The effects of summer pruning on flower bud formation are extremely variable. This is partly explained by the different techniques of summer pruning employed, the different timings of the pruning and the different responses of scion varieties.
- On spur bearing varieties, any summer pruning which removes entire strong extension shoots back to their base, should have no negative effect on flowering.
- Indeed, in cases where shoot growth on the tree is very dense, such summer pruning should expose the spur buds to light and improve their quality.
- The aim usually is to remove strong upright shoots, which are shading fruits from light.
- In contrast, summer pruning that involves various degrees of heading back (tipping) of extension shoots may have a deleterious effect on flowering.
- Heading back shoots to half or one third their length will stimulate regrowth on the shoots and possibly depress the number and quality of spur flowers produced.
- Tipping or lightly heading extension shoots of some varieties may, however, aid flowering.
- This is mainly beneficial on tip bearing varieties, such as Worcester Pearmain.
- On these varieties, the aim should be to encourage as many as possible short extension shoots (dards or brindles) with strong terminal flower buds.
- Summer pruning of shoots, if carried out at the optimum stage of growth, can encourage this production of short shoots.
- On spur bearing varieties, only summer prune to remove strong upright shoots and those shading fruits within the canopy.
- Remove whole shoots back to their base. Do not head back.
- On tip bearing varieties, light tipping of shoots during the summer may aid the production of short laterals and terminal flowers.
- Where excessive growth is produced regularly and summer pruning is necessary each year to enhance fruit colour development, the need for a change in tree management practices is indicated.