Picea pungens

Picea pungens
Foliage and young cones
Conservation status
Least Concern (IUCN 2.3)
Scientific classification
Kingdom:	Plantae
Division:	Pinophyta
Class:	Pinopsida
Order:	Pinales
Family:	Pinaceae
Genus:	Picea
Species:	P. pungens
Binomial name
Picea pungens Engelm.

Picea pungens, also known as the Blue Spruce or Colorado Blue Spruce, is a species of spruce native primarily to the Western United States, and also the Northeastern U.S. and south-central Eastern Canada.

Distribution

Picea pungens is widely occurring in the montane zone of the central and southern Rocky Mountains, from southeast Idaho and southwest Wyoming, south through Utah and Colorado to Arizona and New Mexico.

It grows at high altitudes from 1,750–3,000 m (5,740–9,800 ft) altitude. Unlike Picea engelmannii (Engelmann Spruce) in the same region, it does not reach the alpine tree-line. It is most commonly found growing along stream sides in mountain valleys, where moisture levels in the soil are greater than the low rainfall in the area would often suggest.

Description

Picea pungens, the blue spruce, is a medium-sized evergreen tree growing to 25–30 m (82–98 ft) tall, exceptionally to 46 m (151 ft) tall, and with a trunk diameter of up to 1.5 m (4 ft 11 in). The bark is thin and gray, with narrow vertical furrows. The crown is conic in young trees, becoming cylindric in older trees. The shoots are stout, orange-brown, usually glabrous, and with prominent pulvini.

The leaves are needle-like, 15–30 millimetres (0.59–1.2 in) long, stout, rhombic in cross-section, dull gray-green to bright glaucous blue (very variable from tree to tree in wild populations), with several lines of stomata; the tip is viciously sharp.

The cones are pendulous, slender cylindrical, 6–11 cm (2.4–4.3 in) long and 2 cm (0.79 in) broad when closed, opening to 4 cm (1.6 in) broad. They have thin, flexible scales 20–24 mm (0.79–0.94 in) long, with a wavy margin. They are reddish to violet, maturing pale brown 5–7 months after pollination. The seeds are black, 3–4 mm (0.12–0.16 in) long, with a slender, 10–13 mm (0.39–0.51 in) long pale brown wing.

Picea pungens does not normally hybridize with other spruces, though limited hybridization occurs between it and Picea engelmannii.

Picea pungens 'Glauca' is a cultivar selected for gray foliage.

Uses

The Navajo and Keres Native Americans used this as a traditional medicinal plant and ceremonial item.

Symbol

The blue spruce is the State Tree of Utah and Colorado.

Cultivation

Picea pungens and its many cultivars are cultivated as ornamental trees, and it is among the most widely planted ornamental spruces in gardens and parks. It is also grown for the cut Christmas tree industry.

Cultivars

Many cultivars have been selected for a distinctive form and/or foliage color. They include:

• Picea pungens 'Glauca Globosa' - shrub from 3–5 feet (0.91–1.5 m) in height.
• Picea pungens 'Fat Albert' - compact perfect cone to 10 feet (3.0 m) of a silver blue color.
• Picea pungens 'Glauca Jean's Dilly' - shrub from 3–6 feet (0.91–1.8 m) in height.
• Picea pungens 'Glauca Pendula' - drooping branches, spreads to about 8 feet (2.4 m) wide by 4 feet (1.2 m) tall.

Gallery

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  Mature cone

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  Immature cone

External links

• USDA Plant Profile for Picea pungens (blue spruce)
• Conifers.org: Picea pungens (blue spruce) description
• Lady Bird Johnson Wildflower Center NPIN — Native Plant Information Network
• Interactive Distribution Map of Picea pungens
• Picea pungens — U.C. Photo Gallery