Common names: Himalayan knotweed
Persicaria wallichii (Himalayan knotweed) is a perennial herb/ (family Polygonaceae) with white flowers and narrow leaves found in the north and central coast ranges of California. It is native to south-central Asia. It favors grasslands, wetlands, bog and marsh, and riparian and bottomland habitat. It spreads via small fragments that form new plants. Means of dispersal include wind, water, animals and humans.Cal-IPC Rating: Watch
Plant Risk Assessment
Plant Risk Assessment- An evaluation of the potential for a plant to be invasive in California.
Cal-IPC Newsletter Articles
- Eradicating knotweeds and other new invaders on California’s North Coast. Eberwein, Amy. Vol 24, Issue 3
- Japanese knotweed (Polygonum cuspidatum) and other knotweeds. Brusati, Elizabeth. Vol 13, Issue 1
Cal-IPC Symposium Presentations
None for this species.
Other Persicaria wallichii Information
- CalFlora - Distribution information based on submitted observations and herbarium specimens.