The advantage of having acid soil, even though mine is heavy and often wet, is that it has opened up a whole new world of plants to me. It is the first time I have been able to plant camellias and rhododendrons among many, though soil alone does not ensure success – there are other factors to take into account, as I am discovering. But one genus that I can play with is clethra and my first attempt is going well.
Clethra is one of two genera in the Clethraceae and there are 65 species, from around the Northern hemisphere, many from climes much warmer than mine. So not all are hardy. They can be evergreen or deciduous and are closely allied to the Ericaeae. The name clethra is from the Greek word for alder and the one I have planted is C. alnifollia, so we have the alder-leaved alder-like plant.
Clethra alnifolia is from the Eastern USA, where it is called summersweet or sweet pepperbush, from Maine to Florida and west to Texas. It was introduced to the UK in 1731 and has spikes of creamy white, fragrant flowers in mid to late summer. My plant is ‘Ruby Spice’ a sport of ‘Pink Spire’ that arose in 1992. I am not sure what the difference is but ‘Ruby Spice’ has deeper pink flowers.
As a garden shrub, Clethra alnifolia is useful because few shrubs bloom at this time of year. It is hardy, not too fussy about soil type, though it is supposed to prefer moist, sandy soil, and will grow in sun or part shade. My plant was put in in spring, bare root, and has half a dozen spikes of bloom already. They are supposed to attract bees and butterflies but the latter have yet to discover mine. It should make a large shrub up to 2m high. The flowers are pretty but the fact that they are sweetly fragrant makes it really lovely. The fragrance is sweet and slightly spicy. It is supposed to be deer-resistant. The foliage should turn yellow in autumn before it drops. I have been impressed at how long the flowers have lasted and I would suspect that, once fully grown, it would be in bloom, and delighting me, for a month or more. I think I will be planting more.
Breeding work is being done in the USA where there is a wider range of new varieties which include the low and lovely ‘Summer Sparkler’ and ‘Sixteen Candles’, both with white flowers.