Polygonaceae
Polygonum douglasii

Douglas's Knotweed

Erect hairless annual, long upright branches angled just below joints. Stem covering at joints raggedly torn at tip. Leaves long and narrow to oval, never round. Flowers 1–4 per node, with short stalks; petals reflexed in fruit, small, green or pink, with red or white edges. Some flowers never open; others open wide. Plants on serpentine lose leaves before flowering, others just after flowering. Grows in open dry meadows, slopes, at mid- to high elevations. Subsp. majus (pictured) flowers open wider than those of the species. Subsp. spergulariiforme is erect, with leaves that fall before flowering, and grows in rocky places such as serpentine. Subsp. johnstonii is erect, with leaves that persist through flowering, and grows into subalpine areas.

  • Rarity: Common
  • Flowering Time: All Summer
  • Life Cycle: Perennial
  • Height: 8--16 inches
  • Habitat: Meadow, West-Side Forest, East-Side Forest, Shrub-Steppe, Subalpine
  • Found In: Mt. Rainier NP, Siskiyous, Steens, Wallowas, Crater Lake NP, Olympic NP, N Cascades NP
  • Native: Yes