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.
This plant is present in at least 43 states/provinces in this country.
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.
Acer rubrum (aka: Red maple, Scarlet maple)
Ulmus americana (aka: American elm, White elm, Water elm, Soft elm, Florida elm)
Salix nigra (aka: Black willow, Swamp willow, Southwestern black willow, Gulf black willow, Scythe-leaved willow)
Acer saccharinum (aka: Silver maple, Soft maple)
Cercis canadensis (aka: Eastern redbud, Redbud, Cersis Reniformis)
Prunus americana (aka: American plum, Goose plum, River plum, Wild plum)
Malus angustifolia (aka: American crab apple, Buncombe crab apple, Crabtree, Narrowleaf crab, Narrowleaf crab apple, Southern crab, Southern crab apple)
Aronia arbutifolia (aka: Red chokeberry)
Amelanchier arborea (aka: Common serviceberry, Downy serviceberry, Juneberry, Shadbush, Shadblow, Sugarplum)
Prunus serotina (aka: Black cherry, Wild black cherry, Rum cherry, Mountain black cherry, Wild cherry)
Acer negundo (aka: Boxelder, Western boxelder, Arizona boxelder, California boxelder, Texas boxelder, Interior boxelder, Violet boxelder)
Celtis laevigata (aka: Hackberry, Sugarberry, Lowland hackberry, Sugar hackberry, Arizona sugarberry, Netleaf hackberry, Small's hackberry, Southern hackberry, Texas sugarberry)
Pyrus communis (aka: European pear, Common pear)