A member of the Oleaceae family, the Olea genus contains about 40 species, of which the most important is the commercially grown olive. Olea europaea has hundreds of cultivars and is grown around the world.

Form: A single or multi-trunked large shrub or tree.

Lifespan: 300-600 years.

Leaf retention: Evergreen.

Growth rate: Slow to moderate.

Mature Size: 30' high and wide.

Flowers: Small, clustered, creamy-white. The pollen causes severe allergies. Fruitless varieties produce less pollen and little or no fruit.

Bloom: Spring.

Self-fruitful: Yes.

Years before fruiting: 4.

Fruit: Oil-bearing, bitter olives.

Months for fruit to ripen: 6-8. Olives are mature when they reach their full color, whether red, purple or black. At this time they are ready to drop from the tree.

Storage after harvest: Olives must be cured and are not edible until the process is complete.

Leaves: Lance-shaped, narrow, to 3" long, thick, gray-green on top, lighter underneath. This tree provides dense shade.

Stems: No thorns. Gray, bumpy, contorted, gnarled trunk.

Roots: Shallow roots can heave walkways and trip pedestrians.

Wildlife: The fruit attracts birds. Rabbits may eat the bark, especially on young trees, and greatly harm the tree.

Toxic / Danger: Olives must be cured, a long process, to be edible.

Origin: Eastern Mediterranean. Commercial cultivation began more than 5000 years ago.

USDA hardiness zones: 9-11 for fruit-bearing trees. 8-11 for fruitless cultivars.

Chill hours: 200-300. For olives, temperatures above 32°F and below 55°F accumulate chill hours in winter.

Heat tolerant: Yes.

Sun: Full sun.

Drought tolerant: Yes.

Water once established: Once or twice a month in warm months.

Soil: Well drained, dry, low organic content, tolerates pH 5.6-8.5 (acidic to alkaline), but pH 6.6-7.5 (neutral) is considered ideal. Avoid locations near frequently irrigated lawns or plants. This plant is saline tolerant.

Fertilize: Olive trees are better adapted to poor soil than any other fruit tree and seldom suffer nutritional deficiencies. In residential settings, fertilization is unnecessary, even for a good fruit crop. Water and weeding are the most important aspects of olive tree care.

Prune: In spring, in dry weather, after flowers appear, prune to shape. Fruit is produced at the tips of the previous year's growth. Remove excess small fruit within 3 weeks of flowering so that two to three fruit are left per foot of branch. This results in larger fruit.

Litter: High due to fruit drop. The fruit stain concrete.

Propagation: Seed or cuttings.

Uses: Ornamental, fruit production.

Some municipalities allow only sterile, fruitless cultivars in order to reduce pollen levels. Hundreds of fruit-bearing cultivars are available. The picture at bottom shows the fruitless cultivar 'Swan Hill'.

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