I do have an area where Quack grass like to creep into my lilies, and I have often thought that this would be an easy solution. But for me, the window of application is fairly short, when the temp is warm enough for Round Up to work, when the weather is right, when I have the time and when there are no lilies present above the surface. Spring is the only possible time for me, as my lilies don't die back in late summer or early and mid fall. So far, something has always precludes my trialing.
