The eggplant (Solanum melongena) is a perennial in U.S. Department of Agriculture plant hardiness zones 9 through 12, but it is most often grown as a garden annual. Many eggplant cultivars have been developed for both culinary and ornamental uses.
Eggplant is a member of the nightshade family (Solanaceae) and most likely originated in India, making it one of the few edible members of the Solanum genus that is not a native of the New World. The plant was taken to Europe and Africa by Arab and Persian traders, and most of the modern close relatives of the common eggplant are natives of Africa. The common eggplant came to the New World via Spanish explorers, and by the early 19th century, it was established in America.
The common garden eggplant is an upright herbaceous plant that grows 2 to 4 feet in height. The plant does best when temperatures are high, and it requires a long growing season to produce its large fruits.
The types of eggplants traditionally grown in the United States generally produce oval- or pear-shaped fruits up to 9 inches long with glossy, thick, purple-black skins. The fruits' dense inner flesh is white or creamy in color and has a slightly bitter flavor. Varieties of that type include 'Black Beauty,' 'Dusky' and 'Florida Market.'
Not all cultivars of that type produce the traditional black fruits, however. The fruits of 'White Beauty,' for example, are ovoid, large, weigh up to 4 pounds each and have white skins when ripe.
Cultivars commonly referred to as Asian, Oriental, Japanese or Chinese types typically produce fruits that are longer and thinner than the fruits of American types, and their fruits usually have thinner skins and a less bitter flavor. Cultivars of this type include 'Ichiban,' 'Agora' and 'Machiaw.'
'Ichiban' is a popular variety, thanks to its high productivity and the mild flavor of its fruits. Its fruits are slender and about 10 inches long, and their skins are thin and deep purple.
Some kinds of eggplants produce fruits that are either inedible or have a strong flavor that is typically unpalatable to people used to the taste of common eggplant fruits. Although those plants often are called ornamental eggplant, many of them are actually distinct species in the nightshade family.
Ornamental white eggplant (Solanum ovigerum and Solanum melongena var. ovigerum) is an ornamental species that produces small, inedible, egg-shaped, white-skinned fruits; it is hardy in USDA zones 9 through 12. Some species, such as Ethiopian eggplant (Solanum aethiopicum), hardy in USDA zones 9 through 11, produce red or orange fruits, which are sometimes deeply ribbed and resemble small pumpkin or tomato fruits.