Family: Fabaceae

Origin, Description & Uses
Sesbania sesban is a fast-growing small tree or large shrub native to tropical and southern Africa, the Arabian Peninsula, and the Indian subcontinent. Typically reaching 10–20 feet (3–6 m) in height, it produces pinnately compound leaves and clusters of attractive yellow flowers, often marked with purple or brown streaks. Because of its rapid growth and ability to fix nitrogen, it has been widely planted in tropical regions as a fodder crop, green manure, erosion-control plant, shade tree, windbreak, and source of fuelwood. It is also used in agroforestry systems to improve soil fertility and support agricultural production.

Risks & Threats
In Hawaiʻi, Sesbania sesban is naturalized on Kauaʻi, Oʻahu, and Hawaiʻi Island, where it occurs in pastures and other disturbed habitats. This species possesses traits that are cause for concern, including rapid growth, prolific seed production, tolerance of a wide range of environmental conditions, and the ability to establish in disturbed areas. These characteristics increase its potential to spread beyond cultivation and form dense stands that can compete with desirable vegetation and alter ecosystem processes. Because it is already naturalized in Hawaiʻi and could detrimentally impact tropical island ecosystems, caution is warranted when considering its use. Low-risk or native alternatives are recommended whenever suitable options are available. In areas where S. sesban is already widespread, efforts should focus on preventing further planting and limiting its spread into new locations and sensitive natural areas.

High Risk Traits:

• Naturalized in Hawaii/Taiwan; widely introduced
  
• Naturalized on Kauaʻi, Oʻahu, and Hawaiʻi
  
• Congeneric (S. punicea) is invasive
  
• Toxic to livestock (saponins; fatal to chicks at 10% diet)
  
• Tolerates shade, saline, waterlogged, and heavy soils
  
• Self-pollinating; matures in <1 year; prolific, persistent seed bank
  
• Resprouts vigorously after cutting

Low Risk Traits:

• Not considered a serious weed
  
• No spines, burrs, or climbing habit
  
• Palatable; non-toxic to humans
  
• No wind, bird, or external animal dispersal mechanisms
  
• No major pest or pathogen associations