These popular shrubs and climbers are well known for their distinctive flowerheads. The shrubs do best in mild areas, particularly on the coast. The climbers are hardier and will grow on shady walls.
Suitable site and soil. Hydrangeas like rich, moist soil and a sunny, sheltered. Blue varieties do not produce blue on alkaline soil – so dig in peat – dress with aluminium sulphate to balance. do not like acid soils – dress with ground limestone.
Cultivation and care. Plant in late autumn or early spring. Give a manure mulch in spring. Dead-head after flowering.
Propagation. Takeof the climbing species in early summer and of the shrubs in late summer or early autumn and grow on in a . Overwinter in a cold frame and plant out in the spring.
Recommended varieties. H. macrophylla has two main– lacecaps with flat heads and hortensias with round or mopheads. Good lacecaps include: ‘Blue Wave’ – blue or pink; hite Wave’ – white; ‘Mariesii’ – rich pink or blue. Hortensias include: ‘Altona’ – rose-pink; ‘Goliath’ – rich pink or purple-blue; ‘Madame Emile Moulliere’ – white with pink or blue centre. (Height and spread 1.2-1.8m – 4-6ft). H. petiolaris is a vigorous climbing hydrangea with a height of up to 18m – 60ft. It carries greenish-white in early summer.
Pests and diseases. Alkaline soil causes chlorosis, visible in yellow or almost white.
The climbing hydrangea is a very useful plant and one of the few flowering climbers which does best on a shady wall. It needs no support as it is self-clinging and climbs equally well on a tree.