Family: Boraginaceae

Symphytum officinale (common comfrey, boneset) is a perennial herb native to Europe and Asia. It has been cultivated over centuries in Europe and Asia as both a vegetable and herbal medicine. It is reported to be widely naturalized in North America and elsewhere, but has not been documented as naturalized on any Hawaiian Islands to date. 

This plant is considered a weed in North America and grows well in landscaping and on farms. It is also toxic to humans and animals if consumed in large quantities, and this toxicity can also be readily absorbed through the skin. For this reason, the FDA and FTC banned the sale of it for internal use or on open wounds in 2001. It also grows back after repeated cutting, and matures rapidly. These negative qualities place it in the category “evaluate”. 

High Risk Traits:

• Broad climate suitability
  
• Naturalized outside native range (but no evidence from Hawaiian Islands to date)
  
• A weed of gardens, landscaping, and crops
  
• A potential environmental weed in Australia
  
• Other Symphytum species are invasive
  
• Toxic to animals and people if consumed in large quantities
  
• Tolerates many soil types
  
• Reproduces by seeds
  
• Hybridizes with other species
  
• Reaches maturity in one growing season
  
• Seeds dispersed by water, ants, and intentionally by people
  
• Able to be dispersed by tillage that moves plant parts
  
• Tolerates and grows back from repeated cutting

Low Risk Traits:

• Native to regions with temperate to Mediterranean climates (may only be a threat in higher elevation tropical regions)
  
• Unarmed (no spines, thorns, or burrs)
  
• Provides fodder for livestock (palatable despite reports of toxicity)
  
• Not reported to naturally spread vegetatively
  
• Self-incompatible
  
• Primarily bumblebee pollinated (may limit seed production)
  
• Limited seed production
  
• Transient seed bank
  
• Herbicides may provide effective control