Why winter is the right time

Apple trees sleep through the coldest months, and that dormancy is your window. Between leaf fall and bud burst — roughly November to early March in most of the UK — the tree is not pushing sap, the skeleton of branches is finally visible, and the wound response is quick when growth starts again in spring. Prune now and you direct the tree's energy into the shoots and spurs you want to keep.

There are a few days to avoid. Don't cut when the wood is frozen solid or when a hard frost is forecast, because brittle branches shatter rather than slicing cleanly. Leave it alone during September and October too, while sap is still moving and the tree is storing reserves. If you grow trained forms — cordons, espaliers, fans — those are usually summer-pruned in August to keep growth tidy and encourage fruiting spurs, but free-standing bushes and standards want winter attention.

Know your tree before you cut

Stand back with a mug of tea and look properly. You are aiming for a permanent framework of five to seven main branches, well spaced, radiating from a short trunk. Everything else is either helping that framework or competing with it.

Learn to tell the two types of bud. Fruit buds are fat, round and often slightly downy, sitting on short spurs or at the tips of last year's shoots. Wood buds are slim, flat and pointed, hugging the stem. On most garden varieties the fruit comes from spurs on wood two years and older, so you can shorten last year's growth quite hard without losing next autumn's crop. Tip-bearing varieties are the exception — cutting all the young tips off those costs you fruit, so leave some unpruned.

Start with the three Ds

Before you think about shape, clear the obvious problems. Work in this order and the rest becomes much easier to see:

• Dead wood. It looks grey and shrivelled, snaps rather than bends, and shows no green when you nick the bark. Cut it back to clean, live wood — a pale ring of healthy tissue around a darker centre.
• Diseased wood. Canker shows as sunken, cracked patches with a swollen edge. Cut well below the damage, into clean wood, and wipe your blade with a garden disinfectant before moving to the next tree so you don't carry it around the plot.
• Crossing and rubbing branches. Where two limbs chafe, the bark wears away and lets in disease. Remove the weaker, less well-placed of the pair.

While you're at it, take out any branch growing steeply into the middle of the tree, and any shoot sprouting from below the graft union on the trunk — that's rootstock growth and it will never fruit.

Building an open goblet shape

The classic free-standing apple is pruned to an open centre, like a wine glass. Sunlight reaches the middle of the tree, ripening the fruit and colouring it properly on all sides, and moving air dries the leaves quickly, which is your best defence against scab and canker in a damp British summer.

Cut back to an outward-facing bud, angling the cut away from it so water runs off rather than sitting on the new shoot. Leave no stubs — they die back and invite rot — but don't cut flush against the trunk either. Look for the slight ridge where branch meets trunk, the branch collar, and cut just beyond it; the tree seals that wound far better than a flush cut.

Never take off more than about a quarter of the canopy in one winter. If a tree needs serious work, spread it over two or three years.

Young trees, old trees, neglected trees

A young tree is being trained, not just tidied. Shorten the main leaders by a quarter to a third each winter, always to an outward bud, and keep the centre open from the start. Remove any shoots that would crowd your chosen framework.

An established spur-bearing tree needs thinning rather than shortening. Take out some of the oldest spur systems to stop the tree becoming a dense thicket, and lightly tip the new growth on the main branches. If the tree is cropping heavily every other year, thinning the spurs in the "on" year helps even things out.

A neglected old tree is a longer project. Take out the largest, most congested branches first, along with the three Ds, and come back next winter for the rest. Don't be tempted to restore it to glory in one afternoon — the shock can push a mass of useless water shoots and leave you worse off.

Clean cuts, sharp tools, and something for wildlife

Use bypass secateurs for anything up to your thumb thickness, loppers up to about four centimetres, and a pruning saw beyond that. Sharp blades make clean cuts, and clean cuts heal. Skip the wound paint — modern advice is to leave the tree to seal itself.

Before you start on a hedge-line or a tree with dense cover, check for nesting birds. Never prune during the nesting season, roughly March to August, and if you're working near ivy or a thick hedge in winter, check anyway. Leave a dead limb standing where it's safe to do so, and stack a few prunings in a quiet corner; dead wood is a nursery for beetles, fungi and solitary bees, and the pile will be claimed by hedgehogs before long.

Do this well and the reward is visible by September: apples hanging in sunlight, spaced enough to swell, on a tree that will carry on cropping for decades.