While gladioli, dahlias, cannas, and tuberous begonias are perennials, they are not winter hardy in Iowa. These tender perennials must be dug up in the fall and stored indoors over winter. The storage requirements for several widely grown tender perennials are provided below.
Carefully dig up the caladiums when the foliage droops and begins to yellow with the onset of cool fall temperatures, or wait until after the first hard frost. Place the plants in a warm, dry location for 1 or 2 weeks to cure. Afterwards, cut off the dry foliage and bury the tubers in dry peat moss or vermiculite. Store the tubers in a cool (60 to 65 F) dry location.
Calla Lily (Zantedeschia spp.)
After a killing frost, cut off the foliage 1-to 2-inches above the soil surface. Carefully dig up the rhizomes. Do not cut or injure the rhizomes. Dry the rhizomes in a warm, dry location for 1 or 2 weeks. After drying, bury the rhizomes in peat moss or vermiculite and store them in a cool (50 to 60 F) dry location.
Cut the plants back to within 4-to 6-inches of the ground a few days after a hard, killing frost. Then carefully dig up the canna clumps with a spade or fork. Leave a small amount of soil around the cannas. Allow them to dry for several hours. Afterwards, place the cannas in large boxes, wire crates, or in mesh bags. Store the cannas in a cool (40 to 50 F) and dry location.
Several days after a hard frost, cut the plants back to within 2-to 4-inches of the ground. Carefully dig up the tuberous roots with a spade or shovel. Gently shake off the soil, then cut the stems back to the crown. Wash the tuberous roots to remove any remaining soil. Allow the tuberous roots to dry to the touch (usually about 1-day). When dry, place the dahlia clumps upside down in boxes or other containers and cover them with vermiculite, peat moss, or wood shavings. Store the dahlias in a cool (40 to 50 F) and dry location.
Elephant's Ear (Colocasia esculenta)
Dig up the plants after the first fall frost. Cut off the foliage. Dry the tubers in a warm, dry location for 1 or 2 weeks. After drying, bury the tubers in peat moss or wood shavings and store them in an area with a temperature of 70 to 75 F.
Carefully dig up the plants with a spade in late summer/early fall. Gently shake off the soil from the bulb-like corms. Then cut off the foliage 1-to 2-inches above the corms. Dry the corms for 2 to 3 weeks in a warm, dry, well-ventilated location. When thoroughly dry, remove and discard the old dried up mother corms located at the base of the new corms. Remove the tiny corms (cormels) found around the base of the new corms. Save the small corms for propagation purposes or discard them. Place the corms in mesh bags or old nylon stockings and hang in a cool, dry, well-ventilated location. Storage temperatures should be 35 to 45 F.
Carefully dig up the tuberous begonias within a few days of a killing frost. Leave a small amount of soil around each tuber. Cut off the stems about 1 inch above the tubers. Place the tubers in a cool, dry area to cure for 2 to 3 weeks. After curing, shake off the remaining soil, then bury the tubers in dry peat moss, vermiculite, or sawdust. Store the tubers in an area with a temperature of 40 to 50 F.
This article originally appeared in the 9/17/2004 issue.