Family: Polygonaceae
Origin, Description & Uses
Persicaria chinensis (Chinese knotweed) is a sprawling to climbing perennial plant native to tropical and subtropical Asia. It produces slender stems that can root at nodes, with glossy green leaves and small white to pinkish flowers followed by bright red, berry-like fruits. Often introduced as an ornamental groundcover or medicinal plant, it has also been used in traditional herbal practices in parts of its native range. Its vigorous growth habit allows it to quickly spread across soil surfaces and climb over nearby vegetation, forming dense mats in favorable conditions.
Risks & Threats
In Hawaiʻi, Chinese knotweed is naturalized on Oʻahu and Hawaiʻi Island and exhibits traits that are cause for concern, including rapid vegetative spread, strong adaptability, and the ability to smother low-growing vegetation. These characteristics allow it to outcompete native understory plants and alter habitat structure in tropical island ecosystems. Because it can spread aggressively in both disturbed and natural areas, this species could detrimentally impact Hawaiʻi’s ecosystems if left unmanaged. Choosing a low-risk or native alternative is recommended when available to help protect native biodiversity and prevent further spread.
High Risk Traits:
- Broad climate suitability (up to 3300m elevation)
- Native or naturalized in tropical/subtropical regions
- Naturalized in Hawaii (agricultural/disturbed areas)
- Weed of tea crops in India
- Congeneric weed
- Unpalatable to grazing animals
- Climbing or smothering growth habit
- Reproduces by viable seed
- Propagules dispersed unintentionally (contaminant of agriculture)
- Propagules dispersed intentionally (medicinal/edible uses)
- Bird-dispersed seeds
- Seeds survive gut passage
- Tolerates herbicides (can be controlled, but implies persistence)
Low Risk Traits:
- No spines, thorns, or burrs
- Non-toxic to animals or humans (used as medicine/food)
- No adaptation for wind or water dispersal
- No external animal attachment
