Bulb · Liliaceae
Crown Imperial
Fritillaria imperialis
A commanding spring bulb topped with drooping bells and a skunky scent that teaches voles to keep their distance.
Full sun
Every 7–14 days
USDA 5–8
3–4 ft · 0.9–1.2 m
Overview
Crown imperial towers over the usual spring bulbs, throwing up a stout stalk 3 to 4 feet (91 to 122 cm) tall that carries a ring of drooping bells beneath a pineapple-like crown of leaves. A member of the lily family, it comes from the rocky slopes of the Middle East and the Himalayas. Give it the back of a border, where its early color reads at a distance.
Every part of the plant releases a strong skunky, musky smell, and that odor works in the gardener's favor. It deters voles, mice, and other burrowers from disturbing the bulbs. The trade-off is placement: keep it back from a path or doorway, because you will smell it whenever you brush the foliage.
This bulb performs best when it is left undisturbed. It establishes slowly, then flowers for years, and it resents being lifted, so choosing the right spot up front matters. Get the drainage right and orient the bulb correctly at planting, and crown imperial settles into a reliable perennial that returns each spring on its own.
Care
The short version: full sun and deep, rich, sharply drained soil. Keep it evenly moist while it grows in spring, let it dry once the foliage yellows and dies back, and leave the bulb in the ground rather than lifting it.
Light
Crown imperial flowers hardest in full sun, though it accepts a little afternoon shade in regions where spring turns hot early. In deeper shade the stalks stretch and lean toward the light and set fewer bells.
Water
Hold the soil evenly moist through spring growth, watering every 7 to 14 days whenever rainfall runs short. When the foliage dies back in early summer, cut off water and let the bulb dry, because standing moisture is what rots it once it goes dormant.
Soil
Plant into deep, rich, well-drained loam or clay loam worked over with organic matter. A pH between 6.0 and 7.5 suits it, but the drainage outranks everything else here, since water sitting around a dormant bulb is fatal to it.
Temperature
This is a tough, cold-hardy bulb rated for -20°F to 75°F (-29°C to 24°C). It needs the winter chill to set flower and takes hard frost without harm, but it resents the heat and humidity of hot summers.
Humidity
Ordinary open-air humidity is all it asks, so there is no target reading to hit. What counts more is air moving through the leaves, because still, crowded, damp foliage is exactly what leaf spot and rust need to take hold.
Feeding
Work a balanced bulb fertilizer or compost into the soil at fall planting, then feed once more in early spring as the shoots break the surface. That seasonal feeding is all it requires to flower well.
Pruning
Cut away the spent flower stalk once bloom finishes, but leave the leaves in place until they yellow and die back naturally. Those fading leaves are moving next season's flower back down into the bulb as stored energy.
Repotting
Crown imperial does best left in the ground. Lift and divide a clump only every 3 to 5 years, and then only when flowering tails off or the bulbs have grown too crowded to perform.
Size & spacing
Each stalk climbs 3 to 4 feet (91 to 122 cm) tall and spreads roughly 12 to 18 inches (30 to 46 cm). Space the bulbs 9 to 12 inches apart so clumps have room to develop and air can pass between the stems.
When to plant
Crown imperial keeps time by the bulb's own cycle. Plant in fall while the soil still works easily, let the shoots come up early, and enjoy the bells from mid to late spring before the top growth dies back and the bulb rests underground through summer.
Northern hemisphere
Southern hemisphere
Typical months for a temperate climate: start earlier in warm zones, later where spring frosts linger.
- Plant: Plant bulbs in fall, 6 inches deep and 9-12 inches apart, positioned sideways to prevent water collecting in the stem cavity
- Harvest: Mid to late spring, April to June
Hardiness
USDA hardiness zones: 5–8
Temperature: down to -29°C
Troubleshooting
Nearly every crown imperial problem begins at the bulb below ground or appears on the leaves once growth is underway. Read the symptoms early and you can respond before a single plant becomes a spreading problem. Find the match below, then act while intervention still changes the outcome.
A soft, mushy bulb and a plant that never comes up
You are looking at bulb rot, and the cause is nearly always saturated ground or a bulb set upright, which lets water sit in the hollow stem cavity and rot the tissue from the center out. Lift a suspect and you will smell it: the flesh around the central hole turns brown and foul. Cull anything far gone, replant the firm survivors on their side in sharply drained soil, and fork in grit so water keeps draining rather than pooling.
Fix:
- Discard severely rotted bulbs
- Replant healthy bulbs on their side in sharply drained, raised soil
- Improve drainage with grit or organic matter
Mottled, streaked leaves and a plant losing vigor
Irregular light-and-dark mottling that stays put when you rub it is the mark of mosaic virus, and aphids are the usual carriers moving it plant to plant. Once a bulb is infected there is no treatment, so rogue out the affected plants and destroy them. Keep the sap-sucking insects that spread it under control, and disinfect blades between plants so a single cut does not seed the whole bed.
