Here is a link that might be useful: Quackgrass
oh......that's not good.
Any ideas on how to get rid of it? I've got one nice crop of it.
I don't sure if there is a selective quackgrass herbicide, but if not you could wipe the leaves with roundup. It's easy to do if you mix a little roundup in a bucket and then wear one of those yellow heavy rubber gloves (the ones they sell in the cleaning supply section at the store) covered with a cotton glove and then dip into the solution, squeeze excess and then run you glove from the base to the tip in one smooth swipe. If you try to pull it up you could be pulling up runners for a very long way across the area. If you try to till it up you will be sending pieces of root every which way...each piece grows a new plant!
Best luck to you :)