Polygonum sawatchense

Knotweed

Family: Polygonaceae · Type: annual · Native

Knotweed is a California native annual found in rocky or disturbed habitats at elevations from 1,500 to 2,500 meters. Flowering from July to September, this plant produces tiny green to reddish-purple flowers with white or pink margins, clustered in spike-like inflorescences. Growing with erect stems 10 to 40 centimeters tall, the plant has slender green to brownish stems that are slightly angled and sometimes papillate-scabrous. Its narrow linear to oblanceolate leaves are 8 to 45 millimeters long, with margins rolled under or flat and acute tips. The small black, shiny fruits are elliptic and nestled within the plant's flower clusters.

California counties: Alpine, Lassen, Plumas, Tulare, Shasta, Tuolumne, Mono, Trinity, San Bernardino, Fresno, Siskiyou, Ventura, Riverside, Sierra, Inyo, Modoc

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