Family: Salicaceae

Origin, Description & Uses
Salix babylonica (Babylon weeping willow) is native to northern and eastern China and parts of Korea. It is a fast-growing, deciduous tree best known for its graceful, drooping branches and narrow, lance-shaped leaves that create a soft, cascading canopy. Often found near water, it thrives in moist soils and is commonly planted in parks, large landscapes, and along streams or ponds for its striking ornamental appearance and shade. Beyond its aesthetic value, weeping willow has also been used in traditional settings for erosion control and as a symbolically significant tree in gardens and cultural landscapes.

Risks & Threats
Although Salix babylonica is currently not known to be naturalized in the Hawaiian Islands, it does possess traits that are cause for concern, including vigorous growth and a strong affinity for wet habitats that could make it competitive in sensitive riparian areas. In other regions, willows have shown potential to spread and alter waterways, sometimes outcompeting native vegetation and changing stream structure and hydrology. If it were to establish in Hawaii, it could pose risks to native wetland and riparian ecosystems that are already limited and highly vulnerable. For these reasons, it is recommended to choose a low-risk or native alternative when such options are available to help protect Hawaii’s unique island environments.

High Risk Traits:

• Naturalized outside native range
  
• Environmental weed (forms pure stands along waterways, alters hydrology)
  
• Congeneric weeds (other Salix species are invasive)
  
• Host for multiple pests and pathogens
  
• Tolerates a wide range of soils (saline, infertile, waterlogged, etc.)
  
• Produces viable, small, wind-dispersed seeds
  
• Hybridizes naturally with other willows
  
• Reproduces via vegetative fragmentation (dispersed by floodwater)
  
• Intentionally spread by people (ornamental, forestry)
  
• Prolific seed production
  
• Tolerates mutilation and coppicing (strong sprouting ability)

Low Risk Traits:

• No garden/agricultural weed status
  
• No spines, thorns, or burrs
  
• Not parasitic, toxic, or a fire hazard
  
• Palatable to livestock (used as fodder)
  
• Not shade tolerant (light-demanding)
  
• Dioecious (requires both sexes for seed)
  
• No evidence of bird, animal, or unintentional human dispersal
  
• No persistent seed bank (seed viability ~5–10 days)
  
• Well controlled by herbicides (e.g., glyphosate)