Clematis Montana

can anyone advise me on my clematis? It is 15 years old and never been pruned. It flowers beautifully every year but is beginning to look a bit woody underneath. I am currently renovating my garden and have painted all the fences... except the one behind here!!! I want to know how far I can cut it back without killing it. It is about to flower but I am off on holiday at the moment and want to clear it and fungicidal wash the fence for a few days before painting. Therefore I am prepared to sacrifice the flowers for a year. The main stem is really thick. I just don’t know how far back I can go. Thanks.

 

You can cut a Montana back to about 3 feet now. You will lose this year's flowers. The new growth this year will flower in 2020. Normally with Montana you just light prune to shape and remove damaged growth, or cut back after flowering.

 

hiya Markymark
You can hard prune Montana and it, usually, comes back. Flowers will be lost for a year or two. It will prob be slow to regrow in its first year so be patient.
As Harry said, pruning every year after flowering is the way to treat Montanas to keep them looking good all the time

 

Fantastic! Thank you so much. I’m going to go for it!