Bulb · Cannaceae
Canna Lily
Canna × generalis
Give it full sun, rich moist soil, and summer heat, and the canna throws bold leaves and flame-bright flowers until frost.
Full sun
Every 2–5 days
50–95°F · 10–35°C
70–120 days
Overview
The canna lily brings a tropical look to a temperate garden, with broad paddle-shaped leaves and tall spikes of bold flowers. Despite the name it is not a true lily at all, but a rhizome-rooted perennial in the family Cannaceae, closer kin to gingers and bananas. It grows fast and big, from a knee-high bedding type up to a towering plant near 8 feet (240 cm) tall.
Heat and water are what it lives for. Plant it in full sun and rich, moist soil, keep it watered through the hot months, and it rewards you with bloom from midsummer right up to the first frost. It shrugs off conditions that wilt fussier plants, which is part of why gardeners reach for it to anchor a bed or fill a large pot.
Hardiness sets the one real limit. In zones 7 to 10 the rhizomes ride out winter in the ground, but anywhere colder you lift and store them once frost cuts the plant down. Dividing those rhizomes every couple of years keeps the clump vigorous and hands you free new plants.
Care
The short version: full sun, rich soil kept evenly moist, and plenty of warmth. Feed monthly through the growing season, divide the clump every few years, and lift the rhizomes for winter wherever the ground freezes.
Light
Canna wants full sun, at least six hours a day, to flower its best. It will take partial shade or partial sun, but the bloom thins out and the stems stretch and lean toward the light.
Water
Keep the soil evenly moist, especially through active growth and hot spells. Canna is one of the few garden plants that tolerates some standing water, yet an established clump can ride out a short dry spell. Water every 2 to 5 days in the heat of summer.
Soil
Plant in rich, moist, well-drained ground worked with plenty of organic matter. It isn't fussy about pH, taking anything from 6.0 to 8.0, but drainage is what really matters, since soggy soil rots the rhizomes.
Temperature
Canna thrives in heat, growing happily from 50°F to 95°F (10°C to 35°C). It has no cold tolerance at all, so the first frost cuts it down and the rhizomes need lifting wherever winters freeze.
Humidity
Average outdoor humidity suits it fine, with no number to worry about. Its tropical roots mean it never minds muggy summer air.
Feeding
Feed monthly with a balanced all-purpose fertilizer through spring and summer while the plant is growing hard. For an in-ground clump, a soil test is the best guide to how much it actually needs.
Pruning
Cut off the spent flower stalks to keep new blooms coming and the plant looking tidy. After the first fall frost in cold zones, cut the foliage back to 2 to 3 inches (5 to 8 cm) before you dig the rhizomes for storage.
Repotting
Canna doesn't need routine repotting, but a crowded clump does need dividing every 2 to 3 years. Watch for dense growth, fewer flowers, or rhizomes shoving up out of the soil, all signs the plant has outgrown its space.
Size & spacing
Plants run from 18 inches to 1.5 to 8 feet (46 to 239 cm) tall depending on the type, so check the variety before you place it. Set the rhizomes 1.5 to 3 feet (45 to 90 cm) apart to give the big leaves room to spread.
When to plant
Canna runs on warmth and won't tolerate frost. In cold zones, start the rhizomes indoors a month or so before the last frost, move them out once the soil has warmed, and the flowers arrive from midsummer through the first fall frost.
Northern hemisphere
Southern hemisphere
Typical months for a temperate climate: start earlier in warm zones, later where spring frosts linger.
- Sow: Start rhizomes indoors in pots 3-4 inches deep about 4-6 weeks before the last frost in cold zones.
- Plant: After the last frost when soil has warmed, planting rhizomes 3-4 inches deep and 18-36 inches apart.
- Harvest: Blooms mid-summer through the first fall frost (about July to September).
Hardiness
USDA hardiness zones: 7–10
Temperature: down to -18°C
Troubleshooting
Most canna trouble traces back to wet soil or a handful of common pests, and it shows up on the leaves or the rhizomes. Catch it early and you can usually save the plant or the rest of the clump. Match what you see below, then act before it spreads.
