When should you prune spring-flowering shrubs versus summer-flowering shrubs, and why?

• A. Spring-flowering after bloom; summer-flowering in late winter or early spring before bud break; to avoid removing next year's flowers on wood
• B. Spring-flowering in late winter; summer-flowering after bloom; to encourage more flowers
• C. Both types should be pruned in mid-summer; to maintain shape
• D. Spring-flowering shrubs should be pruned right after flowering; summer-flowering shrubs should be pruned in late winter; this preserves next year's bloom

Answer: (D)

The timing hinges on whether a shrub forms its flower buds on old wood (last year’s growth) or on new wood (this year’s growth). Spring-flowering shrubs set their flower buds on wood from the previous season, so if you prune them after they’ve finished blooming you’re not cutting off next year’s buds. Pruning soon after bloom preserves those future flowers and helps shape the plant without sacrificing the next display. Summer-flowering shrubs form their flower buds on new growth produced this year, so pruning in late winter or very early spring before growth begins encourages a strong flush of new shoots that will carry blooms later in the season. Pruning these shrubs after flowering or in midsummer can remove those developing buds and reduce next year’s bloom. In short: prune spring bloomers right after flowering; prune summer bloomers in late winter before new growth starts.