How to Plant and Grow Canna

Cannas (also called canna lilies) are large plants that add bold, tropical texture to a garden, whether used in containers or planted directly in the ground. In cool climates, cannas are fast-growing plants that are treated as annuals to fill a space with color quickly. In warm climates, they create dense stands of lush foliage and vibrant blooms throughout the summer, year after year.

When cannas first began to be used for their ornamental appeal, the flowers (which come in bright colors displayed on tall stalks) were the real stars. In recent years, the introduction of hybrid crosses means these plants have become known as much for their colorful foliage as their brightly-hued flowers. In addition to plain green, the foliage colors and patterns now include blue-greens, striped burgundy and gold, and cream-splashed greens. These additional options have made cannas highly desirable plants for use in gardens and containers.

Where to Plant Canna

Bold cannas are perfect for the back of a border (some grow as tall as 8 feet) and add a tropical feel wherever they are planted. They prefer a moist soil and sunny conditions although partial shade is tolerated.

Cannas are cold-hardy in USDA Zones 7–10. In areas where the plants are not hardy, canna rhizomes can be dug up and stored for the following year.

How and When to Plant Canna

Plant canna rhizomes in the garden in late spring to early summer after the last frost. They can also be started indoors in pots a month before the last frost in spring.

In the garden, plant them in full sun or partial shade in rich garden soil that has been amended with compost or organic matter. Cannas prefer moist soil. Dig holes and plant each canna rhizome about 6 inches deep with the eyes pointing up. Space them about 2 feet apart unless you are planting miniature varieties, in which case, space them 1 foot apart. Water gently to settle the soil.

When planting cannas in containers, use good-quality potting soil and a container about 18 inches wide. Plant a single rhizome 4–6 inches deep in the center of the pot. If the container is larger, plant two or three rhizomes in the pot.

Canna Care Tips

Cannas are easy to grow, and they deliver an unforgettable show in the garden when their basic requirements are met.

Light

As a group, cannas tolerate a variety of sun conditions. Older varieties and species tolerate some shade, but full sun brings out the best leaf color and flower show. Cannas growing in warm southern climates need a bit of afternoon shade to keep foliage from bleaching. Taller varieties need full sun to prevent flopping, which necessitates staking.

Soil and Water

In their native habitats, cannas are often seen growing close to and even in the water. These plants also do fine in regular garden soil as long as they get consistent moisture, especially in warmer climates. When planted in the ground, they need plenty of compost and other organic matter.

Temperature and Humidity

Cannas prefer humid air and are evergreen in the warmest areas. They won’t survive a frost, although their rhizomes may. They like sun and are comfortable with temperatures as warm as 90°F or slightly higher. In cooler areas, they can be dug up and overwintered.

Fertilizer

Cannas are heavy feeders. Apply a slow-release granular fertilizer (5-10-5 or 10-10-10) to the soil to keep cannas relatively happy. An occasional dose of liquid flower fertilizer (following the label directions) keeps them looking their best during the bloom season.

Pruning

During the growing season, trim off any dead or damaged leaves at the bottom and deadhead the blooms regularly to prolong flowering. In fall, wait until the first hard frost kills off the foliage and cut it off at ground level.

Potting and Repotting Canna

Bigger is better when potting a canna in a container. The roots need a lot of space to grow, and the plant will soon be tall. Select a ceramic, terra-cotta or plastic container—or half a whiskey barrel—making sure it has drainage holes. Fill the container to within a couple of inches of the top with good-quality garden soil amended with compost. Plant the rhizomes about 5 inches deep with the “eye” pointing upward.

Canna roots spread rapidly and become crowded, so the plant will need to be divided and repotted every year or two.

Pests and Problems

Like many garden plants, cannas can attract unwanted aphids, spider mites, and mealybugs, all of which can be treated with insecticidal soap or neem oil.

Cannas are susceptible to several viruses, none of which are treatable. When you see yellow-streaked leaves or contorted growth, dispose of the plant and any nearby because nothing can be done to cure the viruses.

How to Propagate Canna

Cannas can be propagated by divisions or seeds.

To divide a canna, lift it and its root ball from the ground using a spade. Shake the soil off the roots and divide the rhizomes by hand into three or more sections. The ones with the strongest shoots will deliver the most abundant foliage. Replant the divisions right away and water them well.

To grow canna from seed, wait until late winter and then soak the seed for 24 hours. Fill a pot or flat with seed-starting medium. Sow the seeds and lightly cover them with the medium. Water well and wait for any excess water to drain off. Cover the flat or pot with clear plastic wrap and put it in a warm place at about 70°F to 75°F. The seeds germinate in about two weeks. When they germinate, remove the plastic and put them in a sunny window or under a grow light. Wait until all danger of frost has passed before hardening off the seedlings and planting them outside.

Overwintering Canna

As the first frost approaches, gardeners in cool zones need to think about overwintering their cannas. If the cannas are being grown in containers, keep them in the same pot and withhold water as temperatures drop in late fall. Once the foliage begins to die back, move the pots to a cool, dark place, such as an unheated garage or basement. Keep the soil dry throughout the winter until spring warms back up and watering can resume.

If the cannas grow directly in the ground, dig the tender rhizomes after the first frost knocks back the foliage. Store them in a dry, cool, dark place after wrapping them in dry to slightly moist peat moss (no two rhizomes should touch), and then place them in a plastic bag with a few holes cut for aeration. Once the soil has thawed and all danger of frost has passed (probably late spring), unwrap the rhizomes and plant them directly in the ground.

Types of Canna

‘Lucifer’ Canna

This selection of Canna produces bright red flowers edged in yellow atop a dwarf plant to 4 feet tall. Zones 7–11

‘Australia’ Canna

This variety of Canna offers a bold combination of deep purple foliage with crimson flowers. It grows to 5 feet tall. Zones 7–10

‘Cleopatra’ Canna

Canna ‘Cleopatra’ bears lush, broad leaves that accompany stems of clustered bright gold flowers with an occasional orange bloom or orange stippling on yellow petals. It grows to 4 feet tall. Zones 7–11

‘Intrigue’ Canna

Grown more for its foliage, this variety of Canna does have orange blossoms in late summer. The 7-foot-tall foliage has narrow, burgundy leaves that look stunning in the back of a border. Zones 7–10

‘Pretoria’ Canna

Canna ‘Pretoria’ is a large, lofty variety that flaunts yellow-striped, broad leaves and sizable orange blooms. It grows 6 to 8 feet tall and is hardy in Zones 7–11

‘Tropical Rose’ Canna

Canna ‘Tropical Rose’ is a compact, award-winning variety topped with gigantic bouquets of rose-pink flowers. It grows to 2½ feet tall. Zones 7–11

Tropicanna Canna

Flamboyant orange veining on broad green leaves makes Tropicanna® cannas different. Golden orange flowers complete the paradise palette. The plant grows to 4 feet tall. Zones 7–11

‘Wyoming’ Canna

Canna ‘Wyoming’ delights with huge, ginger-orange flowers that glow against the backdrop of deep purple-green foliage. It grows 3 to 4 feet tall. Zones 7–11