It's definitely a clematis and does appear by leaf shape and flower to be Clematis ternifolia or SAC, although SAC typically is a very rampant vine and blooms profusely in our area regardless of care. At any rate, it is a pruning group 3 or one that blooms on new growth. While pruning is never a requirement on clemmies after establishment, most do prune annually to clean up the vine and maintain a manageable size. And some types of clemmies will rebloom if pruned lightly after the first flush (not this type, however).

Pruning group 3's are typically hard pruned, cutting the plant back to the third set of buds from the ground (about 18-24 inches on established plants) at the same time one would prune roses here....February or March. You'd fertilize at the same time if this were necessary - I've never fertilized my SAC (no need), but I do fertilize many other, less rampant forms of clematis.

My SAC has been in the ground somewhere around 15 years now and has developed a very thick, woody main trunk. It is trained primarily on a large antique wrought iron screen and I prune to fit the screen - the main budding stems begin about 3 1/2 feet from the ground. So the actual height one cuts back to when you do your pruning does depend a bit on the specific situation. I am seriously thinking of removing mine although I do appreciate the late season bloom and honey-like fragrance - it just too darn big and aggressive, devouring the screen, the fence and any other nearby plantings, including growing 1/2 way up my apple tree. This year it glommed onto my golden Hinoki cypress, planted about 15 feet away - it's becoming a little shop of horrors plant!! There are just so many other wonderful clematis selections (and other vines) that behave a little bit more modestly to take its place. But this still is a very popular and sought after clem, despite its being listed as invasive in many parts of the country - it does not appear to be so here, yet.

There is a very active Clematis forum here on GW that a number of PNW posters participate in. You could also post there if you have further questions about these plants.

Thank you so much, gardengal48. This is very helpful. With all the snow damage all around our place, I think I and my felcos are going to be very busy in Feb and March!