Family: Fabaceae

Origin, Description & Uses
Senna pendula (Christmas senna, climbing cassia) is a shrub or small tree native to Mexico, Central America, and tropical regions of the Americas. It is valued as an ornamental plant for its bright yellow flowers, long blooming season, and attractive foliage. Depending on the variety and growing conditions, it may grow as a sprawling shrub, climbing plant, or small tree. Christmas senna has been widely planted in tropical and subtropical landscapes, gardens, and roadsides because of its showy appearance and ease of cultivation.

Risks & Threats
Senna pendula is naturalized on Kauaʻi and Oʻahu and possesses traits that are cause for concern in Hawaiʻi. It grows rapidly, produces abundant seeds, and can establish in disturbed areas, forest edges, and other natural habitats. Birds and other animals may aid in seed dispersal, allowing populations to spread beyond cultivation. These characteristics increase its potential to invade native ecosystems, where it can compete with native plants and alter habitat structure. Because this species is already naturalized in Hawaiʻi and could detrimentally impact tropical island ecosystems, planting should be avoided where low-risk or native alternatives are available. In areas where Senna pendula is already established, landowners and managers are encouraged to prevent further spread and avoid introducing it into new locations or sensitive natural areas.

High Risk Traits:

• Thrives in tropical climates
  
• Widely naturalized, including all main Hawaiian Islands
  
• Disturbance weed of pastures and natural environment
  
• Other Senna species are invasive
  
• Tolerates many soil types
  
• Forms dense stands
  
• Reproduces by seeds
  
• Seeds dispersed by water, ants, rodents, soil movement, dumped garden waste and intentionally by people
  
• Prolific seed production
  
• Seeds form a persistent seed bank
  
• Able to coppice and resprout after cutting, pruning or fire

Low Risk Traits:

• Unarmed (no spines, thorns or burrs)
  
• Palatable to browsing and grazing animals
  
• Non-toxic
  
• Ornamental
  
• Not reported to spread vegetatively
  
• Herbicides provide effective control