Family: Fabaceae

Origin, Description & Uses
Retama raetam (retem, white weeping broom) is a flowering shrub native to southern Sicily, the Mediterranean region, the Sahara Desert, and the Arabian Peninsula. It is well adapted to dry, arid environments and typically grows as a multi-stemmed, airy shrub with long, flexible green branches that may appear leafless for much of the year. In spring, it produces abundant small, fragrant white flowers that are highly attractive to pollinators. In its native range, it is sometimes used for ornamental landscaping in dry climates, erosion control, and traditional medicinal or cultural purposes.

Risks & Threats
Although Retama raetam is currently not known to be naturalized in the Hawaiian Islands, it possesses traits that are cause for concern. Its high tolerance for drought, ability to thrive in poor soils, and prolific seed production could allow it to establish and spread if introduced. In other regions, similar broom-like shrubs have shown invasive tendencies, outcompeting native vegetation and altering open, dry habitats. If it were to become established in Hawaiʻi, it could potentially disrupt fragile tropical island ecosystems, particularly in dry and coastal areas. Because of these risks, it is recommended to choose low-risk or native plant alternatives when available to help protect Hawaiʻi’s unique biodiversity.

High Risk Traits:

• Naturalized and invasive in Australia, with potential negative impacts to native ecosystems (may compete with and exclude native vegetation)
  
• Other Retama species are invasive
  
• May be toxic to animals and people if ingested
  
• Edible, despite potential toxicity, but palatability is low
  
• May increase fire risk in arid environments
  
• Tolerates many soil types
  
• Nitrogen fixing (may modify soil nutrients)
  
• Reproduces by seeds
  
• Reaches maturity in 2+ years
  
• Seeds dispersed by water, internally by animals, as a soil contaminant, and intentionally by people
  
• Prolific seed production (up to 3000/m2)
  
• Forms a persistent seed bank (5-20 years longevity)
  
• Resprouts after cutting, and low intensity fires

Low Risk Traits:

• Unarmed (no spines, thorns, or burrs)
  
• Provides fodder for livestock (palatable despite reports of toxicity)
  
• Grows in arid, high light environments (may be unable to spread into dense, intact forest)
  
• Not reported to spread vegetatively
  
• Herbicides may provide effective control