As far as what cultivars do best in full sun I won't make any suggestions except try and find out the parentage of the ones you want. Tenifolia parentage likes more shade. My suggestion is on you day off, go to the spot you think you want to plant in several times of that day to see exactly where the sun is. Tell your family you need time away get a book you have been wanting to read, a good drink, and a comfortable chair. Sit in the shade and watch. Depending on the season what you see will give you a good idea of sun strength in a particular spot.

Early blooming flowers benefit from the sunlight and build energy before the leaves are on the trees and then go dorment until next season.

Think of the sun as a large hose. Sunlight as water. Depending on the distance and angle if you spray straight down at an orange(think plant)you get everything wet except right under the overhang. From an angle part will be in bright sun, part in light spray (non-yellow light rays) and the part directly around the orange receives no water except for runoff. Perhaps someone can explain why some plants need more of the yellow spectrum than others. At the distance from the sun to earth unless directly under something all the other light waves should hit the shady side of anything.

They flower best when in full sun (at least 6 hours of direct sun). In more shady areas of the garden, foliage takes priority over flowers.

I have 2 white peonies that have faired well with only afternoon sun. This soil is great though. :) i have seen pics of larger size peony plants than my 2, but mine still have enough blooms to fill vases for a few weeks.

I find that Itoh and tree peonies do well in only half day sun.

Florence Nichols is a white peony that has bloomed in its first spring after planting in the pervious fall and has many buds this 2nd spring. I have it in morning sun only.

This year

totoro Z7b MD , lovely!