Blue spruce

[8] It has scaly grey-brown bark with a slight amount of a cinnamon-red undertone on its trunk, not as rough as an Engelmann spruce.

[6] Blue spruces are conifers with a pyramidal or conical crown when young, but more open and irregular in shape as they become older.

[6] The narrow, needle-like, evergreen leaves are quite sharply pointed and may be dull green, blue, or pale white.

[17] The ripe seeds have a 1.17% yield of essential oils while the cones produce only 0.38% when steam distilled for four hours.

[3] Picea, the genus name, is thought to come from the Latin word pix meaning "pitch", a reference to the typical sticky resin in spruce bark.

[9] Blue spruces are also rarely called silvertip fir,[23] but this name is also applied to Abies magnifica especially when sold as Christmas trees.

[12] It grows in mesic montane conifer forests, often associating with Douglas-fir, ponderosa pine, or white fir.

It also may be found alongside the quaking aspen (Populus tremuloides) in the high mountain habitats of desert ranges in the Intermountain West.

[28] Blue spruce usually grows in cool and humid climatic zones where the annual precipitation mainly occurs in the summer.

Winter is the season with the poorest rainfall, the precipitation is usually less than 20 percent of the annual moisture falling from December to March.

Fifty percent[dubious – discuss] of the annual precipitation occurs during the growing season of the plants.

[37] Blue spruce seedlings have shallow roots that penetrate approximately 6 centimeters (2.5 in) into the soil during the first year of growth.

[38] Although freezing can't damage much in blue spruce, frost heaving will cause seedling loss.

[41] The blue spruce is attacked by two species of Adelges, an aphid-like insect that causes galls to form.

Mites can also infest the blue spruce, especially in a dry summer, causing yellowing of the oldest needles.

Canker caused by Cytospora attacks one of the lower branches first and progressively makes its way higher up the tree.

West of the Uintas blue spruces are less frequent in canyons south of Salt Lake City.

It has also become established to some extent in many western and northern European countries including Iceland, Norway, Sweden, the United Kingdom, France, and Belgium.

In middle and southern Europe it is found in Germany, Switzerland, Austria, the former Czechoslovakia, and mainland Italy.

[3] The tallest documented blue spruce tree is an individual in the San Juan Mountains of southern Colorado in the Hermosa Creek area.

[53] Common cultivars (those marked agm have gained the Royal Horticultural Society's Award of Garden Merit):[54] The Navajo and Keres Native Americans use this tree as a traditional medicinal plant and a ceremonial item, and twigs are given as gifts to bring good fortune.

[67] It officially became Colorado's state tree on 7 March 1939 when House Joint Resolution 7 was enacted by the legislature.

Seeds of blue spruce
The branches and cones of Picea pungens , then called Picea parryana as illustrated by Charles Edward Faxon in The Silva of North America [ 18 ]
'Mission Blue' blue spruce new growth in spring
Foliage of the cultivar 'Globosa'