Gardeners often use evergreen trees to add year round green color, ornamental interest and wind screens to lawns and gardens. Various evergreen varieties naturally occur in the western region of the United States (U.S.). Gardeners in this area should select evergreen trees according to appropriate hardiness zone, mature size, intended use and potential problems.
Western Red Cedar
Western red cedar trees (Thuja plicata) naturally occur along the Pacific coastline. Also known as giant red cedars, mature trees reach up to 70 feet in height and 25 feet in width. This member of the Cupressaceae plant family features a columnar shape, pale brown cones and aromatic, red-brown bark. The deep green, needle-like leaves keep their color throughout the winter. Hardy in United States Department of Agriculture (USDA) Hardiness Zones 5 to 7, this tree prefers moist, well-drained soils in full sun positions. Western red cedars sometimes suffer from rots and bagworms. Gardeners often plant western red cedars in large lawns. Pruned trees work well as screens and hedges.
The Douglas fir (Pseudotsuga menziesii), a large member of the pine family (Pinaceae), reaches between 40 and 80 feet in height with spreads ranging from 12 to 20 feet. Winter hardy in USDA Zones 4 to 6, this fir variety prefers moist soils in fully sunny locations. The Douglas fir features a cylindrical form, short cones and forked cone bracts. Aromatic, bluish-green needles have white bands on the undersides. This hardy tree has few disease or insect problems. Gardeners along the Pacific coast often use the Douglas fir as a landscape tree.
Giant sequoia trees (Sequoiadendron giganteum), members of the Taxodiaceae plant family, can live up to 3,000 years and weigh more than 200 tons. In garden settings, these evergreens typically range from 60 to 275 feet tall with spreads ranging from 25 to 60 feet. The giant sequoia prefers moist, cool climates and loamy soils that receive full sun. Indigenous to California, the giant sequoia typically grows well in USDA Zones 6 to 8. Sequoias feature red-brown bark, fruiting cones and bluish-green, needle-like leaves. Butt rot and blights sometimes occur. Younger sequoias work well in large landscape areas.
Ponderosa pine (Pinus ponderosa), an evergreen in the Pinaceae family, is the state tree of Montana. In garden settings, this pine variety generally ranges from 60 to 125 feet in height and about 30 feet wide. The ponderosa pine often lives to be 600 years old. This tree features bundles of yellowish-green needles, oval pine cones and aromatic twigs. Young ponderosa pines have dark bark, while mature pines feature red-orange to yellow-brown bark. Native to Western North America (N.A.), ponderosa pines typically perform well in USDA Zones 3 to 7. This tree prefers moist, loamy or sandy soils that receive full sun. Needle blight occasionally affects these trees. Gardeners sometimes use ponderosa pines as a landscape tree for larger areas.
The limber pine tree (Pinus flexilis) naturally occurs in the Rocky Mountains and generally performs well in USDA Hardiness Zones 4 to 7. This pine family member (Pinaceae) prefers well-drained, medium moist soils in fully sunny locations. These trees possess large taproot systems that make them hard to transplant once established. Mature limber pines range from 40 to 60 feet in height and 25 to 40 feet in width. The limber pine features a rounded crown, brown cones, flexible twigs and blue-green, needle-like leaves. This low-maintenance tree sometimes suffers from white pine blister rust and weevil infestations. The limber pine works well as a landscape tree for medium to large areas.