The evergreen avocado tree grows to a height of 80 feet. When grown from seed, the avocado tree often takes 20 years before fruit production. Most avocado trees are now grafted onto root stock. These hybrid cultivars begin fruit production at one to two years. The foliage of the avocado tree remains on the tree for up to three years before dropping in the spring and being replaced by new leaves.
Temperature and Protection
The avocado tree is a tropical or sub-tropical tree. Most varieties will not tolerate temperatures that drop below 32 degrees F. The Guatemalan varieties will sustain a temperature that dips to 26 degrees F. and the Mexican varieties will withstand temperatures to 19 degrees F. for a limited time according to the California Rare Fruit Growers. Planting on the south or southeastern side of a building offers limited cold protection
The avocado tree requires wind protection because its brittle branches will sustain damage in high winds. In California and Texas the commercial growers plant their avocado trees within mesh and wood cages to offer wind protection. Stake young trees to offer protection when planted in a home landscape.
Plant at least 10 feet from houses, buildings and fences. Locate the tree away from concrete because the root system often heaves upward and will easily crack concrete. Well draining soil is essential because the tree will not tolerate wet roots. The avocado tree prefers sandy loam or crushed granite based soil. It will tolerate alkaline or acidic soil. The planting location must have at least eight hours of sunlight per day for the tree to produce fruit. The tree will grow when planted in partial shade but it often will produce no fruit. When planting more then one avocado tree space them at least 15 to 25 feet apart.
Cover the grafted bulb union at the base of the tree with several inches of soil to offer protection from cold and heat. Very few plants will grow under the avocado tree due to its abundant canopy and fallen leaves. The leaves contain an oil that makes composting virtually impossible.
Watering and Fertilizing
Water the avocado tree slowly and deeply. The tree requires moist soil conditions to establish and thrive. During the winter months when the heavy rains arrive abstain from watering the tree.
Fertilize the avocado tree monthly from February to September with ammonium sulfate (21-0-0). Use 1/2 cup the first year, 1 cup the second year and 2 cups the third year.
The avocado tree requires little to no pruning each spring. Remove only the wood that is damaged. Varieties of avocado trees that grow in a columnar shape require spring pinching when young to maintain their rounded appearance.
If pruning damaged wood reveals branches or the trunk of the tree then whitewashing of the exposed bark is required according to the California Rare Fruit Growers. The avocado tree sunburns easily when exposed to heat and sunlight. It will easily perish.