Canna Tropicanna®—Featuring the original Tropicanna canna with striped foliage and orange blooms, then Tropicanna Gold with green and yellow striped leaves and a yellow and orange flower, and at right, Tropicanna Black with dark foliage and a red bloom.
Canna lilies bear distinct, paddle-shape leaves which wrap in ruffles around stems, tapering to refined buds that open into large flamboyant flowers in late July and early August. In colder climates, these tropicals need to be dug up and stored for the winter season. Learn how to grow and care for the cannas in your garden!
The canna lily plant is a rhizomatous perennial. You’ll find that they’re commonly referred to as “bulbs,” although they are not true bulbs as they multiply beneath the soil from a rhizome, an underground stem.
Canna blooms are flashy and flamboyant and stand tall on their stems. They would be magnificent even if they never bloomed. However, they keep pumping out colorful flowers from late spring or early summer through to fall frost. When most flowers can’t take the heat of summer, cannas thrive.
The large tropical flowers are somewhat similar to an iris in shape but bloom in tropical colors of 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.
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. Mix cannas with grasses, lantana, zinnias, snapdragons, elephant ears, salvia, periwinkles and more. Cannas bring a tropical touch to water features and they thrive in boggy areas.
Cannas look great in containers, too. Center cannas in large patio pots and surround them with bright annuals. Indoors, display them in large containers near brightly light windows.
Note: In the winter, canna plants can be left outside in the ground if you live in USDA hardiness zones 8 to 10. If you live in a colder climate, you can lose these tropical plants so dig up the roots and throw them in a pot to put in the garage. Learn more about overwintering below.
Cannas will tolerate partial shade, but require at least 4 hours of direct sun. They need fertile, moist soil. Before planting, loosen the soil to a depth of 12 to 13 inches, then mix in 2 to 4 inches of compost.
When to Plant Cannas
Cannas cannot tolerate cold temperatures. Plant outdoors in late spring or early summer. Soil must be 60ºF or warmer. In short-season areas, start cannas in pots indoors or in a greenhouse to transplant outdoors at the right time.
Some people ask how to determine soil temps: Check online for state extension websites that publish this information for your state. Or, dig a small hole two inches deep and insert an old-fashioned mercury thermometer into your soil. Or, buy a soil thermometer at local nursery or hardware store.
How to Plant Cannas
Dig a hole 2 to 3 inches deep and set the rhizome in it, with the “eyes” (bumps or nodes, which are growth sprouts) pointed up.
Cover with 1 to 2 inches of soil, Tamp firmly.
Space rhizomes 1 to 4 feet apart.
If possible, position plants out of strong wind. Their large, soft leaves are vulnerable to damage.
Water thoroughly, then withhold water for as long as 3 weeks, and watch for signs of growth.
When planting new rhizomes, or those dug up and stored to winter over, make sure that each divided piece has at least one eye. From it, new leaves will grow.
Blooms should appear in 10 to 12 weeks..
Canna ‘Tropicanna’® planted among sedum ‘Autumn Joy’ makes for a stunning display in late summer.
Turn-of-the-century gardeners so loved cannas that they grew them from seed, but this isn’t easy; better to leave propagation to experts and plant canna rhizomes instead.
If you grow from seed, be aware that the germination rate is low and the seeds need to be filed or given an acid bath to break down their hard coat.
During the hottest weeks of the summer, give the plants a good soaking drink of water every other day.
If rainfall is less than 1 inch per week, water. Provide a good soaking every other day during the hottest weeks of summer. Water freely in dry spells.
Once sprouted, water at least once a week by slowly soaking the area around the roots.
Maintain a thin layer of mulch to help retain moisture.
Stake tall varieties, if necessary.
Where the soil is fertile, fertilizer is optional.
If desired, apply a 5-10-5 or 10-10-10 fertilizer in spring 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.
Full foliage color develops when days are warmer (59ºF or more). .
As flowers fade, deadhead to promote continued flowering.
Pruning and Cutting Back Canna
There is no need to prune 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!
After canna has been deadheaded several times and with flowers no longer forthcoming, you can also cut the flower stem right off—wherever the stem meets another leaf line. You may see seedpods on your canna! These seedpods 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!
At the end of the season, in cooler climates, you may see that the canna foliage dies 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 also clean them up throughout the season.
If you live in USDA hardiness zones 8 to 10, cannas can be left outside in the ground year-round. In colder zones, you’ll need to dig them up and throw them in a pot in the garage! Zone 7 can be a toss-up. Add a layer of straw or leaf mulch to protect your cannas, or dig them up if you don’t want to risk losing them to cold.
After the first fall frost kills the foliage but before a hard freeze occurs, cut in-ground plants back to 4 inches. It is not essential for canna foliage to be frosted prior to digging, but this is recommended.
Plunge a shovel or garden fork into the soil about 1 foot away from the stem, to avoid damaging the rhizome.
With your hands, gently loosen the soil and lift out the clump. Shake off the dirt and cut off the 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.
In the spring, when spring’s nighttime temperatures are consistently above 50ºF (typically after the tulips have bloomed in northern areas), move canna back outdoors.
When replanting, make sure that each divided piece has at least one node, which is where new leaves will grow from in following seasons. Then plant 4 to 5 inches deep and 1 to 4 feet apart. They will bloom in 10 to 12 weeks.
For a tall canna, the Canna Tropicanna® is a popular choice. Growing to a height of 48 to 72 inches, ‘Tropicanna’® boasts gorgeous tangerine, iris-like blooms and exotic bronze foliage. Plant in the back of your garden bed or in large containers for a dramatic statement on your porch or patio. Don’t worry about deer; they tend to stay away from easy-to-grow cannas.
A medium-size gem is the rich, deep pink ‘Los Angeles’, which has a large floret and opens out so that you can see the face. The plant grows from 42 to 60 inches tall, blooming from June to August.
Image: Credit: Mick49/Shutterstock
As well as the medium- to tall-size canna, you can find smaller “dwarf” sizes and dramatic “giant” sizes!
Dwarf cannas stay under 3 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. Its leaves are the size of a banana plant and creates dramatic statement and very tropical background!
Cut canna flower stems for indoor arrangement. The flowers carry their tropical appeal in the vase. The flowers die in a day or two. However, the foliage continues to make a beautiful backdrop to many bouquets.