Assessing Competitiveness of Fine Fescues (Festuca L. spp.) and Tall Fescue (Schedonorus arundinaceous (Schreb.) Dumort) Established with White Clover (Trifolium repens L., WC), Daisy (Bellis perennis L.) and Yarrow (Achillea millefolium L.)

Regulatory restrictions on herbicide use for managing turfgrass weeds has prompted the search for alternative control strategies. Fescue (Festuca) species were identified for their potential to interfere with growth of annual and perennial weeds. In a study conducted in 2018 and 2019, six fescue cultivars were tested from five different species for interference with the growth of three common turfgrass weeds: white clover (Trifolium repens L., WC), daisy (Bellis perennis L.) and yarrow (Achillea millefolium L.). Fine (Festuca L. spp.) and tall fescues (Schedonorus arundinaceus (Schreb.) Dumort.) were sown and grown in a field trial for 14 days before overseeding with different weeds. vigor and visual quality of grasses, weed cover, and vegetation cover was recorded regularly for 84 days. Differences in mean temperatures and precipitation between the two years of the study resulted in differences in growth of grasses and weeds, as well as in the extent of weed interference of fescue cultivars. Cultivars Musica (F. rubra L. ssp. commutata Gaudin) and Barpearl (F. rubra L. ssp. littoralis) were least affected by weed growth during both years, but there was overlap with other cultivars for the measured parameters. Melyane (tall fescue) was deemed unsuitable for natural weed suppression because growth and vigor declined after first mowing, ultimately leading to unacceptable visual quality. Turfgrass visual scores were moderately negatively correlated to weed cover in both years. Future research should focus on F. rubra L. ssp. rubra Gaudin and F. rubra L. ssp. littoralis subspecies and identify the mechanisms used to interfere with weed growth.