knotweed
Persicaria polymorpha
USDA zones4 to 9
SunHandles full sun or partial sun or full shade
WaterHandles dry to moist soil
Size3 to 5 feet tall3 to 4 feet wide
- Bloom season
- Summer, autumn
- Bloom color
- White
- Soil types
- Sand, loam, clay, chalk
- Soil pH
- Acid, alkaline, neutral
Garden uses
Notes
Knotweed (Persicaria polymorpha) is a perennial for borders, naturalized areas, and low maintenance gardens. It is hardy to USDA zone 4, or down to -30°F (-34°C). This plant likes full sun to full shade and dry to moist soil of most types. It grows in an arching vase shape with astilbe-like masses of white flowers from summer into fall. Pinkish seed heads follow the blooms. Deer rarely make it their first choice.
Pairs well with Hardy geranium, Ostrich fern, and Sedge.
Native range
China and Japan.