I think chives are the classic herbal border plant. My garlic chives are exceptionally vigorous and give me an attractive summer flower. I just planted regular chives as a border today. Knowing me, in that situation I would be trying to plants flowering sub shrubs and bulbs. I'm attaching a picture of the garden sage underplanting my
rose bush. I hard pruned the rose back to three feet early this spring.
Actually, there are a lot of amazing drift roses available these days, if you get as distracted by the pretty as I do. They've been bred to stay under two feet without pruning. So far the only thing preventing me from buying some this spring is that I've already filled all my available sunny spots with annual vegetables. I still might give in and force some of my squash to just grow around them.