Buttonbush, Cephalanthus occidentalis, is a somewhat coarse, deciduous shrub with an open-rounded habit that typically grows 6-12 feet tall. It is common in wet open areas, low woods, thickets, swamps, upland sink-hole ponds, river bottomland and stream/pond margins . Ovate to elliptic glossy bright green are in pairs or whorls. Leaves emerge late in spring. Tiny, tubular, 5-lobed, fragrant white flowers appear in dense, spherical, long-stalked flower heads in early to mid-summer. Long, projecting styles give the flower heads a distinctively pincushion-like appearance. The blooming period occurs during the summer and lasts about 1 month. The flowers are sweetly fragrant. Afterwards, the flower heads are replaced by spherical seed heads that turn red and eventually dark brown at maturity. Each flower is replaced by a small dry fruit that is narrowly obpyramidal (like a narrow upside-down pyramid). This fruit contains 2 cells, each cell containing a single seed (occasionally, one of the cells is empty). The root system is branching and woody.
Habitats include openings in floodplain forests, vernal pools in wooded areas, wet thickets, shrubby swamps, wet depressions in black soil prairies, marshes, bogs, seeps, seasonal wetlands, and borders of rivers and small lakes. This shrub can form extensive colonies at some locations.
Easily grown in moist, humusy soils in full sun to part shade. Grows very well in wet soils, including flood conditions and shallow standing water. Adapts to a wide range of soils except dry ones.
May also be grown in shallow water at the edge of ponds or large water gardens.
Flower heads are very attractive to hummingbirds, butterflies, and other insect pollinators.
Pruning is usually not necessary, but may be done in early spring to shape. If plants become unmanageable, however, they may be cut back near to the ground in early spring to revitalize.