Summer pruning of fruit trees
Why prune in summer?
The simple answer is to reduce the height of out-of-control trees or to make netting and harvesting easier and safer. The more complex answer is to do with when trees are most likely to replace all the wood taken off.
When pruned in winter, spring or autumn, trees will replace the same amount of wood as has been pruned away. You may end up with a better shaped tree, a tree more open in the middle, stronger branches and a healthier tree when dead, damaged or diseased branches are eliminated but height will remain a problem. In winter when sap is rising in the limbs of the tree, limbs will reach for the heavens.
In summer, however, this vegetative expediency is not present. Trees are ‘calm’ in terms of growth so when limbs are pruned they are not replaced if thinning cuts are used. This means cutting out a whole limb back to the trunk. Avoid heading cuts which bring all limbs down to the same height. This type of pruning will result in several missed seasons of fruit. When growth reoccurs, it will result in many spikey shoots on the end of each major cut which will have to be thinned out again. It will also mean all the foliage is high in the tree and it will fail to produce foliage lower down, exacerbating the problem of harvesting and netting.
I have a mulberry that produces at least 20kg of fruit per season. It’s a great tree and provides tremendous shade for the front of the house, reducing internal temperature in summer in our front rooms. It is deciduous, so it allows the sun to warm the house in winter. Having pruned it in both spring and autumn (avoiding winter), I have observed that it doubles its height in about two months. This year I will prune mid January taking off the two tallest branches, both of which are central. This will bring the height down, allow the outer branches to weep (bend over) and open up the middle, so that sunlight can penetrate and ripen the berries that will be low down in the centre of the tree, next season. Although looking large and delicious, because the sun does not reach them, these fruits are quite tasteless.
If necessary I will prune off 2 more branches next summer. Pruning in a measured way in summer prevents trees from going into overdrive and ‘thinking’ they need to replace their severed limbs to survive.
Useful links to posts about pruning
Written by Robin Gale-Baker