Winter is the perfect time to prune many familiar garden plants. When trees and shrubs are leafless, it’s easy to see what growth needs to be removed. When dormant, there is also less likelihood of plants ‘bleeding’ sap and becoming infected by diseases. Correct pruning will help your plants remain healthy, vigorous, shapely, and within the bounds you have set for them.
Cutting into any plant can feel daunting, even destructive, but in most cases it should be good for them and enjoyable for you. If you’re ever in any doubt, equip yourself with a good pruning book: they can be picked up for a couple of pounds in a charity bookshop. The pages will be packed with sound advice and, most importantly useful diagrams. One I can recommend is the RHS book of Pruning and Training. You’ll find links to related posts at this end of this article.
Not all plants should be pruned in winter, but here’s a list of those that will definitely benefit:
- Roses - bush roses such as floribundas and hybrid teas can be cut down to somewhere between 15cm and 30cm in late winter or early spring. Remove older stems of climbers and shrub roses, plus any that are dead, straggly or crossing one another. Tie the remaining growth to supporting structures.
- Deciduous shrubs and fruit bushes - winter is a good time to open up and reduce the bulk of shrubs by cutting out dead wood and congested branches. It’s also the best time to reduce their size, cutting excess growth back to an outward-facing bud. Don’t go crazy - step back and assess your progress from time to time. Your aim is to create an open vase or goblet shape.
- Apple and pear trees benefit from pruning to encourage more flowers and fruit. Cut long, and unbranched stems back to produce short spurs around the main branches. These will produce flowers in a few months. Aim to remove no more than 10-20% of the tree otherwise you might send it into overdrive and encourage too much leaf production.
- Grapes, figs, acers and birches are prone to ‘bleeding’ if they’re pruned at any other time. Tidying them in December or January ensures that wounds heal nicely. Prune vines back to the main structural stems, leaving short spurs from which new growth will shoot in spring.
- Wisteria benefits from tidying up once in summer and again in winter. Tie in any wandering stems you want to keep, for example, to extend the plant along a wall or over a pergola, and remove the remaining growth to 2 or 3 buds from the main branch.
- Clematis need to be treated differently depending on when they flower. Winter is the correct time to prune mid and late-summer flowering clematis (Group 3, including C. texensis and C. viticella cultivars). You can be fairly brutal, removing all the top growth to about 30cm. Chances are that new buds will already be visible when you get around to this satisfying job. Shears can be used on larger plants or if you have lots of clematis to prune.
- Autumn-fruiting raspberries can be trimmed almost to ground level. The next fruit crop will be produced on new stems (‘canes’) that emerge from the soil in spring.
Whenever possible, prune on a mild, dry day: it will be more comfortable for you and help prevent the spread of water-borne diseases. Avoid pruning when frosts are predicted shortly afterwards. If you are pruning a lot of plants of the same variety, dip the blades of your pruning tools in dilute bleach between each one to kill any bacteria.
These shrub roses have been reduced to 2 or 3 main stems with their side branches neatly pruned above an outward-facing bud.
What not to prune in winter
- Don’t touch stone fruit trees, including cherries, plums, damsons, apricots and peaches. Pruning now can spread disease, so wait until early or mid-summer.
- Leave rambling roses alone until late summer unless they have become completely out of control and need serious tidying up.
- Leave willows, hazels and dogwoods with colourful bark or spring catkins until their moment of glory is over.
- Hold fire on hydrangeas, salvias, fuchsias and other less-hardy shrubs until early spring, as old growth will offer tender buds protection from the winter cold.
- Winter, spring and early summer-flowering clematis should be tidied after flowering. Pruning in winter may remove the next season’s flowering stems.
- The same advice applies to early-flowering shrubs that are already forming buds in readiness for spring. These include lilacs, forsythias, magnolias, deutzias, ribes, rhododendrons and azaleas.
- Summer-fruiting raspberries produce fruit on the previous year’s canes, so don’t be tempted to remove these.
Simple Pruning Tips
Pruning is a skill that gardeners never stop learning. Done poorly, it can do more harm than good, but if you observe a few simple rules, doing something is almost always better than doing nothing.
- Use the right tool for the job - if you’re straining or stretching, that’s not a good sign. For more advice on equipment, read How To Prune Like A Pro.
- Make sure secateurs, loppers and shears are clean and sharp before you get started.
- Always know where your fingers are in relation to the blades - enough said!
- Make clean cuts so the plant is not bruised, torn or grazed.
- Remove dead, diseased, weak, snagged or damaged branches first.
- If other branches cross one another, remove one or both of them to prevent them from rubbing together.
- Cut 1cm above an outward-facing bud, at the fork of a branch or just beyond the branch collar (the swelling where a branch joins a main stem or trunk). This ensures that the plant’s energy is channelled toward a new growth point.
- Cut at an angle so water or sap cannot stagnate on the cut surface.
- Mulch heavily pruned plants to help them recover when growth resumes.
- If you cut into wood with no visible leaves, buds or shoots, be sure that the plant can rejuvenate itself. Several plants, including most conifers and woody shrubs like lavender, will not reshoot from ‘old wood’.