Olive Tree

The olive, olea europaea, of the family Oleaceae, good-look, long lived, evergreen, subtropical tree, has been cultivated for at least 40 countries for its edible fruit and its valuable oil. It is native to the eastern mediterranean region, where its culture may have begun as long ago as 3500 BC. The Olive was introduced into the Western Hemisphere in 1560 by Spanish missionaries. To day California grows 99 percent of the olives produced in the United States.

Generally, the tree is medium in stature, about 8 m (25 ft) in height, although some trees may grow as tall as 18 m (60 ft). The narrow leaves are dull green above, silvery beneath; and paired on the stems. (Olive branch are ancient symbols of peace and victory). The flowers are small, fragrant, and light cream colored and cluster at the leaf axils. They are of two types, perfect, in which both the pistil and stamens are functional; and staminate or imperfect, in which the pistil aborts but the stamens function normally. The small fruits vary in shape from round to oblong and are essentially black and very bitter at maturity.

In order to produce flowers and fruit, the trees must undergo chilling at temperatures below 7 C (44 F) for 2 to 3 months in regions where daily mean temperatures are below 10 C (50 F). The trees grow luxuriantly in the range of soil types, provided the soil drains well. Cultivars are propagated mainly by rooting cuttings. In California, commercially important olive cultivars include Manzanillo, Mission, Sevilano, Ascelano, and Barouni. The principal olive product are olive oil and both ripe and green olives for the table. The fruit is rendered palatable by special processing, which involves the use of lye (sodium hydroxide) and salt brine.