17Blue spruce

The blue spruce is an evergreen tree that can grow to heights of up to 40 meters and eight meters wide in optimal locations. The straight trunk has a copper-brown bark. The strong, stiff twigs are glabrous, shiny and distinctly whorled in a regular tiered arrangement. They form a regular pyramidal crown in young trees. In old trees, the branches are more pendulous and form an irregular and open crown.

The needles are square in cross-section and about three centimeters long. They project at right angles from the shoot and are stiff and pointed. The tree is native to western North America; specimens here are usually bred to emphasize their intense steel-blue color, which explains the name "blue spruce."

It is monoecious – separate sexed. Male flower cones are yellow-reddish and are located throughout the crown in small groups at the tips of one-year-old shoots. Female flower cones are pinkish-reddish and form only in the upper crown. They lignify into yellowish-brown, seed-bearing cones, six to ten centimeters long.

The blue spruce prefers mild to cool climates, but makes few demands on soils. Along with its ornamental value, this makes it a popular tree for gardens and parks. It thrives at elevations up to 3,000 meter, prefers sunny locations and is extremely frost resistant. Apart from its use as a Christmas tree, it has little significance in forestry.

The young male catkins are used raw and cooked as a spice. Immature female cones are eaten cooked. The seeds are rich in fats and tasty. However, they are small and difficult to extract from the cones. Like the other edible components of blue spruce, they are an emergency food, used only when other options fail. However, a refreshing tea rich in vitamin C can be made from the young shoot tips.

Blue spruce is the state tree of the U.S. states of Colorado and Utah.