A member of the Pinaceae family, the blue spruce is prized as both a Christmas tree and a windbreak specimen. Well-adapted to the rugged conditions of the mountains, this tree enjoys a significant life span if planted in the proper environment. However, forcing it to grow in an area it is not suited for will produce less than optimal results.
The blue spruce (Picea pungens), also known as Colorado blue spruce or silver spruce, is capable of living in excess of 200 years, according to Northern State University in South Dakota. However, if it is planted in a geographic locale outside of its native range, the life span may be greatly reduced. The University of Minnesota Extension Service advises that blue spruces planted in the bitter cold of Minnesota will live less than 30 years.
The slopes of the Rocky Mountains and forests of the western U.S. are the native habitat of the blue spruce. The tree does not thrive in hot, humid, summer weather or in areas with dry, winter winds and less snowfall than is normal in the typically snow-laden mountain landscape. The blue spruce also demands the thin and rocky soil it is used to in mountainous terrain. Places with heavier soils deny the tree its ability to suck necessary moisture from the ground.
The Colorado blue spruce is healthiest and will achieve its best life span in its native altitude of between 6,000 and 9,000 feet. It requires full sunshine and is considered an ideal specimen in U.S. Department of Agriculture hardiness zones 4a through 7b. The tree normally grows less than 12 inches annually although that rate may be slower if it has suffered the stress of being transplanted. It achieves a mature height of between 30 and 50 feet in the landscape and 75 feet in the wild.
Disease and Pests
Fungal diseases like cytospora canker, needle cast disease and a variety of rust diseases afflict the blue spruce. None are especially lethal, but how long a blue spruce lives when infested with these diseases depends on whether the fungal disorders are brought under control within the span of a few years. Otherwise, the tree will be weakened from the continued attack and may eventually die. Gall-forming insects and the spruce needle miner regularly feed on the foliage of the tree.