Polygonum bolanderi

Bolander's knotweed

Family: Polygonaceae · Type: perennial · Native

Bolander's knotweed is a California native perennial herb found in northwestern California, especially Napa County, the California Ranges, and northern and central Sierra Nevada in open, dry, gravelly, rocky places at elevations of 300 to 1,500 meters. Flowering from June to November, this plant produces delicate white or pink flowers less than 4 millimeters long, with lobes that are elliptic-oblong and slightly recurved. Growing with erect, wiry stems 20 to 60 centimeters tall that become gnarled with age, it develops a distinctive branching pattern. Its leaves are crowded near the stem tips, extremely narrow and linear, measuring just 3 to 15 millimeters long and less than 2 millimeters wide, with spine-tipped margins. The fruit is a small, shiny light-brown structure that remains enclosed within the flower's perianth.

Habitat: Open, dry, gravelly, rocky places

Bloom period: Jun-Nov

Elevation: 300-1500 m

Bioregions: NW (esp Napa Co.), CaR, n&ampc SN.

California counties: Napa, Tehama, Butte, Shasta, Humboldt, Tuolumne, Solano, Sonoma, El Dorado, Placer, Lake, Glenn, Calaveras, Mariposa

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