Juniperus scopulorum / Rocky Mountain juniper

Adjectives: drought tolerant, exposed, highly visible, interesting bits, native, nutrient poor soils, rocky, winter botany

Also known as: Rocky Mountain red cedar, mountain red cedar, Colorado red cedar, western red cedar, river juniper, western juniper, weeping juniper
Synonym: Sabina scopulorum
See also: Pines trees, conifers and evergreens

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Rocky Mountain juniper is a slow growing, long-lived evergreen often found high on exposed slopes and ridges with dry, rocky soil. In form, it is generally rounded. It often grows well separated from other trees. In the Valley, it is only to be confused with the much smaller plastic trees used in model train sets.

Although it is an evergreen and a conifer, it is not (unlike the others on this site) in the Pinaceae but in the Cupressaceae. There are no other members of that family native here, so again, confusion is minimized.

Adult juniper tree leaves are not needle-like, but scale-like; juvenile leaves are more like needles, at least they are very prickly. Young needles grow in whorls of 3.

In addition to the leaves, the two distinctive features are the cones and the bark.

The female cones look like little dark blue berries with a pale blue-white waxy bloom. They are less than 1/2 inch in diameter and take two years to mature after pollination. The pollen (male) cones are smaller and shed pollen in early spring. They look like little brown bumps at the ends of twigs.

Unlike the other conifers in the Valley, junipers are dioecious, meaning that the male and female cones are on different trees. A wide variety of birds, especially Bohemian waxwings, eat the berries and they are the primary means of seed dispersal. If the seeds are lucky (if seeds can be lucky) they get deposited in rocky crevices or other pockets that trap moisture and blowing soil. Given enough time, the mature trees grow to 50 feet tall and 20 feet wide under good conditions. The morphology depends, however, considerably on environment (see gallery photos for examples).

As for the bark, it is variously called shredding or stringy, and it is reddish-brown.

Interesting bits – Juniperus scopulorum is very closely related to the eastern species, J. virginiana (eastern red cedar), and can hybridize with it in regions where they two overlap (the Valley is not one). Both have a red, aromatic heart wood used in making cedar chests (now largely replaced by cedar particle board, alas). In addition to chasing moths away, the wood resists decay; juniper fence posts last a long time.

Rocky Mountain juniper is also related to J. communis (common juniper) which is a low growing shrub that should also be in the area. Juniper berries are the one essential “botanical” in gin, with common juniper being the most used. If you are making yours locally, Rocky Mountain juniper also works.

Finally, Rocky Mountain juniper is one of the more popular trees available in this country to bonsai.