Family: Polygonaceae

Origin, Description & Uses:
Pleuropterus multiflorus (commonly known as Chinese knotweed or fo-ti) is native to China, northern Indo-China, and Taiwan. It is a vigorous, twining perennial vine that can climb over shrubs and trees, forming dense mats of foliage. The plant produces heart-shaped leaves and clusters of small white to greenish flowers, followed by small seed-bearing fruits. In its native range, it is widely known in traditional Chinese medicine (as “He Shou Wu” or fo-ti) where its roots are used in herbal preparations, often promoted for a variety of health and longevity-related purposes. It is also occasionally grown as an ornamental vine in gardens for its fast growth and ability to cover trellises or fences.

Risks & Threats:
Although Pleuropterus multiflorus is currently not known to be naturalized in the Hawaiian Islands, it does possess traits that are cause for concern, and which could detrimentally impact tropical island ecosystems. Its rapid growth, climbing habit, and ability to form dense vegetation can allow it to smother and outcompete native plants, especially in disturbed areas or forest edges. It may also spread through both seed and vegetative fragments, increasing the risk of escape from cultivation and establishment in natural areas. Additionally, its popularity in herbal medicine increases the likelihood of intentional planting and repeated introductions. In some cases, fo-ti has also been associated with toxicity concerns in humans when improperly used, highlighting the need for caution in handling and cultivation. Given these characteristics, continued evaluation is warranted, and prevention of establishment is important. When possible, choosing low-risk or native alternatives is recommended to help protect Hawaii’s vulnerable island ecosystems.

High Risk Traits:

• Thrives in tropical climates
  
• Elevation range exceeds 1000 m
  
• Widely cultivated and naturalized in Japan, Taiwan and Vietnam, and to a lesser extent in Laos and Thailand
  
• Aggressive growth in garden settings
  
• Related species are invasive
  
• Shade-tolerant
  
• Climbing and smothering habit
  
• Spreads by seeds and vegetatively
  
• Reaches maturity in 2 years
  
• Wind-dispersed
  
• Resprouts from rhizomes after removal of above ground vegetative material

Low Risk Traits:

• Not documented to be an environmental weed
  
• Unarmed (no spines, thorns or burrs)
  
• Edible and medicinal uses