I would not recommend that you plant your root in a pot. It is very difficult to get it water right when it is in a pot. You can easily over water or under water it. The most unfriendly environment for a peony root is wet and very hot. This will quickly cause the root to rot. Anyway if you still decide to plant it in a pot, make sure you put it in a shady place where the pot does not get direct sunlight. It can get hot very fast in the pot and the root will surely suffer.
