Sounds like you planted dormant root stock. Here in Michigan we would have planted them in September so they at least got a start on setting some roots before winter -- and planting on hight and dry land. Peonies don't really like it wet. But, sometimes we can't control when we get the time to plant and Mother Nature. Last year we had severe flooding in late winter. Much so that we had to dig trenches all around the greenhouses. The water ran just like a creek. And, then a dastardly thing happened. We had the worst drought we have had in 20 years. We just never know. If it is seriously wet, you may have to pull them out and let the soil dry out a bit so they don't get root rot. I know. 700 peonies. It's alot. Several acres of dahlias is alot as well. We farmers. We're hardy folks.

Warmest Regards,
Trish