Family: Fabaceae

Origin, Description & Uses
Genista monspessulana (cape broom, French broom) is a fast-growing, evergreen shrub native to the Mediterranean region of Europe. It typically reaches 6–10 feet tall and is recognized by its bright yellow, pea-like flowers that bloom in abundance during spring, along with slender green stems and small, three-part leaves. This showy flowering plant has been widely introduced to other regions as an ornamental and for erosion control, roadside stabilization, and landscaping due to its ability to thrive in poor soils and dry conditions.

Risks & Threats
Although Genista monspessulana is currently not known to be naturalized in the Hawaiian Islands, it possesses traits that are cause for concern. In other parts of the world, it has become highly invasive, forming dense thickets that outcompete native vegetation, alter soil chemistry by fixing nitrogen, and increase fire risk due to its flammable biomass. It produces abundant seeds that can persist in the soil for many years, making control difficult once established. These characteristics could allow it to spread rapidly and detrimentally impact tropical island ecosystems if introduced. For these reasons, planting is not recommended, and a low risk or native alternative should be chosen instead.

High Risk Traits:

• Environmentally versatile
  
• Widely naturalized
  
• A weed of forestry plantations
  
• An environmental weed
  
• Related Genista species have become invasive
  
• Reputedly toxic to cattle
  
• May increases fire hazard with flammable biomass
  
• Shade-tolerant
  
• Tolerates many soil types
  
• Can from dense monocultures that exclude other vegetation
  
• Limited self-compatibility
  
• Accidentally and intentionally dispersed by seeds
  
• Prolific seed production
  
• Forms a persistent seed bank
  
• Resprouts after damage from cutting or fire

Low Risk Traits:

• May be limited to higher, cooler elevations in tropical island ecosystems
  
• Unarmed (no spines, thorns or burrs)
  
• Palatable to goats
  
• Does not spread vegetatively
  
• Valued as an ornamental in some locations
  
• Herbicides provide effective control under certain circumstances