Caring for Oakleaf Hydrangea

Oakleaf hydrangea has moderate water needs and performs best with consistent moisture, especially during dry spells in spring and summer when it is actively growing and flowering. Water deeply once or twice a week in dry weather, ensuring the root zone is thoroughly soaked rather than giving frequent shallow sprinkles. Mulch helps retain soil moisture and keeps roots cool; top up the mulch layer each spring. Reduce watering in autumn as growth slows, but don't allow the soil to dry out completely over winter, particularly for young plants. Feed in March or April as new growth begins. Apply a balanced slow-release fertiliser such as blood, fish and bone or a general-purpose granular feed around the base of the plant, following packet rates. Alternatively, use a mulch of well-rotted compost or manure, which feeds the soil as it breaks down. Avoid high-nitrogen feeds, which promote leaf growth at the expense of flowers. A second, lighter feed in April can benefit young or newly planted specimens. Oakleaf hydrangea is fully hardy in zones 5a–9a and requires no special winter protection in temperate Europe. The foliage turns rich shades of bronze, burgundy, and purple in autumn before dropping. Pests are rarely a problem, though aphids may occasionally cluster on soft new growth in spring; a strong jet of water usually dislodges them. Powdery mildew can appear on leaves in dry summers or congested plants; improve air circulation through thinning and ensure consistent watering. Leaf scorch may occur in full sun or very dry soil.