Summer pruning of fruit trees is one of my most favourite gardening activities, and every year, I have to tell myself not to start too soon. It is mostly done to apples and pears that have had their growth restricted and trained into one of the many different forms such as cordon, espalier, fan etc. Some modern trees growing on dwarfing rootstock can also benefit from a summer trim as it helps to reduce their vigour.
When should you prune?
Usually, during July and August, the new shoots will have started to change colour as they develop stiffer woody tissue around the bottom third of this year's growth.
If you prune too soon, the tree can grow new secondary growth, which will not have the time to develop enough before the winter weather. This opens the plant up to frost damage, which could allow disease and viruses access.
So it's essential to check your plant, a vigorous plant in a mild location may need to be pruned early, while in a colder situation you may need to wait a little longer.
Pear trees are typically done first with apples a few weeks later.
Pick an overcast but dry day to prune as this will reduce the amount of stress the plant will experience and the likelihood of fungal infections.
These two, when grown as standard trees are generally maintained during the winter, with the 4D's affected branches being removed first and then the reduction of shoots. This promotes new vigorous growth in spring, but you don't want this on the trained trees you are trying to restrict to a set area. Summer pruning encourages the plant to develop more side spurs, which is where fruit will hopefully grow in future years. It also allows more sunlight to reach the ripening fruit by removing a percentage of the tree's foliage.
Usually, only spur bearing fruit trees are trained as the summer prune would remove all possibilities of a crop from tip fruiting varieties. If you're unsure which type you have, the RHS have put together a helpful guide to identify your type
This tree has been trained as an Espalier with even spaced branches to maximise fruit production.
Tip Clean and sharpen your secateurs, a neat cut will heal faster, putting the tree under less stress.
If the new growth at the end of each branch is longer than 20cm (8") these can be cut back to three leaves above the cluster of leaves the new stem is emerging from. Leave stems shorter than this as the buds at the tip will frequently be fruiting buds.
Look for new shoots coming from side branches of these stems. These can all be cut back to one leaf of this years growth.
If there are several upright stems which are much larger then the remainder, these need to be cut back completely.
If your tree does put on a secondary lot of growth, this can be cut back in September. Sometimes with vigorous trees, it can be worth leaving some longer shoots unpruned, this draws the sap up, and they will grow at the expense of secondary growth elsewhere on the tree. In spring these can be cut back to one bud.
Photo by John Haynes, taken in the garden of Erddig House, showing a double cordon trained tree
Other mature fruit trees that need pruning at this time of year are
Apricot, Plums and Sweet Cherries, these bear fruit on the previous summers new growth. Stone fruit is pruned in summer to avoid diseases such as Silver leaf and bacterial canker from entering the plant. Reduce leading stems to 20Cm (8"), and side shoots back to 15cm (6") before the end of July, as well as any affected by the 4 D's, Dead, Diseased, Damaged or Deranged.
Nectarines, Peaches and sour cherries that have been fan trained are summer pruned as next year's fruit will be produced on this year's growth. Called replacement pruning you can cut away the older woody stems that have finished fruiting back to a new shoot. Tying in the new shoots to fill the gaps.
These stems are not quite ready to cut back
The gentle snipping of branches while admiring the developing fruit on a cool summers evening down on my allotment is only beaten by winter pruning and the resulting bonfire to clear the waste. But I need to be patient. It's not time yet! There's plenty of other gardening tasks to keep me occupied.