Family: Pittosporaceae

Origin, Description & Uses
Pittosporum tobira (Japanese pittosporum) is an evergreen shrub or small tree native to southern Korea, southern and central Japan, and the Ryukyu Islands (Nansei-shotō). It is widely cultivated in warm temperate and subtropical regions for its dense foliage, tolerance of pruning, and fragrant white flowers that bloom in spring. The plant has glossy dark green leaves arranged in clusters at the ends of branches and produces small orange seed capsules. Japanese pittosporum is commonly used as a hedge, screen, windbreak, foundation planting, or ornamental landscape specimen because of its durability and adaptability to coastal conditions, drought, and urban environments.

Risks & Threats
Although Pittosporum tobira is not currently known to be naturalized in Hawaii, it possesses traits that are cause for concern. The species is hardy, tolerant of a wide range of environmental conditions, and capable of forming dense growth that may compete with other vegetation. In other regions outside its native range, it has shown the ability to persist and spread in disturbed habitats. Birds may also disperse its seeds, increasing the potential for escape from cultivation. Ongoing evaluation is needed to determine if this species could negatively impact Hawaii’s ecosystems, and caution is recommended when considering its use in landscapes near natural areas.

High Risk Traits:

• Native to subtropical/tropical climates (USDA zones 8–11)
  
• Widely introduced outside native range as ornamental
  
• Congeneric weeds exist (P. undulatum invasive elsewhere)
  
• Toxic to animals (especially cows)
  
• Shade tolerant
  
• Tolerates wide range of soils (including salt and drought)
  
• Produces viable seed
  
• Bird-dispersed seeds
  
• Seeds survive gut passage
  
• Withstands heavy pruning
  
• Host for pests/pathogens (scales, aphids, nematodes, viruses)

Low Risk Traits:

• Rarely naturalizes (occasional escape in Florida)
  
• Not a garden, agricultural, or environmental weed
  
• No spines, thorns, or burrs
  
• No allelopathic or parasitic traits
  
• No vegetative reproduction
  
• Not dispersed unintentionally or as produce contaminant
  
• Low seed production (~8–10 seeds per capsule)