Spice bush (Calycanthus occidentalis), like so many shrubs, is unspectacular and difficult to identify when not in flower. So I was very excited when earlier this month Leonard and I found spice bushes in bloom along Fender’s Ferry Road in the Shasta Trinity National Forest (Shasta County CA).
Spice bush grows along streams and on moist canyon slopes in the Northern California foothills at altitudes between 600 and 3,500 feet. This shrub, also commonly known as western sweetshrub, is considered native to and endemic in California, although some references report a few isolated colonies in Washington State.
The bark of spice bush, which can grow up to 12 feet in height, is brown and smooth. Leaves are opposite, deciduous and emit a pleasant fragrance when crushed. They have one main vein, short petioles (stalks) and are hairless and broadly lance-shaped.
Spice bush flowers are short-lived, surviving only one or two days. Occurring singly at the ends of branches, these flowers are reddish and as they age the upper third turns brown. The numerous sepals and petals are linear and both are the same color. Numerous stamens surround the 15 to 20 pistils with superior ovaries in an urn-shaped receptacle. At maturity the urn-shaped receptacle contains many velvety brownish achenes (dry seeds).
Indigenous Californians used spice bush for medicinal purposes as well as basket weaving and arrow shafts. Today calycanthus oil is distilled from spice bush flowers and used in perfumes. Stockmen believe spice bush is responsible for the death of cattle, however, cattle are reported to seldom graze this shrub.
Another species of spice bush grows in Eastern United States and there are closely related genera in China. This separated pattern suggests that spice bush might be a relict plant that once had a much larger range.
The genus name, Calycanthus, derives from the Greek “kalyx” meaning covering and “athos” meaning flower and refers to the urn-shaped receptacle.