Some of the best trees for gardens that are shady are deciduous trees. They provide year-round interest with new growth in spring, lush greenery in the summer, vibrant colors in the fall and architecture in the winter. Try the Japanese Angelica Tree which enjoys well-drained soil, bears white flowers and small blackish fruit. The Silky Camellia is another beautiful small shade tree that prefers moist soil. This small tree's beauty lies in its waxy flowers and a bark that peels. Japanese Coral Bark Maple is another shade alternative that makes an elegant statement in any shady garden.
There is a wealth of trees that can tolerate full sun. One of the best for a large garden is the American Beech. It grows from 50-70 feet in height and prefers an acidic soil. This gracious tree matures into a rounded shape with branches falling close to the ground. If your yard is small but sunny try an Amur Maple. This small, multi-stemmed tree grows to about 20 feet in height, with clusters of fragrant flowers in the spring. Fall color can be red or yellow. Callery Pear is a good choice for a medium-sized tree.
If you wish to focus on native trees the American Linden, also called Basswood, is a good choice. This tree can reach 80 feet in height and can be grown in full sun or partial shade. It grows fast, has fragrant flowers and dense foliage. Bur Oak is another native tree that is slightly smaller than a Basswood but has a spreading form. It can tolerate wet and dry soil and enjoys full sun. Green Ash is also native but is not recommended in states where the Emerald Ash Borer insect is present.
One of the best small trees that you can choose to plant is the Eastern Redbud. It features a multitude of bright pink flowers in spring and changes to a brilliant yellow in the fall. It can tolerate sun or partial shade. The Carolina Silverbell is a small native tree with a rounded mature form. It, too, can be planted in full sun or partial shade. The Corneliancherry Dogwood grows to a mature height of 25 feet, bears small yellow flowers and has a mottled bark.