I don't know where to post this.. But I was fishing and in this by a few rocks where I was standing. I was looking at it and realised it wasn't a native plant to my state so I took it out and will be giving it to my dad for his pond.
I have it in a bag for now and its going to my dad's pond tuesday. I have no idea how it ended up in the river, but on the NJ site it said it was an invasive plant, but rarely found in rivers or lakes.
That stuff can take over in warmer climates, though it does have pretty purple flowers. I got a small piece saturday for my little 2 gallon that just has plants I've collected. The delta is choked with the stuff.
My dad still wants it and it might not survive the winter.. but it gets it out of the river. My dad throws plants he finds into his pond a lot and never cleaned them.
It grows in SE Texas, too. It's illegal to keep it because it's considered a non-native invasive. It has gotten into a lot of lakes and rivers...along with cana snails.