A tree up to 40 ft high, forming a round-topped head of branches, its trunk often dividing near the ground; bark reddish brown; young shoots slender. Leaves scale-like, closely pressed to the stem, overlapping, arranged in pairs and altogether very like those of J. virginiana. There is on the back of each leaf a usually well-defined gland. Fruits globose, 1⁄4 in. wide, covered with a bright blue bloom, ripening the second year, carrying one or two seeds.
Native of the western United States, where it represents the J. virginiana of the eastern States. That species is closely akin to it but is well distinguished by ripening its seeds the first season. J. scopulorum, too, has only six stamens to each male flower, whilst J. virginiana has ten to twelve. The former, which was made a species by Sargent in 1897, is quite hardy, but owing to its similarity with J. virginiana has not obtained much notice from cultivators, and although it was introduced in 1839, is quite uncommon today. Numerous cultivars have been named in the United States, some of them dwarf.