I don't prune mine Amsterdam, I know you can for aesthetic reasons, As its an early flowering clematis and flowers on the previous year's growth, But there are other members who have greater knowledge than me and will advise I'm sure.

I used to have a large one covering a wall. The only pruning I did was to trim off the long tendrils where I could and train others back in through the bush. If it had got too unmanageable then I would have had to grit my teeth and cut it down considerably. Glad we moved before it got that far.

But, yes you do prune it after flowering, definitely not in early spring or you won't get any blooms.

Ours gets butchered regularly!!!!! It grows against the shed and the tendrils go all over the place. One year we cut it right to the ground with the thought 'if it grows - good; if it doesn't - tough'. It came back stronger than ever the following year.

So does that mean "bloom before June do not prune" is out of the window?

My dad used to say that to stop spring pruning as it would have cut all the flowers off.

Unless you need to restrict its size, C. montana doesn't need pruning.

I hacked mine right back in late summer as it was swamping the shed and growing under the roof. It didn't seem to mind.