What About Olive Trees?
Native to the Mediterranean, olive trees (Olea spp.) produce tangy, salty fruits for eating and processing into cooking and heating oils. Olives are also used for making soaps, skincare lotions and other beauty products.
Fruit-bearing and non fruit-bearing evergreen olive trees thrive in U. S. Department of Agriculture plant hardiness zones 8 through 10 and other Mediterranean climates. Olive trees growing 20 to 30 feet high and equally wide are striking additions to yard and garden landscapes.
Olive trees grow best in hot, dry climates. With single or multiple stems, trees and shrubs prefer full sun but do well in filtered light. They grow in the spring with temperatures above 70 degrees Fahrenheit but can tolerate cold snaps down to 15 degrees F. Olive trees set fruiting buds during cool nights between 35 and 50 degrees F. and mild winter days below 80 F. Trees can freeze if the thermometer drops below 10 degrees F. Olive trees, with shallow root systems, prefer well-draining soil with pH between 5.5 and 8.5. Trees may die if their roots are left in pools of water for extended periods of time.
Fruit-bearing olive trees (O. europaea) produce green drupes that ripen to black. Spanish olive tree varieties that grow in USDA zones 8 through 10 include ‘Arbequina’ – it has small fruits that ripen in late fall. Black ‘Manzanillo’ olives, which can be pressed for oil, are most often canned for eating. Like other varieties, ‘Mission’ olive trees are self-pollinators that grow up to 20 feet high. Their fruits are brined for table olives or processed into oil. Olives are very bitter when picked from trees. Fruits must be washed, soak in saltwater and often, sodium hydroxide solutions before they can be stored in brine and eaten.
Fruitless Olive Trees
Although referred to as “fruitless,” most tree varieties actually do bear small amounts of olives. For example, 'Swan Hill’ and ‘Wilson’s’ are ornamental olive trees with wide leaves and spreading canopies. Trees must be hand-propagated. ‘Majestic Beauty’ olive trees produce white, summertime flowers. Dwarf olive trees that grow from 12 to 16 feet high bear very little to no fruit. They are suitable for gardens, walkways, hedges and landscapes.
Location and Care
When preparing to plant olive trees, choose a site in full sunlight that is away from driveways and sidewalks, advises California Rare Fruit Growers, because falling fruits may cause stains on concrete and vehicles. Although olive trees are mostly drought tolerant in Mediterranean climates, watering trees regularly encourages fruits to grow larger. Pruning and thinning helps to train young trees into a desired shape. Chemical sprays and baits help to ward off olive fruit flies and maggots. Removing fallen olives helps to keep the tree from drawing unwanted pests.
References and Further Reading
© 2013 Teri Silver