Family: Euphorbiaceae

Origin, Description & Uses
Euphorbia tithymaloides (zigzag plant, slipper flower, Japanese poinsettia, redbird cactus) is a succulent ornamental shrub native to Florida, Mexico, and tropical regions of the Americas. It is known for its distinctive zigzagging stems, fleshy green leaves, and unusual slipper-shaped red flowers that attract hummingbirds and other pollinators. This drought-tolerant plant is commonly grown in tropical and subtropical gardens as an ornamental accent, container plant, or hedge due to its unusual appearance and ease of cultivation. Like many members of the spurge family, it contains a milky sap that can be irritating to skin and eyes.

Risks & Threats
This species is naturalized on Kauaʻi and Oʻahu and is potentially naturalizing on Kuaihelani (Midway Atoll). Euphorbia tithymaloides possesses traits that are cause for concern, including the ability to spread from stem fragments and persist in dry, disturbed environments. Escaped plants may establish in natural or semi-natural areas, where they can compete with native vegetation and contribute to the spread of non-native plant communities. Because tropical island ecosystems are especially vulnerable to invasive species, further spread of this plant could detrimentally impact sensitive habitats and biodiversity. For these reasons, Plant Pono recommends choosing a low risk or native alternative when suitable alternatives are available.

High Risk Traits:

• Naturalized outside native range (Florida, Puerto Rico, South Africa, Hawaii)
  
• Broad climate suitability (USDA zones 9b–11)
  
• History of repeated introductions (widely cultivated as ornamental/hedge)
  
• Unpalatable to grazing animals (caustic sap deters herbivory)
  
• Toxic to animals and humans (sap causes skin/eye irritation, vomiting, diarrhea)
  
• Tolerates wide range of soil conditions (acidic to mildly alkaline, loam, sand)
  
• Produces viable seed
  
• Requires specialist pollinators (hummingbirds)
  
• Vegetative reproduction (stem fragments root readily)
  
• Tolerates pruning and mutilation
  
• Minimum generative time ≤ 1 year

Low Risk Traits:

• No spines, thorns, or burrs
  
• No dense thicket formation
  
• No water, bird, or external animal dispersal
  
• Unlikely to contaminate produce
  
• No prolific seed production (>1000/m²)
  
• Not a serious agricultural/forestry/environmental weed