Common Name: common juniper
Type: Needled evergreen
Family: Cupressaceae
Zone: 2 to 7
Height: 0.75 to 1.50 feet
Spread: 4.00 to 6.00 feet
Bloom Time: Non-flowering
Bloom Description: Non-flowering
Sun: Full sun
Water: Medium
Maintenance: Low
Suggested Use: Ground Cover
Leaf: Evergreen
Fruit: Showy
Other: Winter Interest
Tolerate: Deer, Drought, Erosion, Dry Soil, Shallow-Rocky Soil, Air Pollution
Culture
Winter hardy to USDA Zones 2-6 where it is best grown in medium moisture, well-drained soils in full sun. Tolerates a wide range of soils, including very poor often rocky soils. Established plants have good drought tolerance. Species plants are particularly noted for their superior tolerance for cold temperatures and superior intolerance for heat and humidity. Plants will survive in the wild within the Arctic Circle, but are not recommended for planting in locations south of USDA Zone 6.
Noteworthy Characteristics
Juniperus communis, commonly called common juniper, is a dioecious, needled, evergreen conifer that grows in a variety of different shapes and forms in cool to cold areas of the Northern Hemisphere plus in one isolated population growing in the Atlas Mountains of Africa. It is the most widespread conifer growing in the world today. It is primarily native to coniferous forests, alpine open areas and plains in a circumpolar distribution which includes sites in Europe, Asia and North America, extending in some cases to within the Arctic Circle. In North America, it is widespread from Alaska east to Labrador and Greenland south to Minnesota and New York, extending further south in the Rocky Mountains to Arizona and in the Appalachians to North Carolina.
Growth habit and form in part depend upon such factors as geographic location, temperature and the amount of exposure to the elements. However, it is not unusual for a variety of different forms to be found growing together in the same location. In the U.S., common juniper is most frequently seen as a multi-stemmed shrub (to 5-15’ tall), but is also sometimes seen, particularly in harsh growing conditions, as a prostrate, low-growing, spreading shrubby plant (to 9-12” tall). Infrequently it appears as a medium-sized tree rising to as much as 45’ tall. Prickly, green, needle-like juvenile leaves grow in whorls of three. Exfoliating bark is often an attractive reddish-brown. Small, yellow cones appear in spring but are not considered ornamentally attractive. Male and female cones are produced on separate plants. Female plants produce slightly glaucous, spherical, 0.5" wide, fleshy, fruit-like seed cones which are commonly referred to as juniper berries. Berries emerge green but gradually ripen by fall to a waxy dark blue to black. Each berry usually contains two or three seeds and ripens in the 2nd or 3rd year. Berries are used for a number of purposes including flavoring gin.
Genus name comes from the Latin name for the juniper.
Specific epithet means common.
‘Effusa’ is an evergreen, low-spreading, horizontal selection featuring foliage which is dull green above and silvery-white below. Grows 9-12” tall spreading to 4-6’ wide. Reddish-brown stems are usually visible through the somewhat thin foliage. For use as a ground cover for large areas, starter plants should be set about 3-5’ apart.
Problems
Juniper blight can be a serious problem on many of the different species of juniper, but is less frequently a problem on J. communis. Lesser problems include cedar apple rust and wilt. Insect problems include mites, borers, scale, midges and bagworms.
Uses
Evergreen ornamental ground cover, shrub or small tree. Use depends in large part upon form and size. Species plants are rarely sold in commerce, but a large number of varieties and cultivars are available.