Family: Linaceae

Origin, Description & Uses:
Linum bienne (narrow-leaved flax, pale flax, or small-flowered flax) is native to Europe, western Asia, and North Africa, where it typically grows in grasslands, open woodlands, and disturbed areas. It is a delicate, slender annual or short-lived perennial herb with narrow leaves and small, pale blue to whitish flowers that resemble those of cultivated flax (Linum usitatissimum). While it is not widely cultivated for fiber or seed production like its close relative, it is sometimes grown as an ornamental plant or appreciated in wildflower mixes for its soft, natural appearance and ability to thrive in poor soils.

Risks & Threats:
In Hawaiʻi, Linum bienne is naturalized on Kauaʻi, Maui, and Hawaiʻi Island, meaning it is now reproducing and persisting in the wild outside of cultivation. Although it may appear harmless due to its small size, this species possesses traits that are cause for concern, including its ability to spread in open and disturbed habitats and compete with native groundcover plants. Over time, it could contribute to the displacement of native herbaceous species and alter the structure of sensitive tropical island ecosystems, particularly in areas already impacted by disturbance. Because of these risks, it is best to avoid planting this species and instead choose low-risk or native Hawaiian alternatives that support local biodiversity and ecosystem health.

High Risk Traits:

• Elevation range exceeds 1000 m, demonstrating environmental versatility
  
• Naturalized in regions with tropical climates
  
• Naturalized on Kauai, Maui and Hawaii (Hawaiian Islands); widely naturalized elsewhere
  
• A weed of lawns, disturbed areas, pastures, and potentially of agriculture
  
• Other Linum species are weeds
  
• Seeds may contain toxic compounds
  
• Tolerates many soil types
  
• Reproduces by seeds
  
• Self-compatible
  
• Reaches maturity in one year
  
• Seeds dispersed as a contaminant, possibly by water, and possibly attached to animals, equipment and vehicles
  
• Viable seeds survive gut passage after consumption by horses

Low Risk Traits:

• Despite widespread naturalization and reports of weediness, impacts appear to be minimal, or are generally innocuous
  
• Unarmed (no spines, thorns or burrs)
  
• Shade-intolerant
  
• Not reported to spread vegetatively
  
• Herbicides may provide effective control