What Grows There :: Hugh Conlon, Horticulturalist, Garden Advisor, and Photographer

‘Ogon’ Spirea Is A Standout

Posted by Hugh on March 12th, 2023

Spireas (Spiraea spp.) represent a large number of mostly non-native flowering landscape shrubs. Most are not U.S. natives, indigenous to China and Japan. Baby’s breath spirea (S. thunbergii) is also called Thunberg spirea and Breath of Spring spirea. It is a showy, graceful shrub that grows 3 to 5 feet high and wide with many slender, arching branches (USDA hardiness zones 4-8).

One of the popular cultivars is Golden Thunberg (S. thunbergii ‘Ogon’). This spirea is one tough tough plant. Its abundant flowers and gold leaf color is stunningly beautiful. Tiny white flowers cover the shrub in late winter to early spring before the leaves appear. Narrow, willow-like, sparsely toothed leaves (to 1.5 inches long) emerge golden yellow in spring, transition to chartreuse green in summer and turn interesting shades of orange to yellow in autumn.

‘Ogon’ is an exceptional golden-leaved cultivar best grown in full sun to retain its lovely golden foliage over almost three-seasons. It prefers moist well-drained soils and becomes more drought tolerant as the shrub ages. Pruning is best performed immediately after the spring blooms have faded. Annual pruning helps to maintain the shrub’s shape and appearance. Rabbits and deer are not usually troublesome.

It may be used as a hedge, screening, or windbreak. It may also be considered as a foundation, border planting, or specimen.

Baby’s breath spirea grows in a wide range of soils, medium moisture, well-drained soils and in full sun. The shrub tolerates light shade, and moderate drought. Prune as needed immediately after flowering to maintain shape.

Ogon spirea is rarely troubled by disease or pest problems that plague other members in the rose family including leaf spot, fire blight, powdery mildew, root rot, aphids, leaf roller and scale.

Caveat: Do not confuse this plant with gold mound spirea which is Spiraea japonica ‘Goldmound’.

False Solomon Seal

Posted by Hugh on March 7th, 2023

False Solomon’s seal (Maianthemum racemosum) is a native woodland plant. It earns its common name because it looks very similar to Solomon’s seal (Polygonatum spp.). Both are in the lily family (Liliaceae) and are often seen growing together and easy to distinguish apart by the placement of the flowers on the plants.

Formerly classified Smilacina racemosa, this plant that ranges across most of North America north of Mexico in zones 3-9. Biologists reclassified to the genus Maianthemum a long time ago but is often listed by its old scientific name. Native Americans used the root and leaves medicinally and ate the young shoots and processed roots.

It is an herbaceous perennial, e. g., the foliage dies down to the ground in autumn and re-emerges in spring from the stout, fleshy, persistent rhizomes with secondary fibrous roots. The alternate, ovate leaves are produced on 1–3-feet high arching stems that stand tall well into summer. The slightly hairy, reddish or green stems zigzag slightly between the leaves.

Each smooth, entire leaf measures up to 6 inches long with prominent parallel veins lengthwise. The foliage may turn yellow to gold in the fall but sometimes just goes brown. Over time vigorous plants may form large colonies from slowly spreading clumps.

Flower clusters can form between 20 and 80 individual flowers. Each ¼ inch wide star-shaped flower is comprised of 6 tepals (petals and sepals that look the same), 6 stamens with yellow anthers and a solitary central pistil. Flowers are very different from the bell-shaped flowers of Solomon’s seal that hang from nodes along the stem.

Late summer leaf color and red fruits (*Maianthemum* *racemosu*m)

In late spring and early summer feathery masses of small white to pale yellow, fragrant flowers are produced in flat panicles at the ends of the stems. The flowers are followed by clusters of small berries, each containing a few seeds. They turn from green (or green with purple speckles that gives an overall appearance of a russet color), to translucent red or red and purple-marked when they ripen in late summer or fall.

The berries of False Solomon’s seal are reportedly edible and also are red according to some other sources. Flowers are pollinated by small bees, flies, and beetles. Birds and field mice forage the berries and disperse the seeds to other areas of the property.

