Family: Clethraceae
Common Name: White Alder

Native to North America, Europe and eastern Asia, these evergreen or deciduous trees and shrubs, with handsome oval leaves, bear long sprays of small, sweetly perfumed flowers in summer.

Species

C. alnifolia, sweet pepper bush, zone 3, from North America, grows to 2.5 m (8 ft), with long spikes of delicate, spicily fragrant, white flowers and small leaves which colour yellow in autumn. 'Kowa' produces buds and flowers tinged with pink.

C. arborea, lily of the valley tree, zone 9, from Madeira, needs to be grown in a cool greenhouse in frost-prone climates. It has narrow, elliptical leaves and many, fragrant, white flowers, similar to lily of the valley.

C. barbinenvis, zone 5, from japan, is a deciduous tree or shrub, 6-9 m 120-30 ft) tall, with white flowers.

Cultivation

Clethra likes a well-drained, lime-free soil and plenty of water. An equable climate, free from drying winds, is essential. These are ideal plants for a woodland garden. Plant in spring. Propagate from seed sown in tall or spring, from semi-ripe cuttings in summer, or by layering in spring.

Climate

There are species for various climatic zones.