Abstract: A trimmer apparatus for a lawn mower uses a drive sprocket mounted on the lawn mower cutting blade shaft and adapted for rotating a driven sprocket mounted on a trimmer shaft. The trimmer shaft is supported for rotation by a mounting bracket supported from one side of a housing of the lawn mower. The drive sprocket is engaged with the driven sprocket by a rotational motion transfer device. A string trimmer head is engaged with a clutch adapted for moving the string trimmer head into and out of engagement with the trimmer shaft, so that the string trimmer head may be engaged for rotation with the driven sprocket.