I have a clematis, medium white flowers, which seems to flower in summer. It is in a shady position on a trellis under a tree. It actually climbed into the tree last year but I cut all that back in late Autumn (rightly or wrongly) as it became a bit brown and untidy. This month there are more buds on it than last year but they are all amongst a mass of brown growth on the trellis. I am loathe to prune it down thereby getting rid of all these buds. Should I just leave it this time? What is the best advice please?