Avocado trees (Persea species) are also known as alligator pears, aguacate and palta. The avocado tree originated in southern Mexico and was under cultivation as a crop before European explorers arrived in the New World. Avocados are fruits and belong to the Lauraceae (laurel) family. As of February 2010, California is the top avocado producer, churning out 90 percent of the nation's total.
There are three species of avocado trees, named after their native habitats. Each one has many varieties, and there are hybrid varieties that are a combination of two of the species. The species are Guatemalan (Persea nubigena var. guatamalensis L. Wms.), Mexican (P. americana var. drymifolia Blake) and West Indian (P. americana Mill. var. americana).
The avocado is an evergreen tree that sheds just a portion of its leaves in the spring. The tree grows to 80 feet tall and produces dark green leaves that stay on the tree from two to three years. The small yellow-green flowers bloom from January to March in clusters of 200 to 300. Each group of flowers will produce just one to three avocados, and each avocado can weigh as much as 2 pounds.
Avocados need a climate with mild winters. They do very well in southern California, Florida and Hawaii. Some hardy varieties can grow along the Gulf Coast and in central California. Avocados do not do well near the ocean or in a desert climate.
Avocado trees can grow in shade, but they need full sun to produce fruit. Plant the tree at least 20 feet from other plants and other avocado trees. The roots will take over and destroy the others. The tree likes a loose decomposed granite or sandy loam soil that is very well drained.
Small animals will come after the fruit. Using a tin trunk wrap will keep them off the tree. Leaf-rolling caterpillars can destroy the branch ends. Six-spotted mites can defoliate the tree. Dothiorella (Botryosphaeria ribis) is a fungal canker infection that causes the fruit to rot from the inside out. Root Rot (Phytophthora cinnamomi) is a fungus that lives in the soil that is a danger when the soil is too wet. It is also highly contagious. Sun blotch is a viral disease that causes the young stems to become streaked with yellow and damage to the leaves, trunk and fruit.