Juniperus scopulorum 'Gray Gleam' (Gray Gleam Juniper, Gray Gleam Rocky Mountain Juniper)


Michael's Opinion

An upright juniper to offer winter interest in the landscape. Not just snowflakes sparkle! This ‘Gray Gleam’ Juniper has lovely silvery foliage that brightens in the cold weather and looks its best in the winter. ‘Gray Gleam’ can be pruned as desired and requires little maintenance due to its slow growth rate. An eye-catcher for sure—that is how this cultivar came to be! - Emily DeBeck

Botanical Information

FamilyCupressaceae
GenusJuniperus
Speciesscopulorum
Cultivar'Gray Gleam'
CategoryWoody
TypeTree (evergreen)
ReferencesStevens, M. (n.d). Rocky Mountain Juniper. Retrieved March 12, 2021, from https://plants.usda.gov/plantguide/pdf/cs_jusc2.pdf [ In-text citations: (Stevens, n.d., “Distribution”) (Stevens, n.d., “Description” (Stevens, n.d., “Seed Propagation”) (Stevens, n.d., “Propagation from Cuttings”) (Stevens, n.d., “Uses”) ] Gilman, E. F. & Watson, D. G. (2014, September 12). Juniperus scopulorum: Rocky Mountain juniper. Retrieved March 19, 2021, from http://hort.ufl.edu/trees/JUNSCOA.pdf [ In-text citation: (Gilman & Watson, 2014) ]
OriginScott Wilmore created this cultivar from a chance seedling in Morrison, Colorado, United States of America, 1944. He went on to patent it in 1949 and is still supplied by the Wilmore nurseries.
Ethnobotanical Uses
Disclaimer
Stevens wrote “the Cheyennes steeped the leaves of the Rocky Mountain juniper and drank the resulting tea to relieve persistent coughing or a tickling in the throat” (Stevens, n.d., “Uses”). This tea was a treatment for respiratory ailments as well as to hasten labour in pregnant women. Tribes such as The Blackfeet and The Crow used it for other similar purposes in the form of topical application of boiled leaves for aches and pains and for consumption as medicinal teas (Stevens, n.d., “Uses”). ‘Gray Gleam’ is reserved for ornamental use, but straight species have notable healing properties.

Details

USDA Hardiness Zone4 - 7
USDA Hardiness Ref.
Canadian Hardiness Zone3 - 5
Canada Hardiness Ref.
RHS Hardiness ZoneH7
RHS Hardiness Ref.
Temperature (°C)-35 - -12
Temperature (°F)-30 - -10
Height4 - 6 m
Spread2 - 3 m
Flowering PeriodApril, May, June

Description and Growing Information

General DescriptionJuniperus scopulorum 'Gray Gleam' is hardy in cold climates, low maintenance, and used for colour in the urban landscape. Small and slow growing, it offers its colour throughout the seasons although is at its best in the winter. It has green to blue-silvery scaled foliage and is easy to care for with only occasional pruning. Tolerant of a wide variety of soils with a need for full sun. Used for functional purposes in the garden such as hedges and windbreaks or simply to be admired, the choice is yours.
ID CharacteristicWith an upright, narrow conical growth habit, this cultivar has a unique silvery grey glimmer dense, scaled foliage on display during the winter
Shape‘Gray Gleam’ can be pruned into desired shapes; however, it has a natural upright and densely compact growing habit throughout its lifespan.
LandscapeUsed as a single accent plant in the landscape or grouped as a hedge to provide privacy, this cultivar will give you a showy look. The cold weather enhances its colour, ideal for winter interest and to offer colour in a season that often lacks vibrant attraction.
PropagationStevens’ research offers extensive direction to propagate this cultivar from ripe berries and cuttings. Ripe berries can be gathered through September-October once seeds are fully mature, and then dried to 10-205 moisture and stored at cold temperatures (Stevens, n.d, “Seed Propagation”). Treat with sulfuric acid for 120 minutes, proceed with seed extraction and “follow with 6 weeks of warm stratification at 20 - 30°C (70 to 85°F), or summer planting, then 10 weeks of pre-chilling at 4°C (40°F)” (Stevens, n.d., “Seed Propagation”). Seeds can then be planted in seedbeds 15-20 cm apart and covered with a 0.6 cm layer of soil, with a recommendation to sow in the autumn for prechilling advantages (Stevens, n.d., “Seed Propagation”). Cuttings to be rooted in the greenhouse can be taken at any time during the winter or rooted outdoors on heated beds. Exposing the stock plants to several hard freezes seems to give better rooting. For propagating in an outdoor cold frame, cuttings are taken in late summer or early fall. There may be advantages to using bottom heat. Lightly wounding the base of the cuttings is sometimes helpful, and the use of root-promoting chemicals, especially IBA, is beneficial (Stevens, n.d., “Propagation from Cuttings”).
CultivationA relatively vigorous and low maintenance cultivar, it can grow in poor, acidic or alkaline soils, and is urban and cold weather tolerant. Not able to abide excessive water, it requires sparse watering and is drought tolerant provided it gets plenty of sun.
PestsThere is no recorded pest of note that may deteriorate the planting of this cultivar, although this may be due to lack of substantiated research. Straight species have been recorded as a host for diseases such as cedar-apple rust, hawthorn rust, and quince rust especially in warmer climates (Gilman & Watson, 2014). Bagworms and mites are opportunistic pests commonly known to junipers as well.
Notable SpecimensArboretum at the University of Guelph, Ontario Canada, has a specimen part of their Conifer Tree Collection.
HabitatHorticultural origin.
Bark/Stem DescriptionStevens wrote on the straight species Juniperus scopulorum “the bark is dark reddish-brown in color, thin, fibrous, and usually shreds with age” (Stevens, n.d, “Description”).
Leaf DescriptionScaled needles that are blue green turning silvery green in the winter in thin but densely compact branchlets. Takes on a frosted like appearance in the colder months.
Flower DescriptionDioecious tree that flowers through April – June. Flower is supposedly so insignificant as to be ornamentally unmentionable in research and not a factor in landscape usage for ‘Gray Gleam’.
Fruit DescriptionFemale fruit is dark blue with a waxy filament and berry-like structure, ripening throughout the early autumn during September-October. The fruit are small: 0.4-0.7 cm and male fruit are ovoid-ellipsoid in form, cone-like, and beige coloured, 0.2-0.4 cm (Stevens, n.d., “Description”). Neither are considered ornamentally significant but attract birds. Fruits require 2 years to fully mature.
Colour DescriptionBlue-grey foliage in spring and summer with hints of silver in the autumn, fully brightening in the winter. Reddish-brown bark is obscured by dense foliage.
Texture DescriptionMedium textured plant through all seasons.

Photographs