Can I cut back a Clematis Montana?

littlesparrow11

I have a very old ( over 30 years ) spring flowering Clematis. It is now really ragged and tangled but I have always been told not to prune it too hard.
 It's now at the point where I have been thinking of getting rid of it and planting a new one but if I cut it right back to near the base do you think I could save it?
If so, when would be the best time to do it? 

Sarahspangles

If it’s just finishing flowering, do it now. I’ve never seen one killed by really hard pruning, my mother had one that had a trunk like a small tree, she lopped it at 6” high and it flowered really well the next year.

Next year’s flowers come from the wood (stems) that ripen this year. This is probably why you’ve been told not to prune too hard - ‘tidying’ later in the year or when you can see/get at the whole plant over winter will reduce blooms. But renovation only sacrifices at most one year’s show.

twopenny

Yes cut it back.
You've got a strong established plant. 
Get it to the height you want less a chunk and try to keep some of this years growth here and there for flowers next year.
https://www.gardenersworld.com/plants/how-to-prune-clematis/