Pruning Hydrangea

Hydrangea macrophylla flowers on old wood—buds formed the previous summer—so heavy or mistimed pruning will remove this year's blooms. Prune in March or April, just as the leaf buds begin to swell and you can distinguish live wood from any frost-damaged stems. Use clean, sharp secateurs or loppers. Start by removing any dead, damaged, or weak stems entirely at the base. Then trace each flowering stem down to the first pair of strong, healthy buds below the old flowerhead and cut just above them—typically 10–20 cm below the spent bloom. This encourages the plant to put energy into the buds that will flower in summer. Avoid cutting back into thick, old wood lower down unless you're renovating a neglected plant, as this wood may not break readily. Every few years, remove one or two of the oldest, thickest stems at ground level to encourage fresh, vigorous growth from the base and maintain an open framework. This prevents congestion and improves air circulation, which helps reduce mildew. If your hydrangea has suffered frost damage over winter, wait until April to assess which stems are viable—green tissue beneath the bark indicates life. Don't be tempted to tidy up in autumn; the old flowerheads provide some frost protection to the buds below and look attractive rimmed with frost. If your plant doesn't need renovation, pruning is light and quick: simply deadhead and tidy. Overpruning is the most common mistake and results in a leafy bush with few or no flowers.