Family: Euphorbiaceae

Origin, Description & Uses
Rattlesnake weed (Euphorbia albomarginata) is a low-growing, spreading plant native to the southwestern United States and parts of Mexico. It thrives in dry, sandy, or rocky soils and is often found in open, sun-exposed areas such as roadsides, lawns, and disturbed sites. This species forms dense mats of small, oval leaves edged with a distinctive white margin, giving it a delicate, lacy appearance. Tiny white flowers appear year-round in warm climates. While not widely cultivated, it is sometimes used as a groundcover in xeriscaping due to its drought tolerance and ability to stabilize soil in dry landscapes.

Risks & Threats
On Oʻahu, rattlesnake weed is considered potentially naturalizing, meaning it has begun to establish outside of cultivation but is not currently known to cause significant ecological harm. It spreads primarily by seed and can form low mats that compete with other small plants in disturbed areas. However, it is generally not aggressive and is unlikely to invade intact native ecosystems under current conditions. As with many Euphorbia species, it produces a milky sap that can be irritating to skin and eyes. While this species is regarded as low risk at present, monitoring its spread is important. Choosing non-invasive or native groundcover alternatives is recommended to help protect Hawaiʻi’s unique ecosystems.

High Risk Traits:

• Broad climate suitability (occurs up to 2300 m)
  
• Native to subtropical regions
  
• Congeneric weed (C. nutans is invasive)
  
• Unpalatable to grazing animals
  
• Produces viable seed
  
• Self-compatible
  
• Short generation time (flowers in first season)

Low Risk Traits:

• No spines, thorns, or burrs
  
• Non-toxic to animals or humans
  
• No fire hazard
  
• Narrow soil tolerance (poorly drained clay)
  
• No evidence of intentional dispersal
  
• No specialized seed dispersal adaptations