Family: Fabaceae

Origin, Description & Uses
Wisteria floribunda (Japanese wisteria) is a deciduous, woody vine in the pea family native to Japan. Renowned for its spectacular, fragrant cascades of purple to violet flowers that bloom in spring, it is widely cultivated as an ornamental for arbors, pergolas, trellises, and fences. This vigorous climber twines clockwise around supports and can grow to great lengths, often reaching into tree canopies. Its attractive compound leaves and long lifespan make it a favorite landscape plant in temperate regions, where it is valued for its dramatic floral displays and shade-providing qualities.

Risks & Threats
Although Wisteria floribunda is not currently known to be naturalized in the Hawaiian Islands, it possesses several traits associated with invasive plants and is considered a high-risk species. It spreads by both seed and vegetative growth, forming dense, tangled masses that can overwhelm surrounding vegetation. Its heavy vines are capable of girdling trees, climbing into forest canopies, and smothering native plants, resulting in reduced biodiversity and altered ecosystem structure. These characteristics could detrimentally impact tropical island ecosystems if the species were to escape cultivation. Because of these risks, it is recommended that gardeners and landscapers choose a low-risk or native alternative whenever suitable options are available.

High Risk Traits:

• Naturalized and invasive outside native range
  
• Forms dense, ecosystem-altering thickets
  
• Congeneric species are invasive
  
• Toxic to humans and animals
  
• Tolerates shade
  
• Climbing, smothering growth habit
  
• Nitrogen-fixing capability
  
• Reproduces vegetatively via stolons
  
• Intentionally propagated as an ornamental
  
• Seeds dispersed by water
  
• Resprouts after damage

Low Risk Traits:

• Not naturalized in tropical climates
  
• Not an agricultural weed
  
• Lacks spines, thorns, or burrs
  
• Long juvenile period (slow to mature)
  
• Seeds not adapted for wind dispersal
  
• Seeds not dispersed by birds or animals
  
• Susceptible to herbicide control