All plants need water to survive. However, like plants that require more water, there are plants that grow in lack of water. They are the best drought tolerant plants and can live without water for a long time.
I love colorful foliage plants. They also are perennials and would come up here after year. I think this is a beautiful idea to plant these hosta type plants under a tree with all their different colors
Horsetail and creeping jenny - very compatible, they both like it wet. This kind of plant combination is fairly easy to maintain because it doesn't need a drain hole in pot, you can fill it with many days worth of water, even in hot weather.