Caladiums (Caladium species), known for their striking, paper-thin leaves, are tropical perennials that grow from underground tubers. Native to the warm, humid forests of South and Central America, these plants thrive in high heat and cannot survive freezing temperatures. Overwintering allows the tuber to enter a natural rest period, ensuring the plant conserves energy and returns with colorful foliage the following season. The simplest method for many gardeners is leaving the tubers undisturbed within their containers.
Preparing the Potted Caladium for Dormancy
The cue to begin the overwintering process arrives when autumn temperatures start to cool, typically dropping into the 50°F to 60°F range. Caladiums signal their readiness for dormancy as their vibrant leaves begin to yellow and wilt. Once this natural die-back begins, or immediately after a light frost touches the foliage, you should move the potted plant to a sheltered location.
Gradually withhold water to induce dormancy. Reduce water intake significantly, allowing the potting mix to dry out and signaling the plant to transfer its remaining energy back into the tuber. This drying process prevents the tuber from rotting during its long rest, as excess moisture in cool temperatures is highly detrimental.
After the foliage has completely yellowed and collapsed, use clean shears to trim the dead leaves back to soil level. Allow the soil to dry out completely before moving the container to its final storage location. A dry, cured tuber is more resilient against fungal diseases and decay while stored over the winter months.
Ideal Winter Storage Environment
The primary requirement for winter storage is a consistent temperature range, preferably between 50°F and 60°F (10°C to 16°C). Temperatures consistently below this threshold can cause the tuber to perish. Temperatures that are too warm may prevent the plant from achieving a proper rest period.
The storage area should be kept relatively dry and dark, as dormant tubers require no light. Low humidity discourages the growth of mold or mildew on the soil surface or the tuber itself. However, the environment should not be so arid that the soil becomes powder-dry and potentially shrivels the tuber.
Suitable storage spaces include unheated basements, temperature-controlled garages, or well-insulated closets. If using a basement, ensure the area is not prone to dampness or standing water, which could wick into the pot and cause rot. Choosing a spot away from exterior walls or drafty windows helps maintain the necessary temperature consistency.
Monitoring During Dormancy and Spring Revival
Once the caladium pot is settled in its winter location, the care routine becomes minimal. The dried soil surrounding the tuber acts as a protective layer, and watering is usually unnecessary if the storage temperature is on the cooler end of the acceptable range. If the storage area is warmer, such as a heated room, a small amount of water may be needed once a month to prevent the tuber from desiccating.
Regularly inspect the pots for signs of trouble, such as fuzzy mold on the soil surface or soft spots on the tuber, which indicate decay. Soft tubers should be removed immediately to prevent rot from spreading to other nearby pots. Proper air circulation in the storage area helps mitigate the risk of fungal issues.
The process of waking the tubers begins in late winter or early spring, approximately six to eight weeks before the last anticipated frost date. Start by moving the container to a warmer, brighter location indoors, such as near a sunny window. This increase in temperature and light signals the tuber that the growing season is approaching.
Carefully reintroduce water at this time, providing only light moisture at first to stimulate the tuber without saturating the dormant soil. As new sprouts begin to emerge, gradually increase watering and consider repotting the tuber into a container with fresh, well-draining soil to ensure ample nutrients for the new growth. The pot can finally be moved back outdoors once the nighttime air temperatures are reliably above 60°F, ensuring the delicate new foliage is protected from any late cold snaps.