A walk-behind greens mower having a mobile structure and a ground engaging traction member rotatably coupled to the mobile structure. The ground engaging traction member imparts traction movement to the mobile structure for movement on the ground at a ground speed. An internal combustion engine is supported on the mobile structure and outputs a driving force to the ground engaging traction member. A bed knife is supported by the mobile structure having a cutting edge that cooperates with a grass cutting reel rotatably supported on the mobile structure. An electric motor supported on the mobile structure rotatably driving the grass cutting reel at a rotational speed that can vary depending upon the detected ground speed.