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 can be treated as annuals to fill a space with color quickly. In warmer climates, they'll 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 more recent years, the introduction of hybrid crosses means these plants have become known as much for their colorful foliage as their brightly-hued flowers. Instead of 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.
Related: Guide to Growing Tropical Plants
Canna Care Must-Knows
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. Cannas are also heavy feeders. When planted in the ground, they'll need plenty of compost and other organic matter, as well as an occasional dose of liquid fertilizer (per label directions). A slow-release fertilizer keeps cannas relatively happy when they're planted in containers, but regular doses of liquid fertilizer help them look their best.
As a group, cannas tolerate a variety of sun conditions. Older varieties and species tolerate 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.
In areas where cannas are not winter hardy, they can be stored for the following year. If they 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 bulbs should touch), 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.
Although easy to grow, cannas are susceptible to viruses transmitted by insects. When you see yellow-streaked leaves and/or contorted growth, dispose of the plant because nothing can be done to cure the viruses.