Maximising yield by summer pruning fruit trees

Julian Blackhirst explains the essentials to improve yields from your orchard.

Maximising yield by summer pruning fruit trees

Essentials to improve yields from your orchard.

Whether growing fruit trees as espaliers or free-standing trees, summer pruning is a useful method for shaping and encouraging fruiting in apples and pears.
Developed by French orchardists to help train espaliers, the summer pruning system has the potential to increase fruit yields, bring young trees into maturity and cropping sooner, and also save many hours of pruning work the following winter.

Traditionally, gardeners have pruned their trees in winter when all growth has stopped and the trees are in complete dormancy. Larger branches can be removed and the absence of foliage gives the gardener an opportunity to inspect the framework of the tree and do any major structural pruning.
Winter pruning, however, is followed by a huge burst of growth every spring. Hard pruning over winter shocks the tree, stimulating it to grow back with increased vigour in spring. If the gardener is not careful, it is easy to fall into a cycle of severe winter pruning followed by vigorous growth of branches and leaves in summer, only to lop them off again next time winter comes around. Not only does this create unnecessary work but it wastes the tree’s energy, producing branches and leaves rather than buds, flowers and fruit.

Summer pruning has the opposite effect. During summer and autumn, small cuts are made to remove some of the new (current year’s) growth. Rather than promoting vigour and new growth, summer pruning restricts the growth of leaves and branches; at the same time releasing a chemical called ethylene which promotes the formation of fruiting spurs. This ensures the tree’s energy is then directed into growing and ripening fruit, rather than unwanted branches and vegetative growth.

Whips of new growth are removed back to 2 or 3 leaves when they reach the thickness of a pencil. In our climate this is usually done in January or February, although sometimes it may be necessary to do this more than once over the growing season.

Summer pruning focuses solely on managing the new growth of the tree. Care should be taken to avoid removing older, fruiting spurs and any wood bearing flowers or fruit. Usually, fruiting buds appear fatter, develop closer to the original branch and lack the vigour of new leafy shoots.

Leafy new growth is flexible, pointed and usually grows vertically up towards the sun. When removed or shortened, the tree is encouraged to produce fruiting spurs below the pruning cut. Because pruning is done during the growing season and only small amounts of growth are regularly removed, the tree does not experience the same shock that would come from a hard winter prune. Pruning in summer restricts the tree’s growth rather than stimulating it.

On older fruit trees or neglected orchards sometimes it is necessary to do a ‘renovation prune’. This involves severe winter pruning to remove old, damaged or dead wood and encourages the tree to grow back with renewed vigour.

The following burst of growth can be controlled and managed using the same summer pruning techniques, directing the tree’s growth into spaces where new branches are required and removing unwanted growth.

Some considerations:

Only prune new current year’s growth in summer. Structural pruning and pruning of older hardwood should still be done in winter.
Vertical, vigorous growth is likely to produce branches and leaves rather than fruit and should be shortened or removed.

Fruiting spurs are permanent buds which fruit year after year. Do not remove them during summer pruning. Most apples, pears, plums and apricots fruit on permanent fruiting spurs and can be successfully summer pruned. If you’re unsure, observe where the fruit or flowers develop on your tree and don’t remove fruiting wood.