Elephant ears, primarily encompassing the tropical plants Colocasia and Alocasia, are prized for their dramatic, oversized foliage. Because they originate in warm, humid regions, they are not equipped to survive freezing temperatures. While the above-ground foliage will perish with frost, the plant’s underground storage structure—the tuber or corm—is built to survive. This survival mechanism is dormancy, a period of inactivity triggered by cold weather and shorter daylight hours, allowing the plant to persist until favorable growing conditions return.
Dormancy: The Elephant Ear’s Winter Strategy
Dormancy functions as a biological survival strategy, where the plant’s energy is pulled from the dying leaves and stored in a specialized underground organ. This tuber, or corm, contains the concentrated starches necessary to fuel the plant’s regrowth in the following spring. The ability of this storage organ to survive winter is determined by the local climate, specifically the USDA plant hardiness zone. These tropical plants begin to slow growth when temperatures consistently drop below 50°F, and a light frost around 32°F will typically kill the foliage, signaling the start of dormancy. Sustained freezing temperatures that penetrate the soil deep enough to freeze the tuber solid are lethal.
Protecting Elephant Ears Outdoors (In-Ground Method)
Leaving elephant ear tubers in the ground is a viable option for gardeners in warmer climates, typically USDA Hardiness Zones 8 through 11, where the ground does not freeze solid. The success of this method depends entirely on sufficient insulation to protect the dormant tuber from cold and excessive winter moisture. Allow the foliage to die back naturally after the first light frost, as cutting the leaves back too early can invite rot into the crown.
Once the leaves have collapsed, trim the remaining stems back to about six inches above the soil line. Cover the area over the plant’s crown with a substantial layer of insulating mulch. Materials such as straw, shredded leaves, or hay are effective, as they trap air and prevent deep cold penetration.
Apply this protective layer generously, aiming for a depth of six to twelve inches, extending well beyond the plant’s diameter. This heavy mulching helps maintain a more stable, warmer soil temperature around the tuber. The mulch should remain in place until the last expected frost date in spring has passed.
Indoor Overwintering of Tubers (Digging and Storage)
For regions experiencing hard frosts and prolonged freezing ground, typically Zones 7 and colder, digging up the tubers for indoor storage is the necessary strategy. The optimal time to lift the tubers is in the fall, after a light frost has killed the leaves but before a hard, deep freeze can damage the underground structure. Carefully dig up the corm or tuber with a shovel or garden fork, taking care not to puncture its surface.
After lifting, trim the remaining stems to four to six inches. The tubers should be set aside to cure in a warm, dry, and well-ventilated location for several days, ideally between 60°F and 70°F. This curing process allows the surface to dry completely, which helps prevent rot during storage. Gently brush off excess soil, but do not wash the tubers with water.
The dried tubers are then ready for storage in a medium that provides ventilation and absorbs excess moisture. Suitable materials include dry peat moss, vermiculite, or sawdust, which should fully surround the tubers in a cardboard box or mesh bag. The storage container needs to be kept in a cool, dark place that maintains a consistent temperature range, typically between 40°F and 60°F, and never drops below freezing.
Check the stored tubers periodically throughout the winter for signs of shriveling (too dry) or soft spots (potential rot). If tubers appear overly dry, lightly mist the storage medium, but excessive moisture must be avoided to maintain successful dormancy.
Reawakening and Spring Care
The process of ending dormancy and preparing for the next growing season begins well before the last spring frost. Gardeners can start stored tubers indoors approximately six to eight weeks before the final expected frost date for a head start. Pot the tubers in a container using a standard potting mix, ensuring the soil is warm, ideally 65°F to 70°F, to encourage sprouting.
When planting, place the tuber with the rounded side down and the pointed end (where the stem was cut) pointing up, just below the soil surface. Potted tubers require bright light and a warm environment to break dormancy. Initial watering must be light and conservative, as overwatering a dormant tuber can easily lead to rot before the roots have established.
For in-ground tubers, carefully remove the heavy winter mulch once the danger of a hard frost has passed and soil temperatures begin to warm, ideally reaching 65°F. The appearance of new growth shoots signals the end of dormancy, and regular watering and feeding can commence.