In these dog days of summer, when it’s so hot and humid outside, something healthy, flowering and green is a welcome sight in the garden. There is one shrub that shines this time of year, and that is the shrub aptly known as summersweet or sweet pepperbush, or clethra alnifolia.
Clethra is native to the coastal plain, our ecoregion here in Southern Delaware. You’ll see it naturally growing in low spots in the forest, so from that habitat you can tell it loves moist to wet, sandy soil.
It is one of the few shrubs that will bloom in the shade; its preference is a bright, dappled shade but it will tolerate full shade. It can take full sun, too, as long as the soil stays consistently moist. If it’s in the shade, it will grow in somewhat drier soil. A good layer of mulch will help keep the root zone cool and moist. It also tolerates salt spray, making it suitable for our gardens here. Even better, it’s not a deer favorite, although they might munch on it some.
The species itself can get anywhere from 5 to 8 feet tall. It has a fairly upright growth habit and will sucker, spreading into a nice-sized clump. It is very easily controlled, however, if you want it to stay smaller.
It has beautiful glossy dark green leaves that shine in the shade. They can turn an attractive yellow in the fall, but this shrub is primarily grown for its beautiful flowers. And they are fragrant! The narrow, upright inflorescence (the complete flower head) gets from 3 to 6 inches long, and is made up of hundreds of small white or pink flowers. Pollinators love it! It is blooming now, and the name pepperbush comes from the attractive seed heads that last into winter, each one resembling a peppercorn.
It has no serious pest or disease problems. It also needs very little maintenance, other than giving it some water. It can be pruned in late winter or early spring, if you really need to keep it in bounds. To control its size, like any shrub, you can cut back about a third of the oldest stems close to the ground every few years, but do it randomly to preserve a more natural look.
There are some great cultivated varieties:
- Hummingbird only gets to about 3 feet, with large, beautiful white blossoms;
- 16 Candles also stays small, with great flowers; and
- Ruby Spice can get to 6 feet and has lovely, deep pink flowers.
This is a wonderful, easy-to-grow shrub that deserves far more use in our gardens. Try one today.