Thanks all!
Yan, if I have to transplant it I can try rooting hormone but I am not if it's good to transplant it now.
Liz, I am not sure it has enough feeder root (you mean a think one with all saved nutrients?), I probably cut half of what I received from Adelman's but also cut a few eyes leaving only 3, thought that was a good balance but I don't know. In March I kept the pot in a warm and sunny spot indoors, when it became too warm (I guess peonies don't like very warm environment in general and when they don't have a developed root system in particular) I placed the pot in a cooler though still warm place. When outside day temperatures became nice (up to 50F) I started to put it outside for a day. I return it back inside when evening temperatures drop to ~40F. One leaf bud shows some green and still hope for the best. But remembering Postillion with a small leaf which rotted anyway I am afraid it can happen to The Machinac Grand too. Would leaving just one bud help the plant to give all energy to that future leaf?
Tracey, I try to stay on a drier side and water lightly when my finger feels dry soil on 2" depth. Should it be more dry? The pot is not very deep (6") so I am afraid to dry out the peony.