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When clothed in new growth, some trees have the appearance of being frosted with pale blue, at which time they are unexcelled in beauty among evergreen trees. Burton O. Longyear

These trees are not consistently powdered with that look of stage moonlight; they are predominately dark green, even somber, like most Spruces, with little blue about them, except for a brief season, the tips of the new growth, or here and there, a young specimen that is fairly azure all over. Donald Culross Peattie

The Blue spruce is renowned for its unique silver or blue-green color and even tapering shape. The silvery appearance is due to a fine white powder on the surface of young blue-green needles. The pale blue color is common on horticultural varieties seen in cities, but native trees of the forest tend more to the dark green color of Engelmann spruce.

In Wyoming and Colorado Blue spruce is found between 6000 and 9500 feet elevation, on moist slopes and along streams, often as single individuals. In New Mexico it grows a little hgiher, from 7000 to 10000 feet elevation. Usually it is found near or among Ponderosa pine, Douglas fir, Subalpine fir, and Engelmann spruce. It is never abundant and usually grows below the Engelmann spruce - Subalpine fir forest. It clearly favors moist locations, but actually is drought resistant, and can survive extremes of temperature. Blue spruce is widespread along the Roaring fork and the higher parts of the Crystal River valley near Aspen, Colorado.

It typically grows to 40 to 60 feet in height and one to two feet in trunk diameter in Colorado. The largest known Blue spruce grows in Colorado; it was 126 feet high and 15 feet 8 inches around the trunk when measured in 1964. The Blue spruce is the state tree of Colorado, selected by vote of the state's school children on April 15, 1892.

There are over a dozen named horticultural varieties, differing from the wild tree in needles, coloration and form. Ornamental trees planted in towns may be horticultural varieties and differ in detail from natural specimens, and they should not be used as a guide to the native tree.

The seeds are eaten by birds and deer.

The scientific name is Picea pungens. Picea is the Latin name for some spruces, from pix for pitch . Pungens means sharp and refers to the stiff, sharp needles.

 

Identifying features of Blue Spruce

Needles

Needle is the appropriate term for the leaves of the Blue spruce. They are very stiff and sharp. Like all spruce needles they are single and square in cross-section (four-sided); you can roll them between thumb and forefinger, unlike flat fir needles. Length is 1 to 1 1/2 inch long; usually more than 1 inch.

A temporary white coating in lines along each of the four sides of the needles, especially on each new year's new growth, gives the needles a white bloom, and the entire tree may have a whitish-blue-green to silver-blue-green appearance. The powder can easily be rubbed off with your fingers. The white coating of the needles gradually disappears with time, and the older foliage appears darker, even dark green.The silvery color is most striking in midsummer when the new growth is at its peak development. Some trees never develop the white coating to any degree and so appear dark green or blue-green.

The needles are so stiff and sharp it can be painful to grasp a twig of needles firmly. The needles usually stick out evenly from all sides of the twig, nearly at right angles, and are nearly straight.

Each needle stands on a small woody peg which separates it from the twig. The bare twigs are rough after the needles have fallen.

Cones

Mature cones are 2 1/4 to 6 inches long; commonly 2 1/2 to 3 1/2 inches long. Note that this is twice the length of cones of the Engelmann spruce. Clustering in the top third or so of the tree, hanging down from the twig, they are purple to yellow when immature. After reaching maturity in the autumn of the year they blossom, they fall from the tree over the next few months. Scales of the cone are plae brown, thin, stiff but flexible, and have a ragged outer margin.

Bark

Bark thin, pale gray, scaly and smooth on young trunks. Bark on old trunks becomes divided into vertical, scaly, pale gray to dark gray ridges, which distinguishes this tree from large Engelmann spruce with its orange-brown bark color. On older trees light brown or orange-brown spots and tinges may appear under the gray surface scales, but usually the bark is entirely grey.