Pruning Forsythia
When and how — Forsythia x intermedia
Prune your forsythia in March and April — the optimal month is usually April.
The next pruning window is March next year.
When to prune?
The shrub forsythia is pruned in March and April.
Pruning time depends on when the shrub flowers.
The rule of thumb for ornamental shrubs: spring-flowering shrubs (forsythia, lilac, flowering currant) are pruned immediately after flowering, because they set their buds on last year's wood. Summer-flowering shrubs (buddleia, paniculata hydrangea, hardy hibiscus) are pruned in March, because they flower on wood produced this season. Get the timing wrong and you cut off this year's buds. Evergreen shrubs (yew, box) are best pruned around Midsummer (24 June): the first flush of growth is finished and the plant still has time to seal the wounds before winter.
How to prune forsythia
Forsythia flowers on wood produced the previous year, so timing is critical: prune immediately after flowering finishes in March or April, once the yellow blooms have faded. Pruning later in the season or in autumn will remove next spring's flower buds and leave you with a green shrub come March. Use clean, sharp secateurs for stems up to pencil thickness and loppers or a pruning saw for older, thicker branches. Start by removing any dead, damaged, or crossing stems entirely, cutting back to a healthy bud or to ground level. Then tackle the oldest wood: forsythia benefits from renewal pruning, so each year take out up to one-third of the oldest stems at the base to encourage vigorous new growth from below. These older branches are usually darker, thicker, and less productive of flowers. Shorten the remaining stems lightly if you want to control size or shape, cutting just above an outward-facing bud to maintain an open, arching habit. Avoid shearing forsythia into tight geometric shapes—it looks unnatural and reduces flowering. If your shrub has become overgrown or neglected, you can renovate it by cutting the entire plant down to 30–50 cm above ground level in April. It will resprout vigorously but won't flower well the following spring; expect a full display to return in the second year after hard pruning.
Common mistakes
✗ Hard-pruning all hydrangeas in early spring
Mophead hydrangea (Hydrangea macrophylla) flowers on old wood — cut it back in March and you get no flowers. Paniculata flowers on new wood and can be cut back hard. Check the species first.
✗ Trimming everything to the same length
Looks 'chopped' and weakens the shrub. Instead, remove one in three of the oldest stems each year right down to the base (renewal pruning). This keeps the shrub vigorous and natural in shape.
✗ Pruning in summer heat
Fresh cuts dry out quickly in full sun and become an entry point for fungal disease. Wait for an overcast day or postpone until autumn.
Combine with feeding
In March and April you can combine pruning with feeding — efficient, and you only disturb the plant once. Read the full care guide for forsythia →
Too late this year? Here's what to do
Better to wait than prune at the wrong moment. The next optimal window is March next year. Until then: leave the plant alone — only remove dead or diseased wood (which you can do year-round).
