The Thailand Giant Elephant Ear

Colocasia gigantea

Thailand Giant is a perennial elephant ear (Zones 8-10) that has already made an impact in the horticulture world and many gardens demanding attention with its overall size. It towers over other Colocasia species in every way from leaf size to height. In areas north of Zone 8 it is a worthwhile annual used in contianers or the garden. In colder zones further north, tubers can be dug and overwintered indoors for replanting in the spring.

The mature foliage of Gigantea can be 4 to 5 feet in length and 2 to 4 feet in width. The veins and mid-veins are much larger and pronounced than most species. The leaves are a light aqua green to glaucum color. The petioles (stems) are also this light green color and have a white powdery substance on them.

Thailand Giant is one of the fastest growing plants we have ever seen. When planted in the garden from just a a 4 inch pot we've seen the plant reach 8 to 10 feet tall in one season.

Like most parts of Thailand Giant, the flowers are unique. The uniquely fruit-scented flowers will be produced after you see what is commonly called a flag leaf. This unusual thin foliage spike is formed then the older petiole (stem) will push out a cluster of 6 flowers. The flowers are held in a fan shape and usually open one after another for the next 6 days. The flowers are 1 foot tall or larger on mature plants with white spath and spadix. The flowers will open and produce a unique sweet smelling fruit scent. The following day the spadix will drop white pollen.

Where to plant?

When choosing a site to plant a Thailand Giant elephant ear you'll need to consider exposure to sun and wind and soil moisture.

Wind: A site that protects the plant from the wind will result in a much larger plant. High winds will cause a shorter, more stout plant and maybe torn leaves if the winds are strong enough.

Sun: Though Thailand Giant will tolerate full sun, it prefers partial shade. But it doesn't matter at what time of day it gets it. Four to six hours of morning or afternoon sun is preferable, making woodland borders with an eastern or western exposure a great planting spot.

Soil: Thailand Giant adapts to any good average garden soil, even clay-based soils. The plant can handle lots of water but the soil should drain quickly. Avoid planting it in soils that remain consistently wet or soggy as these can cause problems with the roots, specifically root rot.

Feeding: Don't feed Thailand Giant elephant ears until they are at least a foot or two tall and performing well. You can feed with a water-soluble liquid or well-balanced granular fertilizer. Fertilizers designed for vegetable plants work well. You can also use Epson salts or magnesium sulfate. The magnesium sulfate will help to darken the leaves and toughen the plant. Use one tablespoon of magnesium sulfate per gallon of water.

Problems: As with other tropical-type plants, Colocasia species can be visited by some common pests. Spider mites, aphids and mealybug top the list, though we've rarely had any problems with these in our trial gardens. If these insects are present they can be controlled with Neem oil or insecticidal soaps. Before spraying the entire plant, it's probably best to spray one leaf to make sure the chemical will not cause burn or other damage to the plant.

Get planting and care instructions and more details for Thailand Giant Elephant Ear