Bulb · Cannaceae
Canna Lily
Canna × generalis
Hand it full sun, rich moist soil, and summer heat, and the canna piles on broad paddle 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 carries a tropical look into a temperate garden on broad paddle-shaped leaves and tall spikes crowded with bold flowers. The name misleads: it is no true lily, but a rhizome-rooted perennial in the family Cannaceae, nearer kin to gingers and bananas. Growth comes fast and large, from a knee-high bedding form up to a towering plant pushing near 8 feet (240 cm) tall.
Heat and water are what drive it. Set it in full sun and rich, moist soil, keep the water coming through the hot months, and it answers with flower spikes from midsummer straight to the first frost. It pushes through conditions that flatten fussier plants, which is why gardeners reach for it to anchor a bed or fill a wide pot.
Cold is the one hard limit. In zones 7 to 10 the rhizomes sit out winter underground, but anywhere colder you lift and store them once frost has cut the stalks down. Dividing those rhizomes every couple of years keeps the clump vigorous and hands you new plants for free.
Care
The short version: full sun, rich soil held evenly moist, and steady warmth. Feed monthly through the growing season, split the clump every few years, and lift the rhizomes for winter anywhere the ground freezes.
Light
Canna wants full sun, six hours a day at least, to flower at full strength. It will take partial shade or partial sun, but the blooms come thinner and the stems stretch and tip toward the light.
Water
Hold the soil evenly moist, above all through active growth and hot spells. Canna is one of the rare garden plants that puts up with some standing water, yet an established clump can also coast through a short dry stretch. Water every 2 to 5 days in the heat of summer.
Soil
Plant into rich, moist, well-drained ground turned with plenty of organic matter. It is easy about pH, taking anything from 6.0 to 8.0, but drainage is the part that counts, since soggy ground rots the rhizomes.
Temperature
Canna runs on heat, growing happily from 50°F to 95°F (10°C to 35°C). It carries no cold tolerance whatsoever, so the first frost drops it and the rhizomes need lifting anywhere winters freeze.
Humidity
Average outdoor humidity suits it fine, with no figure to track. Its tropical lineage means it never balks at muggy summer air.
Feeding
Feed monthly with a balanced all-purpose fertilizer across spring and summer while the plant is driving growth. For an in-ground clump, a soil test is the surest guide to how much it actually wants.
Pruning
Snip off the spent flower stalks to keep fresh blooms coming and the plant looking clean. After the first fall frost in cold zones, cut the foliage down to 2 to 3 inches (5 to 8 cm) before you dig the rhizomes for storage.
Repotting
Canna asks for no routine repotting, but a crowded clump does need dividing every 2 to 3 years. Watch for packed growth, fewer flowers, or rhizomes shoving up through the soil surface, each a sign the plant has outgrown its room.
Size & spacing
Plants reach from 18 inches to 1.5 to 8 feet (46 to 239 cm) tall depending on the form, so check the variety before you site it. Set the rhizomes 1.5 to 3 feet (45 to 90 cm) apart to give the big paddle leaves room to open.
When to plant
Canna runs on heat and folds at the first touch of frost. In cold zones, start the rhizomes indoors a month or so ahead of the last frost, set them out once the soil has warmed, and the flower spikes climb 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 comes down to wet soil or a few common pests, and it surfaces on the broad leaves or the rhizomes below. Spot it early and you can usually rescue the plant or the rest of the clump. Match what you see to the cases below, then act before it travels.
Mushy rhizomes and stems that stall or fold over
What you are looking at is rhizome rot, and it almost always begins in soil that stays too wet. Pull a rhizome free and the flesh turns up brown, soft to the touch, and sour-smelling, sometimes paired with bud rot or bacterial blight. Cut away every rotted piece, set only the firm sections back into well-drained ground, and pull back hard on the watering.
Fix:
- Lift and discard rotted rhizomes
- Replant healthy firm sections in well-drained, organically rich soil
- Reduce watering and improve drainage
New leaves unfurling streaked, blotched, or twisted
Yellow streaks running through the blade and warped, puckered growth that watering and feeding never correct usually trace to canna mosaic virus or aster yellows. Once a plant carries it, there is no cure. Dig the plant out and destroy it, hold the sap-feeding insects down, and never split rhizomes you suspect of carrying the virus.
Fix:
- Remove and destroy infected plants to limit spread
- Control insect vectors
- Do not propagate from infected rhizomes
Foliage chewed open, punched with holes, or rolled tight
Edges rolled and bound shut with webbing usually conceal the canna leaf roller, the most frequent offender. Japanese beetles, slugs, and snails leave the coarser bite marks and a glistening slime trail across the broad blades. Pluck the pests off with your fingers, tear away the ruined leaves, and rake out the debris so fewer survive into next season.
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
Reassuring word for pet owners and parents: the canna lily is safe. The name throws people off, but it is no true lily and holds none of the poison those plants carry. 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 around cats. The ASPCA marks canna non-toxic, so a curious mouthful of leaf will not bring on poisoning.
Dogs None
No toxicity for dogs. A dog that gnaws a blade or unearths a rhizome risks nothing worse than a mild stomach upset from the fibrous tissue.
Horses None
Horses can browse beside canna unharmed, since the ASPCA rates it non-toxic to them.
Rabbits Safe
The broad foliage holds no known toxin, so rabbits moving through the garden are fine.
Livestock Safe
Cattle, goats, and sheep take no poison from canna; nothing in the plant troubles a grazing animal.
Birds Safe
Birds face no danger near canna, and the hard round seeds move straight through them without harm.
People Safe
No risk to children or adults. The starchy rhizome is even cooked as food in parts of the world.
No special handling required for toxicity; wear gloves if sensitive when dividing rhizomes.
Varieties
Cannas stretch from squat bedding plants to towering forms, in flower colors that run from soft cream to fiery red. A handful of names keep coming up, and these are the ones worth knowing.
Tropical Series
A compact seed-grown line bred to stay short enough for pots and bedding.
South Pacific Scarlet
An award-winning seed-grown cultivar that opens bright scarlet flowers.
Canna indica (Indian Shot)
The wild form, carrying flame-red flowers and the hard round seeds that earned it the name Indian Shot.
How to propagate
Canna comes back most dependably from division, which holds a variety true, though a patient grower can also raise it from the hard round seeds that gave it the name Indian Shot.
DivisionEasy
Spring at planting time, or in fall when lifting rhizomes for storage; divide crowded clumps every 2-3 years. · 2 to 6 weeks
Splitting the rhizomes is the simple route to more canna and the dependable way to hold a variety true. Cut the clump apart in spring or as you lift it in fall, leaving each chunk at least one eye, then let the raw cut faces callus over for a few days before they return to the ground. Break up a crowded clump every 2 to 3 years and each new piece roots down in roughly 2 to 6 weeks.
SeedModerate
Spring, started indoors. · Several weeks to germinate
Raising canna from seed runs slower and far less evenly. The hard round seeds, the very ones that gave it the name Indian Shot, want nicking and a soak before the coat will crack and sprout, and germination still drags on for several weeks. Sow them indoors in spring, but count on seed-grown plants not coming true to type.
Myths
The canna lily is a true lily and is just as toxic to pets as other lilies.
Canna is no lily. It sits in the family Cannaceae, not Liliaceae, and the ASPCA lists it as non-toxic to cats, dogs, and horses. A shared common name is all it has in common with the lilies that actually poison pets.