For good crops, you need two compatible varieties that will cross-pollinate, and garden centers and fruit growers have charts to help you. One of the few exceptions are the new self-fertile Cox’s Orange Pippin, which can be grown on its own.
Trees on dwarfing rootstocks are best for small gardens, and the approximate mature heights for these are:
M27 – 5 ft/1.5m
M9 – 8 ft/2.4m
M26 – 10 ft/3m
MM 106 – 12 ft/3.6m
Apples need a warm, sheltered spot, planted at a distance apart that equals their mature height. The tiniest trees, on M27 and M9, need a rich soil to do well, and because the roots lack vigor, should be staked all their lives to keep them firmly anchored. Other rootstocks need to only be staked (to 2 ft/60cm) for the first two or three years.
Pruning is largely a matter of common sense, and although there are special techniques to encourage extra fruiting. A well-shaped, healthy tree will naturally crop well. The aim is to create an open, goblet shape, so that all parts of the tree receive their fair share of air and sunshine.
In the first winter after planting, take out the leading stem, leaving three or four well-spaced side shoots, which should be cut back by two-thirds at this stage – they will eventually become the main branches.
By the following winter, they will have thickened and produced their own side shoots. Cut back the long new growths of these branches by half and do the same to the side shoots (removing any that is rubbing or that cross the center of the tree).
Thereafter, remove any vigorous upright stems in summer and keeps the tree trimmed to shape in winter, shortening long, whippy stems and removing crossing or weak growths. A few varieties bear fruit only at the tips of the branches, so if yours does this, prune out a third of the fruited shoots each winter, to encourage fresh growth.
Remove any fruits in the first summer, to build up a strong tree.
Brown rot, with concentric rings of white mold, is caused by a fungus entering damaged fruit. Remove and destroy affected apples. Bitter pit causes brown flecking of skin and flesh and a bitter flavor. It is most prevalent after a hot, dry summer, so water deeply during any dry spells.
Scab appears as brown, woody patches and is worst in humid weather and on dense trees. Prune to keep the tree open and destroy any affected fruits and fallen leaves. The caterpillars of the codling moth feed inside the apple and tunnel their way out when the fruit is ripe. Hang pheromone traps in the trees from late spring, to lure the male moths before mating begins. Woolly aphids on stems and trunks cover themselves in a fluffy white “cotton”. They do no great harm and can simply be washed off with the hose.