I have 2 coral louise. They are white with purple centers. They pretty much go with anything.

False Indigo, irises, early blooming penstemons--all bloom with the peonies and look great. Lilies and daylilies bloom after and the foliage is different enough to complement.

How tall do you want the shrubs? There are several types of mockorange, some really big (ornamental tree size) and some smaller. It blooms with the early to mid peonies and make a beautiful filler if you like to cut your flowers for inside. Smells wonderful, too. Joe Pye Weed is one of my favorites. The traditional one is pretty large but there are smaller varieties. I have a chocolate Joe Pye weed that'll never get over 3' and have beautiful foliage. Ornamental elderberries are gorgeous, so is ninebark, but I'm not sure if the size will work for you. The elderberry looks a lot like a Japanese maple. You're in zone 5, the smaller maples might work for you, too.

@lizbest1, I actually had to look a few of these up and can honestly say I don't think I've seen them for sale around my local nurseries, I will be sure to keep an eye out for them - they sure are lovely! I have a serious dislike for ninebark (don't know why) thank you for your great suggestions!

I saw some gorgeous pictures of itoh peonies growing at this website. Please take a look at his beautiful garden. Seems like they look really great with evergreens , irises, and hostas.

http://conradartglassgardens.blogspot.com/p/intersectional-peonies.html?view=flipcard

If you are looking for perennials, I would definitely recommend the Orion hardy geranium and clematis.