Trees are considered the "bones" or structure of garden and landscape design. Ornamental trees can do so much for the garden and landcape, including adding color through their flowers and foliage, providing shade, and creating a privacy screen. They can also provide shelter, and sometimes even food, for songbirds. When selecting ornamental trees for your garden or landscape, consider their shape and size as well as if they grow best in full sun, partial shade or shade. Also note their flowering time and grow zones. Trees can be planted in the spring or fall.