A lawnmower accessory assembly includes an extension arm having an inboard end configured for attachment to a lawnmower and an outboard end configured for supporting a trimming assembly operable for cutting or trimming vegetation. The trimming assembly includes a mounting sleeve fixedly mounted on the outboard end of the extension arm, an inner shaft disposed within the mounting sleeve, a rotatable annular pulley secured at one end of the inner shaft and a rotatable trimming disc having at least one trimming member secured at the opposite end of the inner shaft. The pulley of the trimming assembly is operably coupled with a drive pulley provided on the lawnmower by a drive belt such that rotation of the drive pulley in turn rotates the pulley and the trimming disc of the trimming assembly so that the at least one trimming member cuts or trims the vegetation.
