Family: Euphorbiaceae

Origin, Description & Uses
Euphorbia umbellata, commonly known as African milk bush, is a succulent shrub or small tree native to eastern and central Africa, ranging from South Sudan to Burundi and Tanzania. It is valued for its upright growth habit, attractive clusters of green leaves, and milky white sap characteristic of the spurge family. The plant is widely cultivated in tropical and subtropical regions as an ornamental landscape specimen, hedge, or container plant because of its drought tolerance and distinctive appearance. Its architectural form and ability to thrive in warm climates have made it a popular choice for gardens and urban landscapes.

Risks & Threats
African milk bush is considered a low-risk species for Hawaii. While it has been reported as potentially naturalizing on Oʻahu, there is currently little evidence that it spreads aggressively or causes significant ecological impacts in natural areas. The species reproduces primarily through vegetative propagation and cultivation, which limits its ability to rapidly invade intact ecosystems. As with many ornamental plants, continued monitoring is appropriate to ensure its behavior does not change over time. Gardeners should also be aware that the plant’s milky sap can be irritating to skin and eyes and should be handled with care. At present, however, Euphorbia umbellata is not known to pose a substantial threat to Hawaii’s native ecosystems.

High Risk Traits:

• Evidence of naturalization beyond native range (India, Australia)
  
• Has a history of repeated introductions outside its natural range
  
• Listed as a potentially invasive environmental weed in India
  
• Congeneric weeds exist (e.g., Euphorbia esula)
  
• Toxic to animals and humans (corrosive latex)
  
• Reproduces by seed
  
• Propagules likely dispersed unintentionally via dumped garden waste
  
• Propagules dispersed intentionally by people (ornamental)
  
• May reproduce vegetatively from fragments
  
• Possibly adapted for ant dispersal (rudimentary caruncle)

Low Risk Traits:

• Does not produce spines, thorns, or burrs
  
• No evidence of allelopathic properties
  
• Not shade tolerant
  
• No evidence of prolific seed production (fruit often absent in cultivation)
  
• No evidence of seeds adapted for wind or water dispersal
  
• Not bird-dispersed (dehiscent capsules, not fleshy-fruited)