Family: Poaceae

Phleum pratense (timothy grass, meadow catʻs tail) is an abundant perennial grass native to Europe except the mediterrenean region. It is likely that the plant was named after Timothy Hanson, an American farmer and agriculturalist who is credited with introducing it from New England to the southern states during the early 1700ʻs. Upon his recommendation, it emerged as a significant supplier of hay and cattle fodder to British farmers in the mid-18th century. It is widely cultivated as livestock feed and is a key component in standard grass hay mixes, offering nutritious sustenance for horses. Timothy hay serves as a primary dietary staple for domestic pet rabbits, guinea pigs, chinchillas, and degus, often forming the majority of their food intake. It is reported to be widely naturalized globally including on Kauaʻi, Oʻahu and Maui. This grass is severely allergenic, and causes hay fever. Its grass pollen may trigger or worsen asthma symptoms, such as coughing or wheezing. It is, however, valued as a pasture species and not a widely managed invasive species outside of conservation areas.

High Risk Traits:

• Broad climate suitability
  
• Widely naturalized globally, including on Kauai, Oahu and Maui (Hawaiian Islands)
  
• An agricultural and environmental weed elsewhere
  
• Other Phleum species are invasive
  
• Allelopathic
  
• Host of crop pathogens
  
• Pollen is allergenic and contributes to hay fever
  
• Shade tolerant
  
• Tolerates many soil types
  
• Can form dense swards that exclude other vegetation
  
• Reproduces by seeds and vegetatively by stem fragments
  
• Rapid growth rate
  
• Seeds dispersed by wind, water, attached to animals and equipment, internally by grazing animals, and through intentional cultivation
  
• Prolific seed production
  
• Forms a persistent seed bank (at least 4 years in natural conditions)
  
• Tolerates heavy grazing, mowing and fire

Low Risk Traits:

• Despite naturalization, negative impacts have not been reported from the Hawaiian Islands to date
  
• Valued as a palatable pasture species
  
• Unarmed (no spines, thorns, or burrs)
  
• Non-toxic
  
• Herbicides may provide effective control