In early November the London Orchard Project team visited the 100-year-old Norfolk orchard of our expert apple man Bob Lever, for a workshop on formative pruning techniques for apples and pears. It was a fun and interesting visit and we came away loaded with ideas, new skills and fresh eggs from Bob’s flock of ducks. Bob started by showing us various shapes of trees that may be created depending on the different priorities of the grower. Commercial growers train their apples into spindle-bush form (below left) or pillar systems (below right) that produce the maximum amount of fruit over a short life-span and keep the trees compact for easy harvesting.
In a community orchard there are other things that influence how we manage the trees, such as highlighting the beauty of fresh, local fruit; bringing life and vitality to parks and streets; and creating habitat for urban wildlife. The open centred bush tree meets our requirements, as it is relatively straightforward to prune, accessible for fruit harvest and encourages trees old enough to develop habitat features such as hollows. Pruning basics: In natural growth a tree will have a central leader –the branch that grows tallest through the middle of the tree and a structure of lateral or side branches that form the rest of the tree. In an open centred tree the central leader is removed and four to five scaffold branches, the main limbs that support the fruit-bearing lateral shoots, are developed through formative pruning. The point where a branch forks or where a main limb joins the trunk is called the crotch. Strong crotches have a minimum 45° degree angle. Narrower joins than this may form a weak union that can result in splitting. Trees have two types of buds, the flat, scale-like buds on the left that may develop into a leaf or new branch and the rounded, furry buds growing on offshoots, or ‘spurs’, that will develop into blossom, followed by fruit. It is important to make a good, clean pruning cut about 1/2cm above a bud facing in the direction of desired growth. The cut should slant away from the bud to prevent water runoff collecting around the bud, leading to rot. Formative Pruning First year: the ideal start to the formative pruning is with a maiden tree, or single one-year stem where no side branching has begun. Immediately after planting cut back the maiden by one third to promote branching.
Second year: Select 4-5 well-spaced laterals with wide crotch angles to be the scaffold branches. Prune back remaining new growth and cut back primary shoots by one third to just above an outward facing bud. This will produce a new lateral shoot that will grow away from the centre of the tree. At this stage it is fine to leave any lateral shoots less than 6 inches long, that will grow extra leaves to help the young tree establish.
Third year: Leaving the previous year’s growth, once again cut back the new side shoots by one third to an outward facing bud. By this point the new tree will be developing fruit buds.
Fourth and following years: by this stage the formative pruning work should be complete. Pruning should focus on keeping the centre of the tree clear of growth, removing branches that compete or rub against each other and getting rid of any diseased or weak growth. The key at this point is to limit pruning to no more than 20% of the tree’s mass as any more will promote stem growth over fruit.