A blade assembly for cutting roots is installed on a hand-carried weed cutter or hand-carried sidewalk edger. The blade assembly comprises a rear blade configured to support a plurality of blades on the shaft of the weed cutter. The rear blade has a plurality of teeth disposed around its perimeter, and a central opening configured to be received by the shaft of the weed trimmer. A front blade has a plurality of teeth disposed around its perimeter. Stacks of grinding segments are sandwiched together between the rear blade and the front blade, each stack of grinding segments extending partially around the blade assembly at an angle. Each grinding segment has a plurality of teeth disposed along an outer edge of the grinding segment. Spacers without teeth are adjacent to and separate the stacks of grinding segments from one another. The spacers are also sandwiched between the rear blade and the front blade.
