I have a crossvine growing on a trellis in one of my front flowerbeds. It was here before we moved in and I have no idea how old it is. It blooms in spring and a little (off and on) through the summer and fall so I know it isn't dead. But that is the only sign of life. It doesn't actually grow. It's the same size it was two years ago. The leaves are grubby looking - rather like artificial ones left out for several seasons (attractive mind picture, no?). They don't drop off and new ones don't appear.

It certainly doesn't need pruning because of excessive growth but would it stimulate new growth? Should I actually WASH the leaves? Could I fertilize the poor thing and get a bit more action?

What do you think?