Abstract: A blade assembly for cutting herbaceous terrestrial vegetation at a cutting speed of from about 1,000 to about 10,000 revolutions per minute, wherein said blade assembly is comprised of a U-shaped blade which has a Rockwell C hardness of from about 37 to 40, a flare resistance of less than about 15 degrees, and a bending resistance of less than about 5 degrees, and wherein said U-shaped blade is an integral, symmetrical member comprised a vertically-extending left cutting edge, a vertically extending right cutting edge, and a rotating support member connected to said left and right cutting edges, wherein:(a) said left cutting edge, said right cutting edge, and said rotating support member are integrally formed into a substantial U-shaped structure,(b) each of said left cutting and right cutting edges forms an angle with said rotating support member of from about 90 to about 95 degrees,(c) said U-shaped blade is from about 2.0 to about 15.0 inches long, from about 1.0 to about 3.