Juniperus osteosperma / Utah juniper

Juniperus osteosperma as described by in 1948 by (Torrey) Elbert Luther Little (1907–2004), in Leaflets of Western Botany, vol.5, is commonly known as Utah juniper; synonymous with .J. utahensis. Other common names include desert cedar, as well as sabina, cedro, and sabina morena in the Spanish language. The species name translates into "bone-seed" from the Latin language, referring to its exceptionally hard seeds.

artwork courtesy of Intermountain Flora
artwork courtesy of Intermountain Flora
Description. Utah juniper is an evergreen, coniferous shrub or small tree that grows to mature heights of 10 to 20 feet (3 – 6 m), rarely to 30 feet (9 m). It is largely monoecious with both sexes on the same plant, but around 10% of plants are dioecious, producing cones of only one sex.
  • bark is gray brown to ashy white in color, peeling in long strips.
  • shoots are fairly thick compared to most junipers, measuring 0.06 to 0.12 inch (1.5 – 2 mm) in diameter.
  • leaves are arranged in opposite decussate pairs or whorls of three; the adult leaves are scale-like, measuring 0.04 to 0.08 inch (1 – 2 mm) long, up to 0.2 inch (5 mm) on lead shoots and 0.04 to 0.06 inch (1 - 1.5 mm) broad. The juvenile leaves (on young seedlings only) are needle-like, measuring 0.2 to 0.4 inch (5 – 10 mm) long.
  • pollen cones are 0.08 to 0.16 inch (2 – 4 mm) long, and shed their pollen in early spring.
  • seed cones are berry-like, measuring 0.32 to 0.52 inch (8 – 13 mm) in diameter, colored blue-brown with a whitish waxy bloom, and contain a single seed (rarely two). They are mature about 18 months after pollination. It is largely monoecious with both sexes on the same plant, but around 10% of plants are dioecious, producing cones of only one sex.

Native range of <em>Juniperus osteosperma </em>
Native range of Juniperus osteosperma

Distribution. This species is native to southwestern United States, in Utah, Nevada, Arizona, western New Mexico, western Colorado, Wyoming, southern Montana, southern Idaho and eastern California. It grows at moderate elevations of 4,100 to 8,200 feet (1,300 - 2,600 m) above sea level, on dry soils, often associated with single-leaf pinyon pine (Pinus monophylla).

Cold hardy to USDA Zone 6 (0 to -10ºF / -17.8 to -23.3ºC)

The plants frequently bear numerous galls caused by the juniper tip midge Oligotrophus betheli (Bibionomorpha: Cecidomyiidae); these are conspicuous pale violet-purple, produced in clusters of 5 to 20 together, each gall 0.4 to 0.8 inch (1 – 2 cm) diameter, with dense, modified spreading scale-leaves 0.24 to 0.4 inch (6 – 10 mm) long and 0.08 to 0.12 inch (2 – 3 mm) broad at the base. Seeds are dispersed by jackrabbits, mostly the black-tailed jackrabbit (Lepus californicus spp.), rodents and to a lesser extent by coyotes (Canis latrans).

A Utah juniper, Juniperus osteosperma, growing in nature in Red Rock Canyon, Nevada.
Photo by Fcb981 - via Wikipedia Commons, CC BY-SA 3.0
Juniperus osteosperma, a closeup of foliage and seed cones.
Photo by Stan Shebs, via Wikipedia Commons, CC BY-SA 3.0

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