Cephalanthus occidentalis is a species of flowering plant in the coffee family, Rubiaceae, that is native to eastern and southern North America. Common names include Buttonbush, Common Buttonbush, Button-willow and Honey-bells.
C. occidentalis is a deciduous shrub or small tree that averages 1–3 m (3.3–9.8 ft) in height, but can reach 6 m (20 ft). The leaves are opposite or in whorls of three, elliptic to ovate, 7–18 cm (2.8–7.1 in) long and 4–10 m (13–33 ft) broad, with a smooth edge and a short petiole. The flowers are arranged in a dense spherical inflorescence 2–3.5 cm (0.79–1.4 in) in diameter on a short peduncle. Each flower has a fused white to pale yellow four-lobed corolla forming a long slender tube connecting to the sepals. The stigma protrudes slightly from the corolla. The fruit is a spherical cluster of achenes (nutlets).
There are two varieties, not considered distinct by all authorities:
Cephalanthus occidentalis var. occidentalis (syn. var. pubescens) – Common Buttonbush. Eastern North America from Nova Scotia west to Minnesota and south to Florida and eastern Texas.
Cephalanthus occidentalis var. californicus – California Button-willow. Southwestern North America, from western Texas west to California (Sierra Nevada foothills, San Joaquin Valley, Sacramento Valley, and the Inner North Coast Ranges) and south to Mexico and Central America.
Buttonbush is a common shrub of many wetland habitats in its range, including swamps, floodplains, mangrove, pocosin, riparian zones, and moist forest understory. It is a member of the flora in the Everglades
Waterfowl and other birds eat the seeds. Wood Ducks utilize the plant as nest protection. Deer browse the foliage. Insects and hummingbirds take the nectar, with bees using it to make honey
The species occurs in eastern North America with disjunct populations occurring in the west. In Canada, it occurs from southern Ontario and Quebec east to New Brunswick. Besides the eastern United States, and eastern regions of the Midwest, notable areas range into Arizona, the Mogollon Rim, and other mountain ranges; in California, the entire San Joaquin Valley West of the Great Plains and the Rocky Mountains, only western Texas, Arizona, and California find C. occidentalis.
C. occidentalis has a number of historical medicinal uses, but it is also toxic due to the presence of cephalathin
Buttonbush is cultivated as an ornamental plant for a nectar source or 'honey plant' and for aesthetics in gardens and native plant landscapes, and is planted on slopes to help control erosion.
San Joaquin Valley landmark tree
The town of Buttonwillow, California was named for the Buttonbush (Cephalanthus occidentalis). A lone buttonbush served as a landmark on an old trans-San Joaquin Valley trail, and was used by ancient Yokut Indians as a meeting place. It later became the site of settlers' stock rodeos. This buttonbush tree is listed as California Historical Landmark No. 492, and is now known as the "Buttonwillow Tree.
Button bush was often employed medicinally by native North American Indian tribes who used it to treat a range of ailments. It is little used in modern herbalism. A tea made from the bark is astringent, emetic, febrifuge and tonic[61, 222]. A strong decoction has been used to treat diarrhoea and dysentery, stomach complaints, haemorrhages etc. It has been used as a wash for eye inflammations. A decoction of either the roots or the fruits have been used as a laxative to treat constipation The leaves are astringent, diaphoretic, diuretic and tonic[61, 222]. A tea has been used to check menstrual flow and to treat fevers, kidney stones, pleurisy etc. The plant has a folk reputation for relieving malaria. The inner bark has been chewed in the treatment of toothaches.