Many thanks to both of you. Mary Anne, I do not know the answer to your question, being but a humble engineer, and no botanist. I can say, however, that this garden is famous for its rhododendron, so that would be my best guess.
Charlie, that leaf underneath is beautiful--so large and lacy with those web-like skeletal veins. I've never seen anything like that. What kind of a leaf is it?
--Mary Anne