AbstractInfrequently mowed grass areas on institutional grounds and golf courses can reduce mowing costs and impart a natural appearance to the property. However, weed encroachment into these areas can compromise aesthetic appeal of the stand and increase costs associated with weed control. The objective of this 2‐yr field study was to determine the influence of grass species and mowing frequency on weed cover and stand quality. Six grass species or mixtures of species were established from seed and subjected to three mowing frequency treatments at a 12.5‐cm mowing height: one mowing per year (December); two mowings per year (April and December); and three mowings per year (April, June, and December). Grass species treatment influenced weed cover and quality on all rating dates. Treatments showing the least weed cover over two growing seasons included strong creeping red fescue (Festuca rubra L. ssp. rubra Gaudin) and tall fescue (Festuca arundinacea Schreb). The treatment showing greatest weed cover was autumn bentgrass [Agrostis perennans (Walt.) Tuckerman]. Mowing frequency did not have a significant influence on weed cover. Stand quality varied among species treatments over the course of the study and among mowing frequency treatments for individual species. Autumn bentgrass, a little‐studied species native to North America, generally provided poor quality throughout the study and appeared unsuitable for use in infrequently mowed grass areas on institutional grounds and golf courses. Whereas the quality of strong creeping red fescue and tall fescue varied with time of year and mowing frequency in this study, both species provide effective weed suppression and can likely serve as acceptable plantings in infrequently mowed, out‐of‐play locations on golf courses and in areas that are typically viewed from a distance on large institutional properties.