Rocky Mountain Juniper

(Juniperus scopulorum)

Rocky Mountain Juniper (Juniperus scopulorum Sargent)

Identifying Characters: Rocky Mountain Juniper can usually be identified by a combination of characters. The margins of the scales are smooth, not minutely toothed. The berries are bright blue with a white bloom and lack any reddish tint. The berries have 2 seeds.

Similar Species: Rocky Mountain Juniper can be very difficult to separate from Utah Juniper. The scale margins of Rocky Mountain Juniper are smooth at 20x, but those of Utah Juniper at minutely toothed. The berries of Rocky Mountain Juniper are soft and juicy, but those of Utah Juniper tend to dry and hard. The bark of Utah Juniper is gray while that of Rock Mountain Juniper is red-brown. One Seed Juniper has one seed per berry, but Rocky Mountain Juniper has 2 seeds per berry. The ranges of Western Juniper and Rocky Mountain Juniper do not overlap (compare the distribution maps).

Measurements: A tree with a straight trunk. The crown is cylindrical with a pointed apex; height 15 to 50 feet; diameter 1.0 to 1.5 feet at breast height.

Female Cones: Cones berry-like, about 0.25 inches in diameter, soft and juicy; color bright blue with a white bloom; 2 seeds per berry.

Leaves: Leaves scale-like, opposite in 4 rows, forming quadrate twigs; scale length about 1/16 inches; scale margins smooth, not minutely toothed; color gray-green.

Bark: Bark red-brown, fibrous, and shredding.

Native Range: Of the junipers native to the United States normally reaching tree size, Rocky Mountain Juniper is the most widely distributed in western North America. Within its range the distribution is considerably scattered; however, the concentrations, from central British Columbia and southern Alberta through northwestern Montana and southeastern Idaho into Colorado and northern New Mexico, generally follow the Rocky Mountains. In addition, there are fairly extensive concentrations in western portions of the northern Great Plains, in the Uinta and Wasatch Mountains of Utah, and in a band approximately 100 km (62 mi) wide beginning near the Grand Canyon in northwest Arizona and following the Arizona Plateau southeast into the Black Mountains of southwestern New Mexico. (Silvics of North America. 1990. Agriculture Handbook 654.)

Habitat: Rocky Mountain Junipers occur in a wide variety of habitats, but are usually found on rocky soils, usually limestone or lava. The species is commonly found in open woodlands in the northern, mixing with pinyon pines or junipers further south.