Planting ideas anyone?

I have a small bed about 10' x 3' with a single off centre rose, a bit of yellow sedum and bog standard aubretia.  I've tried to get stuff draping over the wall but the plants always invade the whole bed instead. I usually fill it with bedding but wondered what ideas you great minds could come up with in the way of pernnial or semi perennial planting.  The bed has a twin the other side of the steps up to the lawn with a bit more permanent planting with sedum, rockery calendula, aubretia, oxalis.  The lawn gets mowed (obviously)  and so will anything invading the lawn space, P is not very protective of any plants invading the lawn edge  
I'm not thinking things 4ft high but I'm open to ideas.