The name probably derives from a corruption of Colocasia, another genus of very similar plants belonging to the same family. Evergreen perennials, mostly warm greenhouses, grown for their ornamental foliage of different shape and colors. They are all from tropical Asia and therefore require high temperatures, but Alocasia odora, one of the largest species, native to Formosa and the Philippines, can very well be grown in an almost cold greenhouse; in the milder climates of Italy, it can be grown outdoors in a shaded place. These are poisonous plants.
Cultivated species of Alocasia:
Alocasia argyraea, hybrid of Alocasia longiloba pucciana, with long sagittato-peltate leaves, internally covered with silvery reflections on the dark-green background; A. cuprea, native of Borneo, has leaves peltate, green-shiny copper with deeply depressed veins that make them wrinkled, lower-purple-dark page; A. indica can grow up to m 2, with leaves of about 50 cm and long petioles, forming a short and erect stem; has olive-green sagittate leaves; var. metallic original from Malaysia, with metallic reflections on the upper page of the leaves, the dark purple lower page; A. korthalsii, coming from Borneo, has green-olive sagittate leaves with the main veins strongly marked in white-silver; A. macrorhiza, elephant ears, native to Malaysia and Ceylon, becomes almost arborescent; it has a thick and robust trunk that grows up to 4.50 m, large sagittated leaves, green and fleshy with a central vein detected; the aforementioned A. odora is very similar, but of course none of the two, grown in pots, reaches similar proportions, although they may become remarkably large; A. sanderiana, from the Philippines, has silvery-green, sagittated leaves with white veins and deeply lobed margins surrounded by a white line.
the Alocasia need high temperatures and constant humidity, the watering can be frequent in summer, more space in winter, however a high and efficient drainage of the pot is essential, possibly also with sweet wood coal, because they have big and fleshy roots that rot very easily. For the same reason, the mixture must be very porous, with a ground of leaves that is not ripe, peat, chestnut bark and bits of coal. A sphagnum pad on the pot can be of great help as long as it is kept slightly moist. Sometimes, in the winter, the aerial part can die from external causes, such as lack of atmospheric humidity or mite attack, but if the strain is not rotted and the plant is well established with rhizomes or already formed underground tubers, it will sprout again in spring.