Polygonum aviculare subsp. aviculare

Family: Polygonaceae · Type: annual · Not Native

Knotweed is a naturalized annual plant found in California in disturbed places, roadsides, and cultivated fields at elevations below 2,000 meters. Flowering from May to November, this plant produces small green flowers with white to red margins. Growing with ascending or erect stems 10 to 75 centimeters tall that have widely spreading basal branches, it forms low-spreading patches in open areas. Its leaves are elliptic to oblanceolate, 18 to 50 millimeters long and 10 to 20 millimeters wide, with acute or obtuse tips. The fruit is dark brown, three-angled, and approximately 3 millimeters long.

Habitat: Disturbed places, roadsides, cultivated fields

Bloom period: May-Nov

Elevation: < 2000 m

Bioregions: CA

Data from The California Species Project — 14,000+ California species with verified data from CNPS, CDFW, USFWS, Jepson eFlora, Cal-IPC, and more.