I've been researching EE from library books and the internet. I've found several contradictions. After weeding though them, I've come up with the information below. For those who know, can you please make any corrections you may deem necessary. This is for the coastal area of Texas zone 9. Thank you.

Elephant Ears are not a scientific name but one we comely use. There are three genera, from the family of Araceae, that are the most commonly planted Elephant Ears. They are Alocasia, Colocasia, and Xanthosoma. There are many species within each genus. Before you grow Elephant Ears, you need to research the species you plan on growing. Some can take more sun and moisture than others can. Other species can grow outdoors as far north as zone 7 as oppose to certain species that grow only in tropical climates outdoors. The following information is only a general guideline. There is a wide assortment of species in each genus of Elephant Ears below.

Alocasia, in most cases has shiny, erect, upward pointing leaves with heavily raised veins. The leaves can be divided or undivided. Grown outdoors in a rich well drain moist soil in partial shade. You can find Alocasia usually at damp areas by streams and marshes. You have some giants in the family that can grow over 96" tall.

Colocasia is the Elephant Ear most widely grown in our area. The leaves have a tendency to flop down and usually have a matte finish. The leaves on the Colocasia are always undivided. You can grow this plant in 12" of water so they would be good for your pond. If planted outdoors grow in fertile, humus rich, slightly acidic, moist or wet soil. When it is dormant, try to keep it on the drier side. Colocasia are very heavy feeders. Depending on the species, you can grow Colocasia in sun or part shade.

Xanthosoma leaf on the underside of it leaves is ribbed and the top is smooth. On the Xanthosoma, the leaf stem attaches at the notched edge of the leaf not like the Alocasia and Colocasia, which attaches away from the edge of the leaf. They are grown for their eatable tuber and leaves. Stems are eatable on some species. Grown outdoors in a rich fertile, well drain soil in partial shade. Avoid saturation. Grow in a slightly acidic soil. Feed every 2 or 3 weeks. Xanthosoma includes some of your largest species.