Junipers (C 956)Download PDF
- Cultural Requirements
- Fertilization and Watering
- Pests and Diseases
- Recommended Junipers
Junipers are among one of the toughest plants for the landscape. Their hardy nature and drought tolerance make them ideal choices for many of our southern landscapes.
It is impossible to generalize about the growth habit of junipers as the species vary from low-growing ground cover types to larger conical-pyramidal forms. Foliage color varies from lustrous dark green, to light green, blue, silver-blue, yellow and many shades in between.
There is no limit to the different uses of junipers in the landscape. They make excellent screens, hedges, windbreaks, ground covers, foundation plants and specimens.
Junipers prefer open, sunny locations in well-drained soils. They will tolerate a wide range of pH levels. They are very tolerant of dry, clay soils and many varieties will grow in sand. Some types, such as Sargent juniper and Shore juniper have shown good salt tolerance.
Avoid planting junipers in shaded areas. When located in the shade, they become open, thin and are more susceptible to problems from diseases and insects. Also, avoid planting them in wet or poorly drained soils.
Be sure to properly space plants prior to planting. Junipers, particularly the horizontal types, are often planted too close together. As a result, they can form a thick layer of foliage which can lead to poor air circulation and make plants more vulnerable to insects and diseases.
After removing the plant from the container, separate the dense, root mass by loosening it with your hands or the aid of a knife. Place the top of the root ball level with the soil surface. Water thoroughly after planting and at least twice weekly for the first month to ensure establishment.
Once established, junipers need very little supplemental irrigation. They are one of the most drought tolerant plants in our landscape and can actually suffer from over-watering.
Junipers respond well to a balanced fertilizer at planting such as two teaspoons of 10-10-10 per 1 gallon plant. Incorporate fertilizer into the soil or spread it around the plant, but avoid directly placing fertilizer into the planting hole.
Established junipers will benefit from a complete fertilizer such as 16-4-8 or 12-4-8 applied at a rate of 1/2 lb. per 100 square feet in early spring and again in late summer. Apply prior to rainfall or irrigate immediately after application.
Junipers do not tolerate heavy pruning because of the lack of new growth on old wood. This makes it important to know the growth habit of a particular juniper prior to planting so that future pruning can be minimized. Junipers can be tip pruned and thinned, but not cut back to large limbs. Pruning out old, dead foliage underneath creeping junipers will often contribute to better air circulation and thus better health of the plant.
Although junipers are tough, they do occasionally have some problems. Common insect pests of junipers would include bagworms, spider mites, leaf miner, webworm, scale and aphids, all of which can be controlled with an appropriate pesticide.
Several diseases can occur on junipers, but are almost always associated with poor cultural practices, such as over-watering or too much shade.
There are many cultivars of junipers available. The following are some of the most commonly available cultivars, grouped by plant size.
Low Growing (2 Feet)
Juniperus chinensis 'Sargentii' - Spreading green foliage, grows 18 inches to 2 feet high with a spread of 7 feet. Makes an excellent ground cover.
Juniperus horizontalis 'Plumosa Compacta' - Compact form of 'Plumosa', dense branching, flat (18 inches high) spreading to 8 feet; bronze-purple in winter, stays full in center, gray-green summer foliage
Juniperus horizontalis 'Wiltoni' 'Blue Rug' - Very flat growing form with trailing branches, 6 inches high with a spread of 6 to 8 feet, foliage-intense silver-blue, assumes light purplish tinge in winter; fairly fast growing.
Juniperus horizontalis 'Procumbens' - Spreading, prostrate form, 6 inches by 10 feet to 12 feet, leaves awl-shaped, soft, glaucous green, becoming bluish green with age. The cultivar 'Greenmound' has attractive light-green foliage that does not brown out. The cultivar 'Nana' is a dwarf and is similar to the species.
Juniperus squamata 'Parsoni' - Grey-green needles with a prostrate habit; grows 18 inches tall and 6 feet wide.
Juniperus conferta 'Shore Juniper' - Low growing; spreading habit; is tolerant of poor soils, especially adapted to sandy soils of the seashore. Yellowish-green in color, 12-15 inches tall, spreads to 8 feet.
Juniperus conferta 'Blue Pacific' - Low trailing habit and ocean blue-green foliage color; makes a good ground cover; grows to 12-15 inches tall with a spread of 5 to 7 feet.
Medium Growing (2-5 Feet)
Juniperus chinensis 'Sea Green' - Compact spreader with fountain-like, arching branches, dark green (mint green) foliage; 4-6 feet high, 6 to 8 feet wide; more upright than 'Pfitzeriana', foliage darkens in cold weather.
Juniperus virginiana 'Grey Owl' - Medium growing, widespread juniper with greyish green foliage. Grows to 5 feet tall with an 8 feet spread.
Juniperus chinensis 'Saybrook Gold' - considered one of the brightest gold foliaged J. chinensis type, primarily needle-like foliage, summer foliage is bright yellow, more bronze-yellow in winter, horizontal spreading type probably 2 to 3 feet high by 6 feet wide.
Juniperus chinensis 'Nick's Compact' - A relatively flat-topped, wide-spreading form with green, slight blue overcast foliage; grows to 2 ½ feet high by 6 feet wide.
Juniperus chinensis 'San Jose' - Creeping form, 12 to 18 inches (24 inches) high and 6 feet to 8 feet wide, spreads irregularly; foliage sage green, young plants tend to be acicular, but with maturity there is a mixture of scale and needlelike foliage.
Juniperus chinensis 'Holbert' - Spreading growth habit of 3' high and 8' to 9' across. Blue foliage holds color through the winter months.
Large Growing (5-12 Feet)
Juniperus chinensis 'Aureo-Pfitzerana' (Gold Tip Pfitzer) - Light green foliage with yellow branch tips. Grows to a height of 5 feet with a 10 foot spread.
Juniperus chinensis 'Pfitzeriana - Probably the most widely planted juniper, wide spreading, variable form, grows about 6 feet high and 10 feet wide. Bright green foliage and is attractive as a younger plant. It can look untidy with age.
Juniperus chinensis 'Hetzii Glauca' - Semierect form with light blