Determine mature tree characteristics and decide whether these characteristics will be suitable for the planting site when the tree reaches its ultimate height and spread. If a screen is needed quickly, plant fast growing trees. An alternative is to plant slower growing trees together with fast growing trees, removing the faster growing ones as the more desirable trees mature. When a screen is needed where trees already exist, plant an understory tree. These fast growing weeping willows make a quick screen in an area large enough to accommodate their mature size.
Tall trees can block the view of tall buildings, or add interest to an angular building.
Form and shape When selecting trees for screens, match the needed function to the mature shape of the tree. When planted in rows, trees with a narrow, columnar canopy effectively block an unsightly view, define areas, and act as a barrier. They can be planted close to fences and buildings without hanging over into other areas and can give a building a formal or classical appearance. These narrow, upright junipers can be planted close to a building or fence for screening in a small area. Trees with round or pyramidal canopies are effective for areas that have limited root area but adequate overhead canopy area, such as parking lots or street medians.