Family: Apocynaceae

Allamanda blanchetii (purple allamanda) is a striking, fast-growing ornamental vine or shrub valued for its vibrant purple trumpet-shaped flowers. Native to Brazil, it thrives in tropical and subtropical climates, preferring full sun and well-drained soils. In the Hawaiian Islands, this species is currently only found in cultivation in gardens, landscapes, and as decorative hedges. Its dense foliage and rapid growth make it an attractive choice for adding color and privacy to residential areas.

Although not currently naturalized in Hawaii, caution is advised as Allamanda blanchetii has the potential to escape cultivation and establish in unmanaged areas. Its vigorous growth and ability to root from cuttings could allow it to spread into natural habitats, potentially competing with native plants. Gardeners are encouraged to monitor its growth, avoid planting near natural areas, and responsibly manage garden waste to prevent accidental spread.

High Risk Traits:

• Thrives in tropical climates
  
• Naturalized in Australia and possibly Antigua, West Indies
  
• Reported as a weed in Australia and Antigua, West Indies, but no negative impacts described
  
• Other Allamanda species have become invasive
  
• Sap toxic to animals and people
  
• Toxic sap likely reduces palatability
  
• Scrambling, potentially smothering, growth habit
  
• Seeds, when produced, dispersed by wind and intentionally by people
  
• Suckers profusely (can become problematic in gardens)
  
• Tolerates repeated pruning

Low Risk Traits:

• Unarmed (no spines, thorns or burrs)
  
• Ornamental
  
• Self-incompatible
  
• Reaches maturity in 4+ years (but able to spread vegetatively)
  
• Limited seed set in cultivation makes long-distance or accidental dispersal unlikely