Elephant ear plants, including Colocasia, Alocasia, and Xanthosoma, are known for their large, striking foliage. Their underground structures, often called “roots,” are actually specialized storage organs: corms, tubers, or rhizomes. These organs store energy, fueling the plant’s growth and impressive leaf display throughout the growing season, and enable their perennial nature in suitable climates, allowing them to return year after year.
Understanding Elephant Ear Root Structure
Elephant ear plants develop from distinct underground storage organs. Colocasia species commonly grow from corms, which are swollen, vertical underground stems that store nutrients. These corms tend to have a rough, lumpy appearance and produce roots from their base and shoots from their top. Alocasia plants, conversely, typically form tubers, which are enlarged underground stems that can grow horizontally from the sides of the main plant. Some varieties, particularly Colocasia, may also produce rhizomes, which are horizontal underground stems that can spread and generate new plants.
These structures are not true roots but modified stems, primarily storing carbohydrates. This stored energy fuels the rapid emergence of their signature large leaves and supports the plant’s extensive growth during warm periods. The arrangement of these storage organs allows the plant to anchor itself firmly while efficiently absorbing water and nutrients from the surrounding soil.
Planting for Healthy Root Development
Proper planting is foundational for establishing a robust root system in elephant ear plants. These plants thrive in rich, well-draining soil that is high in organic matter, such as compost or aged manure. Before planting, amending the soil to a depth of 8 inches can improve both drainage and nutrient availability. Elephant ear corms or tubers should be planted when soil temperatures consistently reach at least 65°F, after all danger of frost has passed.
For most varieties, corms are planted 4 to 6 inches deep, with the larger bulbs requiring a slightly deeper placement. The general orientation for corms is with the pointy side facing upward, as this is where the shoots will emerge. If uncertain about the orientation, planting the corm on its side will still allow it to send shoots upwards and roots downwards.
Spacing between plants can vary from 2 to 6 feet, depending on the mature size of the specific variety, allowing ample room for root expansion. After planting, a thorough initial watering helps settle the soil around the corm or tuber, ensuring good contact and initiating growth.
Ongoing Care for Robust Roots
Consistent care throughout the growing season is important for maintaining the health and vigor of elephant ear root systems. These plants require consistent moisture, preferring soil that remains evenly moist but never waterlogged. Overwatering can lead to root rot, so it is important to allow the top inch of soil to dry slightly before watering again. Mulching around the base of the plant with shredded hardwood or leaf compost can help retain soil moisture and regulate soil temperature, benefiting root development.
Elephant ears are considered heavy feeders, and regular fertilization supports strong root growth and overall plant health. Applying a balanced, water-soluble fertilizer monthly during the active growing season provides the necessary nutrients. Organic options like fish emulsion or compost tea can also be beneficial. When fertilizing, it is helpful to water the plant beforehand to aid nutrient absorption and prevent potential fertilizer burn.
Overwintering Elephant Ear Roots
In regions where winter temperatures drop below 40-50°F, elephant ear plants are not hardy and their underground structures need protection. Overwintering begins after the first frost or when the foliage starts to die back naturally. At this point, the stems should be cut back to about 6 inches above the ground.
The corms or tubers are then carefully dug up, taking care to avoid damage. After digging, gently remove excess soil from the structures and allow them to air dry for several days to a week in a warm, dry location. This curing process helps prevent rot during storage. Once dry, store the corms or tubers in a cool, dark, and dry place where temperatures remain consistently above freezing, ideally between 40°F and 50°F. They can be placed in paper bags, cardboard boxes, or bulb crates, often layered with peat moss, sawdust, or dry soil to maintain moderate humidity and prevent desiccation.
Addressing Common Root Issues
Elephant ear plants can experience specific root problems, often linked to environmental conditions. Root rot is a common issue, primarily caused by overwatering or poorly draining soil, which deprives roots of oxygen and leads to decay. Symptoms include yellowing leaves, wilting, and a mushy texture or foul odor from the roots. To address root rot, the plant should be removed, affected mushy or brown root sections trimmed, and then repotted in fresh, well-draining soil.
While less common, underground pests like grubs or nematodes can also damage elephant ear roots. Such damage can lead to a decline in plant vigor, as the roots are compromised in their ability to absorb water and nutrients. Ensuring good soil drainage is the most effective preventative measure against root rot, promoting a healthy root environment.