Few people realize that olive trees need to be pruned differently based on their age. Olive trees are native to the Mediterranean region of the world, and have been cultivated for centuries. Many growers say that pruning is more of an art than a science, but there are some basic rules.
Established and tall olive trees are generally fairly easy to prune. Start by cutting away the suckers from around the roots so that the three or four main central branches, or “charpentes” are exposed. Then, use secateurs to remove any branches that are growing towards the center of the tree. Finally, remove any branches with diseased leaves and any dried out twigs. This allows the sunlight to reach the main branches, allowing it to grow in a healthy way.
Younger, smaller olive trees, however, need a lot more work. This is generally because the main central branches of the tree are much harder to pick out, leaving the gardener to guess which branches should be left and which should be cut. Fortunately, there are a few guidelines to picking the right branches.
Start by looking at the shape and overall balance of the young tree. Try to identify areas that are grossly uneven and diseased. Next, look at the middle of the tree and decide which branches are the charpentes. These should be sturdy, disease-free, and well balanced. Cut these at the center where they start to branch out. Ideally, leave three to four charpentes that will form the tree's basic structure for the rest of its life.
Next, remove all branches that are laying on the ground. Also cut any branches that cross over the others in the middle of the tree. Also make sure that the ground around the young tree is clear of any weeds or other debris. The area should be at least as wide as the top of the tree.
It is tradition to burn the olive tree branches, but the drought in many areas of the world has made this impractical if not illegal. If you cannot use them as firewood, consider mulching the branches or using them in compost pile.
To keep the tree well nourished, many people like to add a combination of straw and manure. Traditionally horse manure is used, but any animal will do. Mix this into the ground around the tree in early spring. Not only will it provide nutrients to the soil, but it will also provide small amount of protection against a late frost.
Try to make sure that each tree gets about twenty gallons of water a month. Be sure to include any natural rainfall so that you do not overwater the young trees.