"Black Magic" elephant ears (Colocasia esculenta “Black Magic”), and other purple cultivars of taro, are the only plants that grow from “bulbs” that produce large purple leaves. Bulb is a misnomer when describing elephant ears, the ornamental form of taro. What looks like a bulb is technically a corm. Showy elephant ears make a good addition to the edge of a garden pond in a water garden.
Bulbs vs. Corms
Although nurseries and garden centers often advertise elephant ear “bulbs,” they’re actually selling corms. Like true bulbs, corms store nutrients for the plant to use while it's dormant. The corms of decorative taro cultivars may be weigh 1 to 2 pounds while those cultivated for food may weigh up to 8 pounds. “Jet Black Wonder” (Colocasia esculenta “Jack Black Wonder”) and “Jet Black Gold” (Colocasia esculenta “Jet Black Gold”) are other decorative taro cultivars with large purple leaves.
Elephant Ear Leaves
Elephant ears grow from 3 to 6 feet tall. Their heart-shaped leaves grow from 12 to 30 inches long and look like taro leaves only they’re purple, not green. Elephant ears are dark purple to nearly black and are spongy, filled with air spaces. They have small, netted veins between larger, parallel lateral veins and deep purple stalks.
In Warm Climates
Elephant ears and other taro cultivars grow as perennials in U.S. Department of Agriculture plant hardiness zones 8 through 11. Elephant ears naturally form large colonies along ditches, canals, ponds, streams, bogs and swamps. Space them 18 to 24 inches apart to give them room to spread. They require moist soil and can be grown in water 12 inches deep. The plants need from three to five hours of full sun daily.
In Cold Climates
Frost will kill the elephant ear stems and leaves but the bulb will survive. When this happens, you can grow it as a summer annual. Dig the corms up and store them over winter in wood shavings or dry peat in a room where temperatures do not fall below 45 degrees Fahrenheit. In late winter or early spring, plant the corms in 1- or 2-gallon pots, water them once and keep them indoors or in a greenhouse. Don’t water them again until they produce new leaves. When all danger of frost has passed, transplant them outdoors.
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