Hi Kelly,
I cut my cattails off below water line and for the most part they just rotted away. The pond is now about 1 ft below normal, so some of the stumps are showing. There are also three or four clumps where they are coming back, but that should be no problem. I left one side of the pond alone as habitat for minnows and small fry.
Two things I should mention:
1. My pond has less than 12" visibility because of suspended clay, so this may help keep the cut plants from coming back.
2. Safety! Somehow, when my dad was cutting with a machety into the water, the blade got reflected and he cut himself pretty bad. Always cut away from you. In the deeper parts, I like to keep the blade under water and cut the plants as close to the bottom as possible.
