Avocado trees, Persea americana, grown from seed need to be about five years old to produce fruit that can be considerably different from the fruit from which the seed was taken, although such fruit is almost always quite good. Some trees need to be twice as old to produce. Grafted trees from nurseries are specific varieties that can start to produce their specific fruit immediately.
Fruit production is notoriously variable. Some healthy trees may be unproductive for a few years, and then suddenly produce more fruit than the limbs can support. Trees that are very reliable and productive may sometimes be unproductive or significantly less productive for a season. It is nearly impossible to determine which environmental factors inhibited bloom and fruit development.
Mature trees can be more than forty feet tall, with awkward branch structure. The lush dark green leaves are about four to eight inches long. The tiny yellowish green flowers barely get noticed until they deteriorate and fall to the ground like corn meal. The dark green and pear shaped fruit is quite heavy. It develops on the tree, but then ripens after it falls or gets picked and brought inside.