Cannas are showy, colorful plants used in flowerbeds, boxes, tubs and borders. They grow from 2 to 10 feet tall. They have large oval shaped leaves and massive clusters of flowers throughout the summer and fall. They come in a variety of colors, ranging from whites, yellows, pinks and reds, and do best in moist, fertile soil and in full sun. The rhizomes must be dug up and stored in areas that get cold enough to frost, but can remain in the ground all year in the Deep South where the weather stays warmer.
Plant canna rhizomes outdoor in the spring when all threat of frost is over. Locate a spot in the full sun that's well drained. You should amend the soil with compost or peat moss if it's needed.
With a shovel, dig holes 4 to 6 inches deep and plant the rhizomes about 2 inches beneath the surface. Space the cannas 1-1/2 to 2 feet apart. Make sure that the eyes of the rhizomes are facing up.
After planting, soak your cannas with water. Add a layer of mulch to the ground to help the cannas retain moisture and discourage weed growth.
You should water the cannas throughout the growing season. Don't let the soil get too dry. You can deadhead the plants by removing spent blooms to encourage them to produce more flowers.
After the first killing frost, when the foliage turns brown, you should lift the canna rhizomes with a shovel. Cut off the foliage and knock off any remaining soil. Place the rhizomes in a box filled with peat moss and store them in a crawl space or cool basement.