Polygonum bidwelliae

Bidwell's knotweed

Family: Polygonaceae · Type: annual · Native

Conservation status: CNPS 4.3

Bidwell's knotweed is a California native annual found in northern California's Butte, Tehama, and Shasta counties in volcanic chaparral, montane woodland valleys, and grasslands at elevations of 60 to 1,200 meters. Flowering from May to June, this delicate plant produces small pink flowers with white margins, each blossom nestled discretely in the plant's upper leaf axils. Growing with slender, wiry green stems 2 to 20 centimeters tall that are minutely rough-textured and slightly angled, the plant forms a compact, sparse structure. Its narrow linear leaves are remarkably small, measuring 5 to 15 millimeters long and less than 2 millimeters wide, with tightly rolled margins and spine-tipped ends that create a distinctive fine-toothed appearance. The fruits are shiny light-brown to brown, small ovate-elliptic structures that remain enclosed within the plant's delicate structure.

Habitat: Thin volcanic soils, chaparral, montane woodland valleys, grassland

Bloom period: May-Jun

Elevation: 60-1200 m

Bioregions: CaR (Butte, Tehama, Shasta cos.), ne ScV (Butte Co.).

California counties: Butte, Shasta, Tehama

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