Waiting until Fall is the route you should be taking. In the meanwhile select the location you will be moving it to, dig an extra large hole, dump two bags of dehydrated cow manure along with some alfalfa pellets if available and cover the hole back up with the soil that was removed. In the next few months the organic matter will decompose and will give you an ideal footing / home when you transplant the clematis in fall. I will also recommend watering the new location periodically to hasten the decomposing of the organic matter. Success is guaranteed with this approach. I have done this on a few of my clematis ( I have like 50 different types in my one acre property) . I got hooked after visiting "Climbery" a clematis garden in German town, New York.

zone 6b OR

Thank You aluvaboy maybe I did not explain well enough. I have tried to wait till fall before with this clem but by that time the plant has disappeared.

I am thinking of letting several buds blossom, meanwhile I will boost the plant for 2 weeks with Epsom salt, mycorrhizae, alfalfa tea. Then move to a better location before the hot weather sets in. I hope that this will work better than waiting till fall and having it disappear again.

I guess you roll the dice and take your chances!