Yep, Alwerdts is a pretty neat place, and they are the only place around that has a GOOD supply of pond plants. I'm sure you noticed the pond there, did you notice the plants in that pond? I kept asking him to give me a start of them, and he would always reply, "Oh, you don't want that, it's invasive!" I asked him why he has it then.

I figure any plant in a pond is invasive only for the pond, and we have to pull out the excess. Anyhow, it's called Water Fringe, and I got 3 plants off of Ebay, kind of was a group deal. Also got a tropical lily that is a day bloomer.
The joke with JW and Addy now is IF it's not totally invasive (takes over my pond by the end of the year), they want some starts of it next spring. LOL Anyhow, it's supposed to have a pretty ruffled yellow flower on it, it grows I think from either the bottom of the pond (my ponds are too deep, I think) or from pots. I'll post pics of the flower if mine bloom this year. Glad you found Alwerdts. They are expensive, but so are all the landscaping places. The only places that are cheaper the the big stores, and they have few if any pond plants.