I certainly don't know the answer. However, since every pond is different, perhaps try some experimentation?

Maybe take some cheap plastic pots and drill some holes near the top, throw some gravel in the bottom, throw some of your pond edge material on top of that, and then try some of your ideas. See what is effective, and then do more of that directly in the pond next year.

Good luck! We do have some members with some nice iris edges. I think they suppress erosion, don't grow tall enough to stop anglers from fishing over them, and do inhibit the colonization of some invasive plants. All of which would be good in your pond.