Clethra alnifolia Ruby Spice

Clethra alnifolia Ruby Spice is a variety of Sweet Pepperbush with a small habit, appreciated for its pink flowering instead of white like the species. With its bushy silhouette and clusters of pink flowers, reminiscent of callistemons, this shrub brings a touch of exoticism to cool and slightly shaded areas of the garden, often lacking in flowers at the end of summer, just like its autumn foliage with its golden hues enlivens the undergrowth at the end of the season. Clethra are shrubs that prefer humus-rich, non-chalky, moist to wet soils. They thrive in the same conditions as rhododendrons and autumn camellias, forming beautiful combinations with them.

Clethra alnifolia is a deciduous shrub with semi-suckering roots native to moist forests and marshy areas in the eastern United States. Its natural range extends from southern Maine to eastern Texas. In the wild, it forms small thickets that can reach 3m (9 ft 10 in) in all directions. It is highly hardy, at least down to -20°C (-4 °F).

The 'Ruby Spice' cultivar forms a compact bush that rarely exceeds 1m (3 ft 4 in) to 1.20m (3 ft 11 in) in all directions. It bears obovate, smooth, serrated leaves measuring 5 to 10cm (2 to 3.9 in) in length, arranged alternately. They are a tender green in summer and turn warm shades of yellow, gold, and orange in autumn before falling. Flowering usually occurs in September, depending on the climate. It takes the form of upright spikes measuring 8 to 15cm (3.1 to 5.9 in) in height, composed of multiple small, campanulate, pink, downy, and fragrant flowers. They open from the base to the top of the flower head. Their honey-like scent attracts many pollinating insects. The flowers are followed by small round fruits, grouped in slender clusters, which remain decorative on the branches in winter if not eaten by birds. These fruits, resembling peppercorns, have earned this shrub its name of 'sweet pepperbush' in the United States.

Clethra alnifolia Ruby Spice will only thrive in acidic and light soils that never dry out, in a partially shaded position. It finds its place in ericaceous beds or at the base of large deciduous trees, if the soil remains moist in summer. Pair it with small rhododendrons in shades of mauve, white, or pink, camellias, Kalmia latifolia, and winter-flowering heathers that will take over after its own flowering. As it tolerates container cultivation well, use it to decorate a terrace or patio.