Picea pungens ‘Koster’ – Blue Colorado – Colorado Spruce – Spruce –

Description

Picea – Spruce – There are 30-45 species of monoecious, evergreen, coniferous trees in the Pinaceae family, in this genus.  They are stiff, narrow, conical, sometimes columnar trees.  They occur in forest in cool temperate regions of the Northern Hemisphere.  They have horizontal to upward pointing branches covered in needle like leaves set singly around the shoots, and varies from bright green, glaucous, blue, silver and gray.  The woody, oval to oblong-cylindrical female cones, held terminal on main shoots and side shoots, are erect at flowering, later pendent, they ripen in a season from green or red when young to purple or brown when mature.  Ovoid, yellow to red purple male cones, 3/4-1 1/4″ long, are borne in spring on previous years shoots.  Spruces are useful for shelter planting or as specimen trees, many cultivars are dwarf or slow growing.  There are prostrate cultivars that make excellent ground covers. Grow in any deep, moist but well drained, ideally neutral to acidic soil in full sun.  It will not withstand polluted environments. Prone to gall insects, aphids, caterpillars, sawfly, red spider mites, lesion nematode, scale insects, butt rot, heart rot, witches broom, mistletoe, rust, gall adelgids, and needle cast P. pungens – Colorado Spruce – This conical to columnar tree from the Rocky Mountains from Wyoming to Colorado grows 50-100′ feet tall and 15′ feet wide. It has scaly, gray bark and thick, orange brown shoots. It produces stiff, thick, sharp pointed, 4 sided, bluish gray green leaves, ½-1 1/4″ long, arranged radially on the shoots, curve upward, and are covered in glaucous wax.  Cylindrical, green, later pale brown female cones are 3-5″ long with flexible scales. ‘Koster’ – bears glaucous, silvery blue foliage and with cones to 4″ long Zones 2-8