Posted: 21/12/2017 at 13:57
You can, I am doing the same with a row that have been here for a long time and have got terribly untidy, Thing is you will lose the flowers next year but the flowing yer they will look fantastic.
most people say that you should remove a third of the old wood, right back to the base, but if they are so overgrown, I think that looks worse, just having long bits here and there.
Heres a photo of one I pruned right down last April, the lot to the ground. No flowers this year but just wait until next😀
And here’s the row that’s coming right down this April. Don’t do it now as the frost will ruin the new buds.