The required care for canna flower perennials varies based on region. The canna lily is tropical and survives in USDA hardiness zones eight through 12. In other areas, it grows as an annual or needs winter protection. Canna plants, once established, need little care. They reach heights up to 8 feet. The flowers in colors of red, orange, yellow and pink bloom from summer into autumn and attract hummingbirds. The foliage brings a lush, tropical look to the landscape and varies in colors from bright, variegated green to purple.
Plant the cannas rhizomes in the spring after hard frosts have ended. A well-prepared planting site gets them off to the best start. Choose a site with full sun, fertile soil and adequate drainage.
Amend subpar soil by adding a 3- or 4-inch layer of compost. Cannas thrive in rich soil, and you will get a better flower and foliage display. Till or dig the soil to 6 inches. Make sure each root has an eye and place it eye side up in 3-inch deep holes as close as 6 inches apart. Cover with soil.
Water the canna lilies regularly. They do best with plenty of water. You can spread a 3-inch layer of mulch to retain soil moisture during the dry weather.
Fertilize monthly with a 5-10-5 blend. Follow the instructions on the fertilizer for amount per square foot to apply.
Remove dead flower tops and any damaged leaves with pruners. Snip off the dead flowers. New, side stems will grow and produce more flowers for a continuous show of blooms.
Cut the plant to the ground once it has died off. In warmer zones where canna overwinters in the ground, apply a 3-inch layer of mulch over the bed. If you grow cannas in other zones, take them indoors to a cool area, such as an unheated garage or cellar, where the temperatures stay between 40 and 50 degrees.
Dig the roots out of the ground on a dry day after the first frost. Shake or brush most of the soil off the roots. Place them in a large bucket or pot. You can place them in peat, but it is not strictly necessary. Store them in the designated location for the winter months.
Divide the canna rhizomes in the spring after frost. If you left them in the ground for the winter months, pull back the mulch and dig them up. Separate the roots into sections containing about three eyes. Clean them and replant each section. Divide them every two or three years. Separate the rhizomes of overwintered canna flower perennials at the time of planting them outside.