Polygonum majus

Wiry knotweed, Wiry Knotweed

Family: Polygonaceae · Type: annual · Native

Wiry knotweed is a California native annual found in the Klamath Ranges, northern Coast Ranges, Cascade Range, Sierra Nevada, and southern Baja Mountains in dry plains and meadows at elevations of 500 to 2,000 meters. Flowering from June to September, this plant produces white or pink flowers in small clusters, with delicate blooms 4 to 5 millimeters long. Growing with erect, wiry green stems 15 to 60 centimeters tall that are slightly angled and papillate-scabrous, it has a distinctive slender form. Its narrow leaves are lance-linear to oblong, 15 to 70 millimeters long, with margins rolled under and fine papillate teeth. The fruit is a small, shiny black elliptic seed 3.5 to 5 millimeters long.

Habitat: dry plains, meadows, serpentine or not

Bloom period: Jun-Sep

Elevation: 500-2000 m

Bioregions: KR, NCoR, CaR, SN, SnBr, w MP

California counties: El Dorado, Humboldt, Shasta, Siskiyou, Kern, Napa, Alpine, Plumas

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