PERSEA americana( Mexican Strain)
Plant Common Name
Avocado, Mexican Avocado
Buttery slices of ripe avocado on sandwiches, thick, rich guacamole, milkshakes and salads are just a few of the uses for the versatile fruit of Persea americana. Native to the area from the Rio Grande south through Peru, this tree has been cultivated for centuries. It is now grown worldwide in subtropical and tropical regions as a commercial crop, in home landscapes and orchards.
Avocados are classified into three types based on the area of origin of the trees. The Mexican varieties or strains are native to the mountains of Mexico south to Chile. The small fruits have a very high oil content and have thin, tender skin. They ripen six to eight months after flowering. Leaves are anise scented and the trees are very cold tolerant.
Extremely variable trees, avocados may be tall and erect to moderately-sized, low-branched and spreading depending on type and variety. The leaves are large, alternate on the stem, glossy, dark green on the upper surface and pale to whitish underneath. Leaf shape is also dependent on variety from elliptical or lance-shaped to oval. Semi-evergreen, the leaves may fall continuously throughout the year or during the dry season at flowering.
Many small, fuzzy flowers without petals are produced on un-branched spikes near the ends of the branches from mid-winter through late spring; the exact bloom date is again dependant on variety. The flowers are complex, opening at different times.
There are two flowering classes of avocado, Class A and Class B. These are distinguished by the time of day that the flowers open and male and female reproductive organs are receptive. Both complex class systems are designed to keep the perfect flowers (flowers with both male and female organs) of avocado from self-pollinating.
Class A: New flowers open in the morning. The flowers do not shed sperm-carrying pollen, but the female organ, called the pistil, is receptive to outside pollen and gets fertilized. The flowers close at midday and stay closed until the afternoon of the following day. Then the blooms reopen, but this time the flowers shed sperm-carrying pollen, and fertilized pistil is no longer receptive.
Class B: New flowers open in the afternoon. The flowers do not shed sperm-carrying pollen, but the female organ, called the pistil, is receptive to outside pollen and gets fertilized. The flowers close at dusk and stay closed until the morning of the following day. Then the blooms reopen, but this time the flowers shed sperm-carrying pollen, and fertilized pistil is no longer receptive. For good pollination, growers should plant both Class A and B type flowering trees in close proximity.
Fruit, high in unsaturated oil content follow the flowers. The shape of the fruit is oval to egg-shaped to pear-shaped and small to very large. The skin maybe smooth or rough and variously tinted, bright green, yellow-green to red-blushed or purple. Inside most fruits is a large, hard, papery-skinned seed. Avocados may be grown from seed, but the best trees are grafted for earlier fruiting and to preserve desired variety characteristics.
These versatile trees are tolerant on many types of soil, but most require well-drained conditions. Full sun is best for good growth and fruit production. Drought tolerant once established, avocado fruiting is best when watered regularly during production. They are large trees and require plenty of space for growth. The wood is somewhat brittle and high winds can break branches and dry out the flowers thereby reducing fruiting. Avocados are generally freeze sensitive, though the Mexican varieties will takes temperatures a few degrees below freezing for a few hours.
Avocado trees are beautiful as ornamentals; use them as specimens or shade. They are easy trees to grow and productive in home orchards.