Thanks

Yes, that's it. Declared noxious here as it is so invasive - so much
for that idea.

David

I have the stuff here in CT it came by way of a pet store with
tropical fish.
It is an EXTREMELY fast grower and spreader. I would be wary of it
south of Philadelphia. In one summer a fistfull of the stuff covered
the surface of an unused swimming pool about 4-6" deep.
For me it works as a biofilter as I harvest it from my aquariums and
use it as mulch thus removing excess nutrients.
Again you don't want this plant anywhere it's warm.