By Marlene Finley
The Common Juniper, Juniperus communis, possesses many names, although my favorite name is Bog Juniper. Ground juniper, common juniper, or bog juniper, whatever you wish to call this evergreen plant, can be found growing horizontally and less than three feet high, forming mats. While ground juniper best describes how it grows along the surface, the name bog juniper reminds one of the many places it can be found growing. This plant ranges from alpine tundra and subalpine ridges to coastal areas. It is found in dry, open woods and gravelly ridges to muskeg and lowland bogs. Aptly named “comminus”, this species is found over much of the globe!
Junipers are in the Cypress family (Cupressaceae), along with cedar and redwood. There are about sixty species of junipers throughout the Northern Hemisphere and some, including the bog or common juniper, are able to populate the harshest sites.
Bog juniper can be found in the understory of some forests, although, once mature, it tends to prefer full sunlight. A juniper’s root system extends far beyond the plant’s canopy and is able to suppress nearby grasses which partially explains the mat-like growth characteristics of this species. Junipers produce chemical compounds that inhibit growth of surrounding vegetation, a phenomenon called allelopathy.
The attractive blueish berries on juniper are actually seed cones which provide food for many species of birds and small mammals. The American robin and black-capped chickadee, in particular, are known to feed on the cones of common juniper whenever they are available. And American robins frequently consume large numbers of cones during the spring and fall. In addition to providing food, bog juniper provides cover for birds and small mammals. But while small animals and birds consume the cones, deer and other ungulates only browse juniper as a last resort.
From Deception Pass State Park to Hurricane Ridge and Yellowstone, watch for this low growing juniper stretching prostrate across the ground.