Family: Oleaceae

Origin, Description & Uses
Ligustrum japonicum (Japanese privet or wax-leaf privet) is native to southeastern China and temperate regions of eastern Asia. It is an evergreen shrub or small tree valued in landscaping for its dense, glossy dark-green leaves, upright growth form, and ability to be shaped into hedges or screens. It also produces clusters of small, fragrant white flowers followed by dark berries that can provide seasonal interest and are sometimes used by birds. Because of its toughness and tolerance of pruning, drought, salt spray, and a range of soil conditions, it has been widely planted as an ornamental in warm-temperate and subtropical regions.

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 which could detrimentally impact tropical island ecosystems. Japanese privet produces abundant bird-dispersed seeds, allowing it to spread beyond planting sites, and it can form dense thickets that shade out and displace native vegetation. Its tolerance for a wide range of environmental conditions increases its potential to establish in disturbed habitats, forest edges, and stream corridors, where it may alter habitat structure and reduce biodiversity. Given these risks, caution is warranted in its use in Hawaiʻi. Choosing a low-risk or native alternative is strongly recommended to help protect and preserve Hawaiʻi’s unique ecosystems.

High Risk Traits:

• Grows in temperate to subtropical climates, demonstrating environmental versatility
  
• Able to grow in regions with subtropical climates
  
• Naturalized in several locations (but no evidence in Hawaiian Islands to date)
  
• A garden and environmental weed on the mainland US
  
• Other Ligustrum species are invasive
  
• Toxic to animals (horses) and people
  
• Host of pathogens
  
• Shade-tolerant
  
• Tolerates many soil types
  
• Forms dense stands, excluding other vegetation
  
• Reproduces by seeds and vegetatively by suckering
  
• Seeds dispersed by birds, other frugivorous animals and intentionally by people
  
• Able resprout from cut stumps

Low Risk Traits:

• Unarmed (no spines, thorns, or burrs)
  
• Browsed by deer and cattle (palatable despite reports of toxicity)
  
• Ornamental
  
• Seeds require cold stratification (may limit ability to spread in regions with tropical/subtropical climates)
  
• Reaches maturity in 5+ years
  
• Recalcitrant seeds (unlikely to form a persistent seed bank)
  
• Herbicides may provide effective control