Juniperus virginiana, American juniper or eastern red-cedar (also called red cedar, Virginia cedar, red juniper, or savin), is a medium-sized evergreen coniferous tree in the Cupressaceae (cypress family), widely distributed throughout the eastern half of North America. Although generally not considered to be an important commercial species, its wood is highly valued for specialty furniture and wood products because of its beauty, durability, and workability. It is often used to make or line chests and drawer (as a moth repellent) and for fence posts (because it is rot resistant). It provides cedarwood oil for fragrance compounds, food and shelter for wildlife, and protective vegetation for fragile soils. The number of trees and volume of American juniper is increasing throughout most of its range, as it readily colonizes disturbed sites, and is sometimes aggressively weedy in taking over abandoned fields and roadsides. Dozens of cultivars have been developed for ornamental and landscaping purposes, with a large array of forms and foliage colors.
American juniper typically grows to 23 m (75 ft) high (although many cultivars are smaller), with a pyramidal or conical canopy, and thin bark. The leaves on young growth are needle-like but flattened, and are either opposite or ternate (in whorls of three). Leaves on older branches are scale-like and closely appressed (flattened together). The species is dioecious—male and wind-pollinated female flowers grow on separate plants, and only female flowers develop seed cones, which have fused scales and are round and berry-like, up to 1 cm (0.5 in) in diameter. Seed cones ripen to blue or black with a glaucous (waxy) coating, and typically contain 3 seeds.
The seed cones of various Juniperus species make up 2 to 5% of the diet of 66 species of North American mammals. The species is often bird-dispersed, as seed germination rates may be higher following passage through a bird gut.
Juniper “berries” are also edible by humans—they add the characteristic flavor to gin, and they are featured in teas and herbal supplements, and sometimes used as a flavoring in meat dishes.
Juniperus virginiana, along with several other juniper species, is an alternate host for the fungal pathogen Gymnosporangium juniperi-virginianae, which causes cedar-apple rust. Cedar-apple rust has a complicated life cycle, but causes colorful orange galls on juniper trees, and rust-colored spots (turning to black) on the leaves of apple trees (Malus species) that grow in close proximity to juniper; the fungus can reduce apple production.
(Adams 2008, Bailey et al. 1976, Lawson 1990, Martin et al. 1951, Wikipedia 2012.)