Quack Grass can only be treated effectively and cost efficiently with roundup.
Quackgrass is one the most troublesome perennial grassy weeds in our lawns. Also called couchgrass, this herbaceous perennial dies back to "rhizomes" for the winter, only to appear again early the following spring. Rhizomes are underground stems capable of producing new plants. Because quackgrass is very aggressive and produces many rhizomes, it can quickly dominate a lawn. Many people mistake quack grass for crabgrass. Quack grass can only be treated effectively with roundup. Of course roundup kills everything so you would need to re-seed those areas. ANother option id to soak a towel in roundup and drag it over the taller quack grass, This will minimize killing the good grass as quack grows faster and taller than turf grass.