The avocado tree (Persea americana) is a member of the Lauraceae family of plants. The many varieties of the avocado tree produce fruit in the fall, winter and spring, each one different in appearance, size, texture and taste. The avocado tree has a limited growing area that has the climate that allows for a long growing season, making the fruit of the avocado tree available year-round.
There are three types of avocado trees: Mexican, with a cold-hardy small fruit with thin, smooth skins; Guatemalan, with thick, hard, pebbly skins; and West Indian, with a shiny skin that can have a thin or medium skin. Hybrid varieties of these types are sold in supermarkets.
There are over 500 different varieties of avocado trees. Seven of them are commercially grown in California, which produces 90 percent of the world's avocado crop. California Hass avocados have pebbly skins, average to large in size, oval in shape and black in color when ripe. The Bacon avocado tree produces a fruit that has a green skin, medium size and is available from late fall into the spring. The Fuerte avocado produces a fruit that is pear-shaped, medium size with a smooth, thin green skin. Gwen is similar to the Hass, but larger. Lamb Hass is one of the largest varieties. Pinkerton produces a long, large, pear-shaped fruit with a small seed and a slightly pebbled green skin. Reed is available in the summer and early fall. It is round, large with a thick green lightly pebbled skin. Zutano is pear-shaped, average to large in size, with a shiny, thin, yellow/green skin.
The avocado tree is evergreen and can grow to a height of from 40 to 80 feet. It produces oval-shaped leaves that are 3 to 10 inches in length and small green flowers. The fruit can be round, oblong or pear-shaped with a skin that is smooth or rough and green/yellow, red/purple, purple or black. The avocado can weigh from 1/4 of a lb. to 3 lbs. Dwarf vanities can be grown in containers.
Avocados can be grown in zones 9 to 11, the hottest planting zones in the continental United States and in Hawaii, where the average low temperature in winter does not go below 20 F.
The avocado tree can be grown in any type of soil as long as it is well-drained. The roots cannot be allowed to sit in water. The avocado tree needs to be in an area that is protected from high winds and away from the shore. Wind can damage the trunk, flowers and fruit and it is not salt tolerant.
Avocado trees are susceptible to several diseases--avocado root rot, stem-end rot, fruit rot, antracnose and algal leaf spot. Several insects can also cause a problem--red-banded thrips, armored scales, Chinese rose beetles, fruit flies, mites, black twig borers, mealybugs and plantbugs.