Family: Moraceae

Origin, Description & Uses
Fatoua villosa, commonly known as hairy crabweed or mulberry-weed, is a fast-growing annual herb native to Asia. It is characterized by its soft, hairy leaves, small greenish flowers, and explosive seed dispersal mechanism that allows it to spread rapidly. This species typically thrives in moist, shaded environments such as gardens, nurseries, forest understories, and disturbed areas. While it does not have significant economic or ornamental value, it may occasionally appear as a minor component in ground cover or as an incidental plant in cultivated spaces.

Risks & Threats
Fatoua villosa is naturalized on Oʻahu and poses a high risk due to its aggressive growth, prolific seed production, and ability to spread quickly through ballistic seed dispersal. These traits allow it to form dense populations that can outcompete native vegetation and disrupt understory plant communities. Its adaptability to a wide range of conditions and rapid life cycle make it difficult to control once established. This species possesses traits that are cause for concern and could detrimentally impact tropical island ecosystems. To help protect Hawaiʻi’s unique biodiversity, it is recommended to avoid planting or spreading this species and instead choose low-risk or native alternatives.

High Risk Traits:

• Elevation range exceeds 1000 m, demonstrating environmental versatility
  
• Naturalized in locations with tropical climates
  
• Widely naturalized (including Oahu and possibly Hawaii Island)
  
• Lawn, garden and disturbance weed
  
• Horticultural weed of nurseries and potted plants
  
• Shade-tolerant
  
• Tolerates many soil types
  
• Reproduces by seeds
  
• Quickly reaches maturity
  
• Seeds dispersed by explosive dehiscence and accidentally as a contaminant of soil and media in nurseries and potted plants
  
• Prolific seed production (densities unspecified)

Low Risk Traits:

• Not reported as a weed of crops or natural environment
  
• Unarmed (no spines, thorns, or burrs)
  
• Ornamental
  
• Not reported to spread vegetatively
  
• Herbicides provide effective control
  
• Mechanical control methods can be effective