Rodeo will become your friend in the battle with cattails. It is a version of Round Up that is approved for use in the water. I have used it successfully in my battle at our duck pond - it’s very shallow...so great for ducks, but it's also great for cattails.
It will likely take a few years to get them all under control, but it can be done with persistence. Each seed head is said to contain 250,000 seeds, and they are supposedly good for 100 years. Even so, I try to spray before seed heads are established. If I’m too late, I will cut off the seed heads and bury them somewhere with dry soil. The fewer seeds the better!
Last edited by OAWC; 05-03-2018 at 07:42 AM.