Family: Fabaceae

Origin, Description & Uses
Senna artemisioides (silver senna, silver cassia) is native to Australia, where it grows in arid and semi-arid regions. It is a multi-stemmed shrub or small tree valued for its attractive silvery-gray, finely divided foliage and bright yellow, pea-like flowers that often appear in seasonal flushes. Because of its drought tolerance and ornamental appearance, it is sometimes used in landscaping for xeriscapes, coastal gardens, hedges, and low-water-use plantings.

Risks & Threats
Although Senna artemisioides is currently not known to be naturalized in the Hawaiian Islands, it possesses traits that are cause for concern in tropical island environments. It is highly drought tolerant, can produce abundant seed, and may establish in disturbed dry habitats where it could compete with native vegetation and alter plant community structure. Like other hardy ornamental legumes, it has the potential to spread beyond cultivation under favorable conditions, particularly in open, sunny, low-elevation areas. Given these characteristics, it could detrimentally impact tropical island ecosystems if it were to become established. When available, choosing low-risk or native Hawaiian plant alternatives is recommended to help protect local ecosystems.

High Risk Traits:

• Naturalized outside native range (e.g., Arizona, California).
  
• Agricultural/rangeland weed (forms dense, invasive stands in grazed lands).
  
• Congeneric weeds present (other Senna species are invasive).
  
• Toxic to animals (contains anthraquinone glycosides, affects livestock).
  
• Forms dense thickets.
  
• Nitrogen-fixing (can alter soil nutrients).
  
• Self-compatible & apomictic (can reproduce without pollinators).
  
• Produces viable seed.
  
• Tolerates wide soil conditions & arid climates.
  
• Resprouts after fire & clipping (difficult to eradicate).
  
• Persistent seed bank (long-lived seeds).

Low Risk Traits:

• No spines, thorns, or burrs.
  
• No specialized dispersal mechanisms (seeds lack hooks, flesh, or wind adaptations).
  
• Controllable with herbicides.