Blue Flowering Shrubs

Posted by Hugh on March 1st, 2023

Most associate the color BLUE with the sky, the sea, and an endless horizon. Blue colors evoke feelings of tranquility, calm, and a peaceful state of mind. “Blue Skies” brings out happiness and smiles in people, particularly after consecutive days of dreary weather. Contrarily, a blue mood may elicit feelings of sadness and depression.

The BLUE color spectrum ranges between violet and cyan. In the gardening world few shrubs produce blue flowers, most in the pale blue to lavender range. Below are nine (9) of the best “blues” in the world of shrub flower world.

Bluebeard (Caryopteris x clandonensis), aka blue mist shrub, blooms in late summer into autumn on this 2-3 feet tall shrub (zones 5-9). Cultivars: ‘Longwood Blue’, ‘Beyond Midnight’.

Rhododendron (Rhododendron spp.) cultivars produce numerous lavender blue flowers. Popular varieties include: 1. many catawba rhododendrons (Rhododendron catawbiense) produce lavender-pink flowers from April to early June (zones 4 to 8); 2. PJM rhododendron (Rhododendron x ‘PJM’), bears lavender-pink flowers in early April (zones 4-8); 3. ‘Blue Diamond’ and ‘Blue Baron’ are compact 3 foot high hybrid cultivars bearing blue-lavender flowers in late spring (zones 7 – 9).

Common Lilac (Syringa vulgaris) are available in several color shades of lavender, blue, reds, and white. One of the almost blue cultivars is S. hyacinthiflora Scentara^® with double blue blooms (zones 2-8).

Butterfly bush (Buddleia x) is a subshrub. ‘Blue Heaven’, ‘Blue Chip’, ‘Blue Knight’ are among a long list of blue-flowered buddleias; depending on cultivar grow 5-12 feet high and some even taller (zones 5-9).

Bigleaf Hydrangea (Hydrangea macrophylla) produces huge mophead flowers in summer on 3 to 4 feet tall plants in full sun to partial shade, depending on where you garden. Best blue cultivars: ‘Nikko Blue’, ‘Nantucket Blue’, Endless Summer™ series, Let’s Dance™ Blue Jangles, Let’s Dance™ Rhythmic Blue. (Zones:5-9).

Rose of Sharon (Hibiscus syriacus) is an old-fashioned 8 to 12 feet tall shrub with lacy blooms from summer to fall. Blue cultivars: ‘Blue Bird’, ‘Blue Chiffon’, ‘Lavender Chiffon’ (Zones 5-8).

Lavenders (Lavandula spp.) is a perennial subshrub treasured for their floral beauty and fragrance and also purposed for culinary, medicinal, and decorative potpourri. Select from blue-purple flowered ‘Mumstead’ English Lavender (L. angustifolia) (zones 5 – 8) and some French / Spanish lavender (L. stoechas) varieties (zones 7b-9).

Chaste Tree (Vitex agnus-castus) is a 6-12 foot tall shrub or 12-16 foot small tree. Cultivars: dwarf: ‘Blue Diddley’ and ‘Blue Puffball’ grow 3 – 6 feet tall; ‘Shoal Creek’ (12 feet tall).

California Mountain Lilac (Ceanothus ‘Concha’) bears purple or blue flowers that are highly fragrant (Zones 7 -10).

All About Flowering Quinces

Posted by Hugh on February 22nd, 2023

Flowering Quince (Chaenomeles speciosa) is a deciduous shrub in the Rose (Rosaceae) family and related to apple and pear (Zones 5-9). It is native to China and is relatively easy to grow. Plant quince in moist, well-drained soil; it flowers best in full sun but is moderately shade tolerant. Feed quince shrubs annually in early spring before new growth emerges with a slow-release fertilizer.

Flowering quinces offer multi-seasonal interest. Red, orange, pink, or white flowers (depending on variety) appear around the same time as spring crocus, hyacinths, and early tulips are also beautifying gardens. Flowers are glorious over 10 to 14 days. Blooms, as large as 1.5 inches in diameter, either appear singly or in clusters of 2-4. Several months later, the 2.5 inch long yellow-green quince fruits ripen.

Harvest fruits when they turn from pale green to yellow; they’re usually too hard to eat raw and bitter tasting. Harvest them and bring indoors to ripen. Fruits bruise easily. Store quinces on trays, not touching each other, in a dark, cool spot for 6-8 weeks before using. Also store quinces away from apples. Quince fruits soften with cooking, making tasty preserves and jellies or eat after fully ripened.

