When it comes to outstanding summer flowering shrubs for PNW gardens, one should not overlook the genus Clethra. Clethra is a genus of about 75 species, mostly native to south and east Asia and the Americas. It is one of two genera in the Clethraceae, which is closely related to the Ericaceae (Heather family). They prefer lime-free soil and produce white, fragrant flowers in long racemes or panicles in July or August. I just spent a week exploring a Carolinian forest back in SW Connecticut enjoying the native sweet scented Clethra alnifolia, commonly named Summersweet or Sweet Pepperbush. Upon returning to Seattle, I made an easy decision to refamiliarize myself with our Clethra collection and choose one to feature for this post. It did not take me long to choose my personal favorite, Clethra fargesii, once I saw the spectacular bark on our specimen located outside the Japanese Garden, along the sidewalk plantings adjacent to Lake Washington Blvd.
The stunning Clethra fargesii, a.k.a. Chinese Clethra, is native to Central China prefers partial shade and moist woodland soil conditions for peak flowering and fall color performance. Our specimens could use more summer water, as they were quite sparse of inflorescenses, and none were still in flower.
I can’t wait for leaf peeping season either, as I’ve read this plant turns a rich yellow color.
The only drawback of this beautiful clethra that I have found is it’s lack of availability on the PNW nursery market. However, it can be purchased at Woodlanders Nursery in South Carolina.
Common Name: Chinese Clethra (English); cheng kou qi ye shu (Chinese)
Location: 3 specimens @ Washington Park Arboretum; Accessions 280-61*B & C located on map grid 15-2E and 307-42*A on map grid 3-1W.
Use our interactive map link to pin-point specimen locations.
Origin: Central China – Eastern Sichuan, western Hubei and parts of Guizhou, Hunan and Jiangxi provinces @ 4,000 to 7,800 ft. Introduced in 1900 by Ernest Wilson.
Height and Spread: 10′ x 6′ (mature)
Bloom Time: Summer – July through August