Soft, mushy rhizomes and growth that stalls or topples
This is rhizome rot, and it almost always starts with soil that holds too much water. Lift a rhizome and you'll find brown, soft, foul-smelling tissue, sometimes alongside bud rot or bacterial blight. Throw out the rotted pieces, replant only firm sections in well-drained ground, and ease off the watering.
Fix:
- Lift and discard rotted rhizomes
- Replant healthy firm sections in well-drained, organically rich soil
- Reduce watering and improve drainage
Leaves that come in streaked, mottled, or twisted
Yellow streaking and distortion that no amount of water or feed will fix usually point to canna mosaic virus or aster yellows. There's no cure once a plant is infected. Pull and destroy it, keep sap-feeding insects in check, and never propagate from rhizomes you suspect carry the virus.
Fix:
- Remove and destroy infected plants to limit spread
- Control insect vectors
- Do not propagate from infected rhizomes
Leaves chewed, holed, or rolled shut
Rolled or webbed leaf edges hide the canna leaf roller, the most common culprit. Japanese beetles, slugs, and snails do the more obvious chewing and leave slime trails behind them. Pick the pests off by hand, strip away the damaged leaves, and clear plant debris so fewer of them make it through to next year.
Fix:
- Hand-pick caterpillars, beetles, slugs, and snails
- Remove and destroy rolled or damaged leaves
- Apply an appropriate labeled control if infestation is heavy
Toxicity
Good news for pet owners and parents: the canna lily is safe. The name fools people, but it is not a true lily and carries none of the poison those plants do. The ASPCA lists it as non-toxic to cats, dogs, and horses, and the starchy rhizome is even eaten as food in some countries.
Safe for
People · Cats · Dogs · Horses · Rabbits · Livestock · Birds
Cats None
Safe to have around cats. The ASPCA lists canna as non-toxic, so a curious nibble won't cause poisoning.
Dogs None
No toxicity for dogs. A dog that chews a leaf or digs up a rhizome faces nothing worse than a possible mild stomach upset from the roughage.
Horses None
Horses can graze near canna without harm, since the ASPCA clears it as non-toxic to them.
Rabbits Safe
The foliage carries no known toxin, so rabbits in the garden are fine.
Livestock Safe
Cattle, goats, and sheep are not poisoned by canna; the plant holds no compound that troubles grazing animals.
Birds Safe
Birds are in no danger around canna, and the hard seeds pass through without harm.
People Safe
No risk to children or adults. The rhizome is even eaten as a starchy food in some parts of the world.
No special handling required for toxicity; wear gloves if sensitive when dividing rhizomes.
Varieties
Cannas range from squat bedding plants to giants, in colors from soft cream to fiery red. A few names turn up again and again, and these are worth knowing.
Tropical Series
A compact, seed-grown line bred to stay small enough for containers and bedding.
South Pacific Scarlet
An award-winning cultivar grown from seed that throws bright scarlet flowers.
Canna indica (Indian Shot)
The wild canna, with flame-red flowers and hard round seeds that gave it the name Indian Shot.
How to propagate
Canna multiplies most reliably from division, which keeps a variety true, though patient growers can also raise it from its hard, shot-like seeds.
DivisionEasy
Spring at planting time, or in fall when lifting rhizomes for storage; divide crowded clumps every 2-3 years. · 2 to 6 weeks
Division is the easy way to multiply canna and the surest way to keep a variety true. Split the rhizomes in spring or while lifting them in fall, making sure each piece holds at least one eye, then let the cut surfaces dry for a few days before they go back in the ground. Divide a crowded clump every 2 to 3 years and the new pieces take hold in about 2 to 6 weeks.
SeedModerate
Spring, started indoors. · Several weeks to germinate
Growing from seed is slower and less predictable. The hard-coated seeds, the ones that earn the name Indian Shot, need nicking and a soak before they'll sprout, and even then germination runs to several weeks. Start them indoors in spring, but expect that seed-grown plants may not come true to type.
Myths
The canna lily is a true lily and is just as toxic to pets as other lilies.
Canna isn't a lily at all. It belongs to the family Cannaceae, not Liliaceae, and the ASPCA lists it as non-toxic to cats, dogs, and horses. The shared name is the only thing it has in common with the lilies that do harm pets.