Family: Poaceae

Holcus lanatus, commonly known as common velvet grass or Yorkshire fog, is a soft, fuzzy perennial grass native to Europe and western Asia. It is easily recognized by its velvety leaves and pinkish flower heads that fade to pale tan as they mature. This grass thrives in cool, moist conditions and tolerates a wide range of soils, including nutrient-poor and disturbed areas. Around the world, it has been widely planted for pasture, erosion control, and forage, particularly in temperate regions, due to its rapid growth and ability to establish quickly.

In Hawaiʻi, common velvet grass is naturalized on Kauaʻi, Oʻahu, Molokaʻi, Maui, and Hawaiʻi Island, where it poses ecological concerns. While it has limited forage value in tropical conditions, it readily spreads and can form dense mats that outcompete native plants and alter natural plant communities, especially in wet forests, pastures, and disturbed upland areas. Its ability to colonize open ground and persist under a range of conditions makes it difficult to manage once established. Continued spread of this grass can contribute to habitat degradation and reduced biodiversity, highlighting the importance of early detection, prevention, and responsible planting choices.

High Risk Traits:

• Broad climate suitability and elevation range exceeds 2000 m, demonstrating environmental versatility
  
• Naturalized in regions with tropical climates
  
• Widely naturalized
  
• Agricultural and environmental weed
  
• Other Holcus species are invasive
  
• Alternate host of pests and pathogens
  
• Pollen may be allergenic
  
• Increases fuel load in fire prone habitats
  
• Tolerates shade, but prefers full sun
  
• Tolerates many soil types
  
• Forms dense cover
  
• Reproduces primarily be seeds and secondarily by tillering
  
• Hybridizes with Holcus mollis
  
• Seeds dispersed by wind, water, as a crop contaminant, internally and externally by clinging to equipment, clothing, and animals
  
• Prolific seed production (>1000/m2)
  
• Forms a persistent seed bank (5-20 years)
  
• Tolerates mowing and fire

Low Risk Traits:

• Unarmed (no spines, thorns or burrs)
  
• Palatable to browsing and grazing animals (but lower than other grasses)
  
• Primarily outcrossing (mostly self-incompatible)
  
• Herbicides provide effective control