Polygonum aviculare
Polygonaceae
Common Knotweed
Prostrate stems to 2 ft. long from central stem. Plant hairless. Stems round, branched. Leaves bluish green, lance-shaped. Clusters of 1–5 flowers arise from leaf axils. Flower petals greenish with red or pink edges, united into tube halfway, then spreading. Grows in gardens, dry gravel, edges of concrete, roadsides, disturbed soils. Tolerant of compaction. Very similar P. arenastrum has larger green flowers with white or pink edges and linear leaves.
- Rarity: Common
- Flowering Time: Early Spring, Mid Spring, Late Spring, Early Summer, Mid Summer, Late Summer, Autumn
- Life Cycle: Annual, Perennial
- Height: Prostrate
- Habitat: Disturbed
- Found In: Mt. Rainier NP, N Cascades NP, Olympic NP, Siskiyous, Wallowas
- Native: No
- Also Known As: Yard Knotweed, Doorweed
