Juniperus communis

Common juniper


The Basics

Taxonomy: Kingdom - Plantae (plants). Subkingdom - Tracheobionta (vascular plants). Superdivision - Spermatophyta (seed plants). Division - Coniferophyta (conifers). Class - Pinopsida. Order - Pinales. Family - Cupressaceae (cypress). Genus - Juniperus L. Species - Juniperus communis L.

Ecology: Common juniper is possibly the most widely distributed tree in the world. Common juniper is almost completely circumpolar within the exception of a gap in the Bering Sea region. Common juniper can grow on a wide range of sites. It grows on dry, open, rocky, wooded hillsides, sand terraces, maritime escarpments, and on exposed slopes and plateaus throughout its range. Common juniper is an indicator in a number of forest and shrubland habitat types and community types. It grows as an understory dominant with ponderosa pine (Pinus ponderosa), Douglas-fir (Pseudotsuga menziesii), lodgepole pine (Pinus contorta), limber pine (P. flexilis), white fir (Abies concolor), Engelmann spruce (Picea engelmannii), white spruce (P. glauca), quaking aspen (Populus tremuloides), blue spruce (Picea pungens), whitebark pine (Pinus albicaulis), subalpine fir (A. lasiocarpa), or Rocky Mountain bristlecone pine (P. aristata).


Shrubs or small trees dioecious, to 4 m (if trees, to 10 m), multistemmed, decumbent or rarely upright; crown generally depressed. Bark brown, fibrous, exfoliating in thin strips, that of small branchlets (5--10 mm diam.) smooth, that of larger branchlets exfoliating in strips and plates. Branches spreading or ascending; branchlets erect, terete. Leaves green but sometimes appearing silver when glaucous, spreading, abaxial glands very elongate; adaxial surface with glaucous stomatal band; apex acute to obtuse, mucronate. Seed cones maturing in 2 years, of 2 distinct sizes, with straight peduncles, globose to ovoid, 6--13 mm, bluish black, glaucous, resinous to obscurely woody, with 2--3 seeds. Seeds 4--5 mm.


Fire effects: common juniper is generally described as "susceptible" to fire. Foliage is resinous and very flammable. The degree of damage received increases with progressively greater fire severity. Some fire regimes allow common juniper to survive several fires. Where common juniper is killed by fire, some seeds may survive in the soil on-site and germinate when conditions become favorable. Other seed is brought to the site by bird or, less commonly, mammal dispersers.


Flowering and fruiting: Common juniper is typically dioecious but occasionally monoecious. Seed usually matures during the second growing season, although there have been some reports of cones maturing within only one season. Male strobili are sessile or stalked, and female strobili are made up of green, ovate or acuminate scales. Berrylike cones are red at first, ripening to a glaucous bluish-black. Cones are ovoid to ellipsoid and contain 1 to 3 seeds. Germination rates for common juniper seed are relatively poor and defective seed may also be relatively common.

Vegetative regeneration: Common juniper does not sprout after foliage is removed. However, adventitious root development can occur when branches come in contact with the ground become buried. In the subarctic, plants are often buried at least partially, and production of adventitious roots may aid in water and nutrient intake.

Species Distribution


USDA Plants Database
USDA, NRCS. 2016. The PLANTS Database. National Plant Data Team, Greensboro, NC 27401-4901 USA.

USFS Plant Database
Habeck, R. J. 1992. In: Fire Effects Information System, [Online]. U.S. Department of Agriculture, Forest Service, Rocky Mountain Research Station, Fire Sciences Laboratory.

Flora of North America
Flora of North America Editorial Committee, eds. 1993+. Flora of North America North of Mexico. 19+ vols. New York and Oxford.

The Jepson Herbarium
The Jepson Manual: Vascular Plants of California. B.G. Baldwin, D.H. Goldman, D.J. Keil, R. Patterson, T.J. Rosatti, and D.H. Wilken [editors]. 2012. 2nd edition, thoroughly revised and expanded. University of California Press, Berkeley, CA.

Burke Museum of Natural History and Culture
Burke Museum. 2016 [Online]. University of Washington.
Photo credit: Ben Legler 2004

USGS Plant Species Range Maps
Critchfield, W.B., and Little, E.L., Jr., 1966, Geographic distribution of the pines of the world: U.S. Department of Agriculture Miscellaneous Publication 991, p. 1-97. Little, E.L., Jr., 1971-1978, Atlas of United States trees, volume 1,3,13,17, conifers and important hardwoods: U.S. Department of Agriculture Miscellaneous Publications.

Photo credit: National Agricultural Library.