Pruning occurs after spring flowering to shape the shrub, to remove old dense wood, including all diseased and dead wood, and to stimulate the growth of flowering spurs for the next year. Be careful of their dense spiny wood.

C. speciosa is a tough, hardy plant that would make a great informal hedge. It is moderately salt-tolerant, and in comparison, C. speciosa grows more upright than its relative C. japonica. In general, quinces dislike high pH (alkaline) soils.

Quinces are easy to transplant. Pest and disease problems need to be considered, particularly on old fashioned varieties which were susceptible to fire blight. Modern day cultivars are highly resistant to fire blight disease. Aphids can be a problem on stressed plants.

Double Take series: ‘Scarlet Storm,’ ‘Orange Storm,’ and ‘Pink Storm’ grow to 5 feet high with double flowers of scarlet, orange, or pink. Branches are covered with blooms. Shrubs are shorter overall, do not produce fruits, and are largely thornless. Early arriving butterflies and hummingbirds will visit the early flowers.

Older varieties such as Super Red, Toyo-Noshiki, and Texas Scarlet are spotted in older landscapes as tall 8-10 feet hedges. Beware of their sharp barbed thorns.

Alternative: C. japonica grows only 2-4 feet tall with salmon to orange-colored flowers outward.

Varieties Of Crape Myrtles

Posted by Hugh on February 18th, 2023

Crape myrtles (Lagerstroemia x indica) are small flowering trees and shrubs that are native to Asia and have naturalized in the Deep South of the U.S. Back in the 1970’s thru the 1990’s, plant breeders at the U.S. National Arboretum released 35 winter hardy varieties, named after North American Indian tribes. They varied in sizes ranging from 5-foot shrubby rose-pink flowered ‘Pocomoke’ to 30-foot white flowered tree ‘Natchez’. The U.S. nursery industry followed up with 100 more varieties that fit in most landscape designs.

‘Natchez’ Crape Myrtle (25-30 feet category)

Crape myrtles come in a variety of tree or shrub sizes and flower colors. Many (not all) show off an ornamental patchwork bark. Before purchasing, select a variety based on mature tree/shrub size, flower color, and ornamental bark. Shop the internet or local garden center to find a hardy variety that fit into the garden space.

Plant a crape myrtle any time of year, from early spring to late summer and no later. More than 125 varieties are listed on the internet. Here are over 60 of the best arranged according to their mature height:

Miniature/Weeping: less than 3 feet tall

Baton Rouge (red)
Mardi Gras (purple)
Pixie White (white)
Pocomoke (deep pink)

Dwarf: 3 – 5 feet tall

Berry Dazzle (GAMAD VI) (pink)
Centennial (purple)
Dazzle series (GAMAD I-VII)
Petite Series (6 varieties)
Pink Ruffles (pink)
Tightwad (Whit V) (red)
Velma’s Royal Delight (purple)
Victor (dark red)

Intermediate: 5 – 10 feet tall

Acoma (white)
Cheyenne (red)
Hopi (pink)
Red Rooster (PIILAG III) (rich red)
Siren Red (Whit VII) (red)
Tonto (red)
Zuni (purple)

‘Burgundy Cotton’ crape myrtle (10-20 feet category)

Medium: 10 – 20 feet tall

Apalachee (lavender)
Black Diamond series (9 varieties)
Burgundy Cotton (Whit VI) (white)
Catawba (purple)
Centennial Spirit (red)
Comanche (pink)
Dynamite (Whit II) (true red)
Lipan (lavender)
Osage (pink)
Pink Velour (Whit III) (pink)
Powhatan (purple)
Raspberry Sundae (Whit I) (red/white)
Regal Red (red)
Seminole (pink)
Sioux (pink)
Tuskegee (pink)
Yuma (lavender)

Tall: more than 20 feet tall

Arapaho (red)
Biloxi (pink)
Byers Hardy Lavender (lavender)
Byers Standard Red (red)
Kiowa (white)
Miami (pink)
Muskogee (lavender)
Natchez (white)
Potomac (pink)
Red Rocket (Whit IV) (true red)
Sarah’s Favorite (white)
Townhouse (white)
Tuscarora (pink)
Watermelon Red (red)
Wichita (lavender)

Selecting and Pruning Crape Myrtles

Posted by Hugh on February 14th, 2023

Crape myrtles (Lagerstroemia x indica) are small flowering trees and shrubs. Indigenous to Asia, they have naturalized in our U.S. Deep South. Winter hardiness is a key concern (USDA Hardiness Zones 6-9).

