Comprehensive DescriptionRead full entry
General: Madder Family (Rubiaceae). Common buttonbush is a warm-season shrub or small tree that reaches 6 m in height at maturity. Stem bases are swollen. Young twigs are green, 4-sided with elongated lenticels, and turn brown and scaly upon maturation. Leaves are opposite or whorled, lance-shaped, 18 cm long and 7.5 cm wide, glossy dark green, and emerge in May. Flowers are tubular, 4- to 5-lobed, white to reddish, 4 cm across, and form in dense clusters at the ends of the branches. Long styles give flowers a pincushion appearance. The fruit are ball-like and contain 2-seeded nutlets. Common buttonbush blooms in June through September and sets fruit in September and October.
Key characteristics of common buttonbush are its pincushion flower heads, elongated lenticels, and swollen stem bases. It is also the only wetland shrub that has whorled leaves and spherical-shaped flowers.
Distribution: Common buttonbush is native to North America. It occurs from Nova Scotia to Ontario, south through Florida, and west to the eastern Great Plains with scattered populations in New Mexico, Arizona, California, and northern Mexico. For current distribution, please consult the Plant Profile page for this species on the PLANTS Web site (http://plants.usda.gov).
Habitat: Common buttonbush is a wetland shrub common in swamps, floodplains, marshes, bogs, ditches that are underwater for part of the year, and alluvial plains with intermittent flooding. It is present in riparian and wetland communities and is associated with plants like American beech, red maple, sugar maple, black oak, pin oak, Nyssa species, bald cypress, southern bayberry, red bay, holly, dogberry, grape, viburnum, poison ivy, Indian grass, big bluestem, switchgrass, and sedges.