Blue or Colorado Spruce (Picea pungens)
Family: Pinaceae or Pine
Leaves: Needles borne singly; about 1" long; evergreen; blue-white to dark green; 4-angled; sharp pointed; extend at right angles all around twig; very fragrant when crushed.
Twigs/buds: Twigs glabrous; leaves on a short stalk that remains part of the twig, so twig rough. Buds with scales that tend to turn out into a rosette, especially in spring.
Flowers/fruit: Fruit a papery cone that hangs down; about 2-1/2" to 4" long; light chestnut-brown; papery scales are slightly round-toothed at tip.
Bark: Light to dark gray; made-up of thin scales; wide, thick ridges on older trees.
Wood: Minor importance; similar to Engelmann spruce.
General: Utah's official state tree. Native to Utah, the Rocky Mountains and Intermountain states. Slow growing. Likes moisture and good soil; may not do well with extreme heat or hot, dry winds. Wind-throw can be a problem. Intermediate shade tolerance.
Landscape Use: Beautiful, slow-growing tree but allow enough room--can eventually get quite tall and wide. Best if it is allowed to keep branches and foliage right to the ground. Will as often be green as blue in nature, but blue-foliage cultivars are available. Good visual, sound, and wind screen. Cooley spruce gall adelgid can cause unsightly brown galls to form on twig tips on blue spruces in the landscape. This is a very good tree, but it is over-used in many areas. Zones 2-7.
Engelmann Spruce (Picea engelmannii)
Family: Pinaceae or Pine
Leaves: Needles borne singly; about 1" long; evergreen; blue-green to dark green; 4-angled; not as sharp pointed as blue spruce; tend to be crowded on around upper side of twig; fragrant when crushed.
Twigs/buds: Leaves attached with a short stalk that remains part of the twig, so twig rough; young twigs with minute hairs. Buds with scales that lie fairly flat.
Flowers/fruit: Fruit a papery cone that hangs down; about 1" to 2-1/2" long; light chestnut-brown; papery scales are slightly round-toothed at tip.
Bark: Red to purple-brown; made-up of thin scales; thinner than blue spruce.
Wood: Moderate importance; heartwood not distinct; nearly white to light brown; growth rings distinct; used for lumber, poles, ties, and fuel.
General: Native throughout the Rocky Mountains and parts of the Pacific Northwest and western Canada. Slow growing. Likes cool, moist sites and good soil. Wind-throw (trees being blown over) is a problem if the site is disturbed. Shade tolerant.
Landscape Use: Rarely used, though some mountain homes are built in Engelmann spruce stands. Probably would not do well at lower, warmer, drier locations. Blue spruce is more available and has good cultivars. Zones 2-5.
