How to Grow Crown Imperials (Fritillaria imperialis)
One of the most beautiful spring flowering bulbs to grow are crown imperials, also known as Fritillaria imperialis. If you ever see them for sale, consider buying some for your garden.
Whenever I’m putting together different designs of plant combinations—whether they’re in beds, borders or containers—I always aim to incorporate a focal point.
That’s usually something large, stately and showy—something that stands out above the rest of the display.
When it comes to spring-flowering bulbs, the plants that always satisfy this requirement are the crown imperials.
Fritillaria imperialis, as the common name suggests, is a regal plant, putting on a wonderful display in the late spring that can last for up to four weeks.
It produces whorls of large bell-shaped orange, red or yellow flowers, set beneath a crown of leafy bracts on stems up to 1.2m (4ft) tall. The flowering arrangement gives rise to its other common names—crown on crown or royal crown flower.
How to Grow Crown Imperials
Crown imperials grow best in fertile, well-drained soil in a position of good light, although they will tolerate some shade.
When planting, handle the bulbs carefully as they can be quite fragile. Prepare a rather large planting hole, because the bulbs develop a fairly deep root system.
Mix in plenty of well-rotted compost or other planting medium—well-rotted manure is a good choice since crown imperials need a good, rich soil.
Rotting can be a problem in heavy soils, so a 2–3 inch (5 – 7.5cm) deep layer of sharp sand or grit in the bottom of the planting hole with reduce the likelihood of this.
Similarly, plant bulbs on their side to prevent water collecting in their hollow crown, which leads to rotting.
As for planting depth, much depends on the soil. Some people recommend planting up to 10 inch (25cm) deep in light soils, and only 4in (10cm) deep in heavy soils. Providing you’ve prepared the soil well, I would suggest you plant at 6in (15cm).
You don’t need a lot of bulbs to make a big splash—usually one to three bulbs will create a great display—but plant more if you want to—and space them 6in (15cm) apart.
Because they are heavy feeders, apply a high potash granular feed when the foliage emerges—I use a rose fertilizer—and mulch around the stems with more organic matter.
Failure to flower after the first year is usually due to a lack of potash fertilizer (which is necessary for bloom formation for the following year), or rotting taking place in the crown of the bulb.
Crown imperials also make great pot plants to adorn the patio or greenhouse. For best effect, plant one bulb into a 6 – 8in (15 – 20cm) pot using a good quality compost.
Avoid disturbing the bulbs at any time and only cut down the stems once they have fully turned brown and died back. Although these plants are fairly pest and disease-free you’ll need to watch out for bright red lily beetles, which attack this fritillary as well.
There is one possible downside to crown imperials—the smell. They are supposed to have a bit of a ‘foxy’ whiff to them—although I have never been able to smell it. So, if you have a sensitive nose, they’re maybe not a plant to have too close to the house or patio. However, there is an upside to even this—some people swear that the smell discourages moles, deer, squirrels, rabbits and rodents.
This content is accurate and true to the best of the author’s knowledge and is not meant to substitute for formal and individualized advice from a qualified professional.