Grass Species and Mowing Frequency Influence Weed Encroachment in Naturalized Grass Swards.

Naturalized grass areas on institutional grounds and golf courses can reduce mowing costs and impart a more natural appearance to the property. However, weed encroachment into these areas can compromise aesthetic appeal of the stand, and increase labor costs associated with weed control. The objective of this 2-yr study was to determine the influence of grass species and mowing frequency on weed encroachment and stand quality. The study was conducted at Longwood Gardens in Kennett Square, PA on a silt loam soil amended with compost. Six grass species or mixtures of species were established on September 14, 2009, and subjected to three mowing frequency treatments at a 5 inch mowing height; (1) one mowing yr-1 (December) (2) two mowings yr-1 (April and December); and three mowings yr-1 (April, June, and December). Grass species treatments showing the least amount of weed cover and highest aesthetic quality ratings over the 2-yr test included strong creeping red fescue (Festuca rubra L. subsp. rubra) and tall fescue (Festuca arundinacea Schreb). The treatment showing highest weed cover and poorest quality was autumn bentgrass (Agrostis perennans (Walt.) Tuckerman). Mowing frequency had a significant influence on weed encroachment, with the three mowings yr-1 treatment showing less weed cover for most species than the one mowing yr-1 treatment.