Colocasia culture is straight forward. the more water and nutrients you provide the more plant you will get. Shallow bodies of water or pond edges will produce excellent results, Colocasia can also be grown in regular garden soil so long as the soil doesnt become too dry. Colocasia are heavy feeders and for best growth they will require a soil high in organic fertilizers with plenty of composted material. A pH from 5.5 to 7.0 is satisfactory. Most Colocasia prefer bright non direct sunlight, unless grown in extremely hot, low humidity climates, where full shade is necessary. Elephant ears should be planted slightly deeper than they grow as they will push up. During the growing season, Colocasia will continually produce new leaves as the older leaves continually die off. Growers should periodically remove the dead leaves in order to prevent the leaves from covering ground-cover plants and to keep the garden looking tidy. Colocasia can be propagated by seed or division, Germination should take place within 21 days. In addition you can divide the larger tubers or separate the new plantlets that form at the rhizome tips on the running types. The long runners form nodes along their length, and new growth buds exist at each of these nodes.
As the day length shortens, Colocasia switch their energy resources from producing leaves to flower and corm production. The production of leaves will become smaller and the corm will swell noticeably. At this time, most of the current season's roots will die off. It is important to understand this physiological change in order to successfully overwinter your elephant ear.
Most Colocasia has a solid USDA Hardiness Zone 7b, while Colocasia 'Pink China' is reportedly winter hardy to Zone 6. The rest fall somewhere in between. In Zone 7b, most Colocasia will return without benefit of mulch with a few exceptions. Cover the clump after the first frost with a 1' tall pile of shredded leaves, which works well to protect the main corm. The plants will grow through the leaves when they re-emerge in spring.
In colder zones, the same principle can be used but with a slightly altered technique. Assuming the plant has made good growth during the summer, after the first frost, encircle the base of the plant with a 3' diameter cage of hog wire and fill it with shredded leaves. If left unshredded, the leaves will pack together and hold unwanted moisture against the plant, causing it to rot. When new leaves emerge in spring, remove the cage and filler. Northern gardeners (Zone 7a and north) will need to bring their elephant ears indoors before the temperatures drop below freezing. Over winter, elephant ears can be grown indoors as potted house plants. If you grow your elephant ears outdoors in containers during the summer, cut back all but the top two leaves, then bring the pot indoors the before first frost. If growing elephant ears in the ground during the summer, pot them before frost in an appropriately-sized container and place the pot in a cool area (45-60F is ideal) where the plant receives bright light. Do not over water in winter as the plants are still semi-dormant.
To watch a tutorial video please visit http://www.youtube.com/watch?v=zy0cFAsibqA