Thanks for all the helpful advice and ideas, which I will take on board. I will probably organize and get the rope fitted over the coming months ready for next year, perhaps just pinching any new shoots that reach the gutter now, the Montana will surely slow down it's growth soon. I can't believe how the plant has continued to grow since the flowers faded. I bought the plant as a tiny 3 or 4" plug last year, some of the clematis have done better than others, you are right, it does need plenty of room to spread out and can be a thug but with such beautiful flowers I like to think of it as a pretty strong plant.
We found it much cheaper to buy banister rope from a B&Q equivalent than at a chandlers. And we ended up with polypropylene fake rope! I defy anyone to tell the difference at distance of 6”. Although I prefer not to use plastics, I also prefer not to have to replace the rope when it rots so something indestructible seemed more sensible.
Posts
This sort of thing.....
https://www.ropesdirect.co.uk/beige-polypropylene-rope.html