By Bodie V. Pennisi
University of Georgia
Both groups are evergreen perennial plants found in tropical forests in sunny open places or shaded, usually damp sites. Both belong to the Araceae family, originating from South and Southeast Asia.
Interest in these tropical plants is resurging in the ornamental market, with a growing variety of species and cultivars offered. New breeding and selection efforts have brought small and giant habits, spotted and cup-shaped leaves and pink, red, purple and black petioles, stems and blooms.
Great for GeorgiaBoth plant groups are excellent for Georgia landscapes. They're easy to become established and grow in under a wide range of soil and moisture conditions. They're resistant to deer, too.
They grow mainly from rhizomes, or horizontal, underground stems that often send out roots and shoots from their nodes. Some grow from tuberous roots. They're all easily propagated by dividing the root ball, rhizomes or tubers.
Many species are root-hardy to Zone 8 and some even to Zone 7. For the rest, you can dig up the rhizomes after the first light frost and store them in a dry, dark place that's cool but above 45 degrees.
The leaves of both groups are medium to large and arrow-shaped, with strong veins and fleshy petioles.
The inflorescence, or flowering part, has two main sections. A single bract, called a spathe, forms a shielding shell or hood for a stalk called a spadix. The spadix bears the actual flowers and later the fruit and seeds. Depending on the species, the spathe and spadix may be white to cream-colored, or tan, yellow or burgundy.
Alocasias bloom year-round and produce several blooms per plant at any time. Colocasias are more reluctant bloomers.
Which is which?Since alocasias and colocasias look alike, one is often mistaken for the other. But alocasias have thicker leaves that are often held upright, with petioles attached at the leaf margins. They like to be kept dry and usually need some shade.
Colocasias have thinner, papery leaves that are held perpendicular, with petioles attached in the middle of the leaf. (The botanical term is "peltate.") They like to be kept wet and prefer full sunlight.
Both groups have both green and dark species and cultivars. The green plants generally need full sun and more water but can take more abuse. The purple plants, also called African masks, need partial shade and do best if kept on the dry side. They're more finicky than the green plants.
Handling the plants may cause skin irritation or an allergic reaction, so use protective gloves when you're planting them or trimming leaves or flowers.
Use some of these amazing plants to bring the feel of a tropical retreat into your summer landscape. Plant an alocasia or colocasia -- an elephant ear -- this summer, and catch the tropical wave.
(Bodie Pennisi is a Cooperative Extension floriculture specialist with the University of Georgia College of Agricultural and Environmental Sciences.)