Family: Euphorbiaceae

Origin, Description & Uses:
Euphorbia pulcherrima, commonly known as poinsettia, is a flowering shrub native to Mexico and Central America. It is widely recognized for its bright red, pink, white, or variegated bracts (modified leaves) that surround small yellow flowers, making it a popular ornamental plant, especially during the winter holiday season. Poinsettia grows as a small shrub in tropical and subtropical climates and can reach several feet in height outdoors. It is commonly used in landscaping, container gardening, and as an indoor decorative plant due to its vibrant color and seasonal appeal.

Risks & Threats:
Poinsettia is considered a low-risk species in Hawaii. While it can occasionally persist outside of cultivation in suitable climates, it does not typically spread aggressively or form dense, invasive populations. It lacks many of the traits associated with invasive plants, such as rapid reproduction, long-distance dispersal, or the ability to outcompete native vegetation. Although its milky sap can cause mild skin irritation and is toxic if ingested in large amounts, these risks are generally limited and manageable with proper handling. Overall, poinsettia poses minimal threat to Hawaii’s ecosystems and remains a safe and popular ornamental choice.

High Risk Traits:

• Toxic to animals: Contains toxins linked to poisoning and fatalities
  
• Host for pests & pathogens: Host to 92 fungi and serious pests like Opogona sacchari
  
• Congeneric weeds: Other Euphorbia species are major weeds globally
  
• Unpalatable: Toxic sap deters grazing animals
  
• Benefits from mutilation: Responds well to pruning, aiding persistence
  
• Shade tolerant: Can establish across varied light conditions

Low Risk Traits:

• No naturalization: Not recorded as naturalized despite global cultivation
  
• Not a weed: No record as garden, agricultural, or environmental weed
  
• Lacks key weed traits: No allelopathy, parasitism, climbing, or thicket formation
  
• Low seed output: Produces few seeds per plant
  
• Herbicide sensitive: Easily controlled by common herbicides