Pruning old apple trees to restore healthy fruiting

Why an old apple tree needs a gentler kind of pruning

There is a particular pleasure in inheriting a mature apple tree. Perhaps it came with the cottage, or it has stood at the bottom of the garden since your grandparents planted it. Along with that pleasure usually comes a tangle of congested wood, a canopy that reaches higher than any ladder sensibly allows, and fruit that arrives in a glut one year and barely at all the next.

Old trees are not simply larger versions of young ones. Once an apple tree passes its fortieth or fiftieth year, it tends to lose vigour. It still wants to produce fruit, but it does so on the outer edges of the canopy, where the light is best. The centre gradually fills with shade, dead spurs and rubbing branches. Pruning an old tree is therefore less about shaping and more about restoration: removing what is finished, and reopening the tree so that light and air can reach wood that has been in shadow for years.

Choose the right moment to take up the saw

For the structural work that an old tree needs, prune in the dormant season, roughly from late November to the end of February. The tree is not actively growing, the framework of branches is easy to see, and wounds made now will begin sealing as soon as growth starts in spring.

• Avoid pruning during hard frost, when wood is brittle and splits badly.
• Leave it alone if the tree is carrying a heavy crop of late-hanging fruit; pick first, prune after.
• Save summer pruning for July and August, when it is used to slow down an over-vigorous tree rather than to rebuild a framework.

And do not attempt the whole job in one weekend. Renovating a neglected tree is a two or three year project, and rushing it does more harm than leaving it alone.

Start with the dead, the diseased and the damaged

Before you think about shape, clear out everything that is no longer contributing. Dead wood is often obvious, but in a crowded canopy it can be difficult to spot. Look for bark that has peeled away or turned a dull grey-brown. Scratch a small area with your thumbnail; live wood is green and damp beneath the surface, dead wood is dry and brown.

Work through the tree methodically, removing:

• Dead branches, cutting back to sound, live wood.
• Diseased wood, especially stems with canker, which shows as sunken, cracked patches with a raised edge. Cut well below the affected area, into clean wood, and clean your tools afterwards.
• Broken or storm-damaged limbs, tidying the tear back to a clean cut.

Make each cut just outside the branch collar, the slight swelling where the branch meets the trunk, and leave no stub. Do not paint the wound. A clean cut, made properly, seals itself far better than anything you can brush on.

Thin the crowded branches and open the centre

With the dead wood gone, you can see the tree's true structure, and this is where restoration really begins. The aim is a goblet or wine-glass shape: a clear trunk, a ring of main limbs, and an open centre that lets sunlight fall on the inner branches and air move freely through the tree. Good airflow is one of the best defences against scab and canker.

Stand back and look before you cut anything. Then begin removing:

• Branches that cross and rub, keeping the one that is better placed and angled outwards.
• Branches growing inwards, towards the middle of the tree.
• Whorls of branches arising from the same point on a limb, which create weak, congested joints.
• Over-long limbs that reach up and outward, cutting them back to a side branch to bring the canopy down to a sensible height.

Take out no more than a quarter to a third of the live wood in any one winter. If in doubt, cut less. You can always return next year; you cannot put a branch back.

Dealing with water shoots and overgrown wood

An old, neglected tree often responds to the extra light by throwing out vigorous upright shoots, known as water shoots, from the older limbs. Some of these can be trained in to fill gaps and eventually replace tired branches. Most, however, should be rubbed out while small or cut back hard to a few buds, otherwise they will thicken the canopy again within two seasons.

If the tree is very tall, reduce the height gradually over two or three winters rather than lopping the top in a single go. Sudden heavy cuts on an old tree can stimulate a thicket of regrowth and leave large wounds that never callus over properly.

The seasons after the saw

Expect the tree to look a little bare the first year, and do not be surprised if the crop is light. The following year is usually the one that shows what you have achieved, with fruit forming on wood that has not seen decent light for a decade.

Help the tree along with a mulch of well-rotted manure or garden compost spread over the root area in spring, keeping it clear of the trunk. If the tree sets a heavy crop, thin the fruitlets in late June so that they sit roughly a hand's width apart. This reduces the strain on old branches and gives you larger, better-flavoured apples rather than a quantity of small ones.

Finally, keep records. A rough sketch of the tree each winter, with the cuts you made marked on it, is far more useful than memory when you come back to the job next year. Restoring an old apple tree is slow work, but it is some of the most rewarding work in a garden.