Quackgrass, or Elytrigia repens, is a perennial weed that is typically resistant to most herbicides. The weed is undesirable in lawns and can produce a noxious smell when it is cut down or mowed. The weed can reach to as high as 4 ft. tall and can be an unsightly distraction to your lawn. Quackgrass is also known as couchgrass and can spread quickly by seed. The weeds will die in the winter but return in full growth in the spring if not treated. Since most herbicides that kill specific plants won't work on ridding your lawn of quackgrass, you may have to consider a non-selective herbicide that kills all grass growth.
Resist mowing over the quackgrass to get rid of it. Pull out the weeds with your hands to remove them instead of mowing. Make sure that you wear latex gloves when you pull the weeds out by hand.
Dig out any weeds that may still be stuck in the soil. Quackgrass roots are particularly strong and complex, so you may need to use a spade to remove the entire rhizome from the soil.
Spread a 2-inch layer of mulch over the area where the quackgrass was growing. The mulch can consist of wood chips, grass clippings, dead leaves and manure. The will help to prevent re-growth of the quackgrass.
Continue removing the weeds throughout the summer so that the seeds of quackgrass don't spread. Also, continue adding mulch to the area to prevent the weeds. Consider planting plants around the quackgrass that will shade the area to help prevent re-growth.
Use a post-emergent non-selective herbicide if the weeds continue to come back in the spring. Apply such non-selective herbicide carefully as Finale and Roundup carefully to the quackgrass as it can also kill any surrounding grass.