We studied the allelopathic potential of above-ground vegetative shoots of 3-cultivars ('Ani', 'Bila', and 'Nandu') of Poa pratensis and their effects on the initial growth and development of 6-Acceptor plants spp (Agrostis capillaris cv. Niwa, Festuca arundinacea cv. Asterix, Festuca ovina cv. Espro, Festuca rubra cv. Areta, Lolium perenne cv. Stadion and P. pratensis cv. Bila) present in grass lawn community. Aqueous extracts from shoots of P. pratensis 3-cultivars were tested in Petri dishes on filter paper. Whereas, the dried chopped leaves of P. pratensis cultivars were incorporated in pots containing sand for assay. The phenolics and flavonoids in the plant materials were analyzed by liquid chromatography. The allelopathic potential of Donor P. pratensis cultivars on the acceptor plants were correlated with the leaf contents of flavonoids and phenolic acids and followed the Order: ‘Ani’ > ‘Nandy’ > ‘Bila’. The allelopathic potential of Donor cultivars on the Acceptor plants in Petri dish Bioassays was higher than in Pot assays. Aqueous extracts were more inhibitory to root growth than to seed germination and shoot growth. In contrast, in Pot assay allelopathic substances released from the decomposing cut leaves were more inhibitory to sprouting seeds than shoot elongation. The A. capillaris was most sensitive to allelopathic effects of P. pratensis cultivars followed by F. rubra and P. pratensis. The plants of F. arundinacea and L. perenne were least sensitive. With this in mind, it is advised to remove the cut grass from the lawn surface.