Tina,
You need to balance the roots with the top. I would trim all stems back, leaving no more than 2-3 leaf nodes above ground. Whatever roots you have left will have to support the top growth, and with severe root damage like that it will be tough. Keep your fingers crossed and prepare to not see much growth this year - it needs to regrow its roots before it can expand upward. Good luck!
Grow

I would just add that you need to give it lots of water this year also.

I would also repot this Clematis in a pot until late fall or better yet until Spring. I have many Clematis that have been in large pots> 15 gals pots for 5 or more years and I get more blooms off of them then some of the ones that have been in the ground for several years:

Thank you for the responses!

Grow_darnit, (I like the name), I trimmed the vine back. I had a long piece that I couldn't get myself to throw out so I stuck it into rooting hormone and potted it.

Ophelia, yes, lots of water. It's raining and will continue to do so tomorrow. Plus, the temperature is on the cooler side!

Sandy, I had already put it in the ground and did not want to stress it by digging it up again. But, it's good to hear that they can do well in pots. Only a small section of my yard gets good 4+ hours of sun. I have 40-50' maples and oaks on all sides of the yard. The entrance of the driveway gets the most sun. If the propagation takes, it's going into a pot.

I'll post an update in the fall.

Thanks again,
Tina