Bartlett Tree Experts: Olive

Olea europaea

Naturalized in many regions, olives have long been cultivated in Europe, Africa, the Middle-east, and California. California’s Mediterranean climate is ideal for olives and they are widely grown ornamentally, to produce table olives, or for oil. Many 100+ year old specimens can be found throughout California. Newer ‘fruitless’ varieties are available but are rarely totally olive-free.

Culture
Concerns
Management

Culture for Olive

Performs best on rocky well-drained soils with pH near neutral. Drought tolerant but may need summer irrigation during dry years. Often pruned to promote fruit production at harvestable height, unpruned trees may develop weak extended branches. Olives will tolerate shearing or shaping, resulting in a more dense canopy.

Concerns about Olive

Often suffers from over watering or heavy clay soils with poor drainage. In humid or fog prone areas, peacock leafspot leads to thin canopies. Olive knot, a bacterial gall disease, is also common and leads to twig and branch dieback. Black scales and olive scales, two ‘soft scale’ species are also common. Olive fruit fly is a major problem for production of table or pressed olives.

Management Practices for Olive

Olives should only be irrigated during extremely dry periods of summer. Pruning styles for aesthetics or fruit production purposes vary widely. Peacock leafspot can be managed with preventative fungicide applications. Olive knot can be extremely damaging and all knots should be pruned out prior to rainy season. Copper-based applications prior to rains and during leaf cycling in spring will reduce new olive knot infections. Fruit reduction treatments are often desired.