What you are calling quackgrass may have other names in other parts of the country.
It may be a good idea to first do a Google search with the keywords 'quackgrass botanical name'; the result is Elymus repens.
Look at photos to make sure that is the same plant you know as quackgrass.
Then punch the botanical name into a search adding the words 'common names'.
Couch, twitch, quick grass, quitch grass, quitch, dog grass, quackgrass, scutch grass and witchgrass. Whew, no wonder it's so hard to get rid of; lots of aliases.
Then search for herbicides specifically for that plant. Don't know what herbicides will do to flower plants as most label information is about crops. If you have a feed & seed store they may have something that will work. Also, check with your local county cooperative extension.
