Family: Acanthaceae

Origin, Description & Uses
Strobilanthes hamiltoniana is a large, ornamental flowering shrub native to the Himalayan region, ranging from central Nepal and southeastern Tibet to northern Thailand. It is valued for its attractive foliage and showy spikes of purple to violet flowers, which make it a popular choice for tropical and subtropical gardens. This species can form dense, leafy thickets and is often planted as a landscape accent, hedge, or screening plant in moist, shaded environments.

Risks & Threats
Strobilanthes hamiltoniana is potentially naturalizing in Hawaiʻi and possesses traits that are cause for concern. Its ability to grow vigorously, form dense stands, and reproduce successfully in suitable habitats raises the risk of escape from cultivation into natural areas. Once established, it may compete with native vegetation for light, space, water, and nutrients, potentially altering ecosystem structure and reducing biodiversity. Because tropical island ecosystems are especially vulnerable to invasive plants, this species could detrimentally impact native habitats if its spread continues. Residents and landscapers are encouraged to choose low-risk or native alternatives when available. Where Strobilanthes hamiltoniana is already established, its use should be carefully managed and avoided in areas where it is not yet widespread to help minimize further negative impacts.

High Risk Traits:

• Elevation range exceeds 1000 m, demonstrating environmental versatility
  
• Thrives in tropical climates
  
• Naturalized on Hawaii island (Hawaiian Islands), and in several other tropical locations
  
• An environmental weed in La Reunion
  
• Other Strobilanthes species are invasive
  
• Shade tolerant
  
• Forms dense stands that can exclude other vegetation
  
• Reproduces vegetatively by cuttings and fragments
  
• May reproduce by seed in some locations, although cultivated plants are reported to be sterile
  
• Vegetative fragments dispersed by animals and people
  
• Tolerates and will grow back after repeated cutting

Low Risk Traits:

• Unarmed (no spines, thorns, or burrs)
  
• Non-toxic
  
• Cultivated plants reported to be sterile
  
• Lack of seed production limits dispersal ability