I have this combo in a large bed and it looks great. I love the look of the peony leaves even after its finished flowering. After they're done blooming my salvia, daylilies and coreopsis start coming into their stride.

tracey

Also add some coneflowers like echinacea and rudbeckia....... something with soft foliage like moonbeam would be nice to soften sharp leaves..... :)

Just be sure you plant flowers that don't like to recieve much water, as this is not good for the iris. It will cause fungus. I am moving mine around to put them with more drought resistant perennials. Shasta daisies, coneflowers, coreopsis, liatris.