Olive trees (Olea europaea) have been cultivated for thousands of years for their healthy and tasty fruit, according to the California Rare Fruit Growers Association's website. The trees are also attractive landscape specimens, with billowing canopies and greenish-gray foliage. Olive trees are also hardy, surviving even on poor soil and if neglected, making them a great choice for a beginning home gardener or for anyone who loves olives.
Olive trees bloom in the spring with two different types of flowers, according to the California Rare Fruit Growers Association. One type of flower is called a perfect flower, which has both male and female reproductive parts. The perfect flowers are small and creamy-white. They have a pleasant scent but are usually hidden by the leaves. The other type of flower produces only stamens.
Flowers of olive trees are usually populated by the wind, which blows the pollen off of the stamenite flowers and onto the perfect flowers. Most types of olive trees pollinate themselves, but some cross-pollinate. Many varieties are incompatible with others, so it is important to know which type of olive tree you have if you want pollination to occur, especially if you are planting more than one tree. Late spring frosts can damage or kill the new flowers, affecting fruit production later in the season.
Olive trees begin to produce olives when they are about 4 years old. Olives are drupes, which is a fruit with one seed or pit. All varieties start off green in color, then slowly change as they ripen. Ripe olives range in color from dark green to purplish-black. For ripening to occur, the olive tree must experience a long, hot growing season. For this reason, most olive orchards in the United States are in central California. Olives range in shape from a perfect oval to ovate or even round. Different varieties contain different amounts of oil.
Many olive trees produce a large amount of fruit, but it is more desirable to have larger olives with higher oil content. Therefore, thinning is recommended. Thin new fruit enough so that there are only two or three olives for every 12 inches of branches. Olives can be harvested when ripe by grabbing the trunk and shaking the tree, according to the University of California, Davis--either by hand or through the use of a machine.
Uses for Fruit
Olives are tasty eaten raw, but they are most valuable for their oil. In many areas around the world, olive oil is used every day in the preparation of food. Specialty varieties that produce rare types of oil are even more valuable. The commercial cultivation of olives in California is a multimillion dollar enterprise, according to the California Rare Fruit Growers Association.