The care and effort it takes to overwinter elephant ears (Colocasia spp.), which grow in U.S. Department of Agriculture plant hardiness zones 8 through 11 with some variation within species, depends on your climate. In frost-free tropical and sub-tropical areas, these lush foliage plants grow year-round with minimal winter care. In frost-prone regions, overwintering elephant ears takes a little more effort, but it's worth it when the 2- to 3-foot-long heart-shaped leaves bring a tropical flair to the garden the following summer.
Elephant ears have invasive tendencies in its perennial zones.
Mild Climates Need Little Care
In USDA zones 10 through 11, elephant ear plants will grow year-round, remaining green through the winter. Discontinue watering from late fall through winter so the soil dries out. The soil can dry out completely during the dormant period, but natural rainfall will likely keep the soil moist. Cut back dead foliage and stalks as they die 2 to 4 inches from the soil line. Elephant ear foliage dies back throughout the year, but winter is a good time to tidy plants. You can cut out dead leaves any time of year.
Sanitize your shears before and after cutting elephant ears, or any other plants in the garden, to keep possible diseases from spreading. Use 1 part bleach mixed with 3 parts water. Dip each blade in the solution for 5 minutes, then rinse and air dry.
Frosty Areas Require Some Protection
While elephant ear plants survive winters in frost-prone areas, specifically within USDA zones 8 through 9, the foliage will die back after a frost or cold spell. Once the first frost kills the foliage, cut back the stalks 2 to 4 inches from the soil line, then cover the soil with a layer of mulch 4 inches deep. No additional water is necessary during the dormant period. The mulch helps insulate the soil. Sawdust, seed-free straw, leaf-mold and compost all make good mulching materials.
All parts of the elephant ear are poisonous if ingested. When pruning or trimming, keep any cuttings of the foliage, roots and leaves away from pets and children.
Outside of the growing zone -- anywhere colder than USDA zone 8 -- elephant ears are not reliably hardy. The roots will freeze in the cold soil, killing the plants. In cold areas you have two choices: you can grow elephant ears in pots and keep them in a frost-free area over winter in a dormant state, or dig the tubers in the fall and replant in the spring.
Overwintering Pots Indoors
Before the first frost, move the container to an area that won't freeze over winter. An unheated garage or shed that stays above 50 degrees Fahrenheit works well. Discontinue watering through the winter. This forces elephant ear tubers into dormancy. Cut all the stalks down at the soil level. In the spring when the temperature is consistently at or above 60 degrees F, water when the top of the soil feels dry. Once the last frost has passed, you can return the pots outdoors.
Digging and Storing Tubers
Allow the leaves and stalks to die back naturally with the first of the winter frosts. Once dead, cut back the foliage 2 to 4 inches from the soil, then carefully dig out the roots. Elephant ears have fleshy tubers for roots. Brush soil away from the surface and identify the shape and size of the tuber, then dig down around the outside of the root and lift it from the soil. Brush off extra dirt and pack the tubers in dry sawdust or peat moss in a bucket or tub. Keep the tubers dry in a 50-degrees F spot through the winter.