Juniperus scopulorum

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Juniperus scopulorum

Juniperus scopulorum in North Dakota

Conservation status

Least concern

Scientific classification

Kingdom:	Plantae
Division:	Pinophyta
Class:	Pinopsida
Order:	Pinales
Family:	Cupressaceae
Genus:	Juniperus
Species:	J. scopulorum

Binomial name

Juniperus scopulorum
Sarg.

Juniperus scopulorum (Rocky Mountain Juniper) is a small tree reaching 5-20 m tall, native to western North America, in Canada in British Columbia and southwest Alberta, in the United States from Washington east to North Dakota, south to Arizona and also locally western Texas, and northernmost Mexico from Sonora east to Coahuila. It mostly grows at altitudes of 1,200-2,700 m (down to sea level in the Puget Sound area) on dry soils, often together with other juniper species.

Foliage and cones

The shoots are slender, 0.7-1.2 mm diameter. The leaves are arranged in opposite decussate pairs, or occasionally in whorls of three; the adult leaves are scale-like, 1-2 mm long (to 5 mm on lead shoots) and 1-1.5 mm broad. The juvenile leaves (on young seedlings only) are needle-like, 5-10 mm long. The cones are berry-like, globose to bilobed, 6-9 mm in diameter, dark blue with a pale blue-white waxy bloom, and contain two seeds (rarely one or three); they are mature in about 18 months. The male cones are 2-4 mm long, and shed their pollen in early spring. It is dioecious, producing cones of only one sex on each tree.

It is closely related to Juniperus virginiana, and often hybridizes with it where their ranges meet on the Great Plains. Hybrids with Juniperus horizontalis also occur.

The cultivar 'Skyrocket' is a very popular ornamental plant in gardens, grown for its very slender, strictly erect growth habit. Several other cultivars are also grown to a lesser extent.

One particular specimen, the "Jardine Juniper" in Utah, is thought to be over 1500 years old [1].