Step by step instructions for pruning apple trees in winter are available here.
1) Apple trees can survive and continue to crop despite total neglect, but you will get much better results if you give them some attention. This huge old Granny Smith apple tree has not been touched for many, many years and shows why it is better to start with grafted apples on dwarf root stock. This tree is destined to be cut out in favour of our smaller trees which are easier to care for.
2) Apple trees are currently sporting their new growth which shows as long leafy whips. It is this growth which will give replacement fruiting spurs next summer. Ideally, you should be replacing all fruiting spurs on a two to four year cycle – cutting out old clusters and allowing fresh ones to take their place.
3) Trim the long whips back to about half their length to encourage the fruiting spurs to develop. Surplus whips can be cut right back to a bunch of fruit. You want to keep the tree open and uncluttered to allow the fruit to ripen well.
4) If your apples are looking too bunched up, it is best to thin out the fruit so that those that remain will be better quality. The tree will drop some surplus fruit before it is ripe, but thinning ensures that you keep the best specimens and stops the weight from breaking branches. Cut off very small or deformed fruit, reducing bunches to between two and four fruit. Some people recommend taking out the centre apple from a bunch to give those around it room to develop fully.
5) Codling moth is the single biggest problem and the caterpillars can take out an entire crop if left unchecked. They burrow into the apple, leaving nasty black tunnels. It is too late this season to try organic controls (pheromone traps and collars on the trunk of the tree). You need to start earlier in spring. We are resorting to insecticide spray this year to try and break the cycle. December to February are the times for spraying. It is recommended that it be done fortnightly but we will only do it once or twice.
6) We do not carry out a rigorous spray programme so our trees show black spot, mildew, leaf curl and various other afflictions but we still get crops of apples. Traditional practice is to spray with both insecticide and fungicide every 10 to 14 days after the blossom petals have dropped until harvest – ask at your local garden centre for appropriate sprays. Spraying will give heavier crops of more attractive fruit but we are willing to trade that off by having additional trees and not spraying much at all. The leaf curl shown here is caused by a tiny orange midge and is easily dealt with by cutting off the tips of the branches and burning the leaves.