Family: Fabaceae

Origin, Description & Uses
Sesbania punicea, commonly known as rattlebox, is a small, fast-growing tree or large shrub native to central and southern Brazil, Paraguay, Uruguay, and northeastern Argentina. It is valued as an ornamental for its striking clusters of orange-red, pea-like flowers that bloom over an extended season. The plant typically grows 6–15 feet (2–5 m) tall and produces distinctive inflated seed pods that rattle when dry, giving rise to its common name. Rattlebox has been planted in gardens, parks, and along waterways for its colorful display and ability to tolerate a range of soil conditions, including wet sites.

Risks & Threats
Although Sesbania punicea is not currently known to be naturalized in the Hawaiian Islands, it possesses several traits that are cause for concern. The species produces abundant long-lived seeds, grows rapidly, and can establish dense stands in riparian areas, wetlands, and other disturbed habitats. In regions where it has escaped cultivation, it has become invasive, displacing native vegetation, altering habitat structure, and reducing biodiversity. Its seeds and other plant parts are also toxic to people and animals if ingested. Because of its invasive history elsewhere and its potential to negatively impact tropical island ecosystems, caution is warranted when considering its use in Hawaiʻi. Plant Pono recommends choosing a low-risk or native alternative whenever suitable alternatives are available.

High Risk Traits:

• Naturalized & invasive in multiple regions (USA, South Africa, Mauritius)
  
• Forms dense, native-excluding thickets
  
• Highly toxic to animals and humans (seeds especially)
  
• Matures in <1 year; produces thousands of seeds annually
  
• Water- and wind-dispersed seeds
  
• Persistent soil seed bank (>1 year)
  
• Nitrogen-fixing (alters soil nutrients)
  
• Congeneric species are also weedy

Low Risk Traits:

• Requires full sun (not shade-tolerant)
  
• Does not resprout from roots
  
• Biocontrol agents effective
  
• No vegetative reproduction
  
• No spines or thorns
  
• Herbicide-sensitive