When should I cut my hedge?

Hedge timing does two jobs at once. It has to suit the plant — cutting when it can still make a little regrowth to cover the cut ends, but not so late that soft new growth is caught by frost — and it has to stay clear of nesting birds, which is a legal question rather than a horticultural one. The species table below is the horticultural half; the nesting check applies to all of it.

Safety

What you'll need

• Sharp shears or a hedge trimmer
• Eye protection and gloves
• String line and canes (optional)

Step by step

1. Check the hedge for active nests before every cut.Look into the hedge from both sides and underneath, in good light, and listen. Birds nest low and deep. If a nest is in use, leave that section alone and cut the rest, or wait. This applies in September as well as in May.
2. Formal evergreens: two or three light cuts through the season.Privet, box, yew, Lonicera nitida. Late May or June for the first, then again in late summer, and privet often takes a third. Little and often is what keeps them dense.
3. Yew: one or two cuts, late summer for the main one.Yew is the one common evergreen that will regrow from old wood, so it is also the most forgiving. A main cut in August with a tidy-up earlier if it is a formal shape.
4. Beech and hornbeam: one cut in late summer.Around August. Cut then and the dead brown leaves are retained through winter, which is the whole point of a beech hedge. Cutting in spring loses that and stimulates soft growth.
5. Conifers: late spring and late summer.Leylandii, Thuja, Lawson cypress. Two cuts a year is the minimum to keep them controllable. Never cut into brown wood on leylandii or Lawson cypress — it will not regrow.
6. Laurel: mid to late summer, with secateurs if you can bear it.Cherry laurel has large leaves that a trimmer slices in half, leaving brown-edged mutilated leaves for months. Cutting individual shoots with secateurs looks far better, and on a small hedge it is worth the extra hour.
7. Flowering hedges: cut after flowering.Escallonia, forsythia, flowering currant, hawthorn grown informally. The flowers form on last year's wood, so cutting in spring cuts them off. Cut when the flowers finish.
8. Stop before hard frost.A late cut pushes out soft growth that has no time to harden, and frost then browns the whole outer surface. Late September is a sensible last date for most species in most of the UK, earlier in the north.
9. Avoid cutting evergreens in hard frost or drought.Cutting a hedge under water stress or in freezing weather causes dieback along the cut surface. Wait a week.

Tips

• The rule of thumb for formal hedges is 'little and often'. Three light cuts produce a far denser, finer hedge than one hard annual one.
• Cut when the hedge is dry. Wet foliage clogs a trimmer, and cutting wet spreads fungal diseases such as box blight through the hedge.
• Note the date you cut in a diary. Most people who ask this question every year are one written note away from never needing to.

Common mistakes

• Cutting a beech hedge in spring — You lose the winter leaf retention that is the reason to have a beech hedge, and stimulate soft growth just as the plant is putting energy into extension.
• One hard annual cut on a formal evergreen — It produces a coarse, open hedge with visible cut stubs. Light frequent cutting produces the dense surface people actually want.
• Cutting in late October or November — New growth stimulated by the cut has no time to harden before frost, and the hedge goes into winter with a browned outer skin.
• Cutting during nesting season without checking — It risks committing a criminal offence, quite apart from destroying a brood. The check takes two minutes.

Questions people ask