I don't really grow clemetis so I know little about them. I do have a couple texensis and though they are still small, I would like to try and start one from a cutting. How does that work? Any advice or suggestions would be welcome. I do have some rooting hormone but what else do I need?
Have you considered 'air layering'? I think that's the right term. Sometimes a vine or two of mine will fall down to the ground and will grow roots where a 'joint' comes into contact with dirt or even mulch. If I wanted to root one, I would try that method, since it minimizes the risk of failure by leaving the new plant attached to the 'mother' plant until it grows roots of its own.
To do this, just pull one stem/vine down to the ground and put a little soil over and around it at one of the 'joints' where the leaves grow out. With some varieties you can actually see little air roots growing out of these joints. You want to make sure one of those areas is in contact with the soil. You can hold it down with one of those 'lawn pins' or even a bobby pin or loop of wire that goes over the stem and then into the ground. Or put a rock on the stem, anything to hold it down w/o damaging it.
If you prefer, you can also pull the stem/vine down to a pot of rooting mix instead of the ground. Either way, just leave it there for a while with the stem in contact with the soil or potting mix. Make sure the soil stays moist and check it from time to time for roots going down into the soil. When the roots are sufficiently well developed, cut the stem (like an umbilical cord) between the newly rooted plant and the parent.
The beauty of this method is that even if the stem doesn't take root (and mine always do so wherever they touch soil), you won't loose the stem as you might with a cutting. Thus you will have time to regroup and try again and again, if necessary.
The problem is the plants are still small and do not have multiple stems to play with. I might take another look and see if that might be an option if there is more growth. I like the idea because as you said it means you don't have to loose the stem. I am not that good with cuttings but I have rooted some other perennials as you describe by burying part of the stem in dirt. I hadn't thought of that with these vines. I will let you know how it works out and will take a couple of pictures if I can. Any idea how long rooting takes for this method?
I've never bothered to time it. If the stem already has little nubs where the roots should form, then they will grow quickly once they feel moist soil. If not it will take a bit longer. My guess is probably no more than 2 or 3 weeks, but, again, I've never actually timed one.
I wouldn't 'bury' the stem too deep. It might be better to just pin it down to the soil and maybe put a paper-thin layer of soil on top - but not so much as to suffocate it or cause it to rot. The important thing is to make sure the stem makes good, solid contact with damp soil. That should be all it needs to get the idea to start making roots. You can use the rooting hormone, too, if you like, although I've never needed it (nor have the many clematis vines that have done this on their own in my yard over the years).
When you indicate that your clematis stems aren't long enough to redirect to the ground or a pot of soil, that gives me pause. It may just be that I don't understand your setup, but if the vines aren't long enough to double over and reach the soil again, they probably aren't long enough to be cut away for a new plant. You should allow the existing plant to grow to a certain size and fullness before you even think about removing stems to make new plants. Just be careful that you don't compromise the plant you have. If the existing plant really is too small for its stems to double over and reach the soil, it probably needs to keep all of its leaves to make enough energy to keep itself healthy and continue to grow.
How tall is it now? New stems should spring up and they will be more supple and you can gently bend them down to the soil to root - no hormone needed. The plant itself is feeding the layering. I don't detach it from the mother plant for a year just to be sure I get strong roots.
See the new growth here? They are all green as opposed to the old stems from last year that are brown. It's the new stems that will be suitable for layering when they're tall enough.