A West Indies type avocado is on the left and a dark rough-skinned Mexican type avocado is to the right.
A sliced avocado reveals it's creamy deliciousness.
The avocado tree has shiny evergreen, elliptic leaves 4-8 in (10-20 cm) long. It is a much-branched, medium-sized tree, to 60 ft (18 m) or more in height. The little flowers are greenish and not at all showy. They are interesting in that each flower opens twice. First the female part (pistil) ripens and opens; then the flower closes and some 24 hours later it opens again with the ripe stamens releasing their pollen. This practically insures that the flower will not be self pollinated. The avocado tree is cultivated for its delicious and highly nutritious fruit. Avocado fruits contain up to 30% oil and have the highest protein and oil content of any fruit. Fruits may be pear shaped to round, and smaller than a golfball to almost as big as a football, depending on the variety.
There are three principal races or groups of avocado: Mexican, Guatemalan and West Indian, named for the areas where they were originally cultivated. Mexican avocados have foliage with an anise scent and small fruits about the size of a plum, with black or purple smooth skin. Guatemalan avocados have larger, blackish-green, rough-skinned fruits. The West Indian avocado has the largest fruits, up to 2 lbs (1 kg), with smooth light green skin. Mexican avocados have the highest oil content; West Indian the lowest. The important cultivars now in commercial production are mostly hybrids between these three original races. There are at least 500 named cultivars. One of the most popular cultivars is 'Fuerte', a Mexican-Guatemalan hybrid with smooth-skinned, shiny green, pear shaped fruits. 'Hass', a Guatemala type, has rough-skinned fruits that turn purple when fully ripe. Most of the commercially grown hybrids are self fertile.
Location Persea americana is native to Central America, but is now cultivated throughout the tropical and subtropical world. Archaeologists have found that avocados have been cultivated in Central America for more than 7000 years. Major exporters of avocado today are Mexico, the United States, Israel, Kenya and South Africa. The largest avocados are grown in Hawaii.
The avocado's tiny blossoms are held on branched stalks and appear at the same time as new foliage.
Culture Light: Grow in full sun. Moisture: Avocados must be grown in well drained soil, but with frequent watering. Allow the soil to dry out before watering deeply. Hardiness: USDA Zones 8-11. The Mexican avocado varieties are the most hardy, withstanding winter temperatures to 16 F (-9 C); some can be grown as far north as Charleston, South Carolina. West Indian avocados cannot tolerate temperatures much below freezing. Guatemalan types are intermediate, hardy to 24 F (-5 C) or so. 'Mexicola', "Gainesville' and 'Winter Mexican' are among the hardiest varieties available. One of the tastiest varieties is 'Pollack', a West Indian type that is killed by temperatures below freezing. Propagation: Named avocado cultivars are propagated by grafting to seedling or clonal rootstocks. Grafted plants will produce fruit in 2-3 years. The large seeds of avocado can be suspended in a glass of water with tooth picks so that the wider half lies below water. They will germinate in a few weeks and can then be transplanted to a pot or outdoors. Such seedlings may bear fruit of uncertain quality in 8-12 years.
Avocado trees are evergreen but drop last years foliage just as the current season's is appearing.
Nothing compares with the understated rich buttery taste of a ripe avocado in a salad, guacamole dip, or just cut in half and eaten with a spoon. Avocados should be ripened off the tree. Picked green and firm, an avocado will ripen in a week or two in a warm room; considerably longer in the refrigerator. Left on the tree to ripen, avocados become mushy and develop an undesirable flavor.
Avocado is closely related to the North American red bay (Persea borbonia) and swamp bay (P. palustris), although neither of these has an edible fruit. Altogether there are about 150 species of Persea, occurring in North and South America and southeast Asia. Most are evergreen trees and shrubs.