Scientific Classification Kingdom...: Plantae Division...: Pinophyta Class...: Pinopsida Order...: Pinales Family...: Pinaceae Genus...: Picea Species...: Picea Pungens

Picea Pungens (Blue Spruce or Colorado Spruce) is a species of spruce native to western North America, from southeast Idaho and southwest Wyoming, south through Utah and Colorado to Arizona and New Mexico.

It is most commonly found growing along stream sides in mountain valleys, where moisture levels in the soil are greater than the often low rainfall in the area would suggest.

The Picea Pungens is the official state tree for two U.S. states: Colorado (where it is commonly known as Colorado Spruce) and Utah (where it is commonly known as Blue Spruce).

Blue Spruce or Colorado Spruce trees are often used by homeowners and landscape architects for home security purposes. The sharp needles may deter unauthorized persons from entering private properties, and may prevent break-ins if planted under windows and near drainpipes.

The aesthetic characteristics of the Picea Pungens, in conjunction with its home security qualities, makes it a considerable alternative to artificial fences and walls.

The Picea Pungens is a medium-sized evergreen tree growing to 80 to 100 feet tall, exceptionally to 150 feet tall, and with a trunk diameter of up to 5 feet. 

The bark is thin and scaly, flaking off in small circular plates 2 to 4 inches across. The crown is conic in young trees, becoming cylindric in older trees. The shoots are stout, orange-brown, usually glabrous, and with prominent pulvini. 

The leaves are needle-like, 0.5 to 1.0 inch long, stout, rhombic in cross-section, dull gray-green to bright glaucous blue (very variable from tree to tree in wild populations), with several lines of stomata; the tip is viciously sharp.

The cones are pendulous, slender cylindrical, 2.5 to 4,5 inches long and 0.75 inches broad when closed, opening to 1.50 inches broad. They have thin, flexible scales 0.75 to 1.00 inches long, with a wavy margin. They are reddish to violet, maturing pale brown 5 to 7 months after pollination. The seeds are black, 3 to 4 millimeters long, with a slender, 10 to 13 millimeters (about 1/2 inch) long pale brown wing.

The Blue Spruce or Colorado Spruce is one of the most popular garden conifers, grown for its strongly glaucous foliage. Numerous cultivars selected for particularly bright blue foliage have been selected by the horticultural trade, some of them also slow-growing dwarf forms suitable for planting in small gardens. It is also sometimes used as a Christmas tree, though the very sharp needles make it a poor choice for families with children.