Please clarify the harsh conditions. Is salt tolerance an issue as I suspect? Are you needing a drought tolerant grass? Is rain the only cause of erosion? Also, what is making you second guess yourself & how long ago did you plant these grasses? I do not live by the beach, but these questions may help another answer your question better.

Thanks. We live on Grand Traverse Bay off Lake Mi, so it's a fresh water beach. I have not actually planted the grasses yet. They're still in the containers setting out by the steps. Yes, rain is the only cause of erosion. The area is on a slight decline so a hard rain tends to wash out the sand around the steps. There is a small amount of moisture there because of some irrigation in the lawn, but it's fairly dry overall. Thanks for helping me clarify.

Ammophila arenaria (European beach grass) should work well in this situation, although it can become invasive. Check with your local ag. extension specialist before planting. I don't know how well blue fescue would do in pure sand.

If I'm not mistaken, the Muhly grasses (pink/purple) do well in sandy/loamy soils. Leymus arenaria (European dune grass) is a good suggestion and it is also wise to heed the warning on it's incredible ability to run...

I live in N.E. Colo. on the plains, high winds, low rainfall, heat, cold, and very sandy soil. I have Little Blue Stem, Sand Blue Stem, and Love grass growing wild here. I don't see why they wouldn't grow there. They are all attractive grasses.