- Colorado blue spruce trees thrive in USDA Hardiness Zone 2 when planted in moist, well-drained soils with a pH of 6.0 to 7.5. Within this zone, this tree prefers being grown in an area where it receives full sunlight. Although it prefers moist soils, this spruce is very tolerant of drought conditions. Colorado blue spruce trees require cold climates with an average annual temperature of 39 to 43 degrees Fahrenheit and an average annual rainfall of 18 to 24 inches.
- Colorado blue spruce trees are medium-sized to tall evergreens that mature to a height of 30 to 65 feet and a width of 15 to 25 feet. The single trunk features a dense covering of branches and flaky bark that is ash-brown in color. Colorado blue spruce trees are pyramidal in shape. This tree starts producing seeds at 20 years of age but is the most productive when it is between 50 and 150 years old.
- Colorado blue spruce trees feature needles that measure 3/4 to 1-1/4 inches in length and that can appear dull green, bluish-green or silvery-blue in color. The pointed needles are sharp to the touch and have stomatal lines on both sides.
- The Colorado blue spruce yields monoecious flowers, meaning that they are either male or female. The female flowers (strobili) are purple, while the male stroboli are orange. Each male releases 370,000 pollen grains between May and June. The male strobili are located at the upper part of the tree so that when they shed their pollen, they effectively pollinate the female strobili located farther down on the tree.The females produce 175 to 225 scales, making it possible for each cone produced to contain 350 to 450 seeds. Female flowers begin at an erect position and turn so they are at a 45 degree angle.
- The cones measure 2-1/2 to 4 inches long and contain winged seeds. The cones disperse the seeds from September through winter, spreading the seeds up to 300 feet from the mother plant.
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