Another plant I love that would do well, just a bit away from the semps is Tradescantia, there are a couple lower growing ones, and they have a pretty bloom. (yes I know they can get out of hand, so keep them on the edges of the bed!!)
Also there is "blue eyed grass" or it comes in yellow too, and it looks like mini Irises, again I'd put this on the edge, not right next to your semps.
What a fun project Jojoe!