Back in the 1970’s thru the 1990’s, plant breeders at the U.S. National Arboretum released 35 winter hardy varieties, named after North American Indian tribes. They varied in sizes ranging from 5-foot shrubby rose-pink flowered ‘Pocomoke’ to 30-foot white flowered tree ‘Natchez’. The U.S. nursery industry followed suit with 100 more varieties that fit in most landscape designs.

One significant concern with growing crape myrtles is bad pruning, frequently referred to as “Crape Murder”. Don’t let this tragedy happen in your landscape. Before purchase, spend 5 minutes to measure out the space where you will be planting a new crape myrtle. Next, go buy a hardy variety at a garden center in the plant zone. Don’t buy from big box stores unless you are certain the variety is winter hardy!

According to the plant experts at Mississippi State University, here’s the correct way to prune a crape myrtle:

You need sharp pruning tools based on the diameter of the branches and limbs. Use bypass pruners to easily cut back branches up to 3/4 inch in diameter. For branches up to 1 3/4 inches in diameter, use a robust set of loppers. Use a pruning saw on larger branches.

Nicely pruned crape myrtles should be multi-trunked and well-structured. Maintain an odd number of trunks, such as three or five, looks great and preserves enough space for the tree to produce strong growth.

Remove any unwanted trunks. Cut them as close to the ground as you can. Next, choose the height where you want the branching to start and remove lower branches back to the main trunk.

Remove any branches that are growing into the center of the tree canopy and any crossing or rubbing limbs against each other. This creates space and opens the canopy, reducing the chance of diseases. Cut off seed heads to encourage more growth in the spring.

Finish with the removal of small, thin branches. Use your index finger as a size guide to determine which ones to remove. It is common for crape myrtles of any age or size to have suckers sprout up around the base. Use your hand pruners and cut these off without leaving a stub.

Pruning Times for Flowering Shrubs

Posted by Hugh on February 7th, 2023

The late winter / early spring period are ideal times for pruning many (not all) flowering shrubs. At this time, shrubs are leafless, and you are better able to see the overall shape of the shrub and easily identify dead, damaged, diseased wood, and structural defects. Pruning also stimulates new growth.

Spring flowering shrubs (those that bloom before mid-June) should be pruned after flowering. Their flower buds on “old wood” or the previous growing season. Early spring flowering shrubs include quince, evergreen azalea, forsythia, Japanese kerria, lilac, and weigela. The list includes with May blooming rhododendrons and fall and spring flowering camellias.

Summer blooming shrubs such as summerweet (Clethra alnifolia), panicle hydrangea (Hydrangea paniculata), and blue mist shrub (Caryopteris x clandonensis) are pruned in late winter/early spring. Their flower buds form on new wood produced during the current season. Native deciduous azaleas like plumleaf (R. prunifolium)and sweet (R. arborescens) azaleas are best pruned within one month after flowering.

*Hydrangea paniculata* ‘Bobo’ blooming in August

Popular hedging favorites such as boxwoods (Buxus spp.), hollies (Ilex spp.), privets (Ligustrum spp.), barberries (Berberis spp.), and others are pruned 1-3 times during the growing season. In most areas all hedging should cease by mid-September. Do not shear hedges to the same height as this will destroy formation of new growth buds.

For old or overgrown shrubs that bloom poorly and are still healthy growth-wise, try rejuvenation pruning in early spring. Cut all stems back to the ground. Shrubs usually grow back quickly after fertilizing and flowering resumes in 1-2 years. Plants that respond well to rejuvenation include crape myrtle, forsythia, lilac, and spirea.

To finish fall is not a desirable pruning time as new pruning cuts at that time of year is subject to winter injury.

Pruning timetable for many flowering shrubs:

Spring Flowering Shrubs (Prune After Flowering)

Serviceberry shadbush (Amelanchier spp.)