Fix:
- Remove and destroy infected plants to limit spread
- Control aphid vectors
- Disinfect tools between plants
Spots and rusty pustules on the leaves
This is leaf spot and rust, two fungal problems that establish when leaves stay wet and packed together with no air moving between them. Turn a leaf over and look for raised, rust-colored pustules on the underside, then strip out every marked leaf. Open the planting up for airflow and keep irrigation off the foliage, and the infection has no damp surface left to spread across.
Fix:
- Remove and destroy affected foliage
- Improve air circulation
- Avoid overhead watering
Toxicity
Give this plant real respect. Steroidal alkaloids run through every part of crown imperial, and the bulb is the most dangerous, concentrating imperialine and related compounds. Ingestion brings vomiting and stomach pain, and a large dose can disturb the heartbeat, so keep bulbs away from pets, livestock, and children. The strong skunky odor turns most animals away, but it is a deterrent rather than a safeguard.
Toxic to
Cats · Dogs · Horses · Rabbits · Livestock · Birds · People
Cats Toxic
Expect drooling first, then vomiting and diarrhea, once a cat chews into a bulb. A heavier dose of the steroidal alkaloids can leave the animal weak and dull.
Dogs Toxic
Dogs tend to dig at the bulbs, and a mouthful sets off drooling, an upset stomach, and vomiting. Enough of the alkaloids can push the heart rhythm out of step.
Horses Toxic
The bulb alkaloids irritate a horse's digestive tract and, in quantity, can disturb heart rhythm. Keep crown imperial well away from any grazing.
Rabbits Toxic
Not safe to nibble in any amount. A small taste of bulb or leaf can start a rabbit drooling and refusing food, with diarrhea following.
Livestock Toxic
Cattle, goats, and sheep that reach the bulbs get digestive upset, and a large enough dose of the alkaloids can trigger heart-rhythm trouble.
Birds Toxic
Keep bulbs and foliage off-limits to birds, because the same alkaloids that harm mammals can sicken a bird that pecks at them.
People Caution
No part is food. A fresh bulb brings on vomiting and stomach pain, and a large amount of the alkaloids can affect the heart, so keep bulbs out of reach of children.
All parts of the plant have a strong skunky or musky odor, which usually discourages tasting; wash hands after handling bulbs.
Helpline numbers
United States
ASPCA Animal Poison Control: (888) 426-4435 (fee applies)
Poison Control: (800) 222-1222
Canada
Poison Centres: 1-844-764-7669
Varieties
A handful of named forms turn up most often in gardens, plus one much smaller relative worth recognizing. These are the ones to seek out.
Rubra
The classic form, ringed with nodding bells in burnt orange through to a deep vermilion red.
Lutea
The yellow selection, brightening a spring border with clear gold bells in place of the usual orange.
Fritillaria meleagris (Checkered Lily)
A far smaller relative at 8 to 12 inches, its nodding bells checkered in purple, red-brown, and white after the markings of a guinea hen's feathers.
How to propagate
Crown imperial increases slowly, and the patient vegetative methods reward you far sooner than seed does. Here is how each works and the time each one takes.
Offsets & pupsModerate
Lift and separate offset bulblets in late summer to fall when foliage has died back · 1-3 years to reach flowering size
The reliable route is to lift the whole clump in late summer or fall, after the foliage has died back, and detach the small offset bulbs from the parent. Handle each one gently, since a bruised bulb rots, and reckon on 1 to 3 years before an offset grows large enough to flower. Both bulbs and leaves carry the strong skunky, musky odor, which is normal for the plant.
DivisionModerate
Divide established clumps in fall every few years · 1-2 seasons
As a clump crowds itself, dig it in fall and split it every few years to keep it vigorous. Replant each piece immediately at the correct depth, set on its side so water cannot collect in the bulb, and it will resume flowering within 1 to 2 seasons.
SeedDemanding
Sow fresh seed in fall · Slow; 4-6 years or more from seed to first bloom
Seed is the slow route and demands patience. Sow it fresh in fall and the first bloom is 4 to 6 years off, sometimes longer, which is why offsets or division are the practical choice for most growers.
Myths
Crown imperial bulbs are edible because people say they can be eaten after cooking.
Fresh bulbs are poisonous and hold steroidal alkaloids, and while extension sources rate the poison severity as low, that is not a safe-to-eat rating. Treat the bulbs as toxic and never as food, and keep them out of reach of pets and children.