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
Few plants carry a tropical mood into a temperate garden the way the canna lily does, with its broad paddle-shaped leaves and tall spires of flower reading as a single confident gesture across a bed. The name misleads, since it is not a true lily, but a rhizome-rooted perennial of the family Cannaceae, more closely related to gingers and bananas. It comes on fast and stands tall, scaling from a knee-high bedding form to a presence approaching 8 feet (240 cm).
Heat and water are the conditions it asks for. Set it in full sun and rich, moist soil, keep the water coming through the hottest weeks, and it returns flower from midsummer to the first frost. It carries on where more delicate plants give way, which is why it earns a place anchoring a border or filling a generous pot beside a terrace or doorway.
Cold draws the only firm line. Across zones 7 to 10 the rhizomes overwinter in place, while anywhere colder you lift and store them once frost has cut the plant down. Dividing those rhizomes every couple of years keeps the clump strong and quietly supplies you with new plants to place elsewhere.
Care
The short version: full sun, rich soil kept evenly moist, and steady warmth. Feed it monthly through the season, divide the clump every few years, and lift the rhizomes for winter anywhere the ground freezes.
Light
Give canna full sun, six hours a day or more, and it flowers at its fullest. It accepts partial shade or partial sun, but the bloom grows sparse and the stems lengthen and lean toward whatever light they can find.
Water
Keep the soil evenly moist, above all through active growth and the hottest stretches. Canna is among the rare garden plants that takes some standing water in stride, while an established clump can weather a brief dry spell. Water it every 2 to 5 days in high summer.
Soil
Plant into rich, moist, well-drained ground worked through with plenty of organic matter. It is easygoing about pH, accepting anything from 6.0 to 8.0, but drainage is the part that counts, since waterlogged soil rots the rhizomes.
Temperature
Canna is at home in heat, growing comfortably from 50°F to 95°F (10°C to 35°C). Cold is another matter entirely, so the first frost ends it and the rhizomes need lifting anywhere winters freeze.
Humidity
Ordinary outdoor humidity suits it perfectly, with no figure to track. Its tropical lineage means a muggy summer evening never bothers it.
Feeding
Feed monthly with a balanced all-purpose fertilizer across spring and summer while the plant is in full stride. For a clump in the ground, a soil test is the surest guide to what it truly needs.
Pruning
Clip away the spent flower stalks to keep fresh blooms arriving and the plant looking composed. After the first fall frost in cold zones, cut the foliage back to 2 to 3 inches (5 to 8 cm) before digging the rhizomes for storage.
Repotting
Canna asks for no routine repotting, though a crowded clump does call for dividing every 2 to 3 years. Watch for dense growth, thinning flowers, or rhizomes pressing up out of the soil, all of them signs the plant has run out of 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 choose its spot. Place the rhizomes 1.5 to 3 feet (45 to 90 cm) apart to give those large leaves the space to open.
When to plant
Canna lives on warmth and has no patience for frost. In colder regions, start the rhizomes indoors about a month before the last frost, set them outside once the soil has warmed, and the flowers come on 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 setbacks come down to soggy ground or a few familiar pests, and they read clearly on the leaves or the rhizomes below. Spot them early and the plant, or at least the rest of the clump, can usually be saved. Find what matches your plant below, then move before it spreads.
When the planting slumps and the rhizomes turn soft
What you are looking at is rhizome rot, and it tends to begin with ground that stays too wet for the plant to handle. Dig one up and the tissue comes out brown, soft, and unpleasant to the nose, occasionally paired with bud rot or bacterial blight. Discard the spoiled pieces, settle only the firm sections back into freely draining soil, and pull back on how often you water.
Fix:
- Lift and discard rotted rhizomes
- Replant healthy firm sections in well-drained, organically rich soil
- Reduce watering and improve drainage
Leaves opening up streaked, blotchy, or warped
Yellow streaks and twisted growth that neither watering nor feeding will settle usually signal canna mosaic virus or aster yellows. Once a plant has it, there is no remedy. Take it out and destroy it, keep sap-feeding insects under control, and never start new plants from rhizomes you think may be carrying it.
Fix:
- Remove and destroy infected plants to limit spread
- Control insect vectors
- Do not propagate from infected rhizomes
Foliage that arrives chewed, punched through, or curled tight
A leaf that rolls or webs itself shut is usually sheltering the canna leaf roller, the most frequent offender. The blunter damage, the obvious holes and the trails of slime, comes from Japanese beetles, slugs, and snails. Lift the pests off by hand, take away the spoiled leaves, and tidy plant litter so fewer survive into the 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 news for households with pets or children: the canna lily is safe. The name throws people off, yet it is no true lily and carries none of the toxins 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
A welcome plant in a household with cats. The ASPCA places canna among the non-toxic plants, so a curious taste does no harm.
Dogs None
Nothing to worry about with dogs around. A dog that mouths a leaf or unearths a rhizome risks little beyond a passing stomach upset from the rough material.
Horses None
Horses can stand and graze beside canna with no trouble, since the ASPCA counts it as non-toxic to them.
Rabbits Safe
The leaves hold no known toxin, so rabbits moving through the garden are perfectly fine.
Livestock Safe
Cattle, goats, and sheep come to no harm from canna; nothing in the plant troubles grazing animals.
Birds Safe
Birds face no hazard around canna, and the hard seeds move through them without harm.
People Safe
Safe for children and adults alike. The rhizome is in fact 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 span everything from low bedding plants to garden giants, in shades from soft cream through fiery red. A handful of names come up time and again, and these are the ones worth keeping in mind.
Tropical Series
A compact, seed-grown line kept small enough to suit containers and bedding.
South Pacific Scarlet
An award-winning seed-raised cultivar that opens to bright scarlet flowers.
Canna indica (Indian Shot)
The wild form, carrying flame-red flowers and hard round seeds that lent it the name Indian Shot.
How to propagate
Canna comes back most dependably from division, which holds a variety true, though a patient gardener 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
Dividing is the simplest route to more canna and the most dependable way to hold a variety true. Cut the rhizomes apart in spring or as you lift them in fall, leaving at least one eye on every piece, then set the cut faces aside to dry for a few days before returning them to the ground. Lift and split a crowded clump every 2 to 3 years, and the fresh pieces settle in over roughly 2 to 6 weeks.
SeedModerate
Spring, started indoors. · Several weeks to germinate
Raising canna from seed runs slower and harder to predict. The hard-shelled seeds, the same ones that earned the name Indian Shot, want nicking and a soak before they will break dormancy, and germination still stretches across several weeks. Sow them indoors in spring, with the understanding 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 is no lily whatsoever. Its place is in the family Cannaceae rather than Liliaceae, and the ASPCA lists it as non-toxic to cats, dogs, and horses. A shared name is all it has in common with the lilies that genuinely harm pets.