Colorado blue spruce, or blue spruce, is an attractive tree often used for Christmas trees or as ornamentals, particularly in the eastern United States and Europe. It is the official state tree of both Colorado and Utah. It has a narrow, pyramidal shape and cone-shaped crown. As trees become older, they often take on a more irregular appearance. They are 4-sided and have a very sharp point on the end.
Needles are generally dull bluish-gray to silvery blue and emit a resinous odor when crushed.
The cultivated variety 'glauca' is noted for this type of coloration. Needles occur on small peg-like structures on the twig called sterigmata. The sterigmata persist on the twigs after needles have fallen, which is usually after the third or fourth year. Pollination occurs in late spring and cones mature in one season. In the fall, cones are 2-4 inches long and turn chestnut brown with stiff, flattened scales.