As indicated by the specific epithet, the stems of Juniperus horizontalis are prostrate, making the whole plant typically shorter than 15 cm. Each branch has numerous short, scaly, almost cedar-like, side branches. The leaves are oppositely arrange in four vertical row, laying flat against the branch. The tips of each leaf become apiculate, or pionted, at maturity. The short (1 to 1.5 mm long) leaves are scale-like in appearance and green to a greenish gray in color. The species is diocious, producing male and female cones on separate plants scattered among the leaves. The male cones are egg shaped and approximately 5 mm long. The female cones are berry-like, even referred to as berries by many, bluish purple and up to 6 mm long, appearing in May to June but maturing the following year.
J. horizontalis is found in the dry, rocky, open sites of many ecological sites, from the plains to the subalpine regions, of the Alaska, central British Columbia, Montana,Yukon and Northwest Territory to Wyoming and Colorado. EastwardJ. horizontalis is found in Minnesota, Iowa, and Maine. Known to hybridize with Rocky Mountain Juniper (Juniperus scopulorum) when in the same region, identification of this species can be complicated.
Historically, the female juniper cones, or berries, were used to made a tea for treating kidney ailments, though this concoction can be toxic. The female cones were alos combined with wolfwillow seeds (Eleagnus commutata) to make the beads of necklaces. The branches of J. horizontalis were burned in use as an insect repellent. The female cones and branches were both important parts of religious ceremonies of the northern tribes of native peoples.
Common names of J. horizonatalis include Creeping Juniper and Ground Juniper, indicating the habit of the plant.
Photos taken in the Thompson Recreation Area east of Butte, Montana in May.
Hitchcock, C.L. and A. Cronquist (1994) Flora of the Pacific Northwest, University of Washington Press, Seattle and London.
Kershaw, L., A. MacKinnon and J. Pojar (1998) Plants of the Rocky Mountains. Lone Pine Publishing, Washing, Canada.