Hedge trimmers: When and how to trim a hedge
The expert guide to cutting your hedge
In our gardening how-to guide, we'll tell you the best time of year to trim all your hedges - including cypress, privet, beech and laurel. We also give you tips on how to cut hedges, to leave you with a sharp, neat finish.
If you struggle with your old hedge trimmer, or don't have one, take a look at our Best Buy hedge trimmers.
Box (Buxus) hedges are good for neat edging. Trim in September at the end of the growing season, but hard prune in late spring. Do not cut when the foliage is wet or when the weather is humid as this can increase the risk of box blight infection.
Box blight can devastate hedges, starting with brown patches which lead to large scale die-back. For affected hedges the only solution is to remove the plants and choose an alternative. Spraying with a fungicide will not halt the spread long-term and there are few products available to the home gardener.
There are some good alternatives, including Japanese holly (Ilex crenata) and shrubby honeysuckle (Lonicera nitida).
Lavender also makes a good flowering hedge. Trim after flowering and be ready to replace your hedges after around four years. Lavender is easy to grow from cuttings, so you can grow your own plants to cut the cost of replanting.
Best hedge trimmers
Before you start, check for birds' nests. Birds nest from March through to August and it is illegal to disturb birds nests that contain eggs or chicks.
You can find out which are our current Best Buy hedge trimmers here.
How to trim a hedge
A formal hedge is one that is clipped regularly.
- Choose a dense, fine-leaved plant, such as privet or a conifer.
- Trim regularly to a square, or preferably to a wedge shape with the base wider than the top. This allows maximum light to reach the base and looks more solid.
- Try to keep the top no wider than about 60cm, so you can cut it easily from one side.
- For longer hedges, erect a line using bamboo canes and a string that does not stretch when it is pulled. Push bamboo canes well into the soil at either end of the hedge, and shorter canes at 45o to these, pointing away from the hedge.
Tie string between the slanting and upright canes to stop the upright canes being pulling inwards when you tighten the string along the hedge. Tie the string above the hedge to get a straight side and the about 1cm below the desired eventual height to cut the top. This stops you from cutting so close to the string that you nick it and have to retie it.
- When using a hedge trimmer, start at the bottom of each side and work upwards in smooth, continuous swathes. Cut the top of the hedge last.
- Save time by spreading a plastic sheet beside the hedge to catch the clippings. Brush or rake the clippings from the top of the hedge, or they’ll look unsightly.
- Choose a large-leaved deciduous plant, such as forsythia, escallonia, berberis and hawthorn, which have flowers and berries, too.
- Cut back hard occasionally if you like the berries or give them an annual trim after flowering for a more regular shape.
- You may prefer to cut these hedges with secateurs and loppers for a more natural look.
- Most hedge plants respond well to hard pruning. Check the gallery above for the best time of year to do this.
- All conifer hedges except yew should not be cut back beyond the green growth as they will not regenerate.
- Decide on the height or width you want and use canes and string to mark it out.
- Cut back up to 30cm further than this to allow for new growth.
- To retain a physical barrier, cut back one side of the hedge one year and the other side the next.
- Use loppers or a pruning saw on older branches that are more than around 2cm in diameter.
- Once you've cut it back to the required size, trim regularly with a hedge trimmer. Go to our hedge trimmer reviews to find one to suit you and your garden.
Always cut in dry conditions when you are unlikely to slip on wet ground.
Preferably cut from the ground rather than from a ladder. A long-reach hedge trimmer will let you cut the tops of taller hedges without having to go up a ladder.
Instead of a ladder, use a step-ladder or Henchman-type ladder with a platform. Always make sure the ladder is stable before you climb in. Many stepladders have attachments for the base of the ladder that will make it wider and more stable.
If you have to climb a ladder, make sure someone is with you to help.