Colocasia and Alocasia are two closely-related genera of herbaceous plants in the Araceae—or aroid—family native to the tropical rainforests of Southeast Asia. Commonly called “elephant ears,” these plants are cultivated around the world as ornamentals for their large, showy leaves, and some species are also grown for their edible, bulb-like corms.
Colocasia and Alocasia in Your Garden
Cultivars of both Colocasia and Alocasia are readily available at nurseries and garden centers in a wide range of colors and sizes, from two-foot-tall dwarf varieties to ten-foot-tall giants. They can be grown outdoors in the St. Louis region and will grow vigorously up until the first frost. At that point, the corms should either be dug and stored indoors in a cool, dry place until next spring, or the planting area should be heavily mulched to insulate the corms from winter cold. Although keeping the corms in the ground can work, especially if they are planted in a relatively protected area such as against a foundation or other structure, we recommend digging up the corms and storing them indoors for the best results.
The plants in these genera are both commonly referred to as elephant ears and can be easily confused. Although some sources claim that the orientation of the leaf blades can be used to help identify Colocasia and Alocasia plants, this is not a foolproof method of identification. One way to tell these plants apart is by examining the undersides of the leaves. Alocasias have waxy glands where the main vein splits into the primary lateral veins. Colocasias lack these glands. They can be seen with the naked eye or the aid of a magnifying glass. Try your hand at elephant ear identification on your next visit to the Garden or your local garden center!
Below are some cultivars recommended by the WIlliam T. Kemper Home Gardening Center:
Colocasia esculenta ‘Black Coral’ is a dark-leaved cultivar that will reach up to four feet tall and spread to fill a three-foot area. The glossy, nearly-black foliage will not fade in full sun like other dark-leaved selections. This cultivar was selected as a Plant of Merit in 2019.
Colocasia gigantea ‘Thailand Giant Strain’ is a truly giant elephant ear with leaves that can reach up to six feet long. It can be used as a bold accent specimen for the back of a mixed border. It can also be grown in a container, where it will not reach its full size. This cultivar was selected as a Plant of Merit in 2016.
The leaves of Colocasia esculenta ‘Mojito’ feature streaks and splotches of dark purple. Mature clumps have an upright growth habit and will reach five feet tall with a similar spread.
Alocasia ‘Sarian’ is a hybrid cultivar that features upward-facing leaves with wavy margins. Mature clumps can reach up to ten feet tall and six feet wide when planted in the ground but will not get as large in containers. This cultivar was selected as a Plant of Merit in 2019.
Alocasia × amazonica is probably the most recognizable of all cultivated alocasias, this plant is often grown indoors as a houseplant. It has dark, bronzy foliage with contrasting white veins and wavy margins.
Alocasia LOW RIDER is a dwarf, hybrid cultivar with glossy leaves with wavy margins held on stout leaf stalks. Mature plants will reach 2 feet tall with a similar spread. Perfect for large containers or in mixed borders. This cultivar was selected as a Plant of Merit in 2021.
Kristina Schall DeYong
Digital Media Specialist