I've always been under the impression that the best way to stop cattails from spreading is to pull them out by the roots(Rhizomes),
this is the hard way, but they will still spread thru their root system.
I have them on my floating islands but they haven't spread anywhere else yet.
By the way welcome to the pond boss forum Cellog, it's a great place.
It's amazing how fast cattails can grow even up here in cold country. The first photo was taken April 24, and the second july 6.
