An active rotary harrow is towed with its longitudinal horizontal axis at an acute angle relative to a line perpendicular to the direction of travel. A plurality of unitary tines are mounted by bolts or rivets on mounting plates which are secured to a shaft aligned along the horizontal axis. Each tine is made from spring steel which is flattened on one end, the flattened portion being mounted directly on the mounting plate by two or more fasteners. The tines are curved such that the outer end of the tine, being rounded in shape, is directed towards the trailing end of the harrow when in operation. The tines, and to a lesser extent, the mounting plates, are resilient in nature and can be deflected towards the trailing end of the harrow, when obstacles such as rocks are encountered. The tines are also capable of some pivotal deflection, to a lesser extent.