Quick Guide: summer, hardy, semi-shade, height: 18m/60ft, width: 6m/20ft

The popular hybrids of the shrub Hydrangea macropbylla (1.8 x 1.8m/6 x 6ft) are known as Hortensias, with mop-heads of florets up to 20cm/8in wide, or Lacecaps, with smaller, open heads. Flowers are blue or pink. White-flowered species include H. paniculata and the climber H. petiolaris.

GROWING Plant in autumn or spring in a sheltered position in loamy, moisture-retentive soil previously enriched with well rotted organic matter. H. macrophylla hybrids need top dressings of peat and an annual application of aluminium sulphate for blue flowers, or ground limestone for pink. Each spring, mulch with well-rotted organic matter and cut out damaged shoots. Remove faded flowerheads.

PROPAGATION Climbers: Take 7.5cm/3in cuttings in early summer and insert in a peat/sand mixture in a cold frame. Pot up individually when rooted, stand outdoors and set out in autumn. Shrubs: Take 15cm/6in cuttings in late summer

SPECIES H. petiolaris (above), self-supporting climber, 25cm/10in corymbs of cream flowers, early summer; H. paniculata `Grandiflora', shrub with arching stems, maximum height 4.5m /15ft, 45cm/18in panicles of white flowers, late summer; H. arborescens `Grandiflora', hardy American shrub, compact at 1.2 x 1.2m/4 x 4ft, pure white flowers all summer.