Azaleas (Rhododendron spp.)

Barberry (Berberis spp.)

Beautyberry (Callicarpa spp.)

Sweetshrub (Calycanthus floridus)

Camellia (Camellia x)

Flowering quince (Chaenomeles spp.)

Dogwood (Cornus spp.)

Cotoneaster (Cotoneaster spp.)

Daphne (Daphne spp.)

Deutzia (Deutzia spp.)

Forsythia (Forsythia spp.)

Fothergilla (Fothergilla spp.)

Witchhazel (Hamamelis spp.)

Smooth Hydrangea (Hydrangea arborescens)

Oakleaf Hydrangea (Hydrangea quercifolia)

Mountain laurel (Kalmia latifolia)

Kerria (Kerria japonica)

Golden chain (Laburnum anagyroides)

Privet (Ligustrum spp.)

Spicebush (Lindera benzoin)

Honeysuckle (Lonicera spp.)

Chinese Fringe Flower (Loropetalum chinensis)

Mockorange (Philadelphus coronarius)

Ninebark (Physocarpus orbiculatus)

Japanese Pieris (Pieris japonicus)

Firethorn (Pyracantha spp.)

Currant or gooseberry (Ribes sanguinea)

Roses (Rosa spp.)

Rhododendrons (Rhododendron spp.)

Spiraea (Spirea spp.)

Lilac (Syringa spp.)

Viburnums (Viburnum spp.)

Weigela (Weigela florida)

Summer Flowering Shrubs (Prune in Spring)

Flowering abelia (Abelia x grandifolia)

Butterfly bush (Buddleia x spp.)

Beautyberry (Callicarpa spp.)

Blue Mist (Caryopteris × clandonensis)

New Jersey Tea (Ceanothus americanus)

Summersweet (Clethra alnifolia)

Rose of Sharon (Hibiscus syriacus)

Bigleaf hydrangea (Hydrangea macrophylla)

Panicle hydrangea (Hydrangea paniculata)

St John’s Wort (Hypericum spp.)

Crape myrtle (Lagerstroemia spp.)

Cinquefoil (Potentilla fruticosa)

Sweet azalea (Rhododendron arborescens)

Plumleaf azalea (Rhododendron prunifolium)

Sumac (Rhus spp.)

Roses (Rosa spp.)

Anthony Waterer spirea (Spiraea x bumalda)

Chaste tree (Vitex agnus-castus)

Winter Blooming Vernal Witchhazel

Posted by Hugh on January 30th, 2023

Vernal witchhazel is a U.S. native to the Ozark Plateau extending from southern Missouri through northwestern Arkansas to eastern Oklahoma. It is among the easiest of shrubs to grow @ 10-12 feet tall and two-thirds as wide. Roots spreads by underground stoloniferous.

The leaves are oval, 2³⁄₄–5 inches long and 2 1/2 –5 inches wide and are slightly oblique at the base. Leaf edges are wavy-toothed and shallowly lobed. Leaves are dark green above, and glaucous beneath, and often persist into the early winter.

Flowers are deep to bright red, rarely yellow, with four ribbon-shaped petals 0.28–0.39 inches long with four short stamens arranged in clusters. Flowers of vernal witchhazels emerge in late winter (December to March). On warm wintry days native and some honeybees work the fragrant blooms

Tiny individual fruits (³⁄₈–⁵⁄₈ inch long) are dehiscent hard woody capsules which split explosively at the apex at maturity one year after pollination and propel two shiny black seeds 30 or more feet from branches. Seeds take up to two years to germinate.

Most witchhazels may also be started by vegetative cuttings collected in early winter and rooted in a cool greenhouse under bottom heating. Pruning, if needed, can be performed in any season. Rarely in a wild population will you come upon a variant (see cultivars below).

‘Amethyst’ – is a rounded bush that grows 8 to 10 ft. tall and wide with
gray-green foliage that turns a brilliant red and orange in autumn. Deep
red purple flower best backed by some lighter color. lightly fragrant, reddish purple blossoms in mid-winter.

‘Quasimodo’ – a semi-dwarf selection (4-6 feet tall) introduced to the European nursery industry in 1980. Light orange flowers are highly fragrant, along with a compact-spreading habit. Spring foliage is richly greenish-blue and remains quite attractive throughout the season.

