The aim of the study was to assess how the proportion of dicotyledons in the lawn was influenced by aboveground biomass containing Festuca rubra, cv. ‘Areta’, ‘Nimba’, and ‘Olivia’, cut and left on the lawn surface. This influence was evaluated based on the changes in the species composition of the lawn sward. In the control treatments, the cut turf was removed from the lawn surface immediately after cutting. The study showed that the botanical composition of the lawn varied and depended on the cultivar of F. rubra and the assessment date. In the treatments where the cut turf with F. rubra ‘Areta’ and ‘Olivia’ was not removed, grasses were found to have a higher proportion than dicotyledons and other unsown species, both in the spring and autumn. In the treatments with ‘Nimba’, this effect was only observed in the autumn. ‘Nimba’ demonstrated the greatest ability to limit the proportion of dicotyledons in the lawn sward.