Family: Caprifoliaceae

Valeriana rubra (red valerian, Jupiter’s beard) is a flowering perennial native to the Mediterranean region. It is commonly grown as an ornamental for its showy clusters of red, pink, or white flowers, which bloom over a long season and attract pollinators like bees and butterflies. The plant is drought-tolerant, thrives in poor or rocky soils, and is often found growing on walls, cliffs, roadsides, and garden edges. Because it is hardy and easy to grow, it has been widely planted in landscapes and gardens around the world.

Despite its popularity, red valerian poses ecological risks. It readily escapes cultivation and has naturalized in many regions, including islands and sensitive habitats. The plant produces abundant, wind-dispersed seed, forms persistent seed banks, and can establish dense patches that crowd out native plants. Once established, it can be difficult to fully remove due to repeated reseeding. For these reasons, red valerian is considered a high-risk species, and planting is discouraged in favor of non-invasive or native alternatives to help protect local ecosystems.

High Risk Traits:

• Naturalizes readily outside its native range, including islands and disturbed habitats
  
• Escapes cultivation and spreads from gardens into roadsides, cliffs, walls, and natural areas
  
• Broad environmental tolerance, thriving in dry, rocky, nutrient-poor soils
  
• Produces abundant, viable seed and self-seeds freely
  
• Wind-dispersed seeds, allowing spread beyond planted areas
  
• Forms persistent seed banks, enabling re-establishment after removal
  
• Rapid maturity, often flowering and producing seed within one year
  
• Forms dense patches or monocultures, which can displace native herbs and groundcover
  
• Unpalatable to grazers, reducing natural control
  
• Congeneric relatives are invasive, indicating elevated invasion risk
  
• Hybridization potential with closely related native or endemic species in some regions

Low Risk Traits:

• Not toxic to humans or animals
  
• No spines, thorns, or burrs
  
• Does not increase fire risk and is often considered fire-resistant
  
• Few serious pests or diseases
  
• No known biological hazards (e.g., allergies)
  
• Generally controllable with hand-pulling or herbicides when detected early
  
• Does not spread vegetatively (spread is seed-based only)