Family: Brassicaceae

Barbarea vulgaris (bittercress, yellow rocket) is a low-growing plant with bright yellow flowers that often appear in early spring. Native to Europe and Asia, it commonly grows in disturbed areas and along roadsides. While not naturalized in Hawaii, it spreads rapidly through prolific seed production and can establish quickly in a range of habitats. Its fast growth, ability to outcompete other plants, and persistence in disturbed sites are traits that make it a potential threat to native ecosystems.

Because of these high-risk traits, B. vulgaris is rated as High Risk and is not recommended for planting in Hawaii. Its potential to invade and disrupt natural areas, combined with its aggressive spread, makes careful monitoring and prevention important.

High Risk Traits:

• Elevation range exceeds 1000 m
  
• Widely naturalized
  
• A disturbance-adapted agricultural weed
  
• Related Barbarea species have become invasive
  
• Unpalatable at later growth stage
  
• Toxic to cattle and other animals if consumed in large quantities
  
• Host of crop pathogens
  
• Shade-tolerant
  
• Tolerates many soil types
  
• Self-compatible (with lowered seed set)
  
• Typically reaches maturity in 2 years
  
• Seeds easily dispersed by sticking to animals, people, or machinery
  
• Viable seeds may be dispersed after ingestion by animals
  
• Prolific seed production
  
• Forms a long-lived seed bank (10-20 years)
  
• Will resprout after rosettes or roots are cut

Low Risk Traits:

• Barbarea vulgaris has an obligate requirement for vernalization
  
• An early successional species
  
• Unarmed (no spines, thorns or burrs)
  
• Occasionally consumed as a salad green or a cooked vegetable
  
• Does not spread vegetatively
  
• Well-controlled by herbicides