Bulb · Iridaceae
Montbretia
Crocosmia × crocosmiiflora
Drop the corms in once and crocosmia takes off, firing up arching sprays of fiery summer color that hummingbirds dive for.
Full sun
Every 3–7 days
USDA 5–9
2–4 ft · 0.6–1.2 m
Overview
Crocosmia, the plant most gardeners still call montbretia, is a summer-flowering perennial in the iris family that grows from a corm instead of a true bulb. It came up out of southern Africa and earned a permanent spot in gardens for its arching stems of tubular flowers in red-hot oranges and yellows that fire off from June into August. The leaves shoot up sword-shaped like a young iris, and the blooms line up along one side of every stem.
Best of all, it practically grows itself. Plant it in full sun to light shade on soil that drains and the clump charges outward season after season, multiplying its corms in chains down in the ground. That drive is a thrill to watch, but worth flagging early, because in mild regions crocosmia really runs and has bolted into the wild along the US Pacific coast, so a clump now and then needs pulling back into bounds.
The flowers act like a beacon for hummingbirds, which alone makes growing it a treat, and the whole plant stays safe around pets, children, and grazing animals. Where winters land in zones 5 to 9 the corms tough out the cold right in the ground and surge back stronger every single year.
Care
The short version: plant it in full sun to light shade, sink the corms a few inches down in spring, keep the soil draining freely but never bone-dry, and split a clump every few years to keep the color blazing.
Light
Crocosmia really blooms in full sun, though it takes partial sun or light shade in stride. Pour on the sun and the stems stand sturdier and the flowers come thicker, so grab the most open spot you can give it.
Water
Keep the soil evenly moist all season, because this plant hates to dry out. The trick is that it will not sit in soggy ground either, so the drainage has to move water along or the corms rot. Water every 3 to 7 days when things turn dry, and back off where the soil holds its moisture.
Soil
Set it in humus-rich, well-drained soil, and good news, clay, loam, and sand all do the job as long as water keeps moving through. Crocosmia shrugs off pH worries and grows happily anywhere from 6.0 to 8.0, so most beds welcome it straight away.
Temperature
It powers through a huge range, from about 28°F to 86°F (-2°C to 30°C), and heat barely registers. The corms can take cold damage past their hardiness range, though, which is exactly why colder zones pull them up for winter.
Humidity
Plain outdoor air keeps it happy, so there is no humidity number to fuss over. What to dodge is dry, baking heat, since that stresses the foliage and rolls out the welcome mat for spider mites.
Feeding
Hit it with a balanced general-purpose fertilizer at planting, then again in spring as growth fires up, and that is all it wants. Crocosmia is no heavy feeder, and piling on rich soil just pushes leafy growth and robs you of flowers.
Pruning
Once the blooms burn out, cut the flower stems back to where they meet the leaves. Let the foliage stand until it dies back on its own, because it is still pumping energy into the corm, then cut it to the ground for the season.
Repotting
Crocosmia would rather pack a bed than sit in a pot, and it crowds itself fast. Divide the corm clumps every 2 to 3 years to keep them charging, and read congested clumps, weaker flowering, and smaller blooms as the plant begging for a split.
Size & spacing
A clump rockets to 2 to 4 feet (61 to 122 cm) tall and spreads 12 to 24 inches (30 to 61 cm) wide. Set the corms about 6 inches apart at planting and they knit into a full, thriving stand within a season or two.
When to plant
Crocosmia runs on a wonderfully simple seasonal clock. Get the corms in the ground in spring once the last frost clears, and the flowers come roaring through the heart of summer, roughly June to August. In colder zones, plan to lift and store the corms before the hard freezes hit, and you keep the show rolling next year.
Northern hemisphere
Southern hemisphere
Typical months for a temperate climate: start earlier in warm zones, later where spring frosts linger.
- Plant: Plant corms in spring after the last frost date, 3-5 inches deep and about 6 inches apart.
- Harvest: Summer bloom, roughly June to August.
Hardiness
USDA hardiness zones: 5–9
Temperature: down to -29°C
Troubleshooting
Crocosmia is a tough, easygoing grower, so trouble hardly ever crops up. When it does, it turns up on the leaves or down at the corm, and that is where to look. Match the symptom below, jump on it early, and the plant powers right through.
Mushy corms and plants that never break ground
Corm rot strikes when the soil stays waterlogged or the cold dives below what the corms can handle, and then the plants never break ground. Dig a few up and check for soft, discolored tissue to confirm. Fix the drainage, and in zones colder than 5 either pile on winter mulch or lift the corms and store them dry like gladiolus.
