 With its great ability to set seed, its ease of germination and vigour, it has spread from the fields where it has been planted to roadsides, trackways, footpaths, wasteland, river banks and sand dunes.In countries where it has been introduced, it may be regarded as an invasive species that competes with native plants.Perennial ryegrass is an important pasture and forage plant, and is used in many pasture seed mixes.