There are as many opinions on pruning as there are methods. The information provided below is should be used as a guideline only and research should be conducted into the benefits of the various methods of pruning, and pruning requirements for different types of harvesting. Overpruning is common amongst inexperienced grove managers.
First 12-18 months
- When tree is 300mm to 600mm remove branches which start to grow below 300mm.
- Branches which grow above 300mm and challenge the leader should be cut in half to slow their growth.
- Replace slow growing or damaged leaders with a strong fast growing branch.
- When the tree is between 900mm and 1.2m, remove branches growing from the trunk between 300mm and 600mm.
- When the tree is 2m, cut in half (head) any branches growing between 600mm and 900mm.
- Depending on variety, land preparation and climate, development from 300mm to a 2m tree with a 1.2 metre straight trunk required for mechanical harvesting should take from 18 months to 2 years.
Pruning should be restricted to establishing the tree shape into:
- the most common vase shape, or
- monoconical or single trunk shape, or
- the pyramid shaped tree, or
- the multi-pyramid shaped tree.
Second to fourth year leave the tree to develop its own crown.
- Restrict pruning to removing branches below 1 metre and repairing any damage.
- Tree should develop into a recognisable vase shape over 4 years.
Pruning the mature tree
- Pruning is usually carried out every two years.
- Pruning traditionally starts when harvest is finished.
- In high frost areas pruning should be avoided in winter.
- Avoid pruning when the sap is flowing as wounds do not close properly.
Intensity of pruning should take into account:
- Rainfall during the autumn-winter period immediately prior to pruning.
- The previous years crop.
- Vegetative state of the trees at pruning.
- Crop use for pickling or oil.
- Planting density and type of training.
Prune the tree in sequence according to parts of tree:
- The base.
- The apron.
- The centre.
- The crown.
Olive tree sectioned into four Zones
Start at the base and work up to the crown.
While pruning, establish pathways which allow the free flow of nutrients from the roots to the crown and apron and vice versa. Imagine a sequence of freeways - main roads - roads - streets - lanes - paths.
- Suckers indicate an unbalanced tree.
- Try to find the cause - damage, overpruning, disease.
- Remove sucker shoots unless they are needed to replace ailing tree.
- Remove any shoots sprouting below the principal branching trunks.
Majority of fruiting takes place in this area.
If in doubt 'Don't cut'.
- Remove suckers - vigorous erect branches with sparse leaf development.
- Remove drooping less vigorous branches which are growing towards the inside of the apron and are shaded.
- Remove drooping less vigorous branches which are competing for space.
- Cut the least amount of branches necessary to allow airflow and light penetration.
- Branch development should be approximately half that of the apron and crown.
The Upper Crown
- The crown is crucial to the tree's development.
- The crown is pruned for two reasons:
To limit the height of the tree.
To conform to the vase shape.
- Only prune the crown where there is an obvious healthy leader to take the place of the pruned branch.