We have wrp project that is about 10 years old. for the first 6-7 years we had no problems with cattail or bullrush. the last two years both have exploded. Depth is anywhere from 2 inches to 4 feet (agridrain) We can not drain it completely due to ground water. My dad has a restricted use lisc. and we have been knocking the heck out of the cattail and the arrowhead that is starting to pop up. I sprayed everything this spring (early june) and again about 2 weeks ago (roundup custom per the nrcs). The bullrush looks like i never touched it. The second time I mixed it really hot and used coop surfractant. Any ideas on what else to use?