Getting the greatest benefit out of the shade tree in your yard begins with planting. The keys to enjoying tree shade over your roof, patio or play area are like the old keys to business success: location, location and location. From general planting guidelines to specific energy-savings calculations, you can find help to take the guesswork out of where to plant your shade tree to benefit from maximum shade.
Defining Shade Needs
Before you choose a tree, you need to decide where you want shade to fall in your yard. A tall tree that can shade the roof and windows will be an energy-saver, but it won't provide the cooling shadows you need to use the patio in the afternoon. Shade is produced when the tree sits between the area to be shaded and the sun. Shadows are shorter midday than earlier or later, and the most effective shade blocks afternoon sun, which is usually hotter than morning sun. If you are not certain about where shade will fall from a particular planting location, you may find it useful to put a tall stake -- 6 feet or longer -- in the ground and watch how its shadow behaves throughout the day. From summer to winter, the sun may move as many as 50 degrees closer to the horizon. Watching seasonal changes in the size and extent of your house's shadow will help you decide on your tree-shade needs.
Trees to shade your house should be placed on the west side of your property, and closer to northwest than southwest, advises Arbor Day Foundation. This placement blocks hot afternoon sun. For additional shade, deciduous trees can be planted along the eastern side, blocking morning sun and perhaps shading air conditioners, paving or your patio. While evergreens can be used for shade, most shade tree advice is based on deciduous trees. Deciduous trees let you take advantage of warming winter sun when they lose their leaves. If you choose to plant evergreens, expect the same density of shade year-round. Correct placement of shade trees in your yard can save as much as 30 to 35 percent on utility costs. Some utility companies may help you figure out how much.
Distance From the House
To create as much shade as possible, trees that reach a mature height of 25 feet or more should be planted from 10 to 25 feet east or west of the house, advises Utah State University Forestry Extension. This placement accomplishes several goals at once. For example, a red maple (Acer rubrum), varieties of which can be grown in U.S. Department of Agriculture plant hardiness zones 2 through 8, reaches a height of between 35 and 60 feet. At the same time, its branches extend to form the shade canopy which is usually 30 to 45 feet wide but can be much broader, depending on variety. Further, the tree's root system may extend two or more times the radius of the canopy. Planting this large tree too close to the house can produce a multitude of branches overhanging the roof. Roots close to and obstructed by the house foundation will grow poorly, weakening the tree.
Other Placement Considerations
Planting a tall tree 25 feet away from your house may bring it closer to overhead power lines than is safe. You will also want to place your tree a minimum of 5 feet away from sidewalks, brick or stone walls, and other paving, to prevent root damage and heaving. It may help to remember that even smaller trees can provide good shade. For example, deciduous Korean maple (Acer pseudosieboldianum), only grows 15 to 25 feet tall and wide, in USDA zones 4 through 8, while evergreen "Baby Blueeyes" spruce (Picea pungens "Baby Blueeyes") grows 15 to 30 feet tall and 15 feet wide in USDA zones 2 through 8. Smaller trees can be planted as close as 6 to 10 feet from the house and can be a good choice for shading patios and porches not covered by a taller tree.