Maybe you should do a soil test to see why peonies are not thriving in your garden. Perhaps, it is too acidic? Yes, light is important but I think they should at least give you a few blooms in spite of being in some shade. I have peonies growing in partial shade but still produce a few blooms for me though not as floriferous as those planted in full sun. My Red Charm is planted on the north side of my house and in complete shade most of the day and yet it still produces some blooms for me every year.
