They are both nasty. Like I said, use at own risk. I get away with hardy water lilies the same way, I plant them at the 4-5 ft deep mark. For a few months they are dead and out of water.
Creeping Water Primrose is the number one creek, ditch and water body plant in my area. Good thing is they are easily removed, even by hand. I had a pond where the guy wanted a clear shoreline, covered with them. Boat and a rake cleared out the entire shoreline one season. They don't root all that deep and pretty much entire plant pulls up. You pile them up out of moisture and they die. Plus the water drawdown every season keeps them thinned. If they float to new areas I just hand pull them. They can handle the cold, drawdown, just about everything. Not much else works. They do not spread that fast in a still pond. I'm fishing all of the time anyway, scanning the shoreline. When I see it where I don't want it I pull it. You can also cut it low to slow it way down. The stuff out of the water pulls right up. But it's value as drawdown tolerant forage cover makes pulling it out in other places worth it. Cost is my labor. If I did not have a dead shoreline and the annual drawdown I would not use it or need it. Every pond is different.
