Giant taro or giant elephant ears (Alocasia macrorrhiza) is a tropical perennial herb that develops huge leaf blades on thick, long leaf stalks. These leaf blades are broad, arrowheadlike and are typically held at an upright angle to catch light. Growing from starchy rhizomes that can be boiled and eaten (poi-poi), the foliage is killed back by frosts. Therefore, grow it outdoors only where winter frosts are rare or light, such as in USDA zones 9 and warmer.
Especially ornamental, "Variegata" produces large, bold-textured leaves that also are blotched irregularly in dark green, creamy white and gray-green hues. To ensure that leaves do not brown or scald, plant this variety in very bright indirect light and keep soil moist and humidity high. Dry conditions and hot, direct sunlight in particular can damage the white areas of the foliage, especially on leaf edges.
Look at the leaf stalks on "Violacea" and you will see hints of dark green-purple and the large leaf blades will have a light purple casting. Some plants will have markedly more purplish coloring in the leaf stalks than others.
Pale to medium yellow leaf stalks mark the selection named "Lutea." As the plant ages and reaches larger size, the yellow veins on larger leaves contrast the medium green on the leaf blades nicely, adding an attractive foil to the tropical shade garden. Prune away surrounding plants in order to get an unimpeded view of the architecturally striking leaf stalks at the base of the plant.
New Guinea Gold
Potentially an improved, more colorful form of "Lutea," "New Guinea Gold" has golden yellow leaf stalks and veins that spread out into the deep green leaf blades. In the heat of midsummer into the warm, tropical autumn, the leaves that unfurl tend to have irregular variegation of cream and yellow in the typically green areas of the leaf blade.
Truly an Alocasia worthy to rival the size of a real elephant, "Borneo Giant" is grown as an ornamental strictly to produce massive leaves. On healthy specimens, an individual leaf blade can measure 6 feet by 4 feet wide atop a leaf stalk that is 4 to 6 feet tall. The dark emerald green leaf blade also has a rippled texture.
- "A-Z Encyclopedia of Garden Plants"; Christopher Brickell and H. Marc Cathey, eds.; 2004
- Floridata: Alocasia Macrorrhiza