They have been growing in my stream in Northeast Ohio for many years. They weren't planted. They just appeared. It laughs at Roundup. I thought of using a little blowtorch to cut them down, but I'm afraid of starting an uncontrolled fire in a residential neighborhood. I'm older, so doing something that requires a lot of muscle isn't possible. It used to be a nice stream with just a few cattails, but no longer. I want to be able to put bridges I've purchased to the other side, but that could also be a problem if the phragmites grow back. after they're cut down.