Pruning trees and shrubs: when, how and why

Pruning: the skill every gardener needs

There's a peculiar satisfaction in pruning. A wild, overgrown shrub restored to a beautiful shape in an hour. A tree finally letting light through to the plants below. Yet pruning makes many gardeners nervous: am I cutting too much? When should I actually prune?

GardenWorld helps you visualise your garden's potential after seasonal care. It's a brilliant way to see which shrubs need attention and how the garden looks once everything is tidied up.

When to prune what?

The rule of thumb is straightforward: shrubs that flower before June get pruned after flowering. Shrubs that flower after June get pruned in early spring. The reason? Spring-flowering shrubs form their flower buds on last year's wood. Prune that away in spring and you'll have no flowers that season.

In practical terms: forsythia, lilac, hawthorn and rhododendron get pruned in May or June, after flowering. Hydrangea paniculata, buddleja, hibiscus and lavender get pruned in March.

The nesting season

Keep the bird nesting season in mind. Between March and August, avoid drastic pruning of hedges and dense shrubs. Light maintenance is fine, but always check for nests first. The RHS provides helpful guidance on wildlife-friendly gardening.

Basic rules for good pruning

Always use sharp, clean tools. Blunt secateurs tear branches rather than cutting them cleanly, increasing the risk of disease. Disinfect your secateurs between different plants with a bit of surgical spirit.

Always prune just above an outward-facing bud. This encourages new growth to head outwards, keeping the shrub open. Cut at an angle so rainwater runs off the wound rather than sitting on it.

The three D's

Start every pruning session with the three D's: dead, damaged and diseased wood. You can remove these at any time of year. Also remove crossing branches that rub against each other. Then assess whether the plant needs further thinning.

Pruning fruit trees

Apple and pear trees are best pruned in winter while the tree is dormant. Cherries should be pruned in summer, after harvest, to prevent silver leaf disease.

The goal with fruit trees is an open canopy where light and air can reach all the fruit. Remove water sprouts (those vigorous upright shoots) and thin twiggy growth that congests the centre. Many garden centres run pruning demonstrations in winter. Incredibly useful, even if you've been pruning for years.

Cutting hedges

A hedge gets trimmed twice a year: late June and late September. Cut the top slightly narrower than the base so the bottom also gets enough light. A formal hedge gets cut with hedge shears; an informal hedge with secateurs, branch by branch.

Beech hedge is best left until late June, otherwise it regrows too quickly. Conifer hedges won't tolerate being cut back to old wood: never prune beyond the green growth.

Common mistakes

Most gardeners prune too cautiously. Plants are tougher than you think. A healthy shrub that gets a hard prune comes back stronger. But there are exceptions: conifers and some evergreen shrubs like skimmia won't tolerate hard pruning.

Another mistake: pruning everything into a ball shape. It might look tidy, but the lower part of the plant gets no light and goes bare. Try to follow the plant's natural form instead.

What to do with pruning waste?

Thin twigs can be shredded and used as mulch. Thicker branches get cut up for green waste collection. Or better yet: create a log pile in a quiet corner of the garden. Hedgehogs, toads and insects will thank you.

Pruning is one of those jobs that always leaves you feeling satisfied afterwards. The garden looks instantly tidier and your plants grow healthier for it.

Curious how your garden looks after a good prune? Discover it on GardenWorld and visualise your garden at its best.