WordNet (r) 3.0 (2006):

evergreen grass
    n 1: coarse perennial Eurasian grass resembling oat; found on
         roadside verges and rough grassland and in hay meadows;
         introduced in North America for forage [syn: tall oat
         grass, tall meadow grass, evergreen grass, false
         oat, French rye, Arrhenatherum elatius]