How to Prune Shrubs

Pruning keeps shrubs healthy, shapely and flowering well. The key is knowing when to prune – get the timing wrong and you may lose a year's flowers.

The basic rule

The timing of pruning depends on when the shrub flowers:

• Spring-flowering shrubs: Prune after flowering. They flower on wood made the previous year.
• Summer-flowering shrubs: Prune in late winter or early spring. They flower on new growth.

Spring-flowering shrubs

Prune immediately after flowering to give new growth time to develop and form flower buds for next year.

• Forsythia, flowering currant, lilac
• Philadelphus (mock orange), weigela, deutzia
• Spiraea (spring-flowering types)

Remove flowered stems, thin out congested growth, and shorten long shoots to maintain shape.

Summer-flowering shrubs

Prune in late winter or early spring before growth starts.

• Buddleia, hardy fuchsia, lavatera
• Caryopteris, perovskia, ceratostigma
• Spiraea (summer-flowering types like S. japonica)

Cut back hard to a framework of main branches. New growth will carry this year's flowers.

Evergreen shrubs

Most evergreens need little pruning. If needed, prune in late spring after the risk of frost has passed:

• Remove dead, damaged or diseased growth.
• Trim to shape if necessary.
• Avoid cutting into old, bare wood – many evergreens do not regrow from it.

Renovation pruning

Overgrown shrubs can often be rejuvenated by hard pruning:

• Cut back to 30-60cm from the ground in late winter.
• Not all shrubs tolerate this – check before cutting.
• Shrubs that respond well: buddleia, forsythia, philadelphus, viburnum, cornus.
• Shrubs that do not: lavender, cistus, broom, most conifers.

Basic pruning cuts

• Cut just above an outward-facing bud to encourage open growth.
• Make clean cuts with sharp tools – ragged cuts invite disease.
• Remove crossing or rubbing branches.
• Take out dead wood at any time of year.

When not to prune

• During severe frost – wounds heal slowly and may be damaged.
• In autumn – new growth may be killed by winter cold.
• When birds are nesting (March-August) – check before cutting hedges and dense shrubs.