Flashy and flamboyant, canna lilies are perennial flowers that thrive in the heat of July and August. Learn how to plant and grow cannas—as well as how to deadhead, cut back, and over winter.
Canna (Canna Indica) are unrelated to true lilies, even though they’re commonly called “canna lilies.” This flowering perennial plant is related to bananas and gingers! This may not be surprising when you consider their huge paddle-shape leaves in those gorgeous red, orange, and bronze colors.
They may look tropical, but several canna species are native to the United States. The flowers are somewhat similar to an iris in shape. Their huge leaves wrap in ruffles around stems, tapering to refined buds that open into large, rainbow-hued flowers all summer long even in intense heat.
Though often called “bulbs,” cannas are not true bulbs as they multiply beneath the soil from a rhizome, an underground stem.
Canna is hardy to USDA zones 8 to 11. They’ll grow up to 8 feet tall in one season.
“I decided that if I could paint that flower in a huge scale, you could not ignore its beauty.” –Georgia O’Keeffe (1887–1986), speaking of her work titled Red Canna
Cannas can be both focal points and stylish accents. Use them to bring structure as a tall border or to add depth to narrow spaces. They add a colorful splash to garden orders and poolside plantings, bring a tropical touch to water features, and thrive in boggy areas (NOT salt water). Mix cannas with grasses, lantana, zinnias, snapdragons, elephant ears, salvia, periwinkles, and more.
Note: Canna plants can be left outside in the ground all winter in zones 7 to 10. They will also grow equally well in large containers dragged inside during the dormant period. In colder climates, cannas are easy to lift and store during cooler months. (Learn more below.)
Cannas need full sun for good flowering and consistently moist soil with a pH of around 6.0-6.5. Add lime before planting if your garden soil is acidic (low pH). Position plants away from strong wind; their large, soft leaves are vulnerable to damage.
When to Plant Cannas
Cannas can not tolerate cold temperatures. Soil must be 60ºF or warmer before planting rhizomes—often the time when folks put tomatoes in the ground. See our Planting Calendar for tomato-planting dates. Dig a small hole 2 inches deep and insert a thermometer to determine soil temps.
In cold, short-season areas, start canna rhizomes in pots indoors or in a greenhouse, ready to transplant outdoors at the right time.
How to Plant Cannas
Space rhizomes 1-1/2 to 2 feet apart to give cannas enough room. Containers need to be at least 18 inches in diameter (per rhizome).
Before planting, loosen the soil to a depth of 1 foot, then mix in 2 to 4 inches of compost.
Dig a hole 2 inches deep and set the rhizome 1 to 2 inches below the soil with the “eyes” (bumps or nodes, which are growth sprouts) pointed up.
Cover with 1 to 2 inches of soil. Tamp firmly.
Water thoroughly, then withhold water for as long as 3 weeks, and watch for signs of growth. Cannas are slow to sprout. Once sprouted, water at least once a week by slowly soaking the area around the roots.
Full foliage color develops when days are warmer (59ºF or more). Blooms should appear in 10 to 12 weeks.
Cannas should not need to be staked as they have strong, upright stems.
Cannas need wet soil. If the soil doesn’t remain moist, provide a good soaking once a week and every other day during the hottest weeks of summer. Water freely in dry spells.
Maintain a thin layer of mulch to help retain moisture.
Stake tall varieties, if necessary.
Where the soil is fertile, fertilizer is optional. However, canna are big eaters and would benefit from slow-release fertilizer at planting and twice during the growing season. Fish emulsion fertilizer, which is a little higher in nitrogen, is a beneficial organic alternative. Higher nitrogen fertilizers tend to increase canna height. Rose or tomato food products are also suitable.
To promote blooming, check your canna every few days to deadhead (i.e., remove spent flowers)
When deadheading, use small garden pruners or scissors. Do not pinch with your fingers.
Canna stems grow several flowers on a single stem. Snip off only the spent flower where it joins the main stem, leaving the other spikes to continue to bloom.
Once all the flowers on a single canna spike have bloomed, you may cut that part of the stem back but avoid cutting off any new budding spikes.
Cutting Back and Pruning Canna
After the entire plant has been deadheaded several times and with flowers no longer forthcoming, cut the flower stem back to the foliage.
Only at the end of the growing season should you cut the plant—down to around 6 inches off the ground.
If the plant looks “trashy” or the leaves get sunburnt, however, you can simply trim off the brown edges (like a haircut) or trim off any dead leaves at the bottom near the stem.
Be careful not to nick the main stem. If the stem is damaged, cut it back to the ground.
You may see seed pods on your canna! These seed pods will make more cannas, so you can clip off and put them right in the soil of your cannas; it may take a few years to get going, but you’ll have more cannas for the future.
How to Store Cannas for Winter
In zones 7/8 and warmer, cannas can be left in the ground year-round. After frost kills the foliage, cut in-ground plants back to 4 inches. Add a healthy layer of straw or leaf mulch in the fall to protect rhizomes from the cold as the plants overwinter in place. (Note: Zone 7 doesn’t always experience canna-killing winter temperatures, so it’s a judgment call.)
Bring cannas grown in pots indoors into a garage or basement for winter. Keep them dry (do not water) until spring’s night time temperatures are consistently above 50°F., typically after the tulips have bloomed in northern areas. Only then move them outside for the summer.
In zones 6 or colder, it is necessary to dig up (lift) in-ground cannas in the fall and bring them inside for the winter. After cutting the canna back (as above), dig out the rhizome with a shovel. Avoid damaging the rhizome by digging about 1 foot away from the stem. With your hands, gently loosen the soil and lift out the clump. Shake off the soil and cut off any foliage. Divide clumps into 3 to 5 rhizomes, each with eyes.
Cure the rhizomes in the sun or in a garage or closet for a few days to toughen them up and help them to resist rot. Wrap each rhizome in newspaper or a paper bag, along with a small about of dry growing medium, such as peat moss, to absorb moisture and prevent rot. Rhizomes should not touch each other.
Store cannas over the winter in a dry place where the temperature will not drop below 40º. Often this is a basement, attic, or garage. Check the rhizomes a couple of times over the winter to make sure that they don’t dry out. Mist with a bit of water, as needed. If you find rot, trip it away or discard the entire rhizome.
When spring’s nighttime temperatures are consistently above 50°F., replant outdoors. Make sure each divided piece has at least one eye; from it, new leaves will grow. Blooms should appear in 10 to 12 weeks.
For a tall canna, the Canna Tropicanna® is a popular choice. Growing 4 to 6 feet tall, ’Tropicanna’® boasts tangerine, iris-like blooms and exotic bronze foliage. Plant in the back of your garden bed or large containers for a dramatic statement on your porch or patio.
A medium-size gem is ‘Los Angeles’, which has large, deep pink florets and opens out so that you can see the face. Growing 4 to 5 feet tall, this canna blooms from June to August.
As well as the medium- to tall-size canna, you can find smaller “dwarf” sizes and dramatic “giant” sizes!
Dwarf cannas stand 2 to 4 feet tall and are easy to fit into our downsized modern gardens. The ‘Picasso’ is a real attention-getter with bright yellow flowers and deep red leopard-like spots; it blooms from July to frost. The ‘Wyoming’ has dark burgundy stems and lush orange flowers that brings life to a quiet bed from mid-summer until frost.
Interested in a giant canna? One of the most popular is the ‘Musifolia’, which grows up to 8 feet! With 3-foot-long red-vein leaves and red blooms, it makes a statement.
To create an indoor arrangement with a tropical feel, cut the canna flower stems. Although the flowers themselves only last a day or two, their foliage makes for a stunning backdrop in many bouquets.
The name canna comes from the Greek word kanna, meaning “reed” or reedlike plant.
During the Victorian era, gardeners so loved cannas that they grew them from seed, but this isn’t easy. The germination rate is low, and the seeds need to be filed or given an acid bath to break down their hard coat.
Canna are seldom bothered by deer nor prone to disease. Rust, fungal leaf spot, Botrytis blight, and bacterial bud rot may happen when cannas are kept too wet and crowded.
Cannas rarely have issues with pests, though caterpillars can munch on leaves. Slugs, snails, spider mites, and caterpillars are the most common culprits.