'Ruby Spice' Clethra: Shrub of the Week

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The other day at the College of Wooster, their horticulturist Phil Olsen was showing the new landscape that Phil, grounds manager Beau Mastrine and his fellow grounds maintenance group had designed and installed near the Ruth W. Williams Science Building. The ‘Ruby Spice’ clethra is the perfect mid-summer shrub: wonderfully aromatic, and with its ruby and soft pink flowers in a great layered planting with the taller salmon-colored flowers of Joe-Pye weed and a dwarf burgundy-leaved Japanese maple, the design pleased the eye. 


Clethra planting at the College of Wooster in Ohio
Clethra 'Ruby Spice' planted between Joe-Pye weed and Japanese maples at the College of Wooster


Ruby Spice clethra flowers
Opening blossoms of 'Ruby Spice' clethra


Clethra flowers
Ruby-colored buds open to soft pink on 'Ruby Spice' clethra


Overall effect of 'Ruby Spice' clethra flowers
Pollinator visits the clethra.  This is a great pollinator plant for butterflies and other pollinators.  


Clethra alnifolia, also known as summersweet and sweet pepperbush, is an Eastern U.S. native that thrives in moist sites and tolerates clay soils. The small candle-like upright panicles of the Ruby Spice’ cultivar has pinkish-white flowers attractive to butterflies and other pollinators, and is a little smaller (maybe 4’ by 4’) than the straight species. New spring foliage and fall foliage is an attractive yellow while summer foliage is a lustrous green. Remnant fruits are attractive in the fall and winter landscape.  Plant near a patio and you will be duly rewarded with customer satisfaction for the sweet aromas added to summer cookouts.


Early spring foliage of clethra
Remnant fruits and early spring foliage of clethra on the High Line in New York City


clethra at Walden Pond
Clethra fruits at Walden Pond in the Fall



Classification: Clethra  was named by Linnaeus in 1753 and was later classified in the Clethraceae family, with one other genus Purdiaea.  The bell-like blossoms remind me a bit of the Ericaceae family (heaths and azaleas, blueberries and pieris), and it turns out that both Clethraceae and Ericaceae are in the Ericales order (An order is a group of related families). 


Clethra and Glass Flower Exhibit at Harvard
Check out the Glass Flower exhibit at Harvard. Clethra is one of thousands on display


Rising Sun redbud
Phil Olsen with his newly installed 'Rising Sun' redbud at the College of Wooster