Abstract: A grass trimmer includes a structural support frame, a single ground engaging wheel connected to the frame, a rotary trimmer positioned to rotate around the wheel, a motor mechanism to drive the trimmer mechanism and a user handle attached to the frame. The single wheel and location of the wheel relative to the trimmer mechanism allows the operator to very accurately guide the apparatus and to adjust the cutting height of the trimmer quickly and easily to the terrain by tilting of the apparatus about the wheel to one side or the other or from front to back by rotation about the axis of the wheel.