Juniper

(Cupressaceae - Cypress Family)

Form

• evergreen woody plant that is variable in size and function as a groundcover, spreading shrub, upright shrub, or tree form (depending upon species and cultivar)
• groundcover forms have a procumbent mat growth habit, while spreading shrub forms have a spreading oval growth habit (where the oval is on its side); both forms are much wider than tall
• upright shrub forms and tree forms have an upright columnar, narrow pyramidal, or upright oval growth habit
• slow to medium growth rate, depending upon species and cultivar

Culture

• full sun to partial sun
• prefers moist, well-drained soils in full sun, but is very urban tolerant, especially to poor soils, compacted soils, soils of various pH, heat, drought, and moderate pruning or constant shearing; will not tolerate full shade or wet sites
• propagated primarily by rooted cuttings or grafting onto a rootstock
• Cypress Family, with several serious potential diseases (especially twig blight [Phomopsis], but also various rusts) and pests (especially midge, but also aphid, bagworm, scale, webworm, beetle, and mite)
• abundantly available, with the many forms often sold in containers, but the larger selections are also sold in ball and burlap form
• many shrubform spreading Junipers are sheared as semi-formal foundation or entranceway shrubs

Foliage

• evergreen foliage is found as scale, awl, or needle forms, depending upon species, cultivar, and especially the juvenility or maturity of the individual plant
• foliage color ranges from kelly green, dark green, blue, silver, steel, gray, chartreuse, or yellow, depending upon species and cultivar
• foliage often becomes darker green or bronzed in the Winter

Flowers

• often dioecious (male and female flowers are on separate plants), but ornamentally inconspicuous; sometimes noticeable as brownish or yellowish elongated knobs amidst the foliage in Spring

Fruits

• often inconspicuous, but sometimes quite noticeable on female plants as very glaucous blue-black or light blue small "cones" of generally ovoid or rounded shapes held tightly against the stems and foliage

Twigs

• reddish brown in many cases, often unnoticed due to the dense awls, scales, or needles that tightly and completely cover the stems
• stems are aromatic when crushed or pruned
• stems and foliage often give a prolonged itch when brushed against

Trunk

• on large shrub or tree forms, the trunk(s) often has an exfoliating reddish- or purplish-brown bark, generally hidden by the dense foliage

ID Summary

• evergreen miniature foliage is found as scale, awl, or needle forms, often with more than one form on the same branch
• foliage is usually held so densely and tightly against the stems that the stems and branches are often obscured in terms of their bark color and exfoliating character
• members of the genus occur in tree, upright shrub, spreading shrub, and groundcover forms, and various cultivars have evergreen foliage that may be various shades of green, blue, or gold

USAGE

Function

• groundcovers, sheared shrubs, group or mass plantings, screens, specimen shrubs, topiaries, or trees, depending upon species and cultivar; those with non-green foliage (shades of yellow or blue) often serve as a focal point in the landscape

Texture

• fine texture
• thick density

Assets

• extremely urban tolerant (except for salt spray), especially to heat, drought, full sun, light reflection, and poor soil conditions
• various species exist in a multitude of growth habits, mature heights, mature spreads, and evergreen foliage colors
• often tolerant of repeated shearing into a desired shape
• foliage is mildy fragrant when crushed, and may serve as indoor greenery during the Winter

Liabilities

• serious disease (especially twig blight [also known as Phomopsis]) and pest (especially midge, mite, and bagworm) problems surface with age on some species or cultivars
• species that are spreading groundcovers or shrubforms often grow far beyond expectations for their given sites, and as a result must be repeatedly pruned to keep them in-bounds
• foliage and stems usually give a prolonged itch when brushed against

Habitat

• zones 3 to 5 for its northern limit, and 7 to 9 for its southern limit, depending upon species
• species come from all over the world

SELECTIONS

Alternates

• evergreen trees, shrubs, or groundcovers for neglected sites, poor soils, intensely sunny sites, wind-exposed sites, property borders, and building foundations (cultivars of Picea abies, Taxus x media, Thuja occidentalis, etc.)

Variants

• Juniperus chinensis - Chinese Juniper - shrubs are often sprawling, typically about 5' tall by 10' wide, with a generally irregular growth habit (but this species is the most variable of all Junipers)
  • 'Hetzii' - gray-green to blue-green foliage
  • 'Pfitzerana' - bright green foliage, very common
  • 'Spartan' - columnar to narrow pyramidal growth habit, to 20' tall
• Juniperus conferta 'Blue Pacific' - Shore Juniper - 1' tall by 6' wide, salt-spray tolerant, bluish-silvery-green foliage (best blue shading occurs in Spring and Summer), best groundcover Juniper for disease and pest resistance, and the most tolerant Juniper for partial shade conditions
• Juniperus horizontalis 'Wiltonii' - Blue Rug Juniper - 4" tall by 6' wide, silvery-blue foliage bronzes heavily in winter, subject to tip blight dieback with age and salt spray damage near roads and walkways
• Juniperus scopulorum - Rocky Mountain Juniper - columnar to narrow pyramidal growth habit, to 30' tall by 10' wide, but with its several cultivars usually shorter in height
  • 'Gray Gleam' - silvery-gray foliage intensifies in Winter, to 15' tall by 3' wide at the base
  • 'Skyrocket' - bluish-gray foliage, 15' tall by 1' wide with many ascending tightly held side branches, sometimes pruned into a helical or barber-pole fashion
• Juniperus squamata 'Blue Star' - a facer shrub or specimen shrub, having dense silvery-blue foliage that turns bluish-purple in Winter, to 1.5' tall by 2' wide with a very short triangular growth habit that is more spreading with age
• Juniperus virginiana - Eastern Red Cedar - common wasteland or primary succession Juniper after deforestation, to 30' tall by 10' wide, an inexpensive Christmas tree that loses its lower limbs and innner foliage with age, usually single-trunked and long-lived, also valued for its finely-grained scented wood used to make "cedar" chests or fence posts

NOTES

Translation

• Juniperus is the Latin name for the Junipers.

Purpose

• Juniper is a very common evergreen woody plant for various groundcover, spreading shrub, or upright shrub usages, with a variety of narrowleaf evergreen foliage colors and shades.

Summary

• Juniperus is a large genus composed of many species that serve as evergreen groundcover, shrub, or tree forms that are extremely adaptable and urban tolerant, with many cultivars that differ in growth habit, shape, mature size, and foliage color.