Caring for Smooth Hydrangea

Smooth hydrangea 'Annabelle' has high water needs, especially during dry spells in spring and summer when it's producing foliage and flowers. Water deeply once or twice a week in dry weather, soaking the root zone rather than sprinkling lightly. Mulch helps retain moisture, so top up the organic mulch layer each spring if it has broken down. In autumn and winter, rainfall is usually sufficient, but check containerised plants or those under eaves. Feed in March with a general-purpose balanced fertiliser such as blood, fish and bone, scattering a handful around the base and lightly forking it in. Apply a second feed in April as growth accelerates, then a final dose in June to support flowering. Avoid high-nitrogen feeds after midsummer, as they promote soft growth vulnerable to frost. 'Annabelle' is fully hardy (zone 3a–9a) and needs no special winter protection in temperate Europe. The stems die back naturally or can be left standing for winter interest, then pruned away in March. Pests are rarely a problem, though aphids occasionally cluster on soft new shoots in spring—a strong jet of water or insecticidal soap deals with them. Powdery mildew can appear on the foliage in dry summers, especially if the roots are stressed; ensure consistent watering and avoid overhead watering late in the day. Leaf spot may occur in wet seasons but is usually cosmetic. Remove and bin affected leaves, and improve air circulation by thinning congested growth during the annual prune.