Delicious and popular tropical fruit, native to Mexico and to Central and South America. Three races of avocado (Persea americana) are grown, and numerous hybrids among them exist. The Mexican (the hardiest, often surviving to 18F) is grown in the colder parts of central Florida, while the Guatemalan (hardy to 2125F) and the West Indian (the most tropical type, often perishing at temperatures below 25F) and their hybrids are cultivated southward. Mexican race seedlings are often grown in home gardens across South Texas. For this plant's ornamental relatives, see Persea.
Plants bloom in late winter, and pollination is complex. Most types will produce some fruit if grown alone, but production is heavier when two or more selections are planted. Fruit ripens from summer into winter, depending on selection. Guatemalan and West Indian fruit differs from Mexican in generally being larger and having a lower oil content.
When planting an avocado tree in the landscape, consider that most selections will eventually grow quite large (to 40 feet.), produce dense shade, and shed leaves all year. Growth is quite rapid, but plants may be shaped by pinching terminal shoots. Avocado takes well to container culture, and selections in marginal climates can be moved to a protected location during cold spells. 'Day' is especially suited to life in a pot.
Florida selections include hardy 'Brogdon', 'Gainesville', 'Mexicola', and 'Tonnage' (all moderately scab resistant); somewhat less hardy 'Booth', 'Hall', 'Monroe' (all moderately scab resistant), and 'Choquette' (very scab resistant); and least hardy 'Pollock', 'Simmonds', and 'Waldin' (all very scab resistant). Two hardy types that set good crops without cross-pollination are the commercial selections 'Lula' (susceptible to scab) and 'Taylor' (very scab resistant). In Texas, 'Lula' is grown commercially in the lower Rio Grande Valley.
Most avocado trees in home gardens are selections developed from Mexican race seedlings that survived cold winters. For the selections that grow best in your area, check with a local garden center or Cooperative Extension Service office.
Gardeners in warmer coastal selections beyond Florida and Texas are growing and fruiting selections that are more cold hardy. These include 'Brazos Belle' (15F), 'Joey' (15F), 'Lila' (15F), 'Pancho' (15F), and 'Winter Mexican' (18F). Naturally, plant hardiness also depends on microclimates and the duration of the cold.
All avocado trees require good drainage; constantly wet soil encourages fatal root rot. Tree is shallow rooted; do not cultivate deeply. In the absence of rainfall, irrigate lightly and frequently enough to keep soil moist but not wet. A mulch is helpful; the tree's own fallen leaves can provide this. Scab disease can be a problem in Florida; choose resistant selections. Cercospora leaf spot and anthracnose are also serious problems there. Anthracnose is a secondary pathogen, usually taking advantage of injury or another disease, such as leaf spot, to gain entry. Both problems can be prevented by applying appropriate fungicides and handling the fruit carefully.