Picea pungens
Needles and mature cone of Blue SpruceUS FWS photo
One of America's loveliest and most-loved native trees is the blue spruce (picea pungens). It's also called the Colorado spruce or the Colorado blue spruce. "Pungens" in its Latin name refers to the sharpness of its needles. "Blue" in its English name refers to the distinctive blue-green color of its needles.
Arbor Day Foundation reports that the tree was unknown until 1862 when it was found growing at high elevations of the Rocky Mountains, in meadows and on moist slopes along streams. As one might expect from a tree that chooses such places in nature to grow, it prefers rich, gravelly, moist soils and a sunny location.
Despite its preferences, the blue spruce is a tough tree that will tolerate sandy soils or even heavy clay soils. It won't survive in a site where it frequently stands in water, but on the other hand, the tree does need to be watered during periods of dry weather.
Its blue coloration is caused by a waxy silver-blue powder called "bloom" that is naturally formed on its needles, especially in summer. The South Dakota Division of Forestry assures us that the intensity of a blue spruce's color is determined by the genes of that particular tree, not by the care the tree has been given.
The perfect conical shape of the blue spruce and its excellent needle retention has made it a popular Christmas tree. The 2004 White House Christmas tree was a blue spruce. In the White House press release photo at right you can see the symmetrical, graceful shape that is characteristic of the species.Blue spruce are long-lived when grown in good conditions. They are mature at 250-350 years and may live beyond 400 years. They are resistant to wind and ice damage, but they do have some fungal diseases and insect problems, so they may require spraying from time to time to maintain their health.
Many cultivars of blue spruce are available from nurseries. Most have been selected for their coloration or for their resistance to disease. If you plant a blue spruce, allow enough room for its ultimate growth. It can attain 75 to 100 feet of height, and its spread will be 20 to 35 feet.
Blue spruce are good wildlife trees. Birds use them for nesting, roosting, and winter cover. Their needles are eaten by grouse and the seeds are enjoyed by chipmunks and many songbirds. Rabbits, squirrels, porcupines, deer, elk and mountain sheep also eat various parts of the tree (bark, twigs, seeds, and/or needles.)
The blue spruce is the state tree of both Colorado and Utah. And according to Wikipedia, "The National Christmas Tree in Washington, D.C. is a 40-foot (12 m) Blue Spruce planted on the Ellipse in 1978."
When I was young, growing up on a ranch in Nebraska, my father planted two beautiful little blue spruce trees on our south lawn. When I revisited my childhood home a few years ago, it was wonderful to see what fine big trees the two blue spruces have become in about 40 years.
"The power to recognize trees at a glance without examining their leaves or flowers or fruit as they are seen, for example, from the car-window during a railroad journey, can only be acquired by studying them as they grow under all possible conditions over wide areas of territory. Such an attainment may not have much practical value, but once acquired it gives to the possessor a good deal of pleasure which is denied to less fortunate travelers."
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