Wonderful plant! Shouldn't be hard to take care of. Bear in mind I am in zone 6, so our winters aren't as cold as long. The Tree forms ( called 'standards') that I have sold in the past actually ARE grafted at top of trunk, like a tree rose BUT unlike a tree rose, those grafts aren't as cold sensitive.
That being said , gardeners in my area don't so anything to prep them for winter. However ( I am a big fan of howevers and buts), I have spent time in the plains states in the winter , mostly Oklahoma, and I do know that the winds , along with the cold, will be this little shrub's worst enemy untill it has had a couple of years to become well established and acclimated. I would be rather nervous until then.
what you will need to do is give it a better support than that bamboo stake it came with. I would remove the bamboo one and replace it with a nice sturdy tomato stake or even a length of pipe. Anything you have that will give support until the trunk is strong enough to support itself.
I would remove the flowerheads. Right now they are just going to load with snow and ice and stress the trunk
I would also erect a 4 sided windscreenusing 4ft 1x1 stakes (furring strips)and any sort of cloth , burlap, leftover weed control fabric, even plastic sheeting. Drive the 1x1's about a foot into the ground ( hope it isn't solid frozen yet) and then staple the cloth to the stakes. I had a really nice drawing, but the hosting site is being stupid.
Well host is still stupid, but click that link.
Umm you may also want to go ahead and do a light cutting back. no more than 3 or 4 buds back on each branch. Tardiva bloom on new wood, in summer, so best to prune either now or early spring ( march)
Um I am not a big fan of tree tape. Has been my experience that it may cause more harm than good. IF you a re worried about critters eating the tender bark, cylinder of 1/4 inch hardware cloth around the trunk ( attatched to the new support) will do wonders, keep most rodents out.
Never hurts to mulch. keep mulch 2 inches or so away from the bark. nice deep 3-4 inch layer extending 4 inches or so past the rootbal. This puts thickest part of mulch right where it needs to be, over the root ends