If you could mount some small eye bolts in the stones near the top to hang strings or wire from, you could have almost any climber/vine. Pole beans, sweet potatoes, cucurbits, climbing roses, or clematis come to mind.
What is your main objective - beauty, usefulness, or the bees? Do you prefer annual or perennial?
Four score and seven years ago, our forefathers brought forth this tiny ad:
Your suggestions have been mashed into the PIE page - wuddyathink?