Canna lilies are showy plants that feature tall stems topped with large, brightly colored flowers. Desirable for their hardy nature, attractive blooms and equally attractive foliage, these rhizome flowers are not cold hardy but can be dug up in the fall and overwintered indoors. There are about 50 species of canna found throughout the world, according to information published by the University of Arkansas, and while they vary slightly in flower shape, color and size, they all have the same basic care needs.
Canna lily plants are hardy to U.S. Department of Agriculture zone 8, according to Cornell University. These plants cannot tolerate freezing conditions.
Choose a planting location that receives a full day's worth of sunlight, which is a minimum of six hours of sunlight per day. Amend the soil down to 12 inches with organic compost, and plant the rhizomes 6 inches down. Lay them horizontally in the hole, and space them by at least a foot and by up to 4 feet apart. These large flowers need plenty of room to spread out, according to the National Gardening association.
Soil and Water
Cannas prefer soil that is consistently moist, according to Cornell University. Water enough so that the soil is barely moist to the touch, but do not place these flowers in a location where standing water collects. Too much water in the soil will rot the delicate rhizomes of canna lilies.
Lay down a thick layer of mulch (3 to 4 inches) in the spring, when the shoots emerge from the ground. This will retain moisture in the soil and stifle weed growth. Some cultivars can reach heights of 8 feet, according to Cornell University, so stake tall varieties to keep the standing upright. Cut off the flowers when they have wilted.
Wait until the first frost of autumn freezes the foliage, then cut the plant back so that there are only about 6 inches remaining. Gently remove the rhizomes from the ground, and place them in a container filled with peat moss. Do not let individual rhizomes touch each other. Store them in a location with temperatures between 45 and 55 degrees Fahrenheit.