Is it OK to plant/train Clematis with Cherry Blossom?

A Clematis would look lovely growing through your Prunus and be no problem to it! Don't go for a C. montana as they would swamp it - too vigorous, but an early summer flowering Clematis from group 2 which only need trimming in the spring would be the most suitable.

Ask at your GC for group 2 plants so you can choose one you like.

If you chose a group 3 one, you'd have to cut it back to just above the ground each year, and disentangle the dead growth in the tree - a nuisance for you..

I'd be inclined to wait a few years until the tree gets established before planting a climber over it. As it is slower growing than the climber, you don't want to give it too much competition and risk it getting swamped at an early age

There are short growing species that wouldn't swamp it! I would agree that a vigorous one would be too much competition. I saw a very pretty pink one with a japanese name... hmmm...having a senior moment, just can't remember its name. Anyway, it only grew to up to 6 feet and was a lovely colour. I shall get one if I see it again!

Thanks for the info guys. I think i will give it a chance to establish first then see what to do with it.