Caladiums, often known as “Angel Wings” or “Heart of Jesus,” are tropical foliage plants valued for their large, vibrantly colored leaves. These striking plants offer a spectacular splash of white, pink, red, or green color in shaded garden spots throughout the warm season. Gardeners often wonder if these beautiful specimens will emerge from the soil again the following spring. The answer depends entirely on the local climate and a specific survival mechanism developed in their native tropical habitat.
Caladiums Perennial Annual or Both
Caladiums are true perennials, meaning they are capable of living for more than two years, but their ability to return naturally is strictly limited by sustained soil warmth. Originating from the warm, humid environments of South and Central America, they are only reliably hardy in USDA Hardiness Zones 9 through 12. In these tropical and subtropical areas, the underground storage organ, called a tuber, can remain in the soil year-round and sprout new growth each spring.
In temperate climates outside of these zones, Caladiums are treated as annuals because the winter temperatures are lethal to the tubers. The tuber will not survive if the soil temperature consistently drops below 50 to 55 degrees Fahrenheit. A soil temperature of at least 60 to 70 degrees Fahrenheit is necessary for the tuber to begin to grow again. If the ground freezes or stays cold for prolonged periods, the tuber will rot and disintegrate, preventing any natural return.
Understanding the Tuber Dormancy Cycle
Caladiums survive the off-season through dormancy, a natural biological process triggered by cooling temperatures and shortening daylight hours. As the growing season ends, the plant initiates a systematic transfer of energy from the foliage back to the underground tuber. This tuber acts as a dense storage bank, accumulating starches and nutrients that will fuel the next season’s growth.
The visible sign of this shift is the wilting and yellowing of the leaves, signaling that its resting state is approaching. Once the leaves have withered and collapsed, the tuber is considered dormant. This period of rest is necessary for the tuber to rejuvenate and prepare for the next cycle of leaf production, ensuring the plant can produce foliage when favorable warm conditions return.
Practical Steps for Overwintering Tubers
Gardeners in cooler zones can ensure their Caladiums return by manually protecting the tubers from cold winter soil. The process begins in the fall, either after the first light frost or when the air temperature consistently drops below 60 degrees Fahrenheit. Once the leaves have fully yellowed, the plant’s energy transfer is complete, and it is the ideal time to carefully dig up the tubers.
After lifting the tubers, the next step is curing, which involves drying them out to prevent rot during storage. Place the tubers in a warm, dry, and well-ventilated location, ideally above 60 degrees Fahrenheit, for approximately one to two weeks. This curing period allows the outer layer of the tuber to harden and any remaining moisture to evaporate.
Once the tubers feel dry to the touch, trim away any remaining foliage or roots before storage. Store them in a dark, cool, and dry location throughout the winter, maintaining a temperature between 55 and 60 degrees Fahrenheit. The tubers should be packed loosely in an insulating, low-moisture medium such as dry peat moss, vermiculite, or coir, and stored in a breathable container like a paper bag or a cardboard box to ensure air circulation.
In the spring, the tubers are ready to be replanted when the threat of frost has passed and the soil temperature has warmed to a consistent 65 degrees Fahrenheit. Planting them too early into cold, wet soil can cause them to rot before they have a chance to sprout. By replicating the warm, dry conditions of their natural dormancy, gardeners in non-tropical climates can successfully ensure the return of their Caladiums year after year.