One of my many planned gardening projects this spring is to put in a row of three tree hydrangeas behind a low fence on which my climbing roses grow (they are New Dawn. Note to rose fans: those New Dawn roses need monthly fertilizer during the summer. In fact, all roses want regular feeding or they will not do well).
I like the old-fashioned look of the tree form, and they can be pruned to keep them small for a garden. The one in the photo is too droopy for my taste, I think, but it makes for a living bouquet.