Taro (Colocasia esculenta) is the technical term for the elephant ear plant, according to the University of Minnesota. It was once the staple of the native Hawaiian diet, and archaeological evidence shows humans using the plant for food as far back as 28,000 years ago, according to the University of Hawaii. This wetland tropical perennial can survive down to USDA hardiness zone 5, but grows best in zones 9 through 11. Even a well-meaning gardener can sometimes experience various cultural, pest and disease problems when growing an elephant ear.
The elephant ear plant requires constant moisture; commercial farmers grow the plant in fields that are submerged for prolonged periods of time. For the backyard gardener, the University of Hawaii recommends keeping the plant's soil perpetually moist but not to the point of puddling. Signs of dehydration include wilting, curling or yellowing of the plant's iconic leaves.
The elephant ear plant has heavy nutrient needs. Signs of malnutrition include stunted foliage or corm development, pale green or yellow leaves and poor plant strength. To support proper development, apply a standard liquid fertilizer once a week. Follow the fertilizer's labeled guidelines, as potency varies by product.
The plant grows vertically from a series of stalks, leaving the ground around the plant bare and exposed. This makes elephant ears susceptible to weeds that compete with the plant for space and soil nutrients, according to the University of Hawaii. Regular hand-pulling of weeds or cultivation with a tool like a hoe will keep weeds at bay. After the plant is four to five months old, its large foliage will shade the surrounding soil and minimize the germination of weed seeds. At this stage of growth, hoe cultivation should be avoided to keep from damaging the plant's roots.
The leaf blight fungal disease attacks elephant ear plants often due to the plant's perpetually moist growing environment. Symptoms include brown spots on the elephant ear's expansive leaves. Unlike with other vegetation, the elephant ear can't be dried out to kill the fungus. Blight risks can be minimized by only watering the plant's base and not getting its leaves wet. If blight is already present, the University of Hawaii recommends any standard plant fungicide.