Very nice! It might be 1 I've killed before
, there have been quite a few over the years...My plant club is full of plant pushers. "Try it, it might grow for you". Hah! I put quotes around pond, I could tell that much. Do you have window light to get it to flower or what?
I was thinking of purple/pink loosestrife, obediant plant, or something similar. Supposedly some the color cultivars don't turn into weeds but I'm skeptical.