Home & Garden

The gardener’s guide to elephant ear

Colocasia and Alocasia

One in an occasional series of guides on growing popular plants. Other guides include lenten rose, peony, redbud, azalea, coleus, lantana, coneflower, savory calamint and rudbeckia.

The elephant ear in its different forms is instantly recognizable for its cluster of oversized arrow-shaped leaves, some reaching five feet or more in length. It is the consummate tropical plant, not just in its origins, but in its capacity (alongside ornamental bananas, caladiums, angel’s trumpets and cannas) to turn any balcony, deck or patio into a tropically themed garden throughout summer and into fall.

The popularity of “tropicals” in recent years has led to a rich array of elephant ear varieties now available to home gardeners. If you can’t get your hands on some of the fancier ones such as the near black-leafed varieties, or the absurdly gigantic green cultivars, the standard green elephant ear remains effectively big and lush. Generally, the leaf tips of colocasias point down and those of alocasia point up, though not all follow this rule. The Colocasia esculenta is the taro, an important food plant around the globe that is harvested mostly for its tuber-like corm, though the leaves and stalks are also eaten. The plant contains irritants and toxins and requires knowledgeable preparation and cooking. Here we will focus on the elephant ear’s ornamental utility.

Size

A single corm will produce a clump of leaves that is typically five feet high and equally wide. The display can be given more breadth by planting additional corms. Dwarf varieties are available where a smaller stature is required or desired. Giant versions grow to nine feet, with individual leaves five feet in length or more.

Use and placement

Use elephant ears anywhere you want to make an impact with a striking foliage plant. In a container, they can stand alone as a statement, but placed with other leafy plants, they become essential elements in conjuring a jungle paradise. In the tight quarters of a balcony or patio, they can create alluring walls of foliage. They also look good on the edge of ponds and can be used as eye-stopping plants to mark transitions in the landscape.

Planting and care

Elephant ears do best in full sun or partial shade. Their most important need is water — they drink a lot to keep the leaves turgid and will show signs of wilting when thirsty. Placement in organically rich soil, and a light mulch, will promote soil moisture retention. They make great container plants — elevated pots give them even greater stature — but the pots should be at least 12 inches across to provide the soil mass they need to maintain even moisture. Still, a potted elephant ear may need watering daily in high summer; make sure to use a pot that drains and leave at least an inch between the soil surface and the pot rim for ease of watering.

(Shutterstock)

They are also heavy feeders and benefit from regular fertilizing. A weekly application with a weak solution (half the recommended strength) of nitrogen-rich fertilizer will encourage the desired lush growth. The plant will continue to produce new leaves through the warm months — remove the oldest leaves as they decline to keep plants looking fresh.

In the Mid-Atlantic, elephant ears should be dug before the first frost of fall and stored indoors, dormant, over winter for planting out the following May. After cutting back the leaves, allow corms to dry in front of a fan for a day or two, then store them in vermiculite or peat moss somewhere cool and dry, but above freezing.

Some varieties do not form corms and can be kept in leaf year-round as houseplants. Varieties with a pronounced single corm at season’s end tend to go winter dormant even indoors.

Varieties

An unnamed elephant ear is most likely to be Colocasia esculenta, the food plant taro, which also makes an impressive ornamental. However, the wild taro is listed as invasive in some states with sub-tropical climates. Check your state’s invasive plant species list before planting. You will pay a premium for more unusual types, including cultivated varieties of the taro, of which there are many.

One of the largest colocasias, at nine feet tall with leaves five feet long and four feet across, is Thailand Giant, a selection of Colocasia gigantea. A related variety is named Laosy Giant. Jack’s Giant is a giant taro. Dark Star is a mammoth green-leafed alocasia, as is the golden-yellow Alocasia lutea. Keep their size and impact in mind when choosing a place for them.

Royal Hawaiian is a branded series of cultivars with a wide range of leaf shapes, sizes, colors and markings. They include varieties such as Maui Sunrise and White Lava, which have creamy centers.

Varieties of near black-leafed elephant ears abound and include Black Coral, Aloha, Black Magic and Coal Miner. These add drama to tropical compositions and pair well with caladiums, dahlias, cannas and annuals with strong red, orange and yellow flowers or leaf markings.

Lime Zinger is a bright acid green (and botanically a Xanthosoma).

A few small and long-leafed alocasia hybrids have been developed as houseplants, notably Alocasia x amazonica. Polly is a dwarf form, growing to 24 inches.

Xanthosoma Lime Zinger. (Missouri Botanical Garden's Plant Finder)
Colocasia Black Magic. (iStock)
Colocasia gigantea Thailand Giant. (Walters Gardens)
Colocasia esculenta Coal Miner. (Shutterstock)
TOP LEFT: Xanthosoma Lime Zinger. (Missouri Botanical Garden's Plant Finder) TOP RIGHT: Colocasia Black Magic. (iStock) BOTTOM LEFT: Colocasia gigantea Thailand Giant. (Walters Gardens) BOTTOM RIGHT: Colocasia esculenta Coal Miner. (Shutterstock)

Lead illustration by Washington Post staff/iStock/Shutterstock. Icon illustrations by Jeannie Phan

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