Fix:
- Improve drainage and avoid standing water
- In cold zones, lift and store corms dry over winter or apply winter mulch
Speckled, bronzing leaves laced with fine webbing
Leaves gone stippled and bronzed under fine webbing mean spider mites have moved in, and they strike fast in hot, dry spells. Hit the foliage with a strong jet of water to blast them loose, then keep the soil moist and steer the plant clear of dry wind. Insecticidal soap or horticultural oil finishes off the stubborn holdouts.
Fix:
- Spray foliage with a strong jet of water to dislodge mites
- Improve air moisture and avoid drought stress
- Apply insecticidal soap or horticultural oil as needed
Chewed-down foliage and flowers that never launch
When the leaves get grazed to the ground and the blooms never launch, rabbits are usually the raiders. Hunt for clean-cut foliage near the ground and droppings nearby to nail it down. A wire cage or fence around the clump is the surest way to lock them out where rabbit pressure runs high, with repellents backing it up.
Fix:
- Protect plants with fencing or wire cages
- Use repellents where appropriate
Toxicity
Here is great news for homes with pets and kids: crocosmia is not toxic. No reputable source flags any part of it as poisonous, and gardeners grow it as a hummingbird magnet precisely because it is safe to have around. Wash your hands after handling the corms, the same quick habit you would keep with any garden plant.
Safe for
People · Cats · Dogs · Horses · Rabbits · Livestock · Birds
Cats None
Nothing to sweat with cats. One that swats at the foliage or chomps a leaf comes to no harm.
Dogs None
Dogs are in the clear too. A curious nibble of the leaves or flowers brings no poisoning, though a big mouthful of any plant can briefly upset a sensitive stomach.
Horses Safe
Horses can graze right beside a clump without trouble, since crocosmia carries no toxin known to harm them.
Rabbits Safe
Rabbits flat-out love the foliage and take no harm from it, which is more a headache for your blooms than for the rabbit.
Livestock Safe
Cattle, goats, or sheep that browse it run no poisoning risk, since the plant is not listed among forage hazards.
Birds Safe
Birds thrive around it, and hummingbirds in particular dive for the tubular flowers and their nectar, a big part of why gardeners grow it.
People Safe
No toxicity is reported for people. Just wash your hands after handling the corms, the same routine you would follow with any garden plant.
Generally considered safe to handle; wash hands after gardening as a routine precaution.
Varieties
Just a handful of named cultivars make up most of what you will find for sale, sorted mainly by flower color and bloom time. These are the standouts worth chasing.
Lucifer
Lucifer, an Alan Bloom hybrid, fires showy scarlet-red tubular flowers down arching stems, and it ranks among the hardiest and most popular of the bunch, a powerhouse pick.
Emily McKenzie
Emily McKenzie packs large orange flowers stamped with mahogany-red throats and kicks off later in the summer than most, stretching the color show.
Solfatare
Solfatare teams soft apricot-yellow flowers with eye-catching bronze-tinted foliage.
Star of the East
Star of the East grabs attention with its large, soft orange blooms.
How to propagate
The best part is that crocosmia all but multiplies itself, so most growers never buy a second batch. Splitting clumps is the fast, sure-fire route to more plants, while seed is a slower gamble worth taking only when patience runs deep.
DivisionEasy
Early spring before new growth begins. · One growing season; flowering typically the same or following summer.
Division is the fast, sure-fire way to crank out more crocosmia. Lift the congested corm clumps in early spring before new growth starts and pull them apart, repeating every 2 to 3 years to keep the plants charging. The divisions dig in within a season and often flower that same or the following summer, so you see results quick.
Bulbs & cormsEasy
Spring, after the last frost. · One growing season.
Here is a bonus the plant hands you: each corm builds a chain of offsets you can break off and grow on. In spring once the frost clears, separate the offset corms and replant them 3 to 5 inches deep and about 6 inches apart. They root and establish over a single growing season, no trouble at all.
SeedModerate
Collect ripe seed from capsules; sow when available. · Two or more seasons to reach flowering size; some seed may not be viable.
Seed is the slower, dicier route, so brace for patience. Gather the ripe seed from the capsules and sow it when you have it, but count on two or more seasons before the plants reach flowering size. Seedlings from hybrids rarely come true to the parent, and some seed just will not be viable, so treat any wins as a bonus.
Myths
Crocosmia corms are true bulbs like tulips and have to be replanted every year.
Crocosmia grows from corms, not true bulbs, and that flips the whole routine in your favor. In zones 5 to 9 the corms stay right in the ground and naturalize, charging back year after year. Only in colder zones do you lift and store them, the same way you handle gladiolus.