Elephant ear plants (Colocasia spp.) make a stunning addition to a garden with their attention-getting leaves. Elephant ears come in all sizes -- small, medium, large or giant. Some of the large or giant elephant ear varieties belong to the Colocasia esculenta genus and can grow more than 5 feet tall, bearing up to 3-feet-long leaves. One of the largest elephant ear plants is native to Thailand, Colocasia gigantea. Colocasia gigantea can reach a height of 9 feet and has leaves up to 5 feet long under optimal growing conditions. Elephant ears are tropical plants that grow as perennials in U.S. Department of Agriculture plant hardiness zones 8 through 11. You can also grow giant elephant ears in temperate climate regions, but you have to take the plants or bulbs indoors during the winter.
Grow elephant ears from seed or tuberous bulbs in spring. For best results, select a garden location that gets half a day of either morning or afternoon sun. You can also plant giant elephant ears in large pots or containers around the garden or patio. When you grow elephant ears from seed, the plant has to produce its bulbs before developing its leaves and so you will not get the huge leaves the first season. Plant the round or oval large, brown elephant ear bulbs 2 to 4 inches deep. In cool climates, you can get a head start by first planting the bulbs indoors in pots. Elephant ears need lots of water, but Colocasia gigantea, unlike Colocasia esculenta varieties, is sensitive to overwatering and needs good draining soil. Giant elephant ears are heavy feeders and grow larger in fertile soil. Elephant ears develop their root system and start to sprout in spring. Leaves emerge in mid- to late spring.
The leaves of giant elephant ears enlarge in summer and reach their biggest size by the end of the season. New leaves are continuously formed as the old leaves die off. Leaf color varies from green, green-gray and green with a blackish hue, depending on the elephant ear plant variety. Some leaves have veins in contrasting colors. Remove dead leaves to keep the garden tidy and to prevent the leaves from suffocating smaller, nearby plants. Water giant elephant ears regularly -- these plants love water. Use a slow-release fertilizer or fertilize with a liquid fertilizer periodically for optimal growth.
Giant elephant ears stop putting their energy into leaf production as the days become shorter in fall. During fall, elephant ear plants switch to flower and bulb production. Flowers are usually white or yellowish and may be up to 8 inches long, often resembling flowers of calla lilies. Frequently, flowers become hidden by the large leaves. At this time, elephant ear bulbs enlarge, storing food energy for the next season.
During winter, elephant ears go dormant -- leaves die back and bulbs stop growing. In USDA zones 8 and higher, bulbs can be left in the ground for another show next year. In cooler climates, cut off leaves and dig up the bulbs. Allow the bulbs to dry (about a day or so) and store them in peat moss or vermiculite indoors. Alternatively, plant the bulbs in 5- to 10-gallon pots and move them indoors to protect them from freezing temperatures.