We have a wildflower nursery just about an hr south of here where I have sourced a bunch of aquatic plants to populate a sewer wetlands system.

They have a ton of variety and a great place shop for such, not sure if they would ship dormant plants or not.

The actual name escapes me right now but I can find them if you would be interested, they are in central MO.

All the really good ideas I've ever had came to me while I was milking a cow.