Facts about olive trees: what is the best way to prune olive trees?
What is olive tree pruning?
When you prune an olive tree you are essentially shaping the tree. It is done every year in the spring before flowering (olive tree flowers have white petals).
The best time to prune varies based on the annual temperature and the rhythms of the trees. It is generally recommended that you prune between February and March.
This way you prepare the tree in order to optimize olive production and ensure a decent harvest in the autumn.
The olive tree: What is the goal of pruning?
The long-term goal of pruning is to adopt a rational approach to your olive trees and satisfy certain aesthetic criteria.
You should prune without totally changing the natural shape of the specific variety of olive and to keep enough foliage so that the olives get adequate exposure to direct sunlight.
It is also essential that you try to shape the tree in order to facilitate certain agricultural activities, mainly harvesting.
There are various types of pruning:
Pic 1: Types of pruning
Pruning to train the tree
This type of pruning is usually meant for grafted trees. A central axis is created and the lateral branches are left free to grow. In about one year, the tree will grow to about 1 m and will be ready for planting.
Pruning for transplanting
This type of pruning is used for mature trees and some small trees that have been grown in the ground and have been transplanted and need to be pruned so that the roots and branches begin to develop normally again.
Pruning to shape the tree
This type of pruning is used to give the tree the desired shape without drastically changing its shape by pruning hard. The goal is to try to direct the branches using cuts and specific techniques in order to create the ideal shape.
Pruning for production
The goal here is to increase olive production by regulating the growth of the tree’s branches and maintaining the right balance between branches and foliage in order to reduce or limit alternating years of low and high productivity, which is typical in olive growing.
This type of pruning is done to restore sick trees or trees requiring intervention.
Here, we’d like to look more closely at polyconic vase pruning.
Pic 2: Olive tree before pruning
Pruning to Train the Tree
Polyconic Vase Pruning
Polyconic vase pruning is very common in areas specialized in olive growing. The shape should be that of an inverted cone.
This shape ensures that the foliage remains close to the ground, which facilitates agricultural activities like harvesting and future pruning.
In polyconic vase pruning, three or four main branches are left to grow out from the central trunk.
These branches are bare close to the trunk but have other small branches growing from them that are directed towards the center of the tree and leafy on the bottom and turned towards the ground.
How to do polyconic vase pruning
To start polyconic vase pruning from scratch, you need to plant a 2-3 year-old tree and cut it to about 1 m tall.
This way, you foster the growth of 3-4 branches that will become the tree’s main branches.
In September, you need to cut off the suckers (extremely vigorous branches that grow quickly because they suck the tree’s sap, which has an overall negative impact on the whole tree).
Again, prune away any suckers and branches on the main trunk, i.e. the lower ones close to the ground.
Identify the main branches and prune away all secondary branches, i.e. the ones growing out of the trunk near the ground or thinner branches that don’t look like they could bear much fruit.
Once they have become stronger, the branches need to be bent outward 45° while continuing to prune away the suckers and other secondary branches.
How do the trees start to bear fruit?
As much foliage as possible needs to be left from the time of planting, only pruning away the suckers and thinnest branches, i.e. those growing randomly, so that the tree will be vigorous and soon ready to start bearing fruit.
How do you form the skeleton of the tree?
If you want to train your trees to have a polyconic vase shape, you will have to forgo having any olives in the first three years.
During this time, the only goal is to direct tree growth and prune a bit harder, leaving less foliage.
Helpful hints to get the right shape:
- To ensure that the main branches do not start to grow upwards, the tree need to be pruned back into the proper shape. This involves pruning away any smaller branches on the top (face-up) side of the main branches.
- To limit branch growth, you can leave the ends loaded with olives so that their weight pulls the branches down.
Pic 3: Olive tree pruned in polyconic vase
Why choose the polyconic vase shape?
This shape with the foliage elevated up off the ground supported by three or four main branches allows the tree to fully develop, facilitates agricultural activities considerably, allows sunlight to reach each branch and fosters an environment that prevents the spread of disease.
“Polyconic vase pruning is done to make pruning more efficient per hectare, facilitate harvest and standardize olive production.”