Pruning fruit trees in the Summer
by Helen Dowsett

There are many good reasons to prune in summer, rather than winter... including the fact that the weather is more conducive to spending time with your fruit trees.

Louis Lorette was Curator and Professore of the Practical School of Agriculture at Wagnonville, France in the early 1900's... he did not prune in winter... he pruned in summer. He was a master of the art of fruit-growing and was an attentive observer of growth.

Lorette pruned to allow free passage of light, air and sun to penetrate the branches (especially those on the lower limbs of the tree). Lorette wanted to see pruned trees bear as freely as those in the fields... growing naturally... and he achieved that goal, admirably.

Georges Truffat, who wrote of Lorette's activities at the time, marveled, I counted up to 100 clusters of flowers to the yard on the branches and almost every cluster comprised from ten to thirteen flowers. What struck the skilled grower most, was to see the flowers spaced out along all the lateral branches... I even saw fruiting spurs on stems and trunks of the pear trees, quite close to the ground.

The marvelous flowering of the trees at Wagnonville in 1912 was seen by many... both amateurs and professionals.

Of course, Lorette's methods were criticised and it was pointed out that 1912 had been a particularly GOOD year for fruiting... but Monsour Tandart, as Director of the school, had been able to take an important series of photos in 1904 that showed that year after year fruit trees pruned by Lorette's method were regularly and abundantly covered with flowers. Truffat said, The Lorette system is a success, for already some are trying to imitate it and some gardeners describe it under the name of 'normal summer pruning' in order not to to give the name of the man who first employed the system...

The system rests on very simple foundations:

1. Each main branch must be given the maximum of light, sun and air.
2. The System of pruning must only be carried out in summer; near the end of June through July, August and early September and only when the shoots have hardened and almost ripened their growth. Another great objection made to the Lorette system is that it made too much fruit and that consequently the trees became exhausted and died early... our reply to this objection is that it is always easy to thin the fruit when there is too much on the tree... moreover, we must also do this anyway and leave only a reasonable number for fruits.

How to Summer Prune:

• Start at the top if your tree is already the size that you want it.
• Prune the lateral stems back to just outside the 3rd leaf, or about 2 inches from the lateral branch. If the stem is somewhat thinner than a pencil (under ½") prune just above the 2nd leaf.
• Prune weak and thin lateral shoots above the 1st leaf. Work down the branch, pruning the remaining laterals, then work your way around the tree, pruning the other branches the same way. With lateral shoots pruned back, the branch is narrower and allows more light into the center of the tree.
• One year later, the pruned lateral shoot will produce a fruiting spur with a fruit, instead of just foliage

Which trees can be pruned and when?

• Any healthy fruit tree older than 3 years, growing on a dwarfing rootstock, can benefit from summer pruning. (It should have developed its main structure) This type of pruning is NOT suitable for standard size trees, which are too vigorous. Summer pruning should always be used on PLUM TREES as winter pruning can encourage "silver leaf", a fungal disease. Winter pruning of apple and pear trees should be reserved only for weak trees and for removing diseased wood.
• Best time to prune is when new growth is about pencil-thick; stem tip should be succulent and the base starting to turn woody
• Pruning is confined to shoots on the lateral branches only (branches that form the main structure of the tree are left unpruned). Leave 2 shoots closest to the ends of the branches unpruned until the tree is the size you want.
• When conditions are right, all the dormant buds in the remaining leaf axils (where a leaf joins the stem of the pruned shoots) will form fruit in the following year.
• Summer pruning increases light on the developing fruit and therefore, increase fruit size, color and sugars. It also often, but not always, forces fruit buds to form, increasing the yield in the following year.
• Do not prune young trees that have yet to grow into their space... instead, SUMMER PRUNE trees that need to be controlled within the space allowed for them. Summer pruning reduces tree vigor.

To explain, think of 2 similary sized trees of the same variety of apple. In the winter when all the nutrients are down in the ground, you prune ⅓ off of ONE tree. In the spring, the soil warms, the nutrients in the roots rise up, but find only ⅔ of the tree! What happens to the excess sap? It forces upper buds to break and the result is lots of "water sprouts" (the Medusa Effect). The tree is invigorated and vegetative wood is produced.
The other tree is left alone during the winter. In the spring the sap rises up and fills the whole tree without producing "water sprouts". In July and August, you remove ⅓ of the tree. In the fall, only the remaining ⅔ of the sap moves down into the roots. Next spring, the ⅔ sap rises up and fill the ⅔ remaining on the tree... again... no water sprouts!

As Georges Truffat said, The only law of nature is variation, in accordance with surrounding conditions. Try the Lorette method for yourselves...

The nice thing about Lorette pruning is that it is such a pleasant time to be working in the garden and spending time with your fruit trees!

Resources

It's strange that neither Louis Lorette nor Georges Truffat are listed in Wikipedia.