They are rooted from what I could reach with the shovel. I know from what I have read, I have "water smartweed". Two others that I read alot about the past few days were swamp and pennsylvania (sp?). One of those could be what you have. Seems there were over 30 different varieties of smartweed. The pond next to the shop is pretty intense. That is why i spaced mine like I did...maybe it won't get ahead of me. lol. We shall see. Do some google searches on it and look at the images. Seems ducks like the penn the best. Something about the waxy coating on the water smartweed like I have...its tough for them to get through.

Maybe my "smart" weed won't end up being a "dumb" weed for my pond...lol

Love to see some pics of what you have though and the other two you spoke of.