Training to the required shape will depend on the type of tree to be grown; standard, bush, dwarf pyramid or cordon.
For a standard, a ‘feathered’ tree should be obtained. This means the small ‘feathers’ or lateral shoots will have been removed by the nurserymen all the way along the stem. A full standard will have a 150-180cm (5-6ft) stem, a half standard a 90-180cm (3-4ft) stem. The formation of the head, which will be the same for bush trees, will be by one of two methods, the ‘open centre’ plan, or the ‘delayed open centre’.
For the first plan, a bush tree should have a good ‘leg’ and, like standards, be allowed to grow unchecked the first year, at the end of summer ‘heading’ back the main shoot to 90cm (3ft) above soil level. This will persuade the tree to ‘break’ and form two or three shoots, which will form the head. Shoots appearing on the lower 45cm (18in) of stem with bushes should be removed. The following winter, the new shoots should be cut back to half way, and the next year the newly formed extension shoots cut back half way, to about 22cm (9in) of their base. The head will now have formed.
The delayed open centre is made by removing only the top 15cm (6in) of the main stem. Then, along the entire length of the stem, buds will form from which new growth will begin and the tree will be built up. Remove any laterals where there is overcrowding, or if several close together are facing in the same direction.
The dwarf pyramid form will produce the heaviest crop in the shortest time. Unlike apples in the bush and standard form, there is no waiting several years. For the tree to make as much wood and as many fruit buds as quickly as possible, bud growth must be stimulated by making a nick in the bark just above each bud on the main stem. The shoots formed from the buds are pruned back to half the new season’s growth each year to encourage the formation of fruiting buds. Throughout its early life, until well established, the central main shoot must be pruned back each year. This enables the tree to concentrate its energies on the formation of side shoots.
Cordons are single-stem trees, planted at an angle of 45° to restrict the flow of sap and prevent the trees from making too much growth. Maiden trees should be planted 90-120cm (3-4ft) apart, and tied in to wires stretched at intervals of 30cm (12in) above ground. Here, the main or extension shoot should never be pruned, only the laterals, which in August should be pinched back to 15cm (6in) of the main stem. This will ensure the formation of fruiting spurs as quickly as possible. When the main stem has reached 180-210cm (6-7ft), it should be cut back to persuade the tree to direct its energies to the side shoots. The removal of surplus fruiting spurs will maintain the quality of the fruit.
The trees should be allowed to grow away in their first year untouched, to form plenty of wood whilst making root growth. The next winter, pruning will begin.
There are three methods: the ‘established spur’ system, for the more restricted or artificially trained trees; the ‘regulated’ system, for trees of vigorous habit; and the ‘renewal’ system, for keeping the tree in continuous new growth.
In the established spur system, wood formed in summer is cut back to four buds. During the following summer, the two top buds will make new growth whilst the lower will develop into fruiting spurs. From the cut made above the top buds, two laterals will form which in turn should be cut back to two buds. Thus the balance is maintained whilst the tree channels its energies into making fruiting spurs. With trees over ten years old, some spur thinning is necessary to maintain the size of the fruit.
The regulated system mostly applies to bush and standard trees. The idea is to keep the tree ‘open’ at the centre by removing crossing branchlets and all in-growing laterals. Commence by shortening the laterals to a third at the end of each summer. Then cut back the laterals as described for the spur system. The tip bearers (those which fruit at the ends of the laterals) are left un-pruned until they have made excessive growth, when some wood must be removed.
The renewal system involves the replacement of old wood by new, thus maintaining the tree’s vigour over many years. The side shoots are cut back to two buds from the base. These will produce two more shoots which will bear fruit. Afterwards, each is pruned back to two buds and the process continues indefinitely.
Old trees may be made more productive by removing all dead wood, using a tree saw. Where there is overcrowding at the centre, entirely remove any branches, to let in sunlight. Make the cut close to the bark so that it will heal (form a callus) quickly. To leave even a few centimetres of the branch will enable brown rot to take hold. Paint the wound with a fungicide or with white lead paint to guard against disease.
De-horning will also increase the yield of old trees. It is the top branches which are de-horned, cutting them back by a third of their length. Make a sloping cut so that moisture will drain away, and treat with a fungicide to heal the cut as described.
If you need to restrict a certain bud, make a notch in the bark just below it. To encourage a bud to ‘break’ into growth, make a notch above it.