Advice
RHS Help & Advice
Trimming new and established hedges
Hedges can be divided into three pruning groups:
Group 1
Upright plants, e.g. a) hawthorn, privet, blackthorn and myrobalan plum, b) box, Escallonia, Lonicera nitida.
Initial pruning
a) On planting (October-March) cut back plants
to 15cm (6in). In summer trim laterals lightly. In the second
year (February-March) cut back growth by half. Throughout
summer trim laterals to maintain tapered sides, and in autumn
cut leading shoots to the desired height.
b) On planting (March-April) cut back all stems by one-third.
Repeat this at the same time next year.
Subsequent pruning
Annually, during May-September, trim back top growth
and laterals every four to six weeks to maintain the desired
shape. Use a template if required.
Group 2
Deciduous stocky shrubs, naturally bushy at the base, e.g. beech, hornbeam, hazel and flowering shrubs such as Forsythia and Ribes sanguineum.
Initial pruning
On planting (October-March) cut back leading shoots and sideshoots
by one-third, cutting to a well placed bud. Repeat this in
the second winter to prevent straggly growth and thicken up
the hedge base.
Subsequent pruning
Annually in June (or after flowering) and again in
August, clip to a tapered shape.
Group 3
Conifers and most evergreens, e.g. Lawson cypress, leylandii, yew, cotoneaster and pyracantha.
Initial pruning
On planting (October or March) leave the leader unpruned,
lightly cutting back any straggly sideshoots. In summer trim
laterals and tie-in the leader to a supporting cane as it
grows. Use secateurs for broad-leaved evergreens (e.g. laurel,
bay).
Subsequent pruning
Clip to the desired shape one to three times during
summer (until late August). Stop the leader at the desired
height.
Pruning flowering and fruiting hedges
Most formal hedges require regular pruning, and so flowers and fruits don't develop. However, informal hedges can be pruned selectively to allow a flowering and fruiting display.
Those plants that flower on the current season's growth (e.g. fuchsia) can be pruned once in spring. Plants that flower on one-year-old growth (e.g. pyracantha) can have the current season's growth reduced by half in summer.
Further information
Hedges and nesting birds
When undertaking work on garden hedges check that there are no birds nesting as it is an offence under the Wildlife & Countryside Act 1981 to damage or destroy the nest of any wild bird while it is in use or being built.