Bulb · Liliaceae
Crown Imperial
Fritillaria imperialis
A tall spring bulb capped with a ring of hanging bells and a bold skunky reek that sends voles packing.
Full sun
Every 7–14 days
USDA 5–8
3–4 ft · 0.9–1.2 m
Overview
Crown imperial towers over the rest of the spring bulbs, throwing up a thick, upright stalk 3 to 4 feet (91 to 122 cm) high that is ringed near the top with hanging, bell-shaped flowers and finished off by a spiky tuft of leaves reading like a pineapple. A member of the lily clan, it traces back to stony Middle Eastern slopes and the foothills of the Himalayas. Give it a place toward the rear of a border where its early color carries across the whole bed.
Every part throws off a heavy skunky, musky odor, and far from being a fault, that reek does real work. The scent drives off mice, voles, and the other burrowing pests before they reach the bulbs. It follows that you'll want the plant set a pace back from any path or door where you would brush against it and stir the scent up day after day.
This bulb asks only to be left in peace. It roots in slowly, then flowers year after year once it has taken hold, and it sulks if you lift it, so choose the site with a steady eye. Sort out the drainage and lay the bulb the right way, and crown imperial turns into one of those quiet performers that comes back each spring on its own.
Care
The short version: give it all-day sun and deep, fertile soil that drains hard. Hold the ground evenly damp through the spring push, let it run dry once the leaves brown off, and leave the bulb where it lies.
Light
Crown imperial throws its best flowers in full sun, taking only a little afternoon shade where the spring runs warm. Set it in deep shade and the stalks stretch tall and lean while the bell count drops off.
Water
Keep the ground evenly moist through the spring push, watering every 7 to 14 days when the rain comes up short. Once the leaves brown off as summer opens, cut off the water and hold the bulb dry, because wet ground is exactly what rots it.
Soil
Set it in deep, rich, well-drained loam or clay loam with a good load of organic matter forked through. A pH from 6.0 to 7.5 suits it well, and sharp drainage counts above all else, since sitting water kills the bulb outright.
Temperature
This is a hardy, cold-loving bulb that rides out -20°F to 75°F (-29°C to 24°C). It needs a winter chill to set flower and takes a hard freeze in stride, but heat and muggy summers wear on it.
Humidity
Plain outdoor air suits it, so there's no number to chase. Moving air around the leaves counts for more here, because packed, damp foliage is what draws in leaf spot and rust.
Feeding
Fork a balanced bulb fertilizer or compost into the ground at fall planting, then feed once more early in spring while the shoots are splitting the surface. That pair of seasonal feeds is the whole of what it asks to flower strongly.
Pruning
Cut away the spent bloom stalk after flowering finishes, but let the leaves stand until they yellow and die back on their own. Those fading blades are pouring next season's flower back down into the bulb.
Repotting
Crown imperial prefers to be left where it sits. Lift and split a clump at most once in 3 to 5 years, and then only where the blooming tails off or the bulbs pack together too tight.
Size & spacing
Each stalk climbs 3 to 4 feet (91 to 122 cm) tall over a spread near 12 to 18 inches (30 to 46 cm). Set the bulbs 9 to 12 inches apart to give each clump elbow room and let air pass between them.
When to plant
Crown imperial keeps to the bulb's own timetable. Set it out in fall as long as the ground still turns easily, watch the shoots break through early, and take in the bells through the back half of spring before the plant browns off and rests below ground all 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
The bulk of crown imperial troubles begin down in the bulb or surface along the blades after growth is underway. Read those first hints in time and a small fault can be stopped before it widens. Pair the description here with what sits in front of you, then act while your effort still counts.
A bulb gone soft and brown, and a stalk that never surfaces
You are dealing with bulb rot, and the cause is nearly always soggy footing, or a bulb stood upright so that water pools inside the stem hole. Dig up a suspect one and the tissue around that central cavity turns brown, slimy, and reeking. Bin the worst of them, tuck the firm ones back onto their sides in ground that drains fast, and fork through grit so the water keeps moving.
Fix:
- Discard severely rotted bulbs
- Replant healthy bulbs on their side in sharply drained, raised soil
- Improve drainage with grit or organic matter
Blotchy, streaked blades and a plant running out of steam
Light-and-dark mottling that stays put no matter how you rub it, along with buckled, twisted leaves, is the mark of mosaic virus, and aphids usually bring it. Nothing cures a plant once it carries the virus. Pull the sick ones and destroy them, keep the sap-feeding insects down, and clean your blades between plants so the virus doesn't ride along.
