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.Rating: Watch
- Plant Risk Assessment - An evaluation of the potential for a plant to be invasive in California.
- Cal-IPC News - Our quarterly newsletter. Each issue is available as a pdf.
- Cal-IPC Symposium Proceedings - Presentations and papers from our annual Symposium.
- Don't Plant a Pest! - Select your region to find non-invasive alternatives to ornamental species. Also see our statewide brochure on trees.
None for this species.