Yes. They like a rich soil based compost. Soak rhem before planting. Not sure about the drying out of the roots though, it is the one thing which Tree Paenies absolutely hate. Even the slightest time of drought when growing can kill them.

You could do this ,as I did with one yellow tree peony for many years ,and got a good result. My pot was too small, about 14 inches, and the shrub gradually had fewer flowers over time. My tree peony is now in the garden. and has come through a severe winter very well and has many buds. Make sure you provide a generous pot as they want to be quite tall shrubs. Feed it too. Some water retaining crystals in the soil might be a good idea too. We had a visitor and no one had answered when I typed this out!!!!