Fast growing evergreen trees are often used for privacy screens and barriers. They provide dense shade and occasionally are used as a high quality specimen tree. Most evergreens live for many years and have few pest and disease problems. Once a limb is removed from an evergreen, the tree does not replace the limb so evergreens rarely need pruning except for shape.
The leyland cypress (Cupressocyparis leylandii) is a high quality fast growing evergreen for most of the US. They grow up to five feet a year and the largest one ever recorded is over 130 feet tall. The leyland cypress is a beautiful evergreen and the branches and greens are often used to make wreaths and floral arrangements during the Christmas holiday season. They are susceptible to a disease called cypress canker disease in the southern US and Gulf coast areas. The leyland cypress in appropriate for USDA horticultural zones 6-10.
The eucalyptus tree (Eucalyptus cordatais) very drought tolerant once established. Some varieties are more sensitive to the cold than others, however. The silvery leaves have a menthol scent when crushed and it grows 3-4 feet a year. The silver dollar variety is one of the most attractive and is appropriate for USDA horticultural zones 6-10.
Blue Sapphire Cypress
Appropriate for USDA horticultural zones 7-9, the blue sapphire cypress (Cupressus arizonica,) is the most drought tolerant of all the cypress trees and grows to 40 feet. It easily adapts to different soils and is also known as the Arizona Cypress. It has an attractive wide upright shape and is a good choice for use in windbreaks or screens.
Nellie Stevens Holly
The Nellie Stevens holly (Ilex) can be grown in USDA horticultural zones 6-9. It grows to 25 feet but can be severely trimmed back to form a dense hedge. They are drought tolerant and grow up to three feet per year.
Thuja Green Giant Tree
The thuja green giant tree (standishii plicata) is an evergreen that is becoming a popular landscaping tree due to its fast growth, up to five feet a year, and tolerance for almost any soil. It is appropriate for USDA horticultural zones 5-9. The thuja green giant is also a good choice for a screen or barrier and grows to 25 feet.