Juniperus osteosperma (Utah juniper; syn.J. utahensis) is a shrub or small tree reaching 3–6 m (rarely to 9 m) tall. It is native to the southwestern United States, in Utah, Nevada, Arizona, western New Mexico, western Colorado, Wyoming, southern Montana, southern Idaho and eastern California. It grows at moderate altitudes of 1,300-2,600 m, on dry soils, often together with Single-leaf Pinyon (Pinus monophylla).
The shoots are fairly thick compared to most junipers, 1.5–2 mm diameter. The leaves are arranged in opposite decussate pairs or 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, 8–13 mm in diameter, Blue-brown with a whitish waxy bloom, and contain a single seed (rarely two); they are mature in about 18 months. The male cones are 2–4 mm long, and shed their pollen in early spring. It is largely monoecious with both sexes on the same plant, but around 10% of plants are dioecious, producing cones of only one sex.
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 5-20 together, each gall 1–2 cm diameter, with dense modified spreading scale-leaves 6–10 mm long and 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).
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