Is it possible to just cut back where it is most intrusive? They really don’t like being chopped totally back. I have a huge one that was accidentally damaged and it nearly bit the dust. Two years later it’s recovering but I did not lose all stems.

Thanks Kaillean. The vine is so tangled inside that it is just bare vines there. It really needs rejuvenating pruning. I looked at some pictures and think the variety is C. montana 'Willsoni'. There is a scent that could be described as "chocolate". Whether this makes a difference to how it responds to pruning, I don't know. But this C. montana is a bit different than the pink ones are. It is a very pretty vine. I don't want to kill it.

Gardengal, you are way more the expert than I am. I've read on some clematis pruning sites that you can cut C. montana at the base to rejuvenate it. One wit is quoted as saying "I think they (C. montana) have been brought to our planet by aliens to wipe out the human race." However if you say it will likely kill the plant, I believe you. My main problem isn't untangling it from adjoining plants. It is all the dead looking vine buildup on the tree trunk that it first grows up and drapes over. Which was the original intention of planting this vine way back when. To cover the old tree trunk. Which it did. But now we have all these ropy tan coloured vines tangled there, with the green stuff on the outside of this giant bird's nest thingy. Can anything be done?

You can cut it back hard.....but that is a relative term :-) 'Hard' in this case may mean no more than to a height of 4-5' or wherever the bulk of the current vining stems emerge from the trunk. Cutting back to the base would be a very risky undertaking if you want to preserve the vine.

If you decide to do a serious prune, do so immediately after the vine has finished blooming. And my recommendation would be to start at the outer reaches and work your way back carefully, stopping when you reach just above the point where you see most of the new growth being produced.

Try pruning out sections in stages over a period of years to encourage sprouting lower down. Stay above the 3 ft. level, mulch, water and fertilize to promote growth.

'Wilsonii' produces notched tepals and unusually long stamens, blooms late summer-early autumn. So yours would appear to be one of the other white Montanas.

"blooms late summer-early autumn"

I don't know where that tidbit came from but it is incorrect. Yes, 'Wilsonii' blooms later than other montanas but only by a couple of weeks, not a couple of months!! COTW and RHS both report bloom time of May-June, whereas other montanas tend to bloom here beginning in midApril in most years.

Mine is blooming right now.

Yes, my research indicated 'Wilsonii' blooms a couple of weeks later than the pink C. montanas. Which is right about now. Also pictures of 'Wilsonii' show pointed flower petals like my vine, plus pale chartreuse center stamens. Also mention of a 'chocolate' scent. My vine hits all those high notes, which is why I think it might be 'Wilsonii'. It isn't C. grandiflora because those flowers have rounded petal ends. Quite different to the pointed ends shown above. I'm going to post a couple more pictures as to what the vine looks like. You guys have been great with your suggestions! You've already convinced me that perhaps cutting things off at the base is not a good idea. But check out these pictures and tell me what you think.