Are they planted in a heavy soil with little amendment? I believe heavy soil tend to have poor drainage. If that is the case then maybe you can raise the bed with a mixture of compost.

Hello weeper,
There is a lady with a peony farm in SK. I have ordered from her; her product was excellent. You can contact her with questions. Not only does she know peonies, but she has knowledge about your province.

Here is a link that might be useful: Boreal Farms

I too lost a few peonies over this harsh winter. I divided an itoh Pastel Splendor, a two years old plant into 3 divisions and two did not make it. When I dug them up, they were all rotted. It was like they were frozen before they were able to put out roots.

I don't think I lost many but the heavy hail storms we had this spring damaged a lot of blooms and stems.