Family: Balsaminaceae

Origin, Description & Uses
Impatiens glandulifera (Himalayan balsam, ornamental jewelweed, policeman’s-helmet) is a fast-growing annual plant native to Nepal, Pakistan, and the western Himalaya. It can reach heights of 6–10 feet and is recognized for its hollow stems and showy pink to purple, helmet-shaped flowers. These nectar-rich blooms attract pollinators and have made it a popular ornamental plant, as well as a resource for beekeeping. It thrives in moist environments such as streambanks, wetlands, and other disturbed areas, where it can quickly form dense stands.

Risks & Threats
Although this species is currently not known to be naturalized in the Hawaiian Islands, it does possess traits that are cause for concern and could detrimentally impact tropical island ecosystems. Himalayan balsam spreads aggressively through explosive seed dispersal, enabling it to dominate habitats and form dense monocultures that outcompete native vegetation. Its seasonal dieback can leave soils exposed, increasing erosion along waterways. In other regions, it has become highly invasive and disruptive to natural ecosystems. To help protect Hawaiʻi’s unique environment, it is recommended to avoid planting this species and instead choose a low-risk or native alternative.

High Risk Traits:

• Elevation range exceeds 2000 m, demonstrating environmental versatility
  
• Grows in temperate and tropical climates
  
• Widely naturalized (although no evidence in Hawaiian Islands to date)
  
• Environmental weed (reduces native diversity)
  
• Other Impatiens species are invasive
  
• Tolerates many soil types
  
• Forms dense stands that exclude other vegetation
  
• Reproduces by seeds
  
• Self-compatible
  
• Annual life cycle (rapidly reaches maturity)
  
• Seeds dispersed ballistically, by water, and both intentionally and accidentally by people
  
• Prolific seed production (>5000 seeds/m2)

Low Risk Traits:

• Unarmed (no spines, thorns, or burrs)
  
• Palatable to browsing/grazing animals
  
• Non-toxic
  
• Ornamental
  
• Not reported to spread vegetatively
  
• Seeds rapidly lose viability (although some reports suggest viability of 18 months)
  
• Herbicides may provide effective control
  
• Not resistant to cutting, grazing, or mowing (mechanical control methods may be effective)