C is for Clethra alnifolia, otherwise known as sweet pepperbush. It was one of the first plants I put in my new, and very wet, garden last summer. It has everything I need: is very hardy, likes some shade, tolerates clay soil, likes a wet so much that it can be used in a rain garden where there is occasional flooding. Clethra is also the right size for my garden. It will grow between 4 to 6 feet…