I moved my rhubarb under my old apple tree in an effort to subdue it (the rhubarb) but it is IMMENSE and vigorous, and the tree is productive as well. I put my lovage there for the same reason, and it is bigger than ever, flourishing in the shade. I have recently added some mint to crawl around in the shade but I can't tell yet what it will do. A New Dawn rose cutting is also there, planning to climb into the tree, and is just really getting going.