According to observations of naturalists and beekeepers.
Where are you?
SOURCE FOR HONEY BEES:
Minor in most areas
Common buttonbush's distribution extends from southern Nova Scotia, New Brunswick, Quebec, and Ontario south through southern Florida and west through the eastern half of the Great Plains States. Scattered populations exist in New Mexico, Arizona, and the Central Valley of California.
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 cm (1.6–3.9 in) broad, with a smooth edge and a short petiole. The flowers are arranged in a dense spherical inflorescence 2–3.5 cm (0.79–1.38 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).
Common buttonbush flowers between June and September and produces fruit between September and October.