I kill lots of cattails. I don't think I have ever seen them in deeper than 3 feet, so that is not their problem. They instead encompass the entire shoreline. I like them in small areas. Some pondowners will treat edges (glyphosate) to keep from spreading. However I promise if established, they will after year one start to spread over the entire littoral zone and this limits fishing from the bank. Also with low fertility water in the south they take up fertilizer intended for phytoplankton.

Greg Grimes
www.lakework.com