I have not yet been to the Garden Museum in London.
They are currently showing the work of one of my favourite garden designers. If you click on Green Fuse: The Work of Dan Pearson on their home page and take a look at the short video I hope you will be as entranced as I was by the beautiful camera work. The camera doesn't move, but the plants do.
For something sadder, and not so beautiful, look at this site's Coronation Wood page (top right) to see our efforts at first aid for trees!