‘Autumn Embers’ – an 8-10 feet shrub with showy, fragrant, copper-red flowers.

Precise Care For Calatheas

Posted by Hugh on January 24th, 2023

Calatheas, also called Peacock plants, are among the most beautiful of foliage house plants, but their care can be challenging. Plants prefer low to medium bright spot in your home and look their best away from direct sunlight. The key to success is high room humidity and are best paired up with similar tropical favorites like philodendrons and Phalaenopsis orchids.

Select plastic, terra cotta, or ceramic containers. The pot should be two inches wider than the one it was purchased in. Grow calatheas in a humus-rich peat /bark /perlite growing media that retains moisture. The soil needs to be moist much of the time to permit roots to breathe. Calathea roots love moist soil but resent overwatering or letting pots set in saucers of water over long periods; this often leads to root rots and eventual loss of the plant.

Houseplants need a regular dose of fertilizer to look their best. The best time to fertilize is when the plant is actively growing; for most plants that means fertilizing in the spring and summer (mid-March to mid-October).

*Calathea lancifolia* (Rattlesnake Plant)

Feed calatheas a weak solution of fertilizer and be careful not splash fertilizer on their sensitive foliage. Calathea leaves are highly sensitive to chemical burn. Similarly, over-fertilizing your Calathea could cause the roots to burn, and this will slowly kill the plant.

Calatheas are susceptible to few pests, principally spider mites and mealybugs. Inspect plant(s) regularly and treat pests is to clean the leaves with a mixture of water and dish soap in a spray bottle. As houseplants calatheas are not harmful to pets and young children. Pruning-wise, remove old worn leaves that have lost most of their decorative color(s).

Plants hobbiests are currently witnessing a calathea renaissance. Some leading varietes are: C. lancifolia (Rattlesnake plant), C. orbifolia, C. ‘Roseopicta’, C. veitchiana ‘Medallion’, and C. zebrina (Zebra plant).

Propagate your plant by separating the plant’s root mass with a sharp knife.

Calatheas are not harmful to pets and young children.

Growing Jewel Orchids

Posted by Hugh on January 12th, 2023

Jewel Orchids (Ludisia discolor) are native to the tropical forests of Southeast Asia. Compared to the tree-climbing epiphytic Phalaenopsis and Cattleya orchids, Jewel Orchids are terrestrial plants that grow on tropical forest floors. Jewel orchids are grown primarily for their spectacular dark and colorful veined ovate foliage and secondarily for their flowering.

Jewel orchid at Biltmore Estates in Asheville, NC

Jewel orchids grow in low light and high humid environs; their roots grow in soil-less media containing sphagnum peat moss or coarse bark. Consider them as low light house plants in 80%-90% shade. Leaves feel velvety and are quite decorative with red-white or golden veins; leaf colors are burgundy to maroon to richly green.

Jewel orchids bloom once yearly, primarily in winter. Plants produce clusters that rise up on long floral spikelets above the dark exotic foliage. Jewel orchids grow well in well-drained, slightly damp soils. You need to lightly fertilize every 2-3 weeks during the spring-summer growing season and half that in late fall and winter months.

Flowering is something to look forward to. Small white flowers appear on long spikes that shoot up. Flowers may lack fragrance, but the bloom stalks are lovely over 4-5 weeks.

Common growing problems are twofold: 1. root rot, likely caused by overwatering or poor media drainage, and 2. brown, curling leaves caused by low humidity or excess light. Foliage spotting is an early symptom; follow up immediately to alter the plant’s environment.

Jewel orchids are not commonly available local garden centers but are sold at on-line plant sources. Two genera – Ludisia discolor and Macodes petola – are popularly listed online. L. discolor ‘Alba’ – leaves are bright green with white veins and white flowers.

There are other genera of jewel orchids to collect: Ludochilus, Anoectochilus, Dossinochilus, and hybrids thereof. Lightning Bolt Jewel Orchid (Macodes petola (velvety leaves / silver veins) and Lava leaf orchid (M. sanderiana x limii).

Jewel orchids are fast growing and make terrific terrarium plants. Repot the plant annually to refresh the soil.