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?
The two armies met. But instead of battle, they decided to eat some pie and contemplate this tiny ad:
Escape to gardens and natural buildings (for free-ish) in Montana