Tree Peonies take a while to get going but when they do they can put on several feet in a year. Have you watered regularly and did you plant in good rich ericaceous compost? I'd also mulch to top dress.

OK thanks for advice, will do all you said

Personally, I would have mixed some compost with the soil rather than digging a hole and filling with compost. Hopefully you haven't created a sump for water if your soil is heavy.

I hope your tree paeony survived. As Fractal says if you do dig a hole it is a good idea to break up the soil in the bottom of the hole to allow water to seep away. They do not like being moved and do take a while to settle in and start flowering.