Colocasia esculenta (ht 1.5m), from tropical East Asia, is sometimes referred to as 'elephant's ears'. The resemblance is rather remarkable and these imposing foliage plants can really make a statement in a garden. These plants belong to the broad plant family known as the Araceae, the members of which are sometimes known as aroids. Many of these plants come from tropical climates and were traditionally used as houseplants. However, in Sydney we can grow many of them outdoors as permanent plantings, or in pots. On the whole, they are best suited to part or dappled shade, with sufficient moisture: many can actually grow well in ponds. They can introduce an element of bold contrast with their distinctive leaves and flowers, and mix in well with other warm-climate plants that grow well here, creating the ambience of a tropical rain forest.
The basic species of Colocasia has enormous, deep green arrowhead-shaped leaves, which provide a very satisfying contrast to ferny, strappy or grass-like foliage in the garden. Their flowers are not very showy, and in fact these day, the species is regarded by the authorities as a weed. I find the dark velvety leaves of the cultivar 'Black Magic' to be the closest to real elephant's ears in terms of colour! It can be used to form dramatic pictures in the garden when paired with purple-variegated or silver foliage, or purple or white shade-loving flowers. There are also patterned forms, such as 'Illustris', which are very beautiful. They combine very effectively with coleus and other dramatic foliage plants in shaded spots in the garden. The fancier cultivars seem a bit more cold sensitive than the basic species and can die back a bit in winter; they are certainly not at their best at that time - I generally cut all the shabby leaves off. In cold gardens, they are probably best grown in pots and moved under shelter in the cooler months. Propagation is by division of the tubers or by runners that may develop from the parent plant.
If any part of this plant is chewed or eaten raw, it can cause immediate burning pain and swelling of the lips, mouth and tongue. Swelling may cause copious salivation and difficulty in breathing, swallowing or speaking. Intense gastric irritation may occur if swallowed.