Family: Fabaceae

Origin, Description & Uses
Senna multijuga (false sicklepod, November shower) is a fast-growing flowering tree native to Mexico, Central America, and tropical South America. It is valued as an ornamental for its abundant clusters of bright yellow flowers, which can create a striking display when in bloom. The species is commonly planted in tropical and subtropical landscapes as a shade tree, street tree, or accent planting. Its attractive flowers can also provide resources for pollinators, contributing to its popularity in gardens and urban plantings.

Risks & Threats
Senna multijuga is naturalized on Kauaʻi and possesses several traits associated with invasive plants, including rapid growth, prolific seed production, and the ability to establish beyond cultivation. These characteristics raise concerns that it could spread into natural areas, where it may compete with native vegetation, alter plant community composition, and negatively affect tropical island ecosystems. Because this species is already naturalized in Hawaiʻi, continued planting may increase the risk of further spread to new locations and sensitive habitats. When selecting trees for landscaping, Plant Pono recommends choosing low-risk or native alternatives whenever available. In areas where S. multijuga is already established, landowners and managers are encouraged to prevent its spread and avoid planting it near natural areas to help minimize additional ecological impacts.

High Risk Traits:

• Naturalized in Kaua'i, Puerto Rico, Australia, and other regions
  
• Suited to broad tropical climates (elevation 50–1100 m, rainfall 1000–4500 mm)
  
• Tolerates poor, infertile, and acidic soils
  
• Congeneric species are weedy
  
• Nitrogen-fixing (can alter soil nutrients)
  
• Potentially self-compatible (aids colonization)
  
• Produces viable seed
  
• Forms a persistent soil seed bank (>1 year)
  
• Dispersed by people, unintentional seed movement, and wind
  
• Widely introduced as an ornamental

Low Risk Traits:

• No documented severe ecological or agricultural impacts
  
• Lacks spines, thorns, or burrs
  
• Non-toxic to humans and animals
  
• Valued as an ornamental landscape tree
  
• No evidence of creating fire hazards