We are blessed in the Northwest to be able to grow a wide variety of plants from many other parts of the world — in addition, of course, to our own native flora.
Because of our proximity to Asia and our shared Pacific marine climate, many of our gardens sport plants from Japan (hence the name “japonica” in plants like Pieris and Euonymus), China (hence the name “chinensis” found in Wisteria), and Korea (think of the Korean or kousa dogwood that so many of us enjoy). I even have a hardy Schefflera taiwaniana, which, as you’ve probably figured out by now, comes from Taiwan.
Most gardeners are always looking for something new and different that is not locally found. But going what seems like a long way away to find new plants isn’t always necessary. Take for example Clethra alnifolia, or summersweet, as it is commonly called.
Summersweet is a delightful deciduous shrub that hails from the East Coast. It is most commonly found in moist woodlands and has an upright growth habit reaching 5 to 8 feet tall and 4 to 6 feet wide — newer forms are more compact. It tends to sucker, forming colonies, but is certainly not invasive like bamboo. The leaves are a bright, shiny green that turn a fabulous intense yellow in the fall.
What gives summersweet its name is its flowers, which come in either white or pink on 3 to 5 inch stalks (think of a radish or mustard flower). In our West Coast climate, summersweet is quite happy in full sun but will also tolerate afternoon shade. The blooms are forming as I write, and should be sporting color before the end of the month and into early August. If you make it into your favorite garden center this month, you won’t miss their sweet fragrance wafting through the nursery aisles.
Generally speaking, summersweet prefers a moist, acidic soil with lots of organic matter, which is precisely what most of us already have, assuming we add some additional compost — which should be an annual ritual anyway.
Since the flowers are produced on the current season’s wood (what we call “new wood”) much like a rose, we can prune it hard in the spring, if we want to keep it contained. Hummingbirds and butterflies are drawn to the flowers, while deer seem to ignore them.
Here are three varieties currently available in your local nursery that you might want to consider:
“Vanilla Spice”: This selection has flowers roughly twice the size of other varieties. Large, fragrant spires of white flowers show up in late July and continue for four to five weeks. Plant one in full sun, and you are bound to see a few swallowtail butterflies visiting them on a warm summer day.
“Hummingbird”: This is a very popular variety that is more compact, topping out at only 3- to 4-feet tall. The dark, glossy green leaves are a nice backdrop for the bright white flowers. As the name implies, hummers (and butterflies) will seek this one out in your garden.
“Ruby Spice”: Possibly my favorite, this has the darkest pink flowers of any of the Clethras. Everything else about this variety is pretty much the same as the others.
Summer-blooming shrubs are so critical to our pollinator populations that all of us should have several in our gardens. Summersweet easily falls into this category, along with roses, hydrangeas and probably one of the latest blooming shrubs for us, the hardy hibiscus, or “Shrub Althea” or “Rose of Sharon.” You can find all of these in garden centers this time of year.
Steve Smith is the owner of Sunnyside Nursery in Marysville and can be reached at firstname.lastname@example.org.