Juniperus scopulorum Seeds | Rocky Mountain Juniper
LATIN NAME: Juniperus scopulorum
COMMON NAME: Rocky Mountain Juniper
Plant Profile
The Rocky Mountain Juniper is a small, slow, evergreen tree of the cypress family that holds dry slopes, canyon rims and broken rock across the American interior from Montana to New Mexico. Its foliage is scale-like and carries a strong blue-grey cast, the mature bark shreds in grey-brown strips, and the small, round, berry-like cones ripen over two seasons to a glaucous, dusty blue that birds strip through the winter. In the wild it is a gnarled, wind-shaped tree of four to eight metres, and in gardens its columnar selections have made it a fixture of dry-climate hedging.
It is a plant of extremes: hot, dry summers, cold winters, thin soils over rock, and years of drought it rides out on a deep root run. Nothing about it is tender.
Science & Biotechnology
The species sits in the juniper complex that also holds the eastern red-cedar, and the boundary between them has been tested with morphology and molecular data, with intermediates where the ranges approach. Its columnar selections, including ‘Skyrocket’ and ‘Wichita Blue’, trace to single wild or seedling finds and are propagated by cutting, and their narrow geometry has been studied in the windbreak literature for the shelter effect a dense, thin screen delivers. Ecologically it is an alternate host in the rust-fungus life cycles that also involve apples and hawthorns, a fact that matters to orchardists wherever the two grow within airborne distance of each other.
The waxy, blue cones are a two-season crop, and their flesh is a juniper berry in the culinary sense, though the flavour of this species is less prized than the Old World one.
Uses & Benefits
In the dry garden it is a structural evergreen for poor, hot, exposed ground: a columnar screen, a windbreak row, a specimen on a bank where irrigation never reaches, and a plant whose blue-grey foliage reads as silver from a distance. It tolerates drought, alkaline soil, wind and urban conditions, and it asks to be left alone once established.
The berries feed birds through winter, the dense foliage shelters nesting birds, and its one drawback in mixed plantings is the rust-host issue near orchards. In its native range it anchors canyon-rim woodland across the driest end of the conifer range.
Growing from Seed
Clean the pulp from ripe cones and give the seed a long treatment: warm stratification for two months followed by cold for three to four, or sow outdoors and expect germination in the second spring; juniper seed is famously slow and erratic. Sow into a free-draining compost and keep it just moist, never wet.
Grow the seedlings in full sun on the dry side, pot on as the root deepens, and plant out into any well-drained soil in full sun, spacing screens at seventy-five centimetres for cut selections or wider for seed-grown variation. Water through the first two summers only; after that it is among the most self-sufficient conifers in cultivation.
Our Take
A blue-grey, berry-loaded juniper built for drought, cold and neglect. The columnar selections make the driest hedge in cultivation; the seed-grown trees make a grove.
Related Reading
More species in the same orbit as Rocky Mountain Juniper: