6–0.9 m) 

Approximately 6 species are found in the genus, but significant selection and 

hybridization have taken place, resulting in many hybrids and cultivars. For sim-

ZANTEDESCHIA 537 

plicity’s sake, callas may be thought of as “summer” or “winter” callas, monikers 

based on their native habitats. 

The summer callas consist of deciduous foliage, green fruit, and disk-shaped, 

flattened rhizomes. The inflorescence of callas consists of 2 parts: the cylindrical 

spadix, consisting of the flowers, and the large ornamental spathe (bract), often 

colored or white. When descriptions include flower color, they refer to spathe 

color. Species included as summer types are Zantedeschia albomaculata (white 

flowers, spotted leaves), Z. elliottiana (yellow, spotted), Z. jucunda (yellow, spotted), 

Z. pentlandii (lemon-yellow, usually unspotted), and Z. rehmannii (pink, usually 

unspotted). The colored hybrids have been developed from these species. 

Winter callas have evergreen foliage, yellow to red fruits, and elongated rhizomes. 

They are represented by Zantedeschia aethiopica (white, unspotted leaves), 

Z. aethiopica ‘Green Goddess’ (white with green flowers), Z. ‘Pink Mist’ (white 

with pink throat), and occasionally the dwarf Z. aethiopica var. childsiana (‘Childsiana’; 

Childsiana white calla). The winter callas are common, but it is the deciduous, 

colored hybrids of the summer callas that are the more popular items for 

cut flowers and potted calla lilies. Rhizomes are rapidly produced through tissue 

culture and division, and are available from U.S. producers as well as from 

abroad. Rhizomes may be left in the ground in Zones 7–10 but should be lifted 

further north. 

Propagation 

Seed: Seed propagation is generally limited to the true species and breeding 

programs. Flowers occur approximately 3 years from sowing (Tjia 1989). Seed 

propagation has yielded a limited number of cut flower cultivars, but by using 

seed-propagated rhizomes rather than those that have been divided, disease is 

reduced. 

Division: Growers should not divide rhizomes before the rhizomes are 2 years 

old, and care must be taken not to introduce bacterial and viral diseases. Rhizomes 

should be lifted after foliage has died back. Lift carefully from the field 

and remove soil, leaving roots to shrivel during curing. Divide with a sharp, sterile 

knife. Cure rhizomes in curing chambers for 10–14 days or until a protective 

skin develops. Curing chambers should be at 70–80F (21–27C), 70–80% humidity, 

and have good air circulation. After curing, store rhizomes at 68–70F (20– 

21C) for 6–8 weeks prior to planting (Welsh and Baldwin 1989). This assumes 

that dormancy has not been broken. If dormancy is broken after curing, temperatures 

of 68–70F (20–21C) may reduce the ability of the rhizome to flower. 

If rhizomes must be stored for a prolonged period, 45–48F (7–9C) will inhibit 

sprouting and maintain the health of the rhizome. Store in single-layer mesh 

trays using dry sawdust or peat moss and provide plenty of air circulation. Do 

not store below 40F (4C), or rapid loss of flowering potential will occur. Rhizomes 

will be destroyed if temperatures fall below freezing (Tjia 1989). 

Tissue culture: This process should be carried out only by competent laboratories; 

growers need not be involved. Stock propagated by division, rather than 

by seed or tissue culture, will likely result in virus-ridden plants that lack vigor.

Zantedeschia aethiopica


Light: Calla lilies do well in high light areas, particularly if forced during the 

winter, but if forced outdoors during the summer, light intensity is seldom a 

problem. The use of shade during field production is most useful to extend the 

length of the flower scape (see “Field Performance”). Low light, sometimes a 

problem during greenhouse forcing in the winter months, results in etiolated 

leaves and flower stems. 

Temperature: Temperature extremes, lack of water, or root disturbance result 

in dormancy of rhizomes. In nature, dormancy of the colored callas normally 

occurs after flowering and is characterized by yellowing of foliage and rapid 

dieback. White callas (Zantedeschia aethiopica) do not go dormant if temperatures 

are cool and moisture is available; they remain evergreen. 

Photoperiod: Flowering is not affected by photoperiod; however, plants grown 

under short days are shorter than those grown under long days. Flower buds 

form and develop under any condition favorable for vegetative growth (Post 

1936). 

Gibberellic acid: Gibberellic acid increases the number of flowers on cultivars of 

colored calla lilies (Funnell et al. 1988). Although most GA research was done 

with potted callas, similar results occur with cut forms. Best results have been 

obtained when GA is applied as a preplant dip to the rhizome, where up to a 

300% increase in flowering can be expected. A wide range of concentrations and 

application times have been recorded as preplant dips or rhizome sprays. A GA3 

quick dip of 25 ppm for 30 seconds, a GA3 soak of 500 ppm for 10 minutes, or a 

Promalin (GA4+7 and benzyladenine) soak of 50–100 ppm (GA equivalents) 

for 30 minutes—all have been effective (Welsh and Baldwin 1989). Corr (1988) 

suggests that best results occur with GA dip after a 6-week storage at 50F (10C). 

A fungicide/bactericide (such as copper hydroxide or copper oxychloride) should 

be incorporated into the solution. Limited success with a rhizome spray has also 

been described (Funell 1993), and Promalin at 1.8% (1.3 tbsp/gallon, 5.5 ml/l) 

is recommended. In summary, many growers have selected 50–100 ppm GA or 

Promalin as a dip (5–15 minutes) or spray to run off over rhizomes as soon as 

they are received. Spraying rather than dipping minimizes spread of disease. For 

many growers, ordering pretreated tubers from a reputable distributor takes the 

guesswork out of timing and application methods. 



Rhizome size: Rhizomes come in bizarre shapes, but commerce nevertheless 

demands they be classified in various sizes. Some classifications try to make 

standard grade: grade 1 (2–2.25", 5–6 cm in diameter); grade 2 (1.5–1.8", 4–4.5 

cm); or grade 3 (0.88–1.4", 2.5–3.5 cm) (Dole and Wilkins 1999). Others use different 

measurements and grade classifications; however, mostly they are simply 

sold as large, medium, and small. Rhizomes of white callas are often further 

divided into “horns” (elongated rhizomes with few side [daughter] rhizomes) 

or “clusters” (compressed rhizomes with attached daughter rhizomes). In gen-


eral, horns are preferred for cuts, clusters for potted callas. (This is true—we 

could not make this up.) 

For colored callas, nearly all rhizomes 1½–2" (4–5 cm) wide will flower with a 

GA treatment, whereas smaller rhizomes may require an additional year to flowering. 

However, research showed that small rhizomes (1", 2.5 cm wide) of Zantedeschia 

elliottiana and Z. rehmannii required the same time from planting to flower 

as rhizomes greater than 2½" (6 cm) in diameter (Corr and Widmer 1991). Treatment 

with GA is recommended for all sizes of colored callas. Smaller rhizomes 

produce smaller flowers (Corr and Widmer 1991). 

Planting: Plant rhizomes as soon as they arrive, but if you cannot, place tubers 

in dry storage of 46F (8C), 70–80% relative humidity for up to 6 weeks (De Hertogh 

1996). Check for incidence of soft rot (Erwinia) and physiological problems 

such as chalking (see “Pests and Diseases”). 

Soil: Rhizomes are best forced in well-drained sandy or silty loam, particularly 

if rhizomes are lifted every year. Clay soils result in poor aeration, poor 

drainage, and a greater incidence of Erwinia. The importance of well-drained 

soils in reducing Erwinia cannot be overemphasized. Clay soils are also difficult 

to clean from the rhizomes after lifting. Adjust pH to 6.0–6.5. 

Fertilization: Fertilize sparingly as excessive nitrogen fertilizer results in leafy 

growth at the expense of flower production. A moderate application of complete 

fertilizer (100–150 ppm N) from emergence to flower color is often used. 

Spacing: Welsh and Baldwin (1989) provide 2 spacing systems, depending on 

whether rhizomes are lifted or not. The increase in flowering by lifting and 

retreating with GA every year may offset the savings in labor and storage of keeping 

the rhizomes in the ground. 

System 1: standard for greenhouse forcing, rhizome multiplication 

Lift annually 

4 rows per bed, rows and plants 8" (20 cm) apart 

43,000 rhizomes/acre (106,000 rhizomes/hectare), 1 1 ⁄2" (4 cm) 

rhizomes 

System 2: standard for field production 

Lift after 2 years 

2 rows per bed, 8" (20 cm) between plants. Beds 16" (40 cm) 

apart 

27,000 rhizomes/acre (67,000 rhizomes/hectare), 1 1 ⁄2" (4 cm) 

rhizomes 

Shading: The use of shade cloth or natural shade (e.g., pine trees) results in 

significant stem elongation of calla lilies. Work at the University of Georgia, 

shown in the following table, demonstrates the effect of shade on stem (scape) 

length (Armitage 1991). Shade was artificially provided by commercial shade 

cloth. Results will differ under different climates and latitude.

The effect of shade on scape length of calla lilies. 

Cultivar Shade level (%) Scape length (in) z 

Black Magic 0 18.0 

55 22.8 

Pacific Pink 0 14.4 

55 21.2 

Pink Persuasion 0 15.2 

55 22.0 

Majestic Red 0 14.0 

55 24.4 



Harvesting: Flowers can be pulled or cut at the base of the stem. Pulling flowers 

often results in extra stem length, but scapes must be turgid. Flowers of 

sparsely rooted plants or plants irrigated improperly should be cut, not pulled. 

Harvest flowers in the cool of the day (see “Postharvest”). 

Scheduling: Research in Georgia and Minnesota showed that 1½" (4 cm) 

spring-planted rhizomes required approximately 11 weeks to produce the first 

flower in the field (Welsh and Baldwin 1989). If planted in the field after danger 

of frost, most callas will bloom in July and August; however, later plantings (late 

May, early June) will give good September production (first blooms 60–90 days 

post-planting). 

Lifting and curing: After the foliage declines, the rhizomes should be lifted, 

cleaned, and cured. Rhizomes may be cured in the fall outdoors under shade or 

in a curing shed with good air circulation (see “Propagation,” information on 

division). After curing is complete, roots should be removed and rhizomes 

inspected for Erwinia and stored at approximately 68F (20C). Provide 8–10 weeks 

of storage prior to replanting (although some growers store as little as 6 weeks), 

depending on how completely the foliage has died down at harvest. 


Rhizomes should be planted in ground beds 6–8" (15–20 cm) apart, or 3 in an 

8½" (22 cm) pot (De Hertogh 1996). Well-drained soils are an absolute must for 

reducing the incidence of Erwinia. Pots may remain pot to pot until the final 3– 

5 weeks. Rhizomes can remain in pots for harvesting and curing. After curing 

and when dormancy is broken, rhizomes may be reflowered. 

Irrigation: White callas (Zantedeschia aethiopica) tolerate moist soils. Colored 

callas are less tolerant of wet soils than the white forms, but plants should not be 

allowed to wilt. 

Temperature: Start plants at 60–65F (15–18C) until sprouting. After sprouts 

have appeared, reduce night temperature to 55F (13C) for white callas and 60F 

(15C) for colored forms (De Hertogh 1996). For colored callas, approximately


64/61F (18/16C) day/night is recommended; for white callas, 64/55F (18/13C) 

(De Hertogh 1996). Warm temperatures result in faster flowering but also 

increase the incidence of disease. 

Spacing: Ostensen (2000) did work on spacing of white callas in raised beds. 

The effect of spacing on Zantedeschia aethiopica. Spacing 

36–42" beds, 2 rows per bed. 

Duration of stand 

1 yr. 2 yr. 3 yr. 

Rhizome size (in) z Spacing (in) z 

1 1 ⁄4 6 8 10 

1 1 ⁄2 8 10 12 

1 3 ⁄4 10 12 14 

2 1 ⁄2 12 14 16 

2 1 ⁄4 14 16 18 


Fertilization: A preplant incorporation of a 30-day slow-release fertilizer with 

N and K, but without P, into the media is recommended. Application of CLF at 

100 ppm N and K should follow. 

Scheduling: Callas normally flower 10–13 weeks from planting, but exact time 

depends on cultivar, planting date, duration of storage, and forcing temperature. 

Work by Corr (1988) with Zantedeschia rehmannii showed that the greater the 

time of rhizome storage time at 59F (15C), the less time was required in the 

greenhouse. Three weeks storage resulted in approximately 20 weeks in the 

greenhouse; 12 weeks storage only required 12 weeks in the greenhouse. Total 

time (storage plus greenhouse time) was essentially the same, regardless of storage 

duration. 

Yield: The average yield per rhizome varies greatly between cultivars, but the 

average for rhizomes wider than 2" (5 cm) bred for cut flower production is 5–12 

stems. Yields from new cultivars are in general better than old, but not always. 



healthy plants of Zantedeschia elliottiana when flower buds were visible but 

prior to flower opening. These are guidelines only and should not be considered 

absolute standards. Based on dry weight analysis.


(%) 

N P K Ca Mg 

3.9 0.34 3.9 0.96 0.23 

(ppm) 

Fe Mn B Al Zn 

300 193 13 90 94 


To ensure good color expression, flowers should be cut when the spathes unroll 

and are almost fully open. 

Postharvest 

Fresh: Cut stems should be placed in a conditioning solution for 8–12 hours 

(Tjia 1989). Flowers persist 7–20 days depending on cultivar and environment. 

Flowers of Zantedeschia aethiopica var. childsiana remain unblemished for 10 days 

(Plummer et al. 1990). Other flower problems include stem splitting and rolling. 

A 2–5% sugar pulse may be used. Do not allow the stems to remain in the sugar for 

more than 30 minutes, or various microorganisms will proliferate. Occasionally, 

flowers are sprayed with an antitranspirant if they are to be shipped a long distance, 

although no objective data have shown any benefit of this treatment. 

Storage: Storage of cut stems is not recommended; however, if necessary, stems 

of Zantedeschia aethiopica may be stored wet at 38F (3C) for up to one week (Plummer 

et al. 1990). Colored callas should be stored at 33–35F (1–2C). Lower temperatures 

can result in chilling injury to the flowers. Ship stems dry and, if possible, 

cool. 

Dried: Flowers may be microwaved, but otherwise do not dry well. 

Cultivars 

It is important to purchase cultivars bred for cut flower use; a good deal of breeding 

has been toward dwarf forms for pot plant use, and stem length of these 

may be disappointing. Pot forms often provide higher yield, however, and if stem 

length is of minor consideration, then the list of cultivars can be expanded. 

Breeding programs in the United States and New Zealand have resulted in 

numerous cultivars useful for cut flowers. Along with the evergreen white-flowered 

Zantedeschia aethiopica and its var. childsiana, deciduous hybrids of yellow, 

pink, green, red, and peach are available. Breeding continues for additional 

flower colors, and breeding for Erwinia resistance remains an important challenge 

to the calla breeder. 

‘Black Eye Beauty’ has lemon-yellow flowers with a dark throat. 

‘Black Magic’ bears flowers of clear yellow with a black throat. Yielded 10–15, 

2–3' (60–90 cm) stems/plant in University of Georgia trials; rhizomes persisted 

for 3 years without lifting.


‘Cameo’ produces peach-colored blooms with a dark pink throat on long stems. 

‘Chianti’ was bred for cuts and pot plant use. The rich purple flowers are produced 

among speckled foliage. 

‘Crystal Glow’ has medium-length stems with rose-pink flowers. 

‘Florex Gold’, bred for the cut market, bears golden flowers. 

‘Golden State’s Hybrid Yellow’ is golden-yellow. 

‘Hazel Marie’ bears apricot flowers with a blush of gold. Long stems. 

‘Hot Shot’ has orange flowers with a red blush and long stems. 

‘Lilac Mist’ is a handsome cut form with lilac-purple flowers. 

‘Majestic Red’ produces deep red flowers. 

‘Mango’ has mango-orange flowers. 

‘Neroli’ has apricot-peach flowers on medium-length stems. 

‘Pastel Magic’ bears lemon-yellow blossoms with a clear center. 

‘Pink Persuasion’ produces rose-pink flowers with a dark throat. 

‘Pot of Gold’ has golden flowers with medium-length stems. 

‘Sensation’ bears salmon-apricot flowers on long stems. 

‘Sunrise’ is a cut form whose flowers are yellow inside with a red rim around 

the edges. 

‘Superba’, a selection of Zantedeschia rehmannii, has light pink blooms. 

‘Treasure’ bears deep orange flowers with medium-length stems. 


All aspects of calla culture must be focused on providing environmental factors 

that favor the plant rather than the disease organisms that can limit production. 

Close attention must be paid to temperature and water management. 

Bacterial soft rot (Erwinia) is the most common and insidious disease organism. 

There is always some level of erwinia in a calla crop, visible or not. Caused by 

injury during handling and digging of the rhizome, infection is characterized by 

milky-colored, foul-smelling areas on the rhizome. The rhizome becomes soft at 

the infected areas. Outbreaks are more common in heavy, poorly drained soils. 

“Gentle” handling and proper curing techniques reduce incidence of the disease. 

Keys to reducing infection are temperature management (soil temperature 


logical treatments promote natural soil balances and minimize losses from 

organisms like Erwinia.” 

Black spot (Alternaria) occurs on the flower spathe when conditions are wet 

and humid. Iprodione is effective in suppressing the fungus (Tjia and Funnell 

1986). 

Chalking is a physiological disorder that is most prevalent in Zantedeschia 

aethiopica var. childsiana. During prolonged storage, the rhizomes develop a hard 

chalky exterior that results in poor sprouting and growth. If rhizomes are stored 

properly, chalking is much reduced. 

Thrips and aphids can also be problems; besides being destructive, they are 

vectors for virus. 


“When spraying, use 100 ppm Promalin or 125 ppm ProGibb. When dipping, 

reduce concentration to 75 ppm Promalin or 100 ppm ProGibb. Gibberellic 

acid is much more effective if you have green shoots to absorb the hormone. 

In general, you can expect at least a 300% increase in flowering with GA3 

treatment.” Patrick Zweifel, Oregon Coastal Flowers & Bulbs, Tillamook, Ore. 

Reading 

Armitage, A. M. 1991. Shade affects yield and flower quality of field grown cut 

flower species. HortScience 26:1174–1176. 

Blom, T. J., and W. Brown. 1999. Preplant copper-based compounds reduce 

Erwinia soft rot on calla lilies. HortTechnology 9(1):56–59. 

Corr, B. E. 1988. Factors influencing growth and flowering of Zantedeschia elliottiana 

and Z. rehmannii. Ph.D. diss., Univ. of Minnesota, St. Paul. 

Corr, B. E., and R. E. Widmer. 1991. Paclobutrazol, gibberellic acid, and rhizome 

size affect growth and flowering of Zantedeschia. HortScience 26:133–135. 





Funnell, K. A. 1993. Zantedeschia. In Physiology of Flower Bulbs. A. De Hertogh and 

M. Le Nard, eds. Elsevier Press, Amsterdam. 

Funnell, K. A., B. O. Tjia, C. J. Stanley, D. Cohen, and J. R. Sedcote. 1988. Effect 

of storage temperature, duration, and gibberellic acid on the flowering of 

Zantedeschia elliottiana and Z. ‘Pink Satin’. J. Amer. Soc. Hort. Sci. 113:860–863. 

Kuehny, J. S., Holcomb, G. E., Chang WenChy, and P. C. Branch. 1998. Chemical 

treatments to control Erwinia soft rot of calla rhizomes. HortTechnology 

8(3):353–356. 

Ostensen, T. 2000. Calla Aethiopica Cultural Recommendations. Rev 8/200. Davids 

& Royston Inc, Gardena, Calif. 

Plummer, J. A., T. E. Welsh, and A. M. Armitage. 1990. Stages of flower development 

and post production longevity of potted Zantedeschia aethiopica ‘Childsiana’. 

HortScience 25:675–676.

546 ZINNIA ELEGANS 

Post, K. 1936. Further responses of miscellaneous plants to temperature. Proc. 

Amer. Soc. Hort. Sci. 34:627–629. 

Tjia, B. O. 1989. Zantedeschia. In The Handbook of Flowering. Vol. 6. A. H. Halevy, ed. 


Tjia, B. O., and K. A. Funnell. 1986. Postharvest studies of cut Zantedeschia inflorescences. 

Acta Hortic. 181:451–459. 

Welsh, T. E., and S. Baldwin. 1989. Calla lilies: a New Zealand perspective. In 

Proc. 2nd Natl. Conf. on Specialty Cut Flowers. Athens, Ga. 

Many thanks to Keith Funnell, Tom Lukens, and Eddie Welsh (first edition) and 

Patrick Zweifel (second edition) for reviewing this section. 

Zinnia elegans Asteraceae 

annual Mexico many colors 2–3'/2' (60–90 cm/60 cm) 

Linnaeus did not shy away from commemorating his fellow botanists. Johann 

Gottfried Zinn (1727–1759), a professor of botany at Gottingen, Germany, lived 

a short but productive life, and his legacy plant has been used as a cut flower for 

years. Although zinnias no longer have the appeal of lesser-known, more exotic 

species, they are useful as an inexpensive “cut and come again” filler crop. Their 

flowering season extends from April to October, and zinnias can even be produced 

in the greenhouse as a winter crop. It is worth noting that zinnias still have 

great appeal to those who don’t see a lot of them in the landscape; off-season production 

makes sense in Florida, the Gulf Coast states, and other such locales. 

Propagation 

Always propagated from seed. Most cut flower types are open pollinated, but 

excellent F1 cultivars have been developed. Approximately 1 oz (28 g) of seed 

yields 1000 plants (Nau 1999). Seed germinates in 3–5 days at 80–85F (27–29C), 

5–7 days at 70–75F (21–24C). If seed is direct sown, 0.4 oz per 100' (37 g per 100 

m) may be used (Kieft 1996). 

Growing-on 

Grow at 60–65F (15–18C) nights and 70F (21C) days. Soil should have a pH of 

6.3–6.8. Fertilize with 100 ppm N at each irrigation. Greater concentrations of 

nitrogen should be avoided. Plant out after 5–6 weeks in the final container. 


Photoperiod: Zinnias are quantitative short day plants. That is, they flower 

more rapidly under short days but eventually flower regardless of photoperiod. 

Daylengths of 12 hours or less stimulate flowering (Armitage 1985). Continuous 

LD produces the longest stems but delays flowering by about 3 weeks (this is

ZINNIA ELEGANS 547 

not a problem in the field but should be considered if forcing in the winter); a 

treatment of SD followed by LD produces flowers on the longest stem in the 

shortest time (Healy 1991). From the commercial point of view, however, control 

of photoperiod is seldom practiced. 

Light intensity: Zinnias are high-light plants and flower poorly on stretched 

stems under low winter intensities. 

Temperature: Temperatures below 60F (15C) result in chlorotic foliage and 

delayed flowering. 


Plants produce higher-quality flowers if sequential plantings are used. Transplant 

or sow to the field every 2 weeks for 6 successive plantings. Transplants may 

be planted as soon as the last frost has occurred. Planting in raised beds is highly 

recommended if soils are heavy (e.g., clay). Some growers use transplants for a 

quicker crop time and the immediate benefit of shading out potential weeds. 

Space as close as 6 × 6" (15 × 15 cm) or on 9–12" (23–30 cm) centers. The 

denser the spacing, the taller and less branched the plants will be. While this 

may be positive, the potential for disease is also greater at close spacings. No 

pinching or support is necessary. 

Planting where zinnias are exposed to winds is a useful production technique 

to reduce the incidence of powdery mildew. Of course, high winds mean plants 

can be knocked over. If wind-aided control of disease makes sense, some support 

may be needed. 


Zinnias are seldom grown as cut flowers in the greenhouse; however, if forced in 

the greenhouse, grow at 65/70F (18/21C) night/days. Fertilize at 150–200 ppm 

N using a balanced fertilizer source. Long days, from incandescent lamps, can be 

applied for 2–4 weeks, followed by short days (


Postharvest 

Fresh: Flowers persist 7–10 days in preservative. 

Storage: There is no scientific basis for the rumor that zinnias don’t do well in 

coolers below 45F (7C). Healy (1991) showed that flowers may be stored wet for 

up to 5 days at 36–38F (2–3C); however, since we are talking about zinnias, the 

less time stored at any temperature, the better. 

Cultivars 

Dahlia- and cactus-flowered forms are often used for cut flowers. They are available 

as mixes only. 

Benary’s Giant series was the ASCFG’S 1999 Fresh Cut Flower of the Year. 

Plants grow 3–4' (0.9–1.2 m) tall with flowers 4–5" (10–13 cm) wide. Until January 

1999, this series was known as Giant Dahlia Benary’s Blue Point Strain. 

Color include bright pink, carmine-rose, coral, crimson, deep red, golden-yellow, 

lilac, orange, purple, salmon-rose, scarlet, and white. Excellent disease resistance 

guarantees their continued popularity. 

Burpeeana Giant Mixed produces bushy, erect plants about 2' (60 cm) tall. 

Also available in separate colors of red, white, pink, rose, and orange. 

‘California Giants’ bears flat-petaled flowers on 34" (85 cm) flower stems. 

Varieties include Giants of California Mix, Indian Summer Mix, ‘Isabelina’, 

‘Orange King’, ‘Pastel Giants’, ‘Purity’, ‘Salmon Queen’, and ‘Violet Queen’. 

‘Candy Cane’ produces striped flowers on 28" (70 cm) plants. People really 

notice them, although the streaking is somewhat unreliable. 

‘Cut and Come Again’ is a mix with 24–28" (60–70 cm) stems. 

‘Early Wonder’ bears double flowers that bloom earlier than others. 

‘Envy’ is a green-flowered zinnia that has received mixed responses from both 

growers and buyers. The unique chartreuse color of the 3" (8 cm) wide flowers 

seems to be loved or hated in equal measure. 

Florist Medium Strain Mixture grows to about 2' (60 cm) with medium-sized 

flowers. The mix includes pink, orange, yellow, white, scarlet, rose, and salmon. 

Giant Mammoth Flowered series carries large 4–5" (10–13 cm) flowers on 

30" (75 cm) stems. ‘Canary Bird’ (golden-yellow), ‘Dream’ (orchid-lavender), 

‘Luminosa’ (deep pink), and Gold Medal Mixture are part of this series. 

Indian Summer Mix has yellow, orange, and red flowers on 3–4' (0.9–1.2 m) 

stems. 

Magnificent Mix contains semi-double 4–5" (10–13 cm) dahlia-type flowers 

on 3½' (1.1 m) stems. 

Oklahoma series from Benary was so named because it performed so impressively 

at cut flower trials at Oklahoma State University in Stillwater. Mainly double 

flowers, 1½" (4 cm) wide, are borne on 28–36" (70–90 cm) stems. Colors 

include golden-yellow, pink, scarlet, salmon, white, and a formula mix. 

Profusion series has been extraordinarily well received by the bedding plant 

trade. Plants are tolerant of inclement weather and are among the most disease 

resistant plants in the trade. For cut flowers, their only drawback is height: they 

are seldom more than 15" (38 cm) tall. Colors include white, cherry, and orange.

ZINNIA ELEGANS 549 

‘Ruffles’ is a fine F1 cultivar available in 4 single colors and mixed. 

‘Sombrero’ is a mix of gold and red and single and double flowers on 2' (60 

cm) stems. 

‘State Fair’, a popular, large-flowered, 2–3' (60–90 cm) tall cultivar, is often 

asked for by name. 

Sun series comes in gold, red, and a mix. Large double flowers are borne on 

24–32" (60–80 cm) stems. 

Sunbow series grows to 24–30" (60–75 cm) and comes in a veritable rainbow 

of colors—orange, purple, rose-pink, scarlet, golden-yellow, white, and a mix. 

‘Swirls’ grows to 24" (60 cm) with double, bicolor flowers of rose and white, 

or red and yellow. 

Whirligig series has large semi-cactus flowers; petals end in contrasting colors. 

Yoga is an early-flowering series with large double and semi-double blooms 

with overlapping petals. Grows 2–3' (60–90 cm) tall. 


Zinnias have been evaluated since the inception of the ASCFG’s national trials 


lengths and yields of zinnias submitted for trialing. These data are averages over 



Year of Stem length Stems/ 

Cultivar trial (in) z plant 

Benary’s Giant Mix 1994 18 12 

Giant Dahlia y Crimson Monarch 1995 17 29 

Giant Dahlia Dream 1996 18 11 

Giant Dahlia Eldorado 1995 15 21 

Giant Dahlia Exquisite 1996 18 11 

Giant Dahlia Golden State 1996 17 8 

Giant Dahlia Hallo 1995 16 27 

Giant Dahlia Polar Bear 1996 16 9 

Giant Dahlia Rose 1995 18 33 

Giant Dahlia Scarlet Flame 1995 17 29 

Oklahoma Golden Yellow 1996 12 12 

Oklahoma Mix 1997 9 17 

Oklahoma Pink 1996 13 18 

Oklahoma Salmon 1996 15 17 

Oklahoma Scarlet 1996 14 14 

Oklahoma White 1996 13 13 


y = in January 1999 the entire Giant Dahlia Benary’s Blue Point Strain was 

renamed Benary’s Giant series



Zinnia haageana ‘Persian Carpet’ produces double and semi-double flowers in 

orange, gold, maroon, and burgundy, some with creamy-tipped petals. Less 

prone to leaf diseases. Short but productive. ‘Old Mexico’ has overlapping 

pointed copper and gold petals on 18" (45 cm) plants. 

Zinnia peruviana (syn. Z. pauciflora) ‘Bonita’ produces smaller flowers than Z. 

elegans, in more muted earth tones. Plants are only 1½–2' (45–60 cm) tall. 


Numerous leaf spot organisms occur, including Alternaria, Cercospora, and Erysiphe, 

the causal agent of powdery mildew. Alternaria can be a very serious problem 

under stressful environmental conditions, like drought or overwatering. Cull 

infected plants. Powdery mildew is a greater problem when warm days are interwoven 

with cool, damp nights. Application of general-purpose foliar fungicides 

at 10-day to 2-week intervals helps control the diseases. 

Sclerotinia sclerotiorum, a soil fungus, is highly lethal to zinnias, particularly 

those under environmental stress. In the South, it is nearly always involved in 

root and foliar problems. This is reduced if more than one crop is planted. Crops 

planted late in the season are less susceptible. 

“Zinnia meltdown” is a term coined by a number of growers to describe the 

rapid (within 24 hours) deterioration of perfectly good-looking flowers after 

being cut. Stems turn brown and mushy. The problem may be caused by a bacterial 

infection, although the application of a copper-based bactericide has had 

only limited success. A floral preservative to reduce pH also appears to help, but 

if the bacteria is present in sufficient numbers, problems may still occur. Some 

cultivars appear far more susceptible than others. Zinnias are sensitive to boron, 

and if high boron is present in the water, similar symptoms may appear. 

Insects that feed on zinnias include grasshoppers, cucumber beetles, blister 

beetles, Japanese beetles, mites, and aphids. Every critter loves a zinnia. Nematodes 

cause angular spots on the foliage and can be quite destructive. 


“After trialing lots of big and small zinnias, I grow only ‘Blue Point’.” Bob Wollam, 

Wollam Gardens, Jeffersonton, Va. 

“It is my experience that [zinnias] look better left out at 70F heat for 2 days 

than in the cooler at 40F.” Ralph Thurston, Bindweed Farm, Blackfoot, Idaho. 

“I think well-grown white flowers are always marketable. It seems we had 

problems with these holding up. . . . I really think people who live in drier climates 

have an easier time raising quality zinnias, than we in the rain-soaked 

Northwest. Especially white and light-colored zinnias seem prone to getting diseases 

that cause them to get mushy after cutting. The other thing about postharvest 

here is that sometimes they last and sometimes they don’t, but I’ve never 

gotten them to last more than a week.” Janet Foss, J. Foss Garden Flowers, 

Everett, Wash.

Reading 

Armitage, A. M. 1985. Zinnia elegans and Z. angustifolia. In The Handbook of Flowering. 


Dharmalingam, S., S. Pitchay, J. L. Gibson, P. V. Nelson, C. R. Campbell, and B. 

Whipker. 2000. Nutrient deficiencies of zinnia. GMPRO 20(7):64–66, 68–78. 


Healy, W. 1991. Cut flowers: cut zinnias. Georgia Commercial Flower Growers Assoc. 

Newsletter 1(5):8–9. 


Netherlands. 


Many thanks to Vicki Stamback for reviewing this section. 

ZINNIA ELEGANS 551


REFERENCES 

References for specific crops are found in the appropriate crop entry; however, 

additional, more “global” references were used during the writing of both the 

first and the second editions of this book. Most are available in reference libraries, 

and some are still sold through various vendors. All are highly recommended. 

Books 

Armitage, Allan M. 1997. Herbaceous Perennial Plants: A Treatise on Their Identification, 

Culture, and Garden Attributes. 2nd ed. Stipes Publishing, Champaign, Ill. 

A good, readable book on perennials. Morphological and taxonomic descriptions, 

uses, and propagation of the common and not-so-common species are 

covered here. References are occasionally made to cut flower uses, but it is mainly 

a book for general perennial plant reference. 

Armitage, Allan M. 2000. Armitage’s Manual of Annuals, Biennials, and Half-Hardy 

Perennials. Timber Press, Portland, Ore. 

The best in-depth book on annuals and also covers biennials and some halfhardy 

perennials. The companion to Herbaceous Perennial Plants and formatted 

similarly. An excellent reference. 

Bloom, Alan. 1956. Hardy Perennials. Faber and Faber, London. 

The only reason for recommending this out-of-print book is the chapter on 

perennials for cutting (chapter 11). Bloom is best known for his nursery, Blooms 

of Bressingham, which specializes in garden perennials. He provides insightful 

comments on the use of perennials for cut flowers. His experiences in the early 

1940s with selling market flowers provide much food for thought—we can see 

how far we have progressed, and yet how similar the problems that beset him are 

to those we still face. He speaks firsthand of “the hazards and disappointments 

of market growing” and has “every sympathy for growers and understands their 

problems—including the need for variety.” 

Bullivant, Elizabeth. 1989. Dried Fresh Flowers from Your Garden. Pelham Books/ 

Stephen Greene Press, London. 

553

554 REFERENCES 

A delightful book written by a grande dame of English gardening. She is certainly 

a fountain of knowledge about drying flowers. Nothing is safe from her 

zeal for drying, and she includes a wealth of information on annuals, perennials, 

berries, foliage, and even vegetables. Not written with the commercial, largevolume 

dryer in mind, this book nevertheless provides some excellent ideas and 

concepts. A great read. 

Byczynski, Lynn. 1997. The Flower Farmer: An Organic Grower’s Guide to Growing 

and Selling Cut Flowers. Chelsea Green Publishing Company, White River Junction, 

Vt. 

Drawing on her own experience as a cut flower grower in northeast Kansas, 

Lynn offers valuable information on production and marketing for small-scale 

farmers. Also features profiles of successful growers across the country. Always 

excellent information within. 



The bible of bulb manuals—each new edition is expanded to include relevant 

information on cut flower crops for greenhouse and field production. While 

greenhouse forcing of tulips, daffodils, and hyacinths still holds center stage, 

the sections on outdoor cut flowers, and diseases and pests of bulb species are 

updated and more useful than ever in this edition of the guide. A must for anyone 

even contemplating the growing of bulb crops. 

Dirr, Michael A. 1998. Manual of Woody Landscape Plants: Their Identification, Ornamental 

Characteristics, Culture, Propagation, and Uses. 5th ed. Stipes Publishing, 


If Gus De Hertogh’s manual is the bible for bulbs, this is the bible for woody 

plants. The manual’s focus is the identification and use of woody species in the 

landscape; however, plant habit, propagation methods, and the most up-to-date 

descriptions of cultivars of any publication are contained within. A truly enlightening 

book and an enjoyable read as well. 

Dole, John M., and Harold F. Wilkins. 1999. Floriculture: Principles and Species. 

Prentice Hall, Upper Saddle River, N.J. 

A comprehensive text mainly designed for greenhouse production. Contains 

useful charts for the propagation of crops and pertinent information on many 

cut flower crops. Highly recommended as a text for references in floriculture. 

Gill, Stanton, David L. Clement, and Ethel Dutky. 1999. Pests and Diseases of Herbaceous 

Perennials: The Biological Approach. Ball Publishing, Batavia, Ill. 

A valuable reference for anyone producing perennial plants. The authors provide 

comprehensive coverage of common pest and diseases with emphasis on 

integrated pest management.

REFERENCES 555 

Hyacinthus orientalis 

‘Woodstock’ 

Kieft, Cornelius. 1996. Kieft Grower’s Manual. 2nd ed. Kieft Bloemzaden, Venhuizen, 

The Netherlands. 

Available through the Association of Specialty Cut Flower Growers (see 

“Newsletters and Periodicals”). Kieft was the first European representative of 

the ASCFG. 

Nau, Jim. 1999. Ball Culture Guide: The Encyclopedia of Seed Germination. 3rd ed. 

Ball Publishing, Batavia, Ill. 

An excellent guide to the seed germination of many annual and perennial 

species. Includes the number of seeds necessary to raise 1000 plants or the num-


ber of seeds needed for 1000 square feet of field production, along with other tidbits 

about many cut flower species. Handy and informative. 

Nell, Terril A., and Michael S. Reid. 2000. Flower and Plant Care: the 21st-Century 

Approach. Society of American Florists, Alexandria, Va. 

A must—the best manual for postharvest information on cut flowers. It covers 

dozens of crops and offers easy-to-read postharvest solutions. Highly recommended. 

Nowak, Joanna, and Ryszard M. Rudnicki. 1990. Postharvest Handling and Storage 

of Cut Flowers, Florist Greens, and Potted Plants. Timber Press, Portland, Ore. 

An in-depth reference on postharvest information on a wealth of cut flower 

crops, now unfortunately out of print. Written mainly for the scientist, the book 

brings together much of the literature on postharvest research from the early 

1900s through the mid 1980s. A excellent resource for answering questions concerning 

stage of harvest, postharvest storage techniques, and floral preservatives. 

Perry, Leonard. 1998. Herbaceous Perennials Production: A Guide from Propagation to 

Marketing. Northeast Regional Agricultural Engineering Service, Ithaca, N.Y. 

Sections on starting a perennials business, building production facilities, and 

planning production systems and schedules are complemented by easy-to-use 

appendices on propagation, germination, pests and diseases, and conversions 

and calculations. Probably the best book on perennial production. 

Pirone, P. P. 1989. Diseases and Pests of Ornamental Plants. 5th ed. Ronald Press, 

New York. 

All the diseases and pests you ever wanted to know about. General sections on 

common diseases caused by bacteria, fungi, and viruses as well as common insect 

pests are covered. Genera are presented alphabetically, and information concerning 

problems and their control for each genus and species are provided. A 

reference book of the highest caliber. 

Sacalis, J. N. 1989. Fresh (Cut) Flowers for Designs: Postproduction Guide. D. C. Kiplinger 

Chair, Ohio State Univ., Columbus. 

Sacalis assembled much of the known literature in the postharvest and handling 

of cut flowers; he treats each species individually and completely. A useful 

guide for the major crops, it was republished in 1993 by Ball Publishing Co., 

Geneva, Ill., as Cut Flowers: Prolonging Freshness. 

Stevens, Alan. 1997. Field Grown Cut Flowers: A Practical Guide and Sourcebook. 

Avatar’s World, Edgerton, Wis. 

New growers especially will welcome the information provided on the production 

of fresh and dried cut flowers. Details on production systems and labor 

management are particularly valuable.

REFERENCES 557 

Vaughan, Mary Jane. 1988. The Complete Book of Cut Flower Care. Timber Press, 

Portland, Ore. 

A marvelous little book, specifically aimed at cut flower care for retailers and 

full of tips concerning vase life, storage when necessary, optimum stage of maturity, 

and when flowers are usually available to the florist. A good section on flowers 

useful for drying is also included. Growers and wholesalers would do well to 

track down a copy of this book, now unfortunately out of print. 

Book Set 

The Handbook of Flowering (CRC Press, Boca Raton, Fla.), edited by Abraham H. 

Halevy, was published from 1985 through 1989 in 6 volumes and 2 supplements. 

It is by far the most comprehensive series of book dealing with the environmental 

and physiological aspects of flowering. Halevy brought together 

dozens of scientists to provide scientific data dealing with all aspects of flowering. 

Heavy reading but excellent information for those who want to know more 

about the crops being produced. Available through university libraries. 

Newsletters and Periodicals 

The Cut Flower Quarterly, the newsletter of the Association of Specialty Cut 

Flower Growers, is an invaluable (and often the only) reference that provides a 

continuous flow of new information on the culture and marketing of specialty 

flowers. Published quarterly, it provides literature updates, regional synopses, 

and articles of national interest by leading growers and researchers. Available 

through membership to ASCFG, MPO Box 268, Oberlin, OH 44074-0268. 

FloraCulture International is an international journal published for American 

growers by GrowerTalks. It concentrates on European floriculture; information 

on cut flowers is frequently provided. 

Greenhouse Grower is a monthly publication for the greenhouse and allied 

trades. Coverage of cut flower features and articles is excellent and includes new 

cultivars as well as analysis of events occurring in the cut flower business. Part of 

the Meister Publication Company. 

GMPRO (Greenhouse Management & Production) is part of the Branch- 

Smith Publishing group, which also includes NMPRO (Nursery Management & 

Production). GMPRO covers field production as well as greenhouse and is generous 

in its coverage of cut flower growers. 

Miscellaneous 

So much information can be found on the web, but it is almost impossible for us 

to list anything that won’t change in the next few weeks. However, searching for 

specific crops can yield a great deal of information, some more valuable than 

others. Karen Gast of Kansas State University has placed some of her research 

work on cut flowers at www.oznet.ksu.edu/library, under “Report of Progress.” 

We used this information and found it most useful.


Excellent catalogs are put out by many seed firms, among them Ball Seed 

Company/PanAmerican Seed, Ernst Benary of America, Germania Seed Company, 

Gloeckner Seed Co., Harris Seeds, Jelitto Perennial Seed, Johnny’s Selected 

Seeds, and Modena Seed Company. 

Many companies produce up-to-date CDs that have excellent photos and 

useful information about their products. These are inexpensive (often free) and 

highly recommended. Check with the appropriate representative in your area: 

Armitage, Allan M. 2002. Armitage’s Photo-Library of Herbaceous Plants. Horticopia, 

Chicago, Ill. 

A large reference containing well over 7000 downloadable photos. The photos 

include cut flower species and cultivars, but it is not designed for cut flower 

growers only. 

Dirr, Michael A. 1996. Dirr’s Photo-Library of Woody Plants. PlantAmerica, New 

York. 

Another large photo reference—7600 images of approximately 3000 different 

woody plants.

APPENDIX I. 

STAGE OF HARVEST 

The following list is a summary of recommendations for the optimal stage of 

harvest for fresh flower use. In general, cut stems when flowers are as tight as 

possible and place in a hydrating solution immediately. Information is derived 

from references (see “Reading” at entries throughout the book) and from field 

observations. 

Achillea Flowers should not be harvested until pollen is visible on 

the inflorescence. 

Aconitum Inflorescences should be harvested when 1–3 basal flowers 

are open. 

Agastache Harvest when the inflorescence is about ⅔ open. 

Ageratum Harvest when flowers are just opening. 

Agrostemma Stems should be harvested when 1 or 2 flowers are open on 

the inflorescence. 

Allium Harvest most species when ½ the flowers are open. Flowers 

of Allium sphaerocephalon may be harvested as early as when ¼ 

of the flowers are open. 

Alstroemeria Pull stems when the first flowers are fully colored and the 

majority are showing color. 

Amaranthus Cut when at least ¾ of the flowers on the inflorescence are 

open. If producing dried flowers, allow the flowers of all 

species to grow until seed has begun to set and the flowers 

feel firm to the touch. 

Ammi Harvest when flower heads are approximately 80% open. 

Anemone Harvest when the sepals have started to separate from the 

center but are not fully open. 

Antirrhinum Cut when ⅓ to ½ of the flowers are open. For long-distance 

shipping, harvest when ⅓ of the flowers are open. 

Artemisia Stems are cut when they are fresh. Flowers are unimportant. 

Asclepias Harvest when ½ to ⅔ of the flowers are open, flowers do not 

open well once stems are cut. 

Aster Cut the stems when 2–4 flowers in the inflorescence have 

opened. 

559

560 STAGE OF HARVEST 

Ageratum houstonianum 

‘Blue Horizon’ 

Astilbe Inflorescences should be harvested when ½ to ¾ of the 

flowers are open. The uppermost buds should be swollen 

and showing color. 

Astrantia Harvest when the uppermost flowers are open. 

Baptisia Flowers are harvested when approximately ⅓ of the flowers 

on the inflorescence are open. 

Belamcanda Harvest fruit when the covering of the fruit begins to shed. 

Fruit should be black before harvesting. 

Buddleia Harvest when ½ the flowers on the inflorescence are open 

but before the open flowers have started to fade. 

Bupleurum Cut when flowers are almost all open. 

Callicarpa Cut stems when the basal fruit clusters are fully colored and 

the terminal fruits are still green. 

Callistephus Harvest when outside ray florets begin to open. 

Campanula Harvest when 1 or 2 flowers of the inflorescence are open. 

Carthamus Cut stems when the majority of buds have begun to open 

and petals are clearly visible. 

Caryopteris Stems should be harvested when buds show color or when 

the first whorl of flowers is open. 

Celosia Flowers should be fully developed on crested forms and 

90–100% developed in the plumose form. 

Centaurea For annuals, harvest when flowers are ¼ to ½ open. In the 

case of multiple flowered stems (i.e., sprays), the uppermost 

flower may be ¾ open. For Centaurea macrocephala, harvest 

when flowers are ½ to ¾ open. 

Centranthus Harvest when the first flowers in the inflorescence are fully 

open. 

Cirsium Harvest when the flowers are open.

STAGE OF HARVEST 561 

Clarkia Harvest when the first flowers on the stem are open. 

Consolida Allow 2–5 basal flowers to open or up to ⅓ of the flowers on 

the stem. 

Coreopsis Harvest when the flowers are fully open. 

Cornus To harvest stems, cut after leaves have dropped and before 

new foliage appears. Harvest flowers when the bracts are 

beginning to open but prior to pollen formation in the 

flower. 

Cosmos Harvest when petals on first flower are just opening, but 

have not yet flattened out. 

Crocosmia The first few flower buds should be showing color but need 

not be open. 

Dahlia Harvest when the flowers are ¾ to fully open but before the 

outer petals begin to decline. 

Delphinium Harvest when ⅓ to ¼ of the flowers on the stem are open. 

Dianthus Harvest when 10–20% of the flowers in the inflorescence are 

open. 

Digitalis Harvest when 2 or 3 lower flowers are beginning to open or 

as late as when ½ the flowers are open. 

Echinacea Harvest when petals are expanding. If used as a disk flower 

only, allow additional time on the plant to color disk, then 

remove petals. 

Echinops Harvest flowers when ½ to ¾ of the globe has turned blue. 

Emilia Harvest stems when the first flower is fully open. 

Eremurus Stems are harvested when about half the flowers are open. 

Eryngium Flowers should be harvested when the entire flower head, 

including bracts, turns blue. 

Eupatorium Cut when the flowers are almost fully open. 

Euphorbia Cut stems when bracts are fully colored but before the 

flowers are open. 

Eustoma Harvest when one flower in the inflorescence is fully colored. 

Forsythia For forcing, harvest when buds are tight. 

Freesia Harvest when the first flower is beginning to open and at 

least 2 additional flowers are showing color. 

Gentiana Harvest when flowers are in colored bud stage or when 1 or 

2 are open. 

Gladiolus Cut when 1–5 flowers on the spike are showing color. 

Gomphrena Harvest when flowers are in color but before fully open. 

Gypsophila For the fresh flower market, stems should be cut with 

60–70% of the flowers open. For drying, 80–90% of the 

flowers should be open. 

Helianthus Cut stems when the flowers are almost completely open. 

Helichrysum Cut flowers when bracts are unfolding and centers are 

visible. Always harvest before flowers are fully open. 

Helleborus For fresh flowers, cut when stamens become visible. For 

drying, flowers can be cut any time but are also useful later


when the follicles (seed capsules) become visible in the 

inside of the flower. 

Hydrangea Stems should be harvested when ½ the flowers on the 

panicle are open. 

Hypericum Harvest stems when fruit is fully colored. 

Ilex Branches should be harvested before the fruit reaches 

maturity. 

Iris Cut all Dutch iris except ‘Blue Ribbon’ (‘Prof Blaauw’) when 

the flower has fully emerged from the sheath (“pencil” 

stage). ‘Blue Ribbon’ should be cut when the falls begin to 

open. All other iris species are cut in tight bud stage. 

Lathyrus Harvest sweet peas when 2 or 3 flowers start to show color 

and stems are about 12" (30 cm) long. Cut the stems or 

snap the stem with the fingers near the base. 

Lavatera Cut when the flowers are uncurling or when they have just 

begun to open. 

Liatris Harvest when 3 or 4 flowers have opened. 

Lilium Cut when the first flower is fully colored, but not yet open. 

Limonium Harvest when 80% of the flower head has opened. 

Lobelia Cut the stems when the bottom ⅓ of the flower is open. 

Lunaria Harvest when the pods are fully developed. 

Lysimachia Cut when flowers in the inflorescence are ⅓ to ½ open. 

Matthiola Stems should be harvested when ½ the flowers in the 

inflorescences are open. 

Moluccella Cut when flowers are ½ open and green. 

Monarda Harvest when the flowers are almost entirely open. 

Narcissus Single, large flowers should be harvested when closed but 

with color showing (goose-neck stage) and at a 90–120° 

angle from the stem. Harvest double-flowered cultivars 

when the flowers are just beginning to open. 

Nerine Harvest when the first flower is just about to open. 

Nigella Harvest when the pods are turning purple-bronze. 

Oreganum Harvest when flowers are purple and ⅓ are open. 

Ornithogalum Harvest when the first flower is open if flowers are to be 

shipped long distances; approximately ¼ of the flowers may 

be open for local sales. 

Oxypetalum Harvest when approximately 6 cymes are present. The first 1 

or 2 should be open, the last showing color. 

Paeonia As a general rule, flowers should be harvested when the first 

true color appears on top of the tight bud. Double-flowered 

types should be further developed than single forms and red 

cultivars should be more developed than whites. 

Papaver Harvest flowers at colored bud stage (fuzzy sheaths are 

splitting open and color is showing). Some flowers fail to 

open if cut too early. 

Phlox Harvest when ½ the flowers are open on the inflorescence.

Nerine bowdenii


Physalis Harvest when the fruit is fully colored. 

Physostegia Flowers may be cut when the spikes are fully elongated but 

before individual flowers are open. 

Platycodon Harvest when 2 or 3 flowers are open on the flower stem. 

Polianthes Harvest when 2–4 flowers are open and others are showing 

color. 

Ranunculus Cut flowers when buds show color and are about to open. 

Rudbeckia Harvest when the flowers are fully open. 

Salix Harvest leafless stems at peak of color. 

Salvia Harvest when 3 or 4 basal flowers are open. For Salvia 

leucantha, the white petals (corolla) should have emerged 

from the blue sepals (calyx) on 3 or 4 basal flowers. 

Scabiosa For the perennial Scabiosa caucasica, flowers may be harvested 

as soon as flower color is visible. The annual S. atropurpurea 

may be harvested when the flower is almost fully open. 

Solidago Harvest inflorescence when approximately ½ the flowers are 

open. 

×Solidaster Harvest when ⅓ of the flowers are open. 

Stachys For flowers, cut when the inflorescence is ½ open. 

Tagetes Harvest when flowers are fully open. 

Thalictrum Flowers should be harvested when most of the flowers are 

open. 

Trachelium Harvest the stem when ¼ to ⅓ of the flowers are open. 

Triteleia Harvest when 4–6 flowers are open. 

Tulipa Harvest flowers when ½ to ¾ of the flower is colored. 

Verbena Harvest when most of the flowers are open. 

Veronica Cut when approximately ½ the flowers on the inflorescence 

are open. 

Veronicastrum Remove terminal flower and cut when the lateral flowers are 

approximately ⅓ open. 

Zantedeschia Flowers should be cut when the spathes unroll and are 

almost fully open. 

Zinnia Harvest when flowers are fully mature.

APPENDIX II. 

ADDITIONAL PLANTS SUITABLE FOR 

CUT FLOWER PRODUCTION 

Over the years working with cut flowers and the people who grow them, it has 

become increasingly obvious that almost any plant can and will be grown for 

cut flower use. Forget the old notion that flower stems must be a certain length 

or that flowers must have a certain shape, color, or fragrance. Also, we have seen 

growers growing “niche” assortments; for example, local native plant material 

(Penstemon, Solidago, Liatris) are planted and promoted. Anything goes, as long as 

there is demand. 

In addition to the plants discussed in detail in the book, many other species 

and cultivars are used as cut flowers, either fresh or dried. From the commercial 

viewpoint, sufficient production must be possible under local conditions, and 

vase life of fresh flowers should be at least 7 days if shipped any distance. However, 

sometimes only a day or two of beauty is needed if flowers are being used for 

special events. 

We have seen all these plants either in the field, in the greenhouse, in the market, 

or in an arrangement. Key to the list that follows: Su = full sun, Ps = partial 

shade, F = fresh flowers, D = dried flowers, Fo = foliage, Fr = fruit, St = stem. 

Exposure refers to plants grown in the field. 

Annuals 

Species Common name Exposure Use 

Alcea spp. hollyhock Su F 

Ammobium alatum winged everlasting Su,Ps D 

Anethum graveolens flowering dill Su F 

Arctotis spp. Cape daisy Su F 

Argyranthemum frutescens marguerite daisy Su F 

Atriplex hortensis orache Su F 

Brassica oleracea ornamental kale Su F 

Bupleurum griffithii bupleurum Su,Ps F,D 

Calendula officinalis calendula Su,Ps F 

Capsicum annuum ornamental pepper Su D,Fr 

565

566 ADDITIONAL PLANTS SUITABLE FOR CUT FLOWER PRODUCTION 


[Annuals] 

Chenopodium quinoa goosefoot Su D 

Chrysanthemum segetum corn marigold Su F 

Craspedia globosa golden drumstick Su F,D 

Cynara cardunculus cardoon Su,Ps F,D 

Dianthus chinensis China pink Su F 

Fibigia clypeata paper pumpkin seed Su D,Fr 

fruit (ornamental) cotton, okra, pepper, Su F,D 

tomato, etc. 

Gerbera jamesonii gerbera daisy Su F 

Helipterum manglesii Swan River everlasting Su D 

Helipterum roseum sunray everlasting Su D 

herbs sage, rosemary, thyme, Su F,D 

etc. 

Iberis amara rocket candytuft Su,Ps F,D 

Jasione perennis shepherd’s scabious Su,Ps F,Fo 

Mentha spp. mint Su F,D 

Moluccella laevis bells-of-Ireland Su,Ps F,D 

Nicandra physaloides shoo-fly Su D 

Reseda odorata mignonette Su,Ps F 

Rhodanthe manglesii rhodanthe Su D 

Tagetes erecta marigold Su F 

Tithonia rotundifolia Mexican sunflower Su F 

Trachymene (Didiscus) blue lace flower Su,Ps F 

Vaccaria pyramidata rose cockle Su,Ps F 

Xeranthemum annuum immortelle Su D 

Zea mays ornamental corn Su D 

Perennials 

Agapanthus spp. blue African lily Su F 

Anaphalis margaritacea pearly everlasting Su,Ps F,D 

Anigozanthos spp. kangaroo paw Su F 

Aquilegia ×hybrida columbine Ps F 

Armeria pseudoarmeria giant sea pink Su F,D 

Belamcanda spp. blackberry lily Su F,Fr 

Carlina acaulis silver thistle Su F,D 

Catananche caerulea cupid’s dart Su,Ps F,D 

Cephalaria gigantea giant scabious Su F 

Chasmanthium latifolium sea oats Su F,D 

Chelone obliqua turtlehead Su F 

Chrysanthemum parthenium feverfew Su,Ps F,D 

Chrysanthemum ×superbum shasta daisy Su F

Dicentra spectabilis bleeding heart Ps F 

Dodecatheon meadia shooting star Ps F 

Doronicum plantagineum leopard’s bane Su F 

Eupatorium purpureum joe-pye weed Su F 

Filipendula rubra queen of the prairie Su F 

Gaillardia ×grandiflora blanket flower Su F 

Gaura lindheimeri gaura Su F 

Gentiana asclepiadea gentian Su,Ps F 

Helenium autumnale autumn sunspray Su F,D 

Helianthus angustifolius swamp sunflower Su F,D 

Heliopsis helianthoides heliopsis Su F,D 

Heuchera sanguinea coral bells Ps F 

Kniphofia spp. red hot poker Su F 

Lavandula spp. lavender Su F,D 

Lupinus spp. lupine Ps,Su F 

Monarda didyma bee balm Su,Ps F 

Penstemon spp. beardtongue Su F 

Perovskia atriplicifolia Russian sage Su F,D 

Polygonatum odoratum solomon’s seal Ps F 

‘Variegatum’ 

Pontederia cordata pickerel weed Su F 

Primula vialii cone primrose Ps F 

Rubus spp. blackberry Su F,D 

Salvia patens gentian sage Su F 

Sedum ‘Autumn Joy’ stonecrop Su F 

Sidalcea malviflora checkerbloom Su,Ps F 

Stachys spp. stachys Ps Fo,F,D 

Typha spp. cattail Su F 

Verbascum chaixii mullein Su,Ps F 

Viola odorata sweet violet Ps F 

Bulbs 

ADDITIONAL PLANTS SUITABLE FOR CUT FLOWER PRODUCTION 567 


Arum italicum ‘Pictum’ arum lily Ps F,Fo,Fr 

Caladium bicolor caladium Ps F,Fo 

Convallaria spp. lily-of-the-valley Ps F,D 

Curcuma spp. hidden lily Su F 

Hippeastrum spp. amaryllis Su F 

Ixia spp. ixia Su F 

Lycoris spp. resurrection lily Su F 

Muscari armeniacum grape hyacinth Su F 

Oxalis spp. oxalis Su,Ps F 

Vallota spp. Scarborough lily Su F



Woodies 

Amorpha canescens amorpha Su F 

Aronia arbutifolia red chokeberry Su Fr 

Aucuba japonica aucuba S,Ps Fo 

Buxus spp. boxwood Su Fo 

Calluna vulgaris heather Su F,D 

Calycanthus floridus sweetshrub Su F 

Camellia sasanqua camellia S F,Fo 

Celastrus spp. bittersweet Su Fr 

Chamelaucium uncinatum Geraldton waxflower Su F 

Chimonanthus praecox fragrant wintersweet Su F,D 

Chionanthus retusus grancy gray-beard Su Fo,F 

Clethra alnifolia summersweet Ps F 

Corylopsis spp. winterhazel Su,Ps F 

Corylus avellana ‘Contorta’ Harry Lauder’s Su St 

walking stick 

Cotinus coggygria smokebush Su F,Fo 

Cytisus spp. broom Su F 

Danae racemosa Alexandrian-laurel Ps Fo 

Daphne spp. daphne Ps,Su F,Fo 

Deutzia spp. deutzia Ps,Su F 

Erica spp. heath Su F,D 

Eucalyptus spp. silver dollar tree Su F,D 

Euonymus alatus winged euonymus Su St,Fo 

×Fatshedera lizei fatshedera Ps Fo 

Prunus sargentii

ADDITIONAL PLANTS SUITABLE FOR CUT FLOWER PRODUCTION 569 

Syringa vulgaris 


Forsythia spp. forsythia Su F 

Gaultheria shallon lemonleaf, salal Ps F 

Hamamelis ×intermedia witch hazel Su F 

Itea virginica Virginia sweetspire Ps,Su F,Fo 

Jasminum mesnyi primrose jasmine Su F 

Kalmia latifolia mountain laurel Ps F 

Kerria japonica kerria Su F 

Koelreuteria bipinnata goldenraintree Su Fr 

Lonicera fragrantissima winter honeysuckle Su F 

Magnolia grandiflora southern magnolia Su F,Fo 

Malus spp. crabapple Su F,Fr 

Michelia figo banana shrub Su F



[Woodies] 

Morus australis ‘Unryu’ contorted mulberry Su St 

Myrica spp. bayberry, myrtle Su,Ps Fo,Fr 

Nandina domestica heavenly bamboo Su F,Fo 

Pieris japonica pieris Ps F 

Poncirus trifoliata hardy-orange Su St 

Prunus spp. apricot, cherry, peach, Su F 

plum 

Rosa spp. rose Su F,Fr 

Ruscus spp. butcher’s broom Su,Ps F 

Sarcococca hookeriana sweetbox Su F,Fo 

Skimmia spp. skimmia Su F,Fr 

Spiraea spp. spirea Su F 

Symphoricarpos albus snowberry Su F,Fr 

Syringa spp. lilac Su F,D 

Ulmus alata winged elm Su St 

Viburnum spp. viburnum Su,Ps F,D 

Vitex agnus-castus chaste tree Su F 

Viburnum carlesii

APPENDIX III. 

USEFUL CONVERSIONS 

To convert inches to cm: multiply inches by 2.54. 

Example: stems that are 40" long are roughly 100 cm, or 40 × 2.54. 

To convert ft 2 to m 2 : multiply ft 2 by 0.09. 

Example: an area of 500 ft 2 is equivalent to 45 m 2 . 

To convert spacing in inches to spacing in plants/ft 2 : multiply spacing in inches, 

then divide product into 144. 

Example (spacing of 9 × 9"): 144/9 × 9 = 1.77 plants/ft 2 , or 177 plants/100 ft 2 . 

Example (spacing of 1 × 2'): 144/12 × 24 = 0.5 plants ft 2 , or 50 plants/100 ft 2 

To convert plants/ft 2 to plants/m 2 : multiply plants/ft 2 by 10.76. 

Example (spacing of 1.77 plants/ft 2 ): 1.77 × 10.76 = 19.04 plants/m 2 , or 1904 

plants/100 m 2 . 

Example (spacing of 0.5 plants/ft 2 ): 0.5 × 10.76 = 5.38 plants/m 2 , or 538 

plants/100 m 2 . 

To convert acres to hectares: divide acres by 2.47. 

Example: 10 acres = 4.08 hectares. 

To convert plants/acre to plants/hectare: multiply plants by 2.47. 

Example: 30,000 plants/acre = 74,100 plants/hectare. 

To convert ounces of seed/100 ft 2 to grams of seed/100 m: multiply ounces of seed 

by 93.5. 

Example: 0.6 oz/100 ft 2 = 56 g/100m 2 . 

571

U.S.D.A. HARDINESS MAP

INDEX OF BOTANICAL NAMES 

Achillea 25, 37, 559 

ageratum 51 

clypeolata 37 

filipendulina 37, 40, 49, 51 

millefolium 37, 42, 48, 49 

ptarmica 37, 49 

sibirica 51 

taygetea 48 

Acidanthera bicolor 294 

Aconitum 25, 52, 559 

×arendsii 55 

×cammarum 55 

carmichaelii 55 

henryi 55, 56 

lamarckii 56 

napellus 52, 55 

orientale 56 

variegatum 55 

Agapanthus 25, 566 

Agastache 57, 559 

auriantica 60 

barberi 60 

cana 59, 60 

coccinea 60 

foeniculum 57, 59 

mexicana 60 

rugosa 59 

rupestris 59, 60 

Ageratum 60, 559 

houstonianum 60, 560 

Agrostemma 65, 559 

githago 65 

Alcea 565 

Alchemilla 25 

Allium 25, 68, 559 

aflatunense 69, 71, 75 

atropurpureum 76 

azureum 76 

caeruleum 69, 76 

cowanii 69 

christophii 69, 76 

giganteum 69, 71, 76 

hirtifolium 76 

jesdianum 69, 76 

macleanii 76 

moly 69 

multibulbosum 76 

nigrum 69, 76 

roseum 69 

schubertii 69, 76 

siculum 76 

sphaerocephalon 69, 73 

stipitatum 76 

thunbergii 76 

triquetrum 69, 76 

Alstroemeria 25, 78, 289, 559 

aurantiaca 82 

aurea 78 

hybrids 82 

ligtu 78, 82 

magnifica 82 

pelegrina 78, 82 

psittacina 82 

pulchella 82 

pulchra 78 

violacea 78 

Amaranthus 83, 559 

caudatus 83 

cruentus 86 

erythrostachys 87 

hybridus 87 

hypochondriacus 87 

573

574 INDEX OF BOTANICAL NAMES 

[Amaranthus] 

paniculatus 87 

tricolor 87 

Amberboa moschata 183 

Ammi 89, 559 

majus 89 

visnaga 89, 92 

Ammobium alatum 565 

Amorpha canescens 568 

Anaphalis margaritacea 566 

Anemone 25, 93, 559 

coronaria 93, 475 

×fulgens 98 

hupehensis 98 

×hybrida 98 

Anethum 25 

graveolens 565 

Anigozanthos 566 

Antirrhinum 25, 99, 559 

majus 99 

Aquilegia 25 

×hybrida 26, 566 

Arctotis 565 

Argyranthemum frutescens 565 

Armeria pseudarmeria 566 

Aronia arbutifolia 568 

Artemisia 108, 559 

abrotanum 110 

annua 108 

dracunculus 110 

lactiflora 110 

ludoviciana 109 

Arum italicum 567 

Asclepias 25, 111, 559 

curassavica 115 

incarnata 115 

physocarpa 115 

syriaca 115 

tuberosa 111 

Aster 116, 559 

cordifolius 127 

ericoides 117, 126, 160 

hybrids 126 

novae-angliae 117, 124, 160 

novi-belgii 117, 125, 160 

tataricus 127 

Astilbe 25, 128, 560 

×arendsii 128 

chinensis 133 

davidii 133 

×hybrida 128 

×japonica 128, 133 

×rosea 128 

simplicifolia 133 

taquetii 133 

×thunbergii 128 

Astrantia 25, 134, 560 

carniolica 137 

major 134 

maxima 137 

Atriplex hortensis 565 

Aucuba japonica 568 

Baptisia 138, 560 

alba 141 

australis 138 

lactea 141 

leucantha 141 

sphaerocarpa 141 

tinctoria 138 

Belamcanda 560, 566 

Bouvardia 25 

Bracteantha bracteata 331 

Brassica oleracea 565 

Brodiaea 513 

californica 515 

Buddleia 142, 560 

alternifolia 146 

davidii 142 

fallowiana 146 

globosa 146 

lindleyana 146 

×weyeriana 145 

Bupleurum 560 

griffithii 565 

Buxus 568 

Cacalia javanica 264 

Caladium bicolor 567 

Calendula officinalis 565 

Callicarpa 25, 147, 560 

albifructus 150 

americana 147 

bodinieri 149 

dichotoma 147, 149 

japonica 150 

Callistephus 116, 151, 560 

chinensis 116, 151 

Calluna vulgaris 568 

Calycanthus floridus 568

Camellia sasanqua 568 

Campanula 25, 161, 560 

carpatica 161 

fragilis 161 

glomerata 161, 164 

isophylla 161 

medium 161, 164 

persicifolia 161 

pyramidalis 161, 164 

Capsicum annuum 565 

Carlina acaulis 566 

Carthamus 166, 560 

tinctorius 166 

Caryopteris 169, 560 

×bungei 171 

×clandonensis 169 

incana 169, 171 

mongolica 169 

Catananche caerulea 566 

Celastrus 568 

Celosia 25, 175, 560 

argentea 175 

Centaurea 25, 183, 560 

americana 183, 184, 187 

crocodyllum 190 

cyanus 183, 184, 187 

dealbata 191 

imperialis 191 

macrocephala 184, 188 

montana 184, 191 

moschata 183, 184, 187, 191 

pulchra 191 

suaveolens 188 

Centranthus 192, 560 

ruber 192 

Cephalaria gigantea 566 

Chamelaucium uncinatum 25, 568 

Chasmanthium latifolium 566 

Chelone 25 

obliqua 566 

Chenopodium quinoa 566 

Chimonanthus praecox 568 

Chionanthus retusus 568 

Chrysanthemum 566 

parthenium 566 

segetum 566 

×superbum 566 

Cirsium 194, 560 

helenioides 197 

heterophyllum 197 

INDEX OF BOTANICAL NAMES 575 

japonicum 194 

rivulare 197 

Clarkia 25, 198, 561 

amoena 202 

elegans 202 

grandiflora 202 

unguiculata 202 

Clethra alnifolia 568 

Consolida 25, 203, 238, 561 

ajacis 204 

ambigua 204 

orientalis 204 

regalis 204 

Convallaria 567 

Coreopsis 211, 561 

grandiflora 211, 213 

lanceolata 214 

tinctoria 215 

Cornus 216, 561 

alba 216, 220 

florida 216, 218 

mas 220 

sanguinea 220 

sericea 216, 220 

stolonifera 220 

Corylopsis 568 

Corylus avellana 568 

Cosmos 220, 561 

atrosanguineus 225 

bipinnatus 220 

sulphureus 220, 226 

Cotinus coggygria 568 

Craspedia globosa 566 

Crocosmia 25, 227, 561 

×crocosmiiflora 227 

hybrids 227 

Curcuma 25, 567 

Cymbidium 25 

Cynara cardunculus 566 

Cytisus 568 

Dahlia 232, 561 

coccinea 232 

hybrids 236 

pinnata 232 

Danae racemosa 568 

Daphne 568 

Daucus 25 

carota 92 

Delphinium 25, 204, 238, 561


[Delphinium] 

×belladonna 242 

cardinale 243 

elatum 238, 243 

grandiflorum 238 

hybrids 242 

nudicaule 243 

semibarbatum 243 

yunnanense 243 

zalil 243 

Dendrobium 25 

Deutzia 568 

Dianthus 25, 245, 561 

barbatus 245, 247 

caryophyllus 248 

chinensis 566 

hybrids 247 

knappii 248 

plumarius 248 

Dicentra 25 

spectabilis 27, 567 

Didiscus 566 

Digitalis 25, 250, 561 

ambigua 253 

ferruginea 253 

grandiflora 253 

lanata 253 

lutea 253 

×mertonensis 253 

purpurea 250 

viridiflora 253 

Dodecatheon meadia 567 

Doronicum 25 

plantagineum 567 

Echinacea 254, 561 

angustifolia 254, 258 

pallida 258 

paradoxa 258 

purpurea 254 

tennesseensis 258 

Echinops 259, 561 

bannaticus 259 

commutatus 263 

exaltatus 263 

ritro 259 

sphaerocephalus 263 

Echium 25 

Emilia 264, 561 

coccinea 265 

flammea 265 

javanica 264 

sagittata 265 

sonchifolia 265 

Eremurus 25, 265, 561 

bungei 268 

himalaicus 268 

×isabellinus 268 

olgae 268 

robustus 268 

×shelfordii 268 

stenophyllus 268 

Erica 568 

Eryngium 269, 561 

alpinum 272 

amethystinum 273 

bourgatii 273 

giganteum 273 

planum 269, 272 

yuccifolium 273 

Eucalyptus 568 

Euonymus alatus 568 

Eupatorium 561 

purpureum 567 

Euphorbia 273, 561 

dulcis 277 

fulgens 277 

marginata 273 

Eustoma 25, 279, 561 

grandiflorum 279 

×Fatshedera lizei 568 

Fibigia clypeata 566 

Filipendula rubra 567 

Forsythia 561, 569 

Francoa 25 

Freesia 25, 289, 561 

×hybrida 289 

Gaillardia ×grandiflora 567 

Gaultheria shallon 569 

Gaura lindheimeri 567 

Gentiana 561 

asclepiadea 567 

Gerbera jamesonii 566 

Gladiolus 25, 293, 561 

byzantinus 294, 296 

callianthus 294 

communis 294, 296 

hybrids 297

tristis 294 

Godetia 198 

Gomphrena 303, 561 

globosa 303 

haageana 303 

Goniolimon tataricum 309, 388, 400 

Gypsophila 25, 312, 561 

elegans 318 

oldhamiana 318 

paniculata 312 

Hamamelis ×intermedia 569 

Helenium autumnale 567 

Helianthus 25, 319, 561 

angustifolius 328, 567 

annuus 319 

debilis 328 

decapetalus 328 

maximiliani 328 

salicifolius 328 

Helichrysum 331, 561 

bracteatum 331 

cassianum 335 

diosmifolium 335 

rosmarinifolium 331 

subulifolium 335 

thianshanicum 335 

Heliopsis helianthoides 567 

Helipterum 566 

manglesii 566 

roseum 566 

Helleborus 336, 561 

foetidus 338 

niger 338 


Heuchera sanguinea 567 

Hippeastrum 567 

Hyacinthus orientalis 555 

Hydrangea 339, 562 

arborescens 339, 344 

macrophylla 339, 344 

paniculata 339, 344 

quercifolia 339, 344 

Hypericum 347, 562 

androsaemum 347 

×inodorum 347 

Iberis amara 566 

Ilex 25, 350, 562 

cassine 353 


cornuta 353 

decidua 350, 352 

glabra 353 

opaca 353 

serrata 350, 352, 353 

verticillata 350, 353 

vomitoria 353 

Indigofera 138 

Iris 354, 562 

hybrids, Dutch 356 

kaempferi 363 

latifolia 354 

sibirica 363 

tingitana 361 

xiphium 354, 356 

Itea virginica 569 

Ixia 25, 567 

Jasione perennis 566 

Jasminum mesnyi 569 

Juniperus 25 

Kalmia latifolia 569 

Kerria japonica 569 

Kniphofia 25, 567 

Koelreuteria bipinnata 569 

Lathyrus 25, 364, 562 

odoratus 364 

Lavandula 567 

Lavatera 25, 369, 562 

thuringiaca 372 

trimestris 369 

Leucanthemum 211 

Liatris 373, 562 

aspera 373, 378 

callilepis 378 

pycnostachya 373, 378 

scariosa 378 

spicata 373 

Lilium 25, 380, 562 

auratum 385 

×elegans 380 

formosanum 386 

hybrids, Asiatic 380 

hybrids, Oriental 380 

longiflorum 380, 386 

speciosum 380 

Limonium 309, 562 

altaica 309, 388, 401


[Limonium] 

bellidifolium 388, 401 

bonduellii 401 

caspium 401 

gmelinii 401 

latifolium 309, 388 

otolepis 401 

peregrinum 401 

perezii 389 

roseum 401 

sinense 400 

sinuatum 391, 401 

suworowii 402 

tataricum 309 

tetragonum 400 

Lobelia 404, 562 

cardinalis 404, 405 

fulgens 405 

×gerardii 404 

siphilitica 404, 405, 406 

×speciosa 404, 405 

splendens 405 

Lonicera fragrantissima 569 

Lunaria 406, 562 

annua 406 

rediviva 409 

Lupinus 567 

Lychnis 68 

chalcedonica 68 

coeli-rosa 68 

coronaria 68 

Lycoris 567 

Lysimachia 25, 410, 562 

clethroides 410 

ephemera 415 

punctata 415 

purpurea 415 

vulgaris 415 

Magnolia grandiflora 569 

Malus 569 

Matthiola 25, 415, 562 

incana 415 

Mentha 566 

Michelia figo 569 

Molucella 562 

laevis 566 

Monarda 562 

didyma 567 

Montbretia 227 

Morus australis 570 

Muscari armeniacum 567 

Myrica 570 

Nandina domestica 570 

Narcissus 25, 424, 562 

Nectaroscordum siculum 76 

Nerine 562 

bowdenii 563 

Nicandra physaloides 566 

Nigella 428, 562 

arvensis 431 

ciliaris 431 

damascena 428 

hispanica 431 


sativa 431 

Oreganum 562 

Ornithogalum 25, 562 

arabicum 432, 436 

dubium 432 

nutans 432 

saundersiae 432, 436 

thyrsoides 432 

umbellatum 436 

Oxalis 567 

Oxypetalum 522, 562 

caeruleum 522 

Ozothamnus 331 

diosmifolius 335 

Paeonia 25, 437, 562 

hybrids 444 

lactiflora 437 

lutea 437 

mollis 437 

officinalis 437 

suffruticosa 437 

Papaver 447, 562 

nudicaule 447 

somniferum 449 

Penstemon 25, 567 

Perovskia atriplicifolia 567 

Phlox 25, 451, 562 

×arendsii 456 

divaricata 456 

maculata 451, 456 

paniculata 451, 456 

Physalis 457, 564

alkekengi 457 

franchetii 457 

Physostegia 25, 460, 564 

purpurea 465 

virginiana 460 

Pieris japonica 570 

Platycodon 466, 564 

grandiflorus 466 

Polianthes 470, 564 

tuberosa 470 

Polygonatum odoratum 567 

Poncirus trifoliata 570 

Pontederia cordata 567 

Primula vialii 567 

Prunus 570 

Psylliostachys suworowii 402 

Ranunculus 25, 475, 564 

asiaticus 475 

Reseda odorata 566 

Rhodanthe manglesii 566 

Rosa 25, 570 

Rubus 567 

Rudbeckia 25, 211, 564 

fulgida 214 

hirta 211, 215 

laciniata 214 

nitida 214 

triloba 214 

Ruscus 570 

Salix 480, 564 

alba 480, 481 

caprea 481 

chaenomeloides 481 

discolor 481 

×erythroflexuosa 480, 483 

gracilistyla 481 

matsudana 480, 483 

melanostachys 481 

sachalinensis 480 

Salvia 484, 564 

farinacea 487, 488 

gesneraeflora 487 

guaranitica 487 

horminum 488 

leucantha 484 

longispicata 488 

nemorosa 488 

patens 567 


sclarea 488 

splendens 488 

×superba 488 

viridis 488 

Saponaria 25 

Sarcococca hookeriana 570 

Scabiosa 25, 489, 564 

atropurpurea 489 

caucasica 492 

columbaria 495 

lucida 495 

ochroleuca 495 

prolifera 495 

stellata 495 

Sedum 567 

Sidalcea malviflora 567 

Silene 25 

Skimmia 570 

Solidago 25, 496, 564 

caesia 502 

canadensis 498 

flexicaulis 502 

graminifolia 502 

odora 502 

petiolaris 498 

rugosa 502 

sphacelata 502 

virgaurea 502 

×Solidaster 496, 564 

luteus 496 

Spiraea 570 

Stachys 564, 567 

Symphoricarpos albus 570 

Syringa 570 

Tagetes 564 

erecta 566 

Thalictrum 503, 564 

aquilegifolium 503, 506 

delavayi 503, 506 

dipterocarpum 506 

flavum 506 

rochebruneanum 505, 506 

Tithonia rotundifolia 566 

Trachelium 25, 507, 564 

caeruleum 507 

Trachymene 566 

Triteleia 25, 513, 564 

californica 515 

hyacinthina 515


[Triteleia] 

laxa 513, 515 

peduncularis 515 

×tubergenii 515 

Trollius 25 

Tulipa 25, 516, 564 

Tweedia 522 

caerulea 522 

Typha 567 

Ulmus alata 570 

Vaccaria pyramidata 566 

Vallota 567 

Verbascum chaixii 567 

Verbena 525, 564 

bonariensis 525 

rigida 527 

Veronica 25, 528, 564 

longifolia 528 

spicata 528, 532 

subsessilis 532 

virginica 532, 533 

Veronicastrum 25, 532, 533, 564 

virginicum 532, 533 

Viburnum 570 

carlesii 570 

Viola odorata 567 

Vitex agnus-castus 570 

Xeranthemum annuum 566 

Xerochrysum bracteatum 331 

Zantedeschia 536, 564 

aethiopica 537, 543 

albomaculata 537 

elliottiana 537 

jucunda 537 

pentlandii 537 

rehmannii 537 

Zea mays 566 

Zinnia 546, 564 

elegans 546 

haageana 550 

pauciflora 550 

peruviana 550

INDEX OF COMMON NAMES 

acidanthera 296 

aconite, Arend’s 55 

Alexandrian-laurel 568 

amaranth 83 

purple 83 

red 83 

amaryllis 567 

amorpha 568 

anemone 93 

Japanese 64 

poppy 93 

apricot 570 

Arabian star flower 432 

artemisia 109 

arum lily 567 

aster 116 

China 151 

heath 117 

New England 117, 160 

New York 117, 160 

September 160 

Tatarian 127 

aucuba 568 

autumn sunspray 567 

baptisia 138 

white 141 

yellow 141 

baby’s breath 312 

bachelor’s buttons 183, 187 

balloonflower 466 

banana shrub 569 

basket flower 183 

American 183, 187 

golden 184, 188 

bayberry 570 

bearded tongue. See beardtongue 

beardtongue 567 

beautyberry 147 

American 147 

Bodinier 149 

Japanese 150 

purple 149 

bee balm 567 

bellflower 161 

chimney 161, 164 

clustered 161, 164 

peach-leaf 161 

bells-of-Ireland 566 

bittersweet 568 

blackberry 567 

blackberry lily 566 

black-eyed susan 215 

blanket flower 567 

bleeding heart 567 

blood flower 115 

blue African lily 566 

blue beard 169 

blue lace flower 566 

blue spirea 171 

boxwood 568 

brodiaea 513 

broom 568 

bupleurum 565 

butcher’s broom 570 

buttercup 475 

butterfly-bush 142 

alternate 146 

butterfly weed 111 

Byzantine gladiolus 296 

caladium 567 

581

582 INDEX OF COMMON NAMES 

calendula 565 

calla lily 536 

camellia 568 

candytuft, rocket 566 

Canterbury bells 161, 164 

Cape daisy 565 

cardinal flower 404 

cardoon 566 

Carmel daisy 495 

carnation 248 

cattail 567 

chameleon plant 277 

chaste tree 570 

checkerbloom 567 

cherry 570 

China pink 566 

chincherinchee 432, 436 

Chinese lantern 457 

Chinese spinach 87 

chokeberry, red 568 

Christmas rose 338 

cockscomb 175 

columbine 566 

common milkweed 115 

coneflower 211 

cutleaf 214 

pale 258 

purple 254 

Tennessee 258 

three-lobed 214 

yellow purple 258 

coral bells 567 

coralberry 350 

coreopsis 211 

lance-leaf 214 

plains 215 

corn cockle 65 

cornflower 183 

cosmos 220 

chocolate 225 

dwarf sulphur 220 

lace 220 

cotton 566 

crabapple 569 

crocosmia 227 

culver’s root 533 

cupid’s dart 566 

daffodil 424 

dahlia 232 

daphne 568 

delphinium 238 

deutzia 568 

dill, flowering 565 

dogwood 216 

bloodtwig 220 

cornelian cherry 220 

flowering 218 

red-stem 216 

drumstick chives 73 

drumstick plant 495 

everlasting 331 

sunray 566 

winged 565 

false blue indigo 138 

false goat’s beard 128 

false queen anne’s lace 89 

fatshedera 568 

fennel flower 431 

feverfew 566 

flamingo flower 176 

flossflower 60 

forsythia 569 

foxglove 250 

Grecian 253 

green 253 

large-flowered 253 

rusty 253 

strawberry 253 

yellow 253 

foxtail lily 265 

freesia 289 

gaura 567 

gayfeather 373 

button 373, 378 

Kansas 378 

rough 378 

tall 373, 378 

gentian 567 

gerbera daisy 566 

giant sea pink 566 

gladiolus 293 

Abyssinian 294 

Byzantine 296 

globe amaranth 303 

golden amaranth 308 

golden aster 496

golden drumstick 566 

goldenraintree 569 

goldenrod 496 

sweet 502 

wreath 502 

goosefoot 566 

grancy gray-beard 568 

grape hyacinth 567 

green mist 92 

hardy-orange 570 

Harry Lauder’s walking stick 568 

heath 568 

heather 568 

heavenly bamboo 570 

heliopsis 567 

hellebore 336 

stinking 338 

holly 350 

deciduous 350 

fine-tooth 352 

hollyhock 565 

honesty 406 

perennial 406 

hortensia 339 

hydrangea 339 

bigleaf 339 

oakleaf 339, 345 

panicle 339 

peegee 344 

smooth 339 

hypericum 347 

hyssop 57 

anise 57 

giant 57 

Mexican 57 

immortelle 331, 566 

indigo 138 

iris 354 

bearded 354 

Dutch 354 

English 354 

Japanese 354 

Louisiana 354 

Siberian 354 

Ithuriel’s sword 515 

ixia 567 

joe-pye weed 567 

INDEX OF COMMON NAMES 583 

joseph’s coat 87 

kangaroo paw 566 

kerria 569 

Korean mint 59 

lacecap 339 

larkspur 203 

lavender 567 

lavender mist 506 

lemonleaf 569 

Lenten rose 336 

leopard’s bane 567 

lilac 570 

lily 380 

Asiatic 380 

Easter 386 

Formosa 386 

goldband 385 

hidden 567 

LA 380 

Oriental 380 

OT 380 

Peruvian 78 

resurrection 567 

Scarborough 567 

Trumpet 380 

lily-of-the-valley 567 

lisianthus 279 

lobelia 404 

big blue 404, 406 

Mexican 405 

loosestrife 410 

gooseneck 410 

yellow 415 

love-in-a-mist 428 

love-lies-bleeding 83 

lupine 567 

magnolia, southern 569 

mallow 369 

Maltese cross 68 

marguerite daisy 565 

marigold 566 

corn 566 

masterwort 134 

meadow-rue 503 

columbine 503 

yellow 506 

Yunnan 503, 506


Michaelmas daisy 117 

mignonette 566 

mint 566 

Miss Willmott’s ghost 273 

money plant. See honesty 

monkshood 52 

common 53 

Oriental 56 

montbretia 227 

mophead 339 

mountain bluet 184, 191 

mountain laurel 569 

mournful widow 489 

mugwort 110 

mulberry 147, 570 

contorted 570 

French 147 

mullein 567 

myrtle 570 

nandina 570 

nigella 428 

Asian 431 

nodding star-of-Bethlehem 432 

obedient plant 460 

okra 566 

orache 565 

orange ball tree 146 

orange star flower 432 

oregano 566 

ornamental corn 566 

ornamental kale 565 

ornamental onion 68 

blue globe 76 

drumstick 76 

giant 71 

Persian 75 

pink and white giant 76 

three-cornered 76 

tumbleweed 76 

ornamental pepper 565 

oxalis 567 

paper pumpkin seed 566 

paperwhites 424 

peach 570 

pearly everlasting 566 

peony 437 

tree 437 

pepper 566 

Peruvian lily 78 

phlox 451 

Arend’s 456 

spotted 456 

summer 451 

woodland 456 

pieris 570 

pickerel weed 567 

pincushion flower 489 

pink 248 

cottage 248 

yellow 248 

plum 570 

poppy 447 

Iceland 447 

opium 449 

possumhaw 350, 352 

prairie gentian 279 

primrose, cone 567 

primrose jasmine 569 

prince’s feather 87 

prince of Wales feather 176 

queen anne’s lace 92 

queen of the prairie 567 

ranunculus 475 

rattlesnake master 273 

red cathedral 83 

red hot poker 567 

red valerian 192 

rhodanthe 566 

rice flower 335 

rocket candytuft 566 

rose 570 

rose campion 68 

rose cockle 566 

rosemary 566 

rose of heaven 68 

safflower 166 

sage 484, 566 

anise-scented 487 

annual 488 

clary 488 

gentian 567 

green 488 

mealy-cup 487 

Mexican bush 484

perennial hybrid 488 

Russian 567 

velvet 484 

white 109 

salal 569 

satin flower 198 

scabious 492 

cream 495 

giant 566 

perennial 492 

shepherd’s 566 

scarlet plume 277 

sea holly 269 

alpine 270, 272 

sea oats 566 

shasta daisy 211, 566 

shoo-fly 566 

shooting star 567 

silver dollar tree 568 

skimmia 570 

smokebush 568 

snapdragon 99 

sneezewort 37 

snowberry 570 

snow-on-the-mountain 273 

solidaster 496 

solomon’s seal 567 

sparkleberry 350 

speedwell 528 

spiked 528 

spirea 570 

St. Martin’s flower 82 

stachys 567 

star-of-Bethlehem 436 

statice 309, 388 

altaica 401 

annual 391 

Caspia 388, 401 

confetti 400 

German 309, 388 

Perez 389 

seafoam 389 

Siberian 401 

sinuata 391 

rat tail 402 

Russian 402 

yellow 400 

stock 415 

stonecrop 567 

strawflower 331 

INDEX OF COMMON NAMES 585 

rosemary 331 

summersweet 568 

sunflower 319 

annual 319 

Mexican 566 

swamp 328, 567 

thinleaf 328 

willow-leaf 328 

swamp milkweed 115 

swan plant 115 

Swan River everlasting 566 

sweet annie 108 

sweetbox 570 

sweetshrub 568 

sweet pea 364 

sweet sultan 183, 188 

sweet william 245 

tampala 87 

tarragon 110 

tassel flower 264 

thistle 194 

globe 259 

Japanese 194 

silver 566 

throatwort 507 

thyme 566 

tickseed 211 

tomato 566 

tree mallow. See mallow 

tuberose 470 

tulip 516 

turtlehead 566 

tutsan 347 

tweedia 522 

veil of flowers 507 

verbena 525 

rigid 527 

South American 525 

tall 525 

veronica 528 

long-leaf 528 

veronicastrum 533 

viburnum 570 

violet, sweet 567 

Virginia sweetspire 569 

waxflower, Geraldton 568 

wheat celosia 176


willow 480 

black pussy 481 

coral bark 483 

fantail 480 

goat 481 

Hankow 483 

Japanese pussy 481 

pussy 480, 481 

rosegold pussy 481 

white 483 

yellow bark 483 

winged elm 570 

winged euonymus 568 

winged everlasting 565 

winterberry 350 

winterhazel 568 

winter honeysuckle 569 

wintersweet, fragrant 568 

witch hazel 569 

wormwood 108 

yarrow 37 

common 37 

fern leaf 37 

sweet 51 

yellow wolfsbane 56 

zinnia 546

Achillea

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