Abstract: A mower for mowing vegetation under a fence supported above the surface of the earth by a series of spaced posts comprising a horizontal boom connected at one end with a prime mover and supporting a mowing head at its other end. The mowing head is pivotal about a vertical and horizontal axes so that when contacting one of the fence posts the mowing head pivots around the position of the post while drawn by the prime mover in a forward direction. The mowing head is angularly tilted vertically for mowing a fence row or other surface on an incline with respect to the surface of the earth supporting the prime mover.