Family: Fabaceae

Origin, Description & Uses
Dichrostachys cinerea, commonly known as sickle bush, is a thorny shrub or small tree native to Africa, parts of Asia, and northern Australia. It typically grows 10–25 feet tall and is recognized by its feathery, bipinnate leaves and distinctive two-colored, bottlebrush-like flowers that are pink or purple on the upper half and yellow on the lower half. The plant produces curved seed pods, giving rise to the name “sickle bush.” It has been used in some regions for erosion control, living fences, fuelwood, fodder, and traditional medicine. Its drought tolerance and ability to grow in poor soils have made it appealing for dryland planting and land rehabilitation projects.

Risks & Threats
Although sickle bush is not currently known to be naturalized in the Hawaiian Islands, it possesses several traits that raise serious concern for tropical island ecosystems. It is a prolific seed producer, forms dense, thorny thickets, and can aggressively outcompete grasses and native vegetation. It is also capable of resprouting after cutting or fire and can alter soil conditions through nitrogen fixation, potentially changing ecosystem dynamics. In other tropical and subtropical regions, it has become invasive in rangelands and natural areas, reducing biodiversity and hindering access for wildlife and livestock. Because of these high-risk characteristics, introducing this species could detrimentally impact Hawaii’s dry forests, grasslands, and coastal ecosystems. Plant Pono recommends choosing a low-risk or native alternative better suited to protecting Hawaii’s unique environments.

High Risk Traits:

• Naturalized in Cuba & Trinidad; forms dense, impenetrable thickets
  
• Serious agricultural/forestry weed (South Africa, Cuba, Ghana); invades pastures & plantations
  
• Disturbance-adapted (clear-cuts, overgrazed land)
  
• Thorny shrub with sharp spines
  
• Wide soil tolerance (infertile, saline, variable textures)
  
• Forms dense, smothering thickets
  
• Nitrogen-fixing (competitive in poor soils)
  
• Vegetative reproduction via suckers & root fragments; difficult to eradicate
  
• Seeds dispersed unintentionally (hoofs) & intentionally (ornamental/medicine)
  
• Animal-dispersed (internal & external); gut passage breaks seed dormancy
  
• Persistent soil seed bank (1–5 years)
  
• Resprouts after cutting, fire, or mutilation

Low Risk Traits:

• Palatable to livestock (fodder species)
  
• Non-toxic to animals
  
• Does not increase fire hazard; fire-resistant
  
• Not wind- or bird-dispersed
  
• Not a prolific seeder (<1000 seeds/m²)
  
• Susceptible to herbicides (e.g., 2,4-D, 2,4,5-T)