Distribution: Occurring on both sides of the Cascades crest in Washington; southern British Columbia to California, east across North America to the Atlantic Coast.
Habitat: Shores of ponds, lakes, backwater channels, and other wetland areas at low elevations, often where disturbed.
Flowers: June-October
Origin: Native
Growth Duration: Annual
Conservation Status: Not of concern
Pollination: Bees, flies, beetles, wasps
Annual, nearly glabrous throughout, 2-12 dm. tall.
Leaves with petioles 1-6 cm. long, pinnately compound, with 3-5 lanceolate, pointed, serrate leaflets up to 10 cm. long and 3 cm. wide.
Heads without rays, the disk about 1 cm. wide; outer involucral bracts 5-8, green and leafy, surpassing the orange disk.
Achenes flat, narrowly wedge-shaped, dark brown, 5-10 mm. long, with persistant pappus of 2 barbed awns.
The leaves of Bidens frondosa have long, slim petioles, while the similar B. tripartita has leaves with winged petioles.
Publication: Sp. Pl. 2: 832. 1753.
PNW Herbaria: Specimen records of Bidens frondosa in the Consortium of Pacific Northwest Herbaria database.
WA Flora Checklist: Bidens frondosa checklist entry.
OregonFlora: Bidens frondosa information.
E-Flora BC: Bidens frondosa atlas page.
CalPhotos: Bidens frondosa photos.
USDA Plants: Bidens frondosa information.
