The present invention relates to cutting tools, in particular, to control systems for cutters such as vegetation cutters, especially hedge cutters or trimmers (10). Hedge cutters (10) frequently suffer in use from a problem of blocked cutting blades when they encounter a twig or branch whose size or density exceeds the capacity of the blades. We describe a vegetation cutting apparatus (10) having a plurality of cutting blades (11,12), at least one of which blades (11,12) is drivable by an electric motor. At least one driven blade (11,12) is movable between two predefined points of maximum travel. The apparatus (10) includes a control mechanism which causes a change of direction in the movement of the at least one movable blade at a point intermediate the points of maximum travel in response to an event sensed by the control mechanism.