There are more than 170 species and varieties of juniper (Juniperus species) available in nurseries. Some of the most commonly grown junipers include Chinese juniper (J. chinensis), creeping juniper (J. horizontalis), savin (J. sabina), Japanese juniper (J. procumbens), and shore juniper (J. conferta).
Junipers are evergreen, coniferous plants, ranging from low-growing shrubs to tall, slender trees. On young plants the leaves are usually needle-shaped and borne in threes. On adult plants leaves generally are small, scale-like, opposite and pressed close to the twigs. The color of the foliage will vary from light to dark green, blue to silver and yellow to gold. The flowers are not very showy and the fruits are berrylike, fleshy cones. Male flowers and female (berry-producing) flowers occur on different plants.
Junipers are popular because of their numerous design characteristics: form, size, color and texture. Low-growing junipers can be used as groundcovers or foundation plantings. Taller-growing plants are excellent for screens, hedges or windbreaks. You can find a juniper in almost any height, width, shape or needle color. They grow throughout South Carolina, in a wide variety of habitats.
One common trait shared by junipers is their tolerance to adverse conditions. Junipers generally enjoy full sun and good drainage. During summer droughts they withstand heat and dry conditions much better than most ornamentals.
The groundcover group includes types ranging from a few inches to 2 to 3 feet high.
Some species, such as creeping juniper, spread 5 to 6 feet. Others only spread 18 inches. Spacing of the plants depends on the species used. During the first years after planting, mulch will help keep the soil cool and the weeds down.
Junipers do not tolerate severe pruning. Do not cut back to older, needle-less wood. Propagate junipers by cuttings, seed, layering and grafting.
Junipers are subject to a number of pests and diseases. Among the most serious pests are bagworms (foliage is stripped), twig borers (branch tips turn brown and die), juniper scale (no new growth and foliage yellowed) and juniper webworm (webbing together and browning of foliage). Spider mites, leaf miners and aphids may also attack junipers. All of these can be controlled with a recommended pesticide.
The following fungal diseases may occur on juniper:
- Cedar apple rust. This disease alternates between junipers and apple trees, producing galls and causing twig dieback.
- Foliage or tip blight.
- Phomopsis dieback. Dieback of leaves and twigs occurs in the spring. Eventually leaves may shed.
- Root rots, caused by the fungi Pythium and Phytophthora. The root cortex sloughs off, roots rot and the entire plant dies.
These diseases may be prevented by growing disease-resistant cultivars.
Junipers resistant to phomopsis twig blight and cedar rusts are the Chinese juniper cultivars ‘Femina, ‘ ‘Keteleeri,’ ‘Mint Julep’and ‘Pfitzeriana’; common juniper cultivars ‘ Aureospica,’ ‘Suecica,’ ‘Broadmoor,’ ‘Knap Hill’ and ‘Skandia’; Eastern red cedar cultivar ‘Tripartita’; and creeping juniper cultivars ‘Wiltoni’ (‘Blue Rug’) and ‘Plumosa’ (‘Andorra’). Control may be obtained by using a recommended fungicide.
The following list of junipers describes a few that are well suited for a South Carolina landscape.
- Chinese juniper (J. chinensis). Grows very large (50 to 60 feet in height and 15 to 20 feet in spread) with an erect, conical narrow tree form.
- J. chinensis ‘Procumbens’ or Japanese garden juniper grows to a height of 2 feet and spreads 12 to 20 feet. Plants have feathery, blue-green foliage on long, wide-spreading, stiff branches.
- Common juniper (J. communis) grows 10 to 12 feet tall with an 8- to 12-foot spread. Common Juniper has reddish-brown bark and gray-green foliage. Several cultivars are available.
- Shore juniper (J. conferta) is a favorite groundcover, which should be planted 5 to 6 feet apart. Plants grow 12 to 18 inches high with a 6- to 8-foot spread. ‘Blue Pacific’ has ocean green foliage and is heat tolerant. ‘Emerald Sea’ is bright green. Shore juniper makes an excellent groundcover near the seashore because it is salt-tolerant.
- Creeping juniper (J. horizontalis) is mainly used as a groundcover, since it grows up to 2 feet high with a 6- to 8-foot spread. There are many landscape uses with different cultivars.
- ‘Bar Harbor’ is low spreading and fast growing. Feathery, blue-gray foliage turns plum color in winter. It tolerates salt spray.
- ‘Plumosa’ or ‘Andorra creeping juniper’ is 2 feet by 10 feet, creeping, gray green in summer and plum color in winter.
- ‘Wiltonii’ or ‘Blue Rug’ is 4 inches high by 8 to 10 feet wide, very flat and creeping. The foliage is an intense silver blue.
- Eastern red cedar (J. virginiana) is a picturesque tree with dark green foliage that turns reddish in cold weather. The tree grows to a height of 40 to 50 feet, tolerates drought and poor soil. Small trees are Christmas tree favorites.
- Southern red cedar (J. silicicola) is very similar to Eastern red cedar, though often more open and wide-spreading. This tree is salt-tolerant and grows well in sandy soils. It is well suited for coastal conditions.
More information on juniper shrubs and trees is available by requesting HGIC 1068, Juniper.