How to Grow and Care for Crown Imperials

Crown imperials makes a bold decorative statement that has been appreciated by plant-lovers since ancient times. These low-maintenance bulbs prefer full sunlight and well-draining soil in USDA hardiness zones 5-8, where they are planted in fall and come back year after year.

Keep in mind that crown imperials are toxic to people and pets.

Crown Imperials Care

Lining a border with these bulbs creates a colorful show in spring. Here are the main care requirements for crown imperials:

• Plant in a sunny spot that ideally gets at least six hours of sunlight per day.
• Prepare nutrient-rich, well-draining soil.
• Plant the bulbs on their side so that water will not accumulate in their stem holes.
• Water occasionally during the growing season, though these bulbs are fairly drought-tolerant.
• Fertilize lightly in spring and again in fall.

Light

Crown imperials prefer full sun (6 to 8 hours of sun per day) and will also grow in semi-shade, woodland conditions.

Soil

Overall, crown imperials are flexible in their ability to grow in a variety of well-drained soils that range from a pH of acid, neutral, or alkaline. Native to locations such as the Himalayas and Turkey, they are most happy grown on cliffs and rocky slopes in well-drained, warm, semi-arid summer soil.

Water

Water only when plants are actively growing in the spring. Give them about one inch of water per week if it does not rain. Take care to keep only the top six inches of soil moderately moist as the crown imperial does not need an excessive amount of water and can tolerate drought.

Temperature and Humidity

Crown imperials are tough plants and can survive in a range of humidity levels and temperatures. The bulbs, in fact, are tolerant to temperatures as low as -30 degrees Fahrenheit.

Fertilizer

You'll want to give your crown imperials an organic fertilizer in the spring and then a diluted liquid fertilizer in the fall. For the amount to use, follow the product label instructions. In autumn, add one inch of compost on top of the bed and two inches of mulch to insulate the bulbs and keep weeds down.

Types of Crown Imperials

There are many varieties of this showy plant, with names that are almost as striking as the flowers they produce—including several that honor famous composers.

• F. imperialis ‘Maxima Lutea’ is perhaps the most popular variety. Its flowers are yellow, creating a crown distinctively dramatic in form.
• F. imperialis ‘Aurora’ has orange-red flowers. It grows 2 to 3 feet tall and is hardy from USA zones 5a to 8b.
• F. imperialis ‘The Premier’ has flowers of a softer orange akin to the shade of a tangerine, with light-purple veins. It grows between 24 and 36 inches tall.
• F. imperialis 'Aureomarginata' displays an even softer shade of orange blooms and dual-colored green-golden foliage similar to a spider plant. It grows up to 36 inches tall.
• F. imperialis ‘Rubra Maxima’ offers a distinct orange-red that looks caramelized and nearly burnt. Flowers are shaped like human eyes, covered with long pistils and stamen. This plant grows between 40 to 44 inches.
• F. imperialis ‘Brahms’ has salmon-pink flowers, and unlike other varieties, it does not have the scent to deter rodents and voles.
• F. imperialis ‘Beethoven’ is a dwarf variety growing about 2 feet tall. It has creamy orange flowers that grow atop a purple base and is especially sensitive to water-retentive soil.
• F. imperialis ‘Bach’ is another dwarf variety growing only an average of 2 feet tall. Flowers are red with nuanced shades of orange. In addition to the usual ability to deter deer and rodents, the Bach attracts bees like many other bee-friendly flowers you can welcome into the garden.

Pruning

In summer, the foliage will go dormant. Trim off spent flowers but leave the foliage on the plant so that it can send energy to the bulb for the next season's growth.

Propagating Crown Imperials

Every three to five years in the late summer or early fall depending on your climate zone (August in the lower end of the zone spectrum), dig up all the mature bulbs, separate, and replant them. This not only produces new plants, it also helps the plants continue to thrive and put on a flower-rich show season after season.

1. Carefully dig up the bulbs with a shovel and try to avoid injuring the bulbs.
2. Gently divide the bulbs into sections or individual bulbs.
3. While you can replant larger bulbs right away at the same depth as the original plant, it is better to pot any smaller bulbs in potting soil and bury them in the ground during the winter to protect the roots from cold injury. You can also plant the bulbs in a cold frame. Let the plants grow for a full year before transplanting them. During that time, they need bright indirect light and should be watered to be kept evenly moist when there is no precipitation.
   

Overwintering

The plants do not need any winter protection, as their foliage has already died back during the summer. If you live in a very mild climate, dig up the bulbs in the early winter and bring them inside. After they are thoroughly dried, store them in the refrigerator for 4 to 6 weeks before replanting them in the ground in early spring. This mimics the natural period of cold temperatures that the bulbs need to spur them into another cycle of growth.

Common Pests & Plant Diseases

This plant is truly resistant to most common diseases and pesky invaders. One thing to watch out for is invasion by scarlet lily beetles which will eat holes in the leaves. Unfortunately, the same insecticides that work on these beetles also harm the plant, so a better strategy is to remove the bugs by hand and/or to set up glue traps around the plant. The skunky odor of the bulb helps deter rabbits, voles, squirrels, and deer.

How to Get Crown Imperials to Bloom

As long as the bulbs have been planted properly, crown imperials should bloom readily each spring, offering a variety of colors depending on which type was planted.

Bloom Months

Crown imperials usually bloom in spring until early summer, from April until June.

What Do Crown Imperials Look and Smell Like?

Crown imperials form a unique shape on top of a bold stem, with pendant, bell-like flowers hanging below a crown of leaves. Different varieties emit different fragrances that range from skunky to sweet.

How to Encourage More Blooms

The striking bell-shaped flowers of this plant reach their full size and color display when situated in full sun. The plant can grow in partial shade as well, but this will lead to duller and smaller blooms. If the plant is not flowering in the first year, it could be that the soil needs a bloom-boosting fertilizer that is high in phosphorus and potassium.

Caring for Crown Imperials After They Bloom

Once the flowers are finished, cut down crown imperials to just above ground level. No particular care is needed until fertilization again in the fall.

Deadheading Crown Imperials

Deadheading crown imperials will not cause them to put out more flowers, but removing the flower stem completely once blooming is finished will give the bulbs time to regenerate energy for next spring.