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Growing Information
Drought Hardiness
Down through thousands of years, the olive tree has proved to be very drought hardy. When many other trees have died, the olive tree has always been amongst the few survivors.
Lifespan
With minimal care olive trees will live and produce fruit for well over 1000 years. There are no age limits to the commercial viability of an olive orchard on average fertility soils, provided the tree receives suitable annual pruning and regular fertilization. A suitably maintained orchard planted on the recommended 5m X 8m spacing will be commercially viable for well over 100 years.
Climate
The olive requires a long, hot growing season to properly ripen the fruit, no late spring frosts to kill the blossoms and sufficient winter chill to insure fruit set. Even though olives are evergreen trees, they still need a cool winter so they can rest to prepare for their main shooting, flowering and fruiting in the spring.
Soil Type
Olives will grow well on almost any well drained soil up to pH 8.5 and are tolerant of mild saline conditions. Olives will grow in hilly, rocky areas that are not suitable for other crops. However, they do not like very heavy soils that hold water after wet periods.
Pests and Diseases
These are fairly much restricted to the brown olive scale and olive lace bug. When very soft and young, the scale can be killed by the application of white oil spray. The adult scale( with the hard black shell) need something stronger like Supracide, or maybe Lebaycid, both being systemic insecticides. The olive lace bug can also be killed by Supracide or Lebaycid or any other suitable insecticide recommended by your local chemical supplier. Insects and pests will be absolutely minimal if trees are kept in good health. At any rate no more than 2 sprays per year are normally necessary. Check with your local supplier to se which chemicals are registered in your state.
Pruning
Proper pruning is important for the olive. It is necessary to keep the tree open in the centre because adequate light into the centre of the tree will encourage good fruit set. Pruning both regulates production and shapes the tree for easier harvest. Once the tree is established and fruiting the main pruning is done after harvest. For mechanical harvesting, the trunk needs to be free of branches for a height of around 1meter from the ground.
Pollination
It is recommended that olive growers plant at least 3 varieties of trees on their plantation to insure some cross pollination and increase yields of their trees.
Irrigation
Olive trees need very little water to survive, however for a good crop mature olives generally need at least 1 deep watering each month. It must be remembered that the olives only real enemy is too much water, especially during the winter months when there is less evaporation taking place. So it pays to keep a good eye on the moisture levels in the soil around the trees. Winter waterings keeps the trees healthy for a good spring flowering and fruit set. When the fruit is set, supplementary watering will be needed to achieve a good fruit size and high yield.
Fertilization
Fertilizing olive trees with the additional supplies of nitrogen has proved beneficial. The systematic application of fertilizers well ahead of the time flowers develop is helpful so trees can absorb the nitrogen before fruit set. Many growers apply organic fertilizers every other year.
Propagation
None of the cultivated varieties can be propagated by seed. Seed propagated trees revert to the original small fruited wild variety. These seedling, of course can be grafted for chip budded with material from desired.This is the method used by Virginian Natural Olive Trees.
The other commonly used propagation method is the use of cuttings. A twelve to fourteen inch long, one to three inch cuttings from the two year old wood of a mature tree is treated with a rooting hormone and planted in a rooting medium and kept moist and left to grow. Not all varieties strike from cuttings.
Commercial Potential
Commercial olive production is a multimillion dollar business. In the Mediterranean region olives and olive oils are common ingredients of everyday foods and are becoming that way in Australia.
There is also a growing interest in specialty olive oils and pickled olives, often produced commercially from small groves of olive trees. Also small growers are joining forces together to create co-ops to increase their production and to be able to create larger scale production of olives and their oils.