I have never done this before so I have a question for you clematis experts! :)

I am rooting a section of my rooguchi clematis on a whim that fell off when I was planting it. I've never done this before but I thought it was worth a try since I would have just had to toss it anyway.

I soaked it in a glass of water for about an hour. I didn't have any rooting hormone so I wasn't sure it'd root. I plan on getting some for next time for sure. I have it in a tiny greenhouse that keeps moisture in and is in the windowsill and gets quite a bit of indirect light.

I cut off all the leaves except for the top two. I noticed that it is now growing leaves from the top and where old leaves were at the nodes.

My question are: Since it is putting off new leaves does that mean it's rooted or is it just using previously store energy?When do I remove it from all the moisture and just treat it like a normal clematis? And lastly, how should I overwinter this very young clematis assuming it really is rooted over a zone 5 winter? Is it best to plant it right before winter or keep it in a large pot? We have an unheated garage I could also put it in.

Thank you for any help!