Clethra Alnifolia (Sweet Pepper Bush)
Summersweet, White Alder or Sweet Pepper Bush
The generic name, derived from the Greek word kleihra, meaning alder, apparently calls attention to the alder-like leaves. The genus contains some 30 species native to eastern Asia and North America. These small shrubs are deciduous, sometimes evergreen; the leaves are generally toothed and hairy. Thehave five sepals and five petals and are borne in terminal racemes or panicles. The fruits are three-valved capsules and the seeds are small.
Summersweet grows to a height of 3 m (10 ft). The leaves are glabrous or sparsely hairy, with sharply serrate margins. The flowers are about 8 mm (¼ in) across, arranged in upright feathery racemes sometimes up to 15 cm (6 in) long, and strongly scented. The flowering period is from June to August. This is one of the hardiest of clethras of which the form `Rosea’ with pink flowers is especially well known.
Propagation is by means of seeds which are sown in February or March. The young seedlings are potted up and planted out with their root balls undisturbed in their permanent site, in the second year. The shrub may also be multiplied by hardwood cuttings which can be forced in a greenhouse in winter. Clethras thrive in soils that are not too heavy but sufficiently moist. They appreciate an application of peat and tolerate partial shade. They can be planted as solitary specimens or in loose groupings at the edge of taller plantings or alongside streams, but they are more suitable for large gardens or parks.