an inproved cutting unit specially suited for grooming turf includes a frame supporting a conventional horizontally mounted driven reel having a number of spirally arranged blades . the cutting unit is supported on the ground by front and rear rollers . the front roller is a slotted expunger roller having numerous annular slots along its axis . immediately behind the expunger roller is mounted a knife roller which includes numerous vertically oriented knife blades aligned with the circular slots of the expunger roller . as the expunger roller rolls along turf , horizontally lying plant material is pulled or puckered up by the expunger roller into the circular slots . the knife roller , driven at a high rate of speed about its own axis , pulls up and slices through the pulled up plant material . the expunger roller is mounted to the frame while the knife roller is pivotally mounted to the expunger roller to allow the height of the knife roller to be varied without changing the height of cut or the distance between the knife and expunger roller axes .