Abstract: A rotary blade (10, 110, 160) for a weed cutter, trimmer, or brush cutter and including a hub (20, 112, 162), in a first plane (28), a cup (30, 114, 164), a crown (32, 116, 166), in a second plane (34), and an outer skirt (40, 118, 168) whose margin defines a third plane (44), with the second and third planes (34, 44) parallel with and preferably on opposite sides of the first plane (28). The outer skirt (40, 118, 168) and the crown (32, 116, 166) protect the driving shaft (16) and the arbor (12) on which the rotary blade (10, 110, 160) is mounted from having fibrous material accumulate and wrap about it. Outer tips (72, 78, 86) of the cutters (50, 54, 58) rotate in different planes, thus cutting materials into short pieces and also helping thereby to protect the shaft (16) and arbor (12).