Fix:
- Remove and destroy infected plants to limit spread
- Control aphid vectors
- Disinfect tools between plants
Discrete spots and rusty bumps marking the foliage
You are looking at leaf spot and rust, two fungal problems that set in where the leaves stay wet and packed close together. Turn a leaf over and check the underside for the raised, rust-colored pustules, then strip off anything marked. Open up the spacing and keep the blades dry, and the trouble stops moving.
Fix:
- Remove and destroy affected foliage
- Improve air circulation
- Avoid overhead watering
Toxicity
Give this one real weight. Steroidal alkaloids run through the whole plant, and the bulb holds the biggest load, packed with imperialine and its relatives. Swallow a piece and it brings vomiting and belly pain, while a large mouthful can knock the heartbeat off its stride, so hold the bulbs well clear of livestock, pets, and any child. The heavy skunky reek turns most animals away, though that is no guarantee.
Toxic to
Cats · Dogs · Horses · Rabbits · Livestock · Birds · People
Cats Toxic
Bite into a bulb and a cat begins to drool, then throws up and gets loose stools. Take in more of the alkaloids and the animal turns weak and dull.
Dogs Toxic
A dog will paw and dig at these bulbs given the chance. Swallowing one sets off drooling, a churning stomach, and vomiting, while a large mouthful can send the heartbeat off its steady rhythm.
Horses Toxic
The bulb's alkaloids sour the gut of a horse and, taken in bulk, can rattle the heart's rhythm. Keep crown imperial nowhere near the grazing.
Rabbits Toxic
No safe nibble here. Even a light taste of the bulb or a leaf sets a rabbit slobbering and turns it away from its food, with loose stools close behind.
Livestock Toxic
Grazing cattle, goats, or sheep that reach the bulbs get a churned-up gut, and a big enough dose of the alkaloids can throw the heartbeat off.
Birds Toxic
Count the bulbs and leaves as off-limits, because the alkaloids that sicken mammals can do the same to a bird pecking at them.
People Caution
Nothing on this plant is food. Swallow a fresh bulb and vomiting and belly ache follow, while a large helping of the alkaloids can reach the heart, so store the bulbs out of a child's reach.
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 crown imperials turn up again and again, plus one much smaller relative worth knowing on sight. Look for the three below.
Rubra
The original crown imperial, holding out a whorl of downward-hanging bells that glow burnt orange to deep vermilion red.
Lutea
The gold-flowered form, its bells a clean, clear yellow that brightens a spring border where Rubra runs orange.
Fritillaria meleagris (Checkered Lily)
A far smaller relative, only 8 to 12 inches tall, with nodding bells checkered in purple, red-brown, and white after the pattern of a guinea hen's feathers.
How to propagate
Crown imperial builds up its numbers at a slow pace, and the unhurried methods reward you far better than growing from seed. Below is what each one involves and how long the wait runs.
Offsets & pupsModerate
Lift and separate offset bulblets in late summer to fall when foliage has died back · 1-3 years to reach flowering size
Your surest route to more plants is to dig the clump toward the end of summer or into fall, after the foliage has withered, and ease off the little offset bulbs at the base. Handle them softly, since they bruise at a touch and a bruised bulb rots, and reckon on 1 to 3 years before one grows large enough to flower. Bulbs and leaves alike give off that strong skunky, musky smell you won't mistake.
DivisionModerate
Divide established clumps in fall every few years · 1-2 seasons
Once a clump grows dense, lift it in fall and break it apart every few years. Set each piece back at once, planted deep and laid sideways so nothing pools in that stem cavity, and it will find its feet and flower again inside 1 to 2 seasons.
SeedDemanding
Sow fresh seed in fall · Slow; 4-6 years or more from seed to first bloom
Seed asks for real patience. Fresh seed sown in fall leaves you waiting 4 to 6 years, sometimes longer, for that first bell to open, so most growers reach for offsets or split a clump instead.
Myths
Crown imperial bulbs are edible because people say they can be eaten after cooking.
The fresh bulb is poisonous and loaded with steroidal alkaloids, and while extension sources put the poison severity at low, that low rating is no invitation to eat it. This is not a food plant, so treat the bulbs as toxic and store them out of reach of children and pets.