Blue spruce (Picea pungens)
Appearance: Evergreen, a very impressive conifer tree, up to 50 m, usually much lower, however – 30-40 meters. The crown is quite densely branched and regular, conical, quite slender shape. Larger branches stick out horizontally. Only in old specimens the branches growing close to the ground point slightly downwards.
Brown-purple or brown-gray bark. it exfoliates with quite thick sand. Young twigs are yellowish-brown or even whitish, almost hairless. Narrow donuts, oval, length approx 6 mm, with numerous lanceolate scales.
Pins placed around the shoots, clustered upwards or at least bent upwards. The pins are long 2-3 cm, they are quite stiff and pointed, dark green or bluish green, only rarely definitely green, while in the most commonly grown ornamental varieties – blue-green or gray-green.
The female pine cone is initially brown-purple, later in the ripening period gray-brown, mostly slightly bent, with a length of up to 12 centimeters, Loose scales, very thin, irregularly serrated on the front edge,
Occurrence: Blue Spruce comes from the southwestern part of North America (Colorado). Today it is still present there in large concentrations, although never in clean stands. For several decades in Europe, it has been cultivated in forests and used as an ornamental tree in gardens. Blueing spruce is one of the most common conifers in European North American gardens.
Flowering period: Maj.
General thoughts; A dark green base form is very rarely seen in gardens and collections, while blue-green varieties. with their shimmering pins, they are represented almost everywhere, These varieties, gardening often referred to as blue spruces, form a circle of blue spruce forms known as' Glauca”. They all come from the tree population, which in the original range is represented by blue-green, relatively gray-green specimens. Cover the pins with a thick layer of wax, making them lighter in color, should probably be seen as a special adaptive trait. In his homeland, Rocky Mountains, these trees have to survive during a very harsh and dry winters, hot summer. A thick layer of wax helps to withstand strong sunlight and therefore reduces heating and water loss.
In garden and forest cultivation, hatching spruce trees are often attacked by Sitka lice - if such an invasion is not recognized in time, the damage can be great. Biological pest control is quite difficult.