Family: Fabaceae

Origin, Description & Uses:
Neonotonia wightii (glycine, perennial soybean) is a vigorous climbing or trailing legume native to tropical and subtropical regions of Africa, the southwestern Arabian Peninsula, India, and Sri Lanka. It is a fast-growing perennial vine with trifoliate leaves and small purple to whitish flowers, followed by seed pods typical of the legume family. Because of its ability to fix nitrogen in the soil, it has been widely introduced in tropical regions as a forage plant for livestock and as a cover crop to improve soil fertility and prevent erosion.

Risks & Threats:
In Hawai‘i, Neonotonia wightii is naturalized on Kaua‘i, O‘ahu, Maui, Moloka‘i, Lāna‘i, Kaho‘olawe, and Hawai‘i Island and threatens at least seven rare or endangered plant species. This species spreads aggressively through both seed and vegetative growth, allowing it to form dense mats that smother native vegetation and compete for light, space, and nutrients. It possesses traits that are cause for concern, including rapid growth, high reproductive output, and adaptability to a range of habitats. As a naturalized high-risk species, it could detrimentally impact tropical island ecosystems by displacing native plants, altering habitat structure, and disrupting ecosystem balance, making careful management and prevention of further spread important.

High Risk Traits:

• Elevation range exceeds 1000 m, demonstrating environmental versatility
  
• Thrives in tropical climates
  
• Widely naturalized outside native range
  
• Disturbance-adapted weed with negative environmental impacts
  
• Host for crop pathogens
  
• Tolerates many soil types
  
• Smothers other vegetation
  
• Reproduces by seeds and vegetatively at nodes
  
• Self-compatible
  
• Seeds dispersed by animals (internally), intentionally by people, secondarily by water and as a contaminant of soil, garden waste or other fodder
  
• Able to reach maturity quickly (in 12 months)
  
• Prolific seed production
  
• Hard-coated seeds capable of forming a persistent seed bank (longevity unknown)
  
• Intolerant of heavy grazing, but tolerates fire

Low Risk Traits:

• Unarmed (no spines, thorns or burrs)
  
• Provides fodder for livestock
  
• Non-toxic
  
• Shade reduces productivity (thrives in high light environments)
  
• Herbicides may provide effective control