Cut back below the wilted area (and dispose of cuttings in garbage or burn) and spray with fungicide such as daconil or mancozeb. I'd post the question on the vine forum and I'm sure they know more than I do about clematis wilt.
It's a good idea when planting clematis to plant deep or mulch heavily to protect this wilt from traveling down to the roots.
Suspect prompt action is necessary to save your plant.

Unfortunately I found out what is wrong and there is nothing I can do. I was just outside looking at my plant trying to figure out what the problem is and I noticed all the way down the bottom on the ground the vine is cut. I figure that my lawn guy screwed up and hit the vine while mowing. Tomorrow I will replace it, there is nothing I can do to save it.

Giniene, plant your replacement close to the old root and leave that in,
chances are pretty good it will send up new shoots, either this year
or next. The root is healthy, these plants, though capricious
and into drama are amazingly tough. I've seen come-backs after several years!
You could even do a different shade and let them mingle.

Giniene, don't be too hasty about replacing it. I have a clematis that I accidentily cut the stem close to the ground on, and it sent up new shoots. Believe me, I was beside my self. I had a gorgeous clematis growing up a stump (7 ' high). There was a wild virgina creeper that snuck onto the same stump and I wanted to get rid of it...I was really being so careful to get the right stem..when all of a sudden I realized I cut the wrong one( there were several of each there)....I was sick..I did it myself! My hubby was so glad it wasn't him, me too, I'd probably be upset with him.. Anyway, it grew several new shoots from the ground and it is even more beautiful that ever. Good Luck, I bet it will be back..

Thanks so much for the advice. I went out this morning and bought a replacement, although it is only about 6 inches high, mine was little more that 5 feet tall already. After reading your posts, I decided to be careful where I planted the new one and sat down to dig. Unbelievable, there are 2 shoots coming up already! I guess the rain last night and all of the sunshine today helped.

That's great news..it must have been happy there, it sounds like it was healthy before the accident...chances are it will regrow quickly...So what did you buy as a replacement?

Congratulations on the resurrection Giniene!

As far as I'm concerned, you can't have too many Clematis.
I just found one blooming up an apple tree by a new pond we're bulding.
It's an incredible almost blue dark purple, Forgot all about it!
I think it's one of the Jackmannii, what a lovely surprise!

She was really healthy, had beautiful deep purple flowers, they looked like velvet last year. I ended up getting a red asao, really wanted to get a white one, I figured it would look nice with the purple if it came back, but red was all I could find. That's ok, I'm just hoping she continues to grow as she was before, she'll be 5 feet tall again in a few weeks.

HI, I'm new. I'm also new at planting. Just 3 years ago my husband and I moved, and I have my first garden. I want to tell you that this site saved my clematis. If it was not for research, I would have just pulled it out. One day soon I'll upload an image of my gorgeous Armandi. Anyway, I planted it in September of 2003. It bloomed a little in May 2004 and then this year. The blooms were all over my fence. Absolutely gorgeous! Then in June the leaves started to turn yellow at the tips. Then brown. Then the whole plant started dying. I was frantic. The woman at the nursery was no help. So I followed the instructions to cut it back. MY CLEMATIS IS REVIVED!! I cut it back up to 1 foot from the ground. Around July 1st I saw the little sprout, and now it 5 feet high! I'm so excited. I hope you can save yours to.

Great story, Maggie, I'm glad it worked out for you. My clematis' are BOTH doing great right now. I'm glad I followed the advice and was careful where I planted the new one.