You must love peonies if you named yourself mudan. It might get too cold in a garage so I would suggest keeping it in a refrigerator instead for a few months until you can plant them out in the spring. If your ground is not frozen, you can probably plant them out now.

thanks Steve! yes, i do love tree peony.
i lost 2 peony last year. some told me the root was not developed enough during the fall and winter and the upper part grow in the spring without the root support, so the plant was stressed to death. they were sent to me too late! so i think this time, i should try to put it in a pot and let it stay warm indoor hopping the root can grown more and be ready for the coming spring . my garage is always about 40 degrade. is this too cold for it?
some said tree peony must stay outside during winter time. is that a must?
thanks

A tree peony benefits from the cold as it needs the dormant, sleep, time to grow roots rather than to attempt to grow foliage.

You must place most of the top stem under ground or growing medium so that roots will grow from the stem rather than the thick nurse, graft, root.

40 should be fine but if you can place near an outside wall would be better as in most buildings the outside walls will be cooler than inside ones.

If you do not have a pot tall enough for most of the stem to be below the surface the plant can be placed at an angle in the medium so that the top is above the soil line. Placing the top above the soil line will prevent rotting of the terminal bud.

thank you for the info. i will move it next to the garage door, the coolest place of the room. my plant is not a graft. it is a real tree peony. i wish i get the graft one, because i feel the grafted can be easily grown any time of the year. i got 4 graft japanese peony last year and planted them in the early spring instead of fall. they all flowered for me. i planted them deep enough so that they may grow into a real tree peony later.
but the Chinese variety doesn't have graft option. they are all imported real plants. they are harder to grow.

The Chinese ones that I have seen were all still on their graft roots. They were between 1-3 years and imported directly from China. Over that age they are not supposed to be imported.

could you tell me where to order them? i haven't seen the graft before.
thanks