Family: Cannabaceae

High Risk Traits:

• Broad climate suitability
  
• Widely cultivated and naturalized in temperate areas (but no evidence in Hawaiian Islands to date)
  
• A yard, garden and general weed of cultivated lands
  
• Potential agricultural and environmental weed (impacts unverified0
  
• Humulus japonicus is invasive
  
• Toxic to dogs
  
• May cause dermatitis to susceptible individuals
  
• Tolerates many soil types
  
• Climbing and potential smother habit
  
• Reproduces by seeds and vegetative fragments
  
• Seeds dispersed by wind, water, animals and intentionally by people
  
• Vegetative fragments dispersed by machinery
  
• Seeds persist for >1 year (possibly 3 years)
  
• Tolerates cutting and freezing (regrows from roots)

Low Risk Traits:

• Primarily grows in temperate climates (may limit ability to persist and spread to higher elevation areas of tropical islands)
  
• Unarmed (no spines, thorns, or burrs)
  
• Provides fodder for livestock (palatable to some grazing animals despite toxicity to dogs)
  
• Integral ingredient in beer brewing
  
• Dioecious (female flowers used in brewing; eliminates seed production if no male plants are present)
  
• Herbicides may provide effective control