That’s a bold experiment, and it’s always a thrill to see foliage turned into something new. I’m intrigued by the idea, but I’d warn you to keep a few of those leaves in a proper archive—nature’s pigments are precious, and they can tell stories if preserved. The wall will look vivid, sure, but just remember the leaves you’re using could be the last record of a tree that might never sprout again. If you can, catalog the specimens before you paint, so the art and the archive both survive.