Canna Lily Growing Guide: How to Plant Canna Bulbs

Cannas are spectacular summer bulbs that thrive in the heat of July and August. Sometimes called “canna lilies,” these perennials are unrelated to true lilies. Learn when and how to plant cannas—as well as how to store cannas, which need to be dug up in colder climates.

About Cannas

Though often called “bulbs,” cannas are not true bulbs as they multiply beneath the soil from a rhizome, an underground stem. They’ll grow up to 8 feet tall in one season. Flashy and flamboyant, this perennial has distinct, paddle-shape leaves which wrap in ruffles around stems, tapering to refined buds that open into large, rainbow-hued flowers all summer-long, even in the heat of late July and early August.

They may look tropical but several species are native to the United States. The flowers are somewhat similar to an iris in shape, blooming in red, orange, yellow, and pink. Canna leaves are often heavily veined, adding even more beauty, especially when backlit by the sun. The foliage color can also vary, ranging from green to maroon to bronze, and in solid or variegated patterns. Most varieties grow between 3 to 5 feet tall, though there are taller types as well as dwarf types for containers.

“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, poolside plantings, and bring a tropical touch to water features and they 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 that can be dragged inside during the dormant period. In colder climates, cannas are easy to lift and store during cooler months. (Learn more below.)

Growing

Cannas need wet soil. If 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 easters and would benefit from slow-release fertilizer at planting and twice during the growing season. Fish emulsion fertilizer, 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.
As flowers fade, deadhead to promote continued flowering.
Trimming & Pruning: Deadhead regularly to prevent plants from setting seed, which will prolong bloom.

Pruning and Cutting Back Canna

After it has been deadheaded several times and with flowers no longer forthcoming, cut the flower stem back to the foliage.

Other than deadheading, there is no need to canna unless you think the foliage looks trashy. Sometimes if it gets really hot, the leaves can get sunburnt. Trim off any dead leaves at the bottom near the stem, being careful not to nick the main stem. Pruning out dead leaves gives the plant room to grow new foliage. If the edges of the leaves are brown, you can simply trim off the brown (like a haircut). It’s as easy as that!

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’ve got more cannas for the future.

How to Store Cannas for Winter

In zones 7/8 and warmer, cannas 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 nighttime 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.

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Comments

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As far as pests goes, I had a terrible time this year with Japanese beetles attacking my canna leaves; I had already put traps out, but the beetles were overwhelming for awhile.

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I live in Northern California I believe zone 8. We purchased a home in the spring with a pond and the most beautiful flowering plants came up out of nowhere seemingly overnight. My google search tells me they are canna lily’s. I have enjoyed them all summer long and now wondering how and when do I cut/prune them? I’m hoping they come back year after year. I also have several large pots with them. I’m not a gardener but I’m trying to learn. Appreciate any advice.
Thanks so much!

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You’re in luck. In warm climates (USDA hardiness zones 8 to 10), canna lilies can simply be left outside in the ground. If you live in a colder climate, you can lose them so dig up the roots and throw them in a pot to put in the garage.

In terms of pruning, you really don’t have to do anything if the foliage looks good. If the leaves look trashy, you can trim out the dead foliage and giving it room to grow new foliage. At the end of the season, in cooler climates, you may see that the cannas die back as the nights get colder. You can chop them down to the ground and they’ll come back again next year.

If you have canna in pots, you can clean them up throughout the season. Sometimes if it gets really hot, the leaves can get sunburnt. You don’t ever want to cut the main stem. Just trim off the brown leaves at the bottom near the stem. You can also just trim the tops of leaves if they’re brown (like a haircut).

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I grew Cana Lilly last year in an old galvanized trash can and got a surprise freeze last winter . I did not get to dig them up and thought they all died. I am in zone 4b. I reused the container for some catnip I got at a yardsale and just stuck them in the same soil. It is now August and I just found a canas come up . How is this possible?

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With enough protection, they can survive colder conditions! The pot that you put kept them in must have been just enough to keep them alive.

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Cannas