Give your flower garden a layered look by planting tall, vertical species in the back-of-the border. They act as a colorful focal point to draw the eye and give the garden visual balance. In this border, pink mallow, which can grow 4 feet tall, teams with 3-foot-tall yellow Asiatic lilies to provide a spectacular backdrop of bloom. Other tall perennials include garden phlox, heliopsis, Oriental lilies, delphinium, allium, and lupine. Source by jeannel67