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?
Everyone is a villain in someone else's story. Especially this devious tiny ad:
grow your own garden and build your own home, in Montana, for free-ish