There are many words you might use to describe the Alocasia genus—stunning, architectural, jewel-like—and all of them are appropriate. Sometimes called elephant ears (a term that is also applied to the Colocasia, Xanthosoma, and Monstera genera), these are very tropical collector’s plants that have a passionate following. They grow outdoors in U.S. Department of Agriculture plant hardiness zones 10 and 11, which means they are grown as houseplants across most of the United States. Although there is some variation among the different species and hybrids, these general rules apply to most Alocasia species.
Keep these special tropical plants healthy inside by following these basic guidelines:
- Light: Needs vary from shade to full sunlight, depending on the variety. Ask the grower if the plant is sun-trained. Leaf color tends to be better among plants that grow best with more light.
- Water: Keep Alocasia plants moist all year; they grow best in very high humidity. They are water-loving plants. To raise the humidity around your plant, place it on a tray filled with pebbles and then add water until it rises to just below the bottom of the pot.
- Temperature: Alocasias will start to suffer below 60 F. Some varieties will die back during colder weather and resprout from the rhizome.
- Soil: Plant in loose, well-drained potting mix.
- Fertilizer: Alocasias can be heavy feeders, especially large specimens. Feed with liquid fertilizer during the growing season or frequent, small applications of granule fertilizer.
Most Alocasia plants can be propagated by clump or rhizome division. Cut off a piece of the underground rhizome and pot it up separately, then keep it warm and moist until new growth begins.
Repot Alocasia varieties annually into larger pots with fresh, free-draining potting soil. Also divide the rhizome annually to keep the plant a manageable size and increase your collection.
There are about 70 species of Alocasia, as well as dozens of hybrids. Alocasia plants are primarily hybridized because of the appeal of their leaf form, color, and size.
Alocasia varieties range in size from the jewel-like Amazon lily (Alocasia Amazonica), which can grow to 2 feet tall and wide, to the truly enormous Alocasia macrorrhizos, which can grow up to 15 feet tall and 8 feet wide. (Of course, only the smaller varieties are appropriate for use as houseplants. Leave the giant-size ones for those who live in zones 10 and 11 and can plant them outdoors.)
Additionally, the plant has been extensively hybridized. Most Alocasia species will do all right in shade, but they often appreciate slightly brighter, filtered sunlight. The bigger ones can be trained to handle full tropical sun. Keep all species warm, moist, and humid. Trim away failing leaves. Like all aroids, Alocasias flower with a typical spathe and spadix, but the flower is usually unremarkable and can even be slightly vulgar.