Abstract: An in-ground lawn cutting device is disclosed that uses a rotating cord to trim and mulch grass much faster than conventional means. A spool rotates at high speed and extends a weighted cord that cuts grass within a circle. The spool height can be slowly lowered to mulch grass as it cuts. When finished, the cord is retracted and the spool can be lowered at least partly below grade. The device can detect the height of surrounding vegetation and/or the presence of nearby obstructions through reflection or transmission between devices of LASER or other light. The device can issue an audible and/or visual alarm when an obstruction is detected, and/or immediately before and during the cutting. In some embodiments the device can be tilted, the cutting cord can be adjusted in length, and/or a controller is included. The controller can be wireless, hand-held, and/or controlled by a hand-held wireless remote.