Family: Rosaceae

Origin, Description & Uses
Pyracantha crenulata, commonly known as firethorn, is a thorny evergreen shrub or small tree native to northern Pakistan through northwestern India and into China. It is valued for its dense branching, glossy green leaves, clusters of small white flowers, and bright orange to red berries that persist through much of the year. Firethorn is widely used as an ornamental hedge, barrier planting, and wildlife garden plant because of its colorful fruit and ability to form dense living fences. It is also sometimes planted for erosion control and as a security hedge due to its sharp thorns. In Hawai‘i, this species has become naturalized on Kaua‘i and Hawai‘i Island.

Risks & Threats
Firethorn is considered a high risk species in Hawai‘i because it possesses traits associated with invasive plants, including abundant fruit production, bird-dispersed seeds, and the ability to establish dense, thorny thickets. These characteristics can allow it to spread into natural areas where it may compete with native vegetation and interfere with ecosystem processes. Because it is already naturalized in Hawai‘i and could detrimentally impact tropical island ecosystems, caution is strongly advised when considering its use in landscaping. Where possible, choose low risk or native alternatives instead of planting firethorn. In areas where the species is already established, landowners and gardeners are encouraged to manage existing plants carefully and avoid planting it near forests, gulches, or other sensitive habitats to help minimize further spread and negative environmental impacts.

High Risk Traits:

• Elevation range exceeds 1000 m, demonstrating environmental versatility
  
• Can grow in higher elevations with subtropical climates
  
• Naturalized on Kauai and Hawaii (Hawaiian Islands), parts of the continental US, Australia, New Zealand
  
• Environmental weed in Australia
  
• Other Pyracantha species are invasive
  
• Spiny
  
• Host of bacterial fireblight
  
• Tolerates many soil types
  
• Forms dense stands that exclude other vegetation
  
• Reproduces by seeds
  
• Seeds dispersed by birds, water, dumped garden waste & intentionally by people
  
• Prolific seed production (densities unknown)
  
• Able to resprout after fire

Low Risk Traits:

• Invasiveness may be restricted to higher elevation of islands with tropical/subtropical climates
  
• Despite invasiveness, valued by some as an ornamental
  
• Requires full to partial sun to grow (dense shade may impede spread)
  
• Herbicides may provide effective control