When to prune lilacs

Prune lilacs soon after they finish blooming in late spring, ideally within about two weeks, because next year's flower buds begin forming in summer.

• The lilac has finished blooming in late spring.
• Next year's flower buds begin forming in summer, so don't wait too long.
• Each cut to a branch tip removes flower buds, so prune after the blooms are done.
• If the lilac is thin and overgrown, remove the oldest branches over two or three consecutive seasons, always right after flowering.