The Differences Between Blue & Green Spruces

Differences

• There is no difference between blue and green spruces. They are one and the same. The Colorado blue spruce (Picea pungens) is sometimes commonly referred to as a green spruce. There is no separate "green" spruce species scientifically named as such. An evergreen tree, the blue spruce grows to a mature height of between 50 and 75 feet in landscape settings and up to 135 feet with a canopy spread of 35 feet when growing in the wild.

Growth Rate

• The blue -- or green -- spruce is considered to be a slow-to-moderate grower which, according to the Arbor Day Foundation, denotes a tree that grows approximately 12 inches annually. Initial growth may be slower if the tree has suffered the stress of being transplanted. It does not tolerate partial shade and prefers full sunshine, although it is also adverse to high heat, humidity and drying winds. It grows best in areas where significant snowfall permeates the ground.

Environment

• The tree is considered an ideal specimen in U.S. Department of Agriculture Hardiness zones 2 through 7, an area that does not include the heat and humidity of the American south or desert sections of the west. Its native habitat is the Rocky mountains, and it thrives in the thin, rocky soil of mountainous slopes and upper elevations, ideally areas between 6,000 and 9,000 feet. Heavy soils that do not allow water to easily trickle to the roots of the blue spruce are not well-suited to the tree's health.

Fun Facts

• The needles of the green spruce contain a color mixture of silver, blue and green, and grow in length to a little over 1 inch, providing the characteristic tint and prickly look that makes the tree popular as a Christmas decoration. No record of the tree exists until it was first spotted by European settlers in the Rocky mountains in 1862. Today, it is largely utilized as a windbreak and ornamental tree and produces 3 to 4 inch cones that hang from the branches.