The Genus Frangula
Buckthorn
Family: Rhamnaceae
Deciduous shrubs growing to 10’ tall or more and about as wide. Greenish white flowers in summer become reddish to black fruits in fall.
Part to full sun in the low desert (definitely avoid reflective heat), regular water, hardy to 10°F.
Larval food plant for the spring azure (Celastrina ladon), gray hairstreak (Strymon melinus), the Rocky Mountain silkmoth (Agapema homogena), and various owlet moths (family Noctuidae). The fruits of coffeeberry are extensively utilized by numerous wildlife species, particularly birds.
Coffeeberry bark is a popular herbal remedy for chronic constipation. The berries, leaves, and bark are all used medicinally, internally and externally by many people. The berries are edible—Frangula californica is more enjoyable than F. betulifolia.
There are about 56 species around the world, 2 in Arizona. The genus name, Frangula, is thought to mean fragile, referring to the brittle twigs of the European species.
Photo of Rhamnus betulifolia by jmotsinger on iNaturalist
Frangula californica is found in chaparral, coniferous forests, and along riparian areas from 3,500-6,500’ in mountains along the coast (from the southwest tip of Oregon down to Baja California, and in the Sky Islands of Arizona and New Mexico into Sonora.
Frangula betulifolia is found usually in higher elevations on stream or creek banks from 4,500-9,000’ in Utah, Arizona, New Mexico, the southern tip of Nevada, into northern Mexico.
California Buckthorn (Frangula californica) is the lower elevation species, photo by Max Licher, SEINET
In Arizona Birchleaf Buckthorn (Frangula betulifolia) usually grows in the shade of trees even in the mountains, photo by Eric Hough, iNaturalist