The immense, heart-shaped foliage of plants commonly called elephant ears makes them a dramatic addition to any garden or container. These tropical giants generally belong to two genera, Colocasia and Alocasia, which both grow from large, starchy underground structures called corms. Correctly orienting this corm during planting significantly speeds up the sprouting process, allowing the plant to establish itself quickly and begin producing its signature large leaves. Positioning the growing tip upward conserves the corm’s stored energy and promotes rapid, successful emergence from the soil.
Identifying the Top and Bottom of the Corm
Identifying the subtle difference between the top, where the leaves emerge, and the bottom, where the roots develop, is the main challenge when planting an elephant ear corm. The side that faces upward is usually smoother and may feature a slight point or concentric rings where previous stems were attached. This smoother end is the apical bud, which contains the dormant growth point for the new foliage.
The underside of the corm, which should be placed facing down, tends to be flatter, rougher, and may show remnants of old, fibrous roots or small, bumpy nodules. This gnarlier texture marks the root plate, where new feeder roots will actively form to anchor the plant and draw in moisture and nutrients. If the top and bottom are ambiguous, a gardener can simply place the corm on its side in the planting hole. Gravity will cause the sprout to grow upward and the roots to grow downward, although this method may delay initial sprouting as the plant expends energy to reorient itself.
Planting Depth and Soil Preparation
Once the proper orientation is determined, the next step involves preparing the environment to support the corm’s development. Elephant ears thrive in rich, fertile soil amended with organic matter, such as compost, to improve texture and nutrient content. Although they require consistent moisture, the soil must still drain well to prevent the corm from sitting in standing water, which can lead to rot.
The ideal planting depth is usually determined by the size of the corm, typically requiring the top to be covered by two to four inches of soil. For larger corms, planting slightly deeper, up to five inches, may be necessary to provide adequate support. When planting multiple corms, spacing them approximately two to three feet apart is important to allow the massive leaves and mature root systems sufficient room for growth and air circulation.
Initial Care for Successful Sprouting
After planting the corm, consistent care is required to awaken the dormant structure and encourage rapid sprouting. Elephant ear corms will not begin active growth until the soil temperature reaches a consistent warmth, ideally between 65°F and 75°F. Planting too early in cool conditions can significantly slow or prevent germination, making a soil thermometer a useful tool for timing.
The newly planted corm requires consistent moisture during the initial rooting phase to stimulate the formation of new roots and the emerging sprout. The soil should be kept continuously moist, but never saturated or soggy, which risks fungal infection and decay of the corm. If the corms are started indoors, providing them with supplemental warmth will help break dormancy and give the plant a head start before it is moved outdoors.