Annual Ryegrass is a cool season perennial grass with a tufted growth habit and glossy dark green leaves which are often purplish at the base. Perennial ryegrass possesses a membranous ligule with a folded venationĀ and characteristic, claw-like auricles. The seed head appears in spring and early summer as a long narrow spike with a long cluster of small dark seeds at the top. Ryegrass can be a challenging weed to control in turf due to its tolerance of close mowing heights and resistance to many herbicides. ItsĀ dark green colour also makes it a desirable turf variety in some parts of the country.