Cannas lilies are a tropical perennial native to South America. This plant variety grows from a rhizome root structure and produces tall foliage up to 6 feet in height with large multi-colored leaves. Many people consider a rhizome and bulb the same thing, Rhizomes are often called a bulb; however, they are not the same root structure. The cannas flower stalk produces a brightly colored blossom during the summer growing months. Cannas lilies grow year round in USDA Hardiness Zones 8 through 11. The plants require winter protection if your garden is in a USDA Hardness Zone below 8.
Winter protect the cannas rhizomes by removing them from the ground after the first hard frost in the fall season. Begin by cutting the stems to a height of 4 to 6 inches and removing all foliage. Dig carefully around the rhizomes and remove the root structure from the ground. Gently brush off soil clumps but do not clean the rhizomes with water. Season the rhizomes for storage by placing them on a gardening tarp in a cool and shaded area for 48 hours. A garage or garden shed works well for this step.
Prepare the rhizomes for winter storage after the 48-hour seasoning period by finding a cardboard box large enough to hold them without the rhizomes touching each other. Add a layer of peat moss to the bottom of the box and set the rhizomes on top so they do not touch. Cover the rhizomes with peat moss.
Store the cannas rhizomes in a dry area that has a temperature between 45 and 55 degrees. Place the box on top of blocks or bricks to prevent moisture buildup at the bottom. Check on the rhizomes several times during the storage months to verify there is not too much moisture around the rhizomes or that they are not drying out. Mist the rhizomes and peat moss lightly with water if the cannas are too dry. If the cannas have too much moisture, remove each rhizome and inspect them for rotting. Add fresh peat moss to the box and place the healthy rhizomes inside.
Remove the cannas from storage in early spring when you are ready to plant them outdoors. The best time to plant cannas rhizomes outdoors is once the ground begins to warm up and there is no longer a risk of frost.
National Gardening Association: Canna
University of Illinois: Bulbs and More
Washington State University: Canna