Avocado trees are very popular evergreen trees that thrive in most parts of San Diego County. There are some exceptions such as areas prone to freezing or frost and locations two to three blocks from the ocean. The two types usually grown here are Mexican and Guatemalan. Fuerte is believed to be a hybrid of the two.
Guatemalan varieties find ideal climate protected from the direct wind. Mexican varieties, usually smaller, less attractive fruit, are hardier and less sensitive to winter cold. Although avocados can survive in 20-24 degree temperatures, severe damage may occur. This is especially true of the bloom, which occurs most often in the winter. Temperatures much below freezing may destroy the bloom or crop. Some avocados tend to bear fruit in cycles, producing heavy crops one year and lighter the next. Even the light crop is usually plenty for the home gardener.
Most varieties will grow to 30 feet and spread as wide if left untrimmed. There are a couple of semi-dwarf varieties. You can easily keep the trees smaller by pruning. Avocados tend to drop leaves throughout the year, however, in late fall or early winter the trees may be unusually sparse. Most avocado growers do not pick up the leaves as they can be left on the ground to provide mulch and added humus to the soil. It is usually best not to try to grow other crops or lawns directly under the trees as they require good draining soil. Use a wide basin under the tree to hold water. Most roots are close to the surface so try not to disturb the surface soil. Water thoroughly but do not keep the trees too wet. At every third or fourth irrigation, water extra heavily to help wash accumulated salts from the soil. This will minimize salt burn, which will be noticeable as brown edges develop on the edges and tips of leaves. Fertilize every three months with Citrus and Avocado Food (usually about one pound for each inch of trunk diameter measured about two feet above the soil). The fertilizer should spread near the edge of the canopy.