Olive trees thrive in Mediterranean climates and are often grown in the UK for ornamental purposes.
They can do well in our climate providing an understanding or their care requirements are met.
Ripe olives are always black. They start off green and turn darker as they ripen. In the Mediterranean these ripe olives are often used only for cooking.
Commercially, olives, green or black, undergo curing processes of hydrolysis, leaching and fermentation to remove their bitterness. These processes can take an incredibly long time, up to many months, depending on the exact method and desired end result. Many black olives, often found in tin cans, have been processed chemically to remove their bitterness which only takes days in comparison to months.
The climatic condition in the UK often limits fruit production on olives trees. Olives that are produced are often very small in size. Bearing all this in mind, if you decide you want to grow an olive tree, my advice would be to grow it for ornamental purposes rather than the hope to get fruit and enjoy a harvest.
Olive trees are the oldest and one of the most important cultivated trees in history. Olive tree culture has been integral to Mediterranean empires and other advanced civilizations for more than 5,000 years. Thought to have originated in the region that now occupies Turkey, the olive tree is a symbol of peace and endurance of life, able to adapt itself to many environments and able to live for more than 1000 years.
Although Olive trees tolerate many soil types and climatic conditions, they do not like being sat in water or extreme colds. Temperatures of -10°C will damage a tree, therefore protection of a conservatory or a glasshouse in winter is recommended. Incorporating a good amount of horticultural grit to container grown plants will ensure good drainage.
Olives grow very slowly; therefore pruning is often left to a minimum. Fruit is produced at the tips of the previous year’s growth, so excessive pruning will prevent fruiting. Olive trees need a two-month period of cold weather with temperatures below 10°C to initiate flowering. Very dry soil conditions can inhibit flowering, therefore watering during dry spells between February and May, especially for container grown plants, is crucial for fruit production. Prolonged cold weather below 7.5°C can also inhibit fruit production.
For ornamental purposes you may want to prune an olive tree to maintain its neat shape. Prune in late spring or early summer by completely removing dead, diseased or dying branches. At the same time branches can be thinned out to allow light into the centre of the tree. Avoid over-pruning as this will result in the production of non-fruiting water shoots. Additional summer pruning may be carried out by pinching out the tips when the tree reaches the desired height to encourage branching.