Hydrangeas: Varieties, Planting & Care
Hydrangeas are among the most spectacular of all flowering shrubs, offering bold colour from midsummer well into autumn. Understanding the different types is the key to getting the best from them.
Choosing the Right Variety
Hydrangea macrophylla (mophead and lacecap) are the most familiar types, producing large rounded or flat flower heads in shades of pink, blue, purple and white. Flower colour in pink and blue varieties is influenced by soil pH — acid soils produce blue flowers, alkaline soils produce pink. Hydrangea paniculata is more vigorous and tolerates a wider range of conditions, producing large conical flower heads that age from white to pink. Hydrangea arborescens 'Annabelle' is a reliable choice for shade, producing enormous white globes from July to September.
Planting
Plant hydrangeas in spring or autumn in a sheltered spot with morning sun and afternoon shade. They prefer a moist, humus-rich, well-drained soil. Dig in plenty of well-rotted compost at planting time and water thoroughly. Avoid planting in exposed, windy positions — the large flower heads are easily damaged.
Pruning
Hydrangea macrophylla flowers on the previous year's wood, so prune lightly in spring — simply remove the old flower heads and any dead or weak stems. Hard pruning will remove the flower buds. Hydrangea paniculata and arborescens flower on new wood and can be pruned more hard in early spring to encourage large flowers on strong stems.
Feeding and Watering
Hydrangeas are thirsty plants, particularly in dry summers. Water deeply and regularly, especially in the first year after planting. Apply a balanced fertiliser in spring and a high-potassium feed in late summer. To maintain or intensify blue flower colour, apply a hydrangea colourant (aluminium sulphate) to the soil in spring.