Distribution: Occurring chiefly west of the Cascades crest in Washington; British Columbia to Mexico and South America, east across North America to the Atlantic coast.
Habitat: Moist to swampy areas, often growing in mud, from the lowlands to the lower mountain valleys.
Flowers: July-September
Origin: Native
Growth Duration: Perennial
Conservation Status: Not of concern
Pollination: Bees, flies
Herbaceous perennial, up to 1 m. tall, usually decumbent and tending to root freely.
Leaves numerous on short petioles, alternate, scarcely reduced upward, lanceolate to oblong-lanceolate with an acute base, 5-12 cm. long; sheathing stipules 1-2 cm. long with bristly hairs around the top.
Inflorescence of 2 or more spike-like, interrupted racemes; perianth greenish to white or pinkish, 2.5-3 mm. long, 5-lobed half the length, the segments oblong and sub-equal; stamens 8 with short filaments
Achene with three sharp angles, black, smooth and shining, about 3 mm. long.
PNW Herbaria: Specimen records of Persicaria hydropiperoides in the Consortium of Pacific Northwest Herbaria database
WA Flora Checklist: Persicaria hydropiperoides checklist entry
OregonFlora: Persicaria hydropiperoides information
E-Flora BC: Persicaria hydropiperoides atlas page
CalPhotos: Persicaria hydropiperoides photos