They are hard to disconnect during the growing season. Attaching tendrils are very delicate and break easily (ask me how I know!!). Depending on type, cutting back could alter the bloom season (type 3's only now coming into bloom in my location) but only temporarily....will be back on schedule next year. Otherwise, cutting back low won't hurt it at all.

Thank you very much for your response. They are finished blooming with just an occasional flower here and there.

No worries then :-) I grow most of my clematis in containers and I do shift the containers periodically, switching out out the early bloomers for those that flower later. And that often involves cutting back the clem from whatever support system I was using. I've done it twice already this season and still have one more to do. Typically the cut back clems respond very rapidly with regrowth - one is already 3' tall and the second, a bigger vine overall, is approaching 6' after just a month or so!

I saw where someone on another thread was recommending Alfalfa meal as a supplement. What is your opinion on using that?

Yes, alfalfa meal or alfalfa tea is excellent for clems. It contains a natural plant growth hormone that encourages basal stemming.....always a good thing for clems!!

Hate to bother you again. Should I use it right after I cut it back or in the fall?

If you intend to use it, use it now. Fall is too late to fertilize.