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Common Name: Blue Spruce
Picea pungens is an evergreen tree that can grow up to 20.00 metres tall.
It is harvested from the wild for local use as a food and source of materials.
South-western N. America - Rocky Mountains.
Banks of streams or on first benches above them, singly or in small groves, 2000 - 3300 metres[
Likes abundant moisture at the roots, if grown in drier areas it must be given a deep moist soil[
]. Tolerates poor peaty soils[
]. Prefers a cold dry high mountain site[
]. Succeeds in wet cold and shallow soils but is not very wind-firm in shallow soils[
]. Resists wind exposure to some degree[
]. This species has a deeply penetrating root system that firmly anchors the tree against winds[
]. Prefers a pH between 4 to 6[
]. Dislikes shade[
]. Intolerant of atmospheric pollution[
A long-lived but slow-growing tree in the wild, with specimens 800 years old recorded[
]. It is planted as a timber tree in N. and C. Europe[
]. Most trees in Britain are grafted and these are slow growing[
]. The few trees of seedling origin tend to be fairly fast growing after a slow start[
]. Annual increases of 30 - 40cm are not uncommon in some of the larger trees.
Trees should be planted into their permanent positions when they are quite small, between 30 and 90cm. Larger trees will check badly and hardly put on any growth for several years. This also badly affects root development and wind resistance[
Seed production is usually good, with heavy crops every 2 - 3 years[
In some upland areas, especially over granitic or other base-poor soils, growth rate and health have been seriously affected by aluminium poisoning induced by acid rain[
Plants are strongly outbreeding, self-fertilized seed usually grows poorly[
]. They hybridize freely with other members of this genus[
There are several named forms, selected for their ornamental value[
Trees are very subject to severe damage by aphids in mild winter areas where temperatures do not regularly fall below -8°c[
All parts of the plant emit a powerful pungent smell when bruised[
Young male catkins - raw or cooked. Used as a flavouring[
Immature female cones - cooked. The central portion, when roasted, is sweet and syrupy[
]. The cones are about 7cm long[
Inner bark - dried, ground into a powder and then used as a thickener in soups etc or added to cereals when making bread[
]. An emergency food, it is only used when all else fails.
Seed - raw[
]. The seed is about 2 - 4mm long[
]. It is rich in fats and has a pleasant slightly resinous flavour but is too small and fiddly to be worthwhile unless you are desperate[
A refreshing tea, rich in vitamin C, can be made from the young shoot tips[
A fairly wind resistant tree, it can be grown as part of a shelterbelt planting[
Wood - light, soft, close grained, weak, brittle and often full of knots[
]. The wood has little commercial value[
], but is used for construction[
] and is also valued for its use in the pulp industry to make paper[
Seed - stratification will probably improve germination so sow fresh seed in the autumn in a cold frame if possible[
]. Sow stored seed as early in the year as possible in a cold frame[
]. A position in light shade is probably best[
]. Seed should not be allowed to dry out and should be stored in a cool place[
]. Prick out the seedlings into individual pots when they are large enough to handle and grow them on in the greenhouse or cold frame for their first winter. They can be planted out into their permanent positions in early summer of the following year, or be placed in an outdoor nursery bed for a year or so to increase in size. They might need protection from spring frosts.
Cuttings of semi-ripe terminal shoots, 5 - 8cm long, August in a frame. Protect from frost. Forms roots in the spring[
Cuttings of mature terminal shoots, 5 - 10cm long, September/early autumn in a cold frame. Takes 12 months[
Cuttings of soft to semi-ripe wood, early summer in a frame. Slow but sure.