If it were me, I would leave GC alone and go buy a new clematis from your local garden center in a gallon sized pot or bigger, to grow up the obelisk. If you cannot buy locally, Silver Star Vinery ships clematis with big roots, that will more than likely bloom the first year.

Thank you pmfermakov. Can I ask why you would leave it?

If I did not like the current location and the clematis was still small, then I would consider potting it up. Another point to consider is how if you keep dirt around the roots, then the dirt will be in the pot with potting soil. I guess that might not be a terrible thing, but I do not like the idea. Anyway, it is just my opinion. Good Luck!

I've moved plenty with no problems.