My peonies have been tarped for 3-4 months now, and I can finally get a sneak peak into the results. Some of them have done a good amount of growth underneath the tarps even though the average outdoor temperatures has lingered only around 32F for the past 2 weeks. It has been colder than average for the entire winter however it looks like the ground will no longer freeze so it should be safe to expose them to the air.
Here are some of the tree peonies that have really sprouted fairly well. The Chinese tree peonies seem to sprout way sooner than the Rockii ones.