Colorado blue spruce, or blue spruce, is an attractive tree often used for Christmas trees or as ornamentals. Leaves (needles) are 1-1 1/2 inches long on lower branches but somewhat shorter on upper branches. They are 4-sided and have a very sharp point on the end. It is this point which gives the species its name "pungens", from the Latin word for sharp as in puncture wound. Needles are generally dull bluish-gray to silvery blue and emit a resinous odor when crushed. Some trees have a more distinct bluish-white or silvery-white foliage.
Both male and female flowers (strobili) occur in the same tree, although in different locations. 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. Cones generally persist on the tree for one to two years after seed fall.
Blue spruce is finding increasing popularity as a Christmas tree as a result of its symmetrical form and attractive blue foliage. The species has an excellent natural shape and requires little shearing. Additionally, needle retention is among the best for the spruces. Its popularity as an ornamental leads many consumers to use blue spruce as a living Christmas tree, to be planted after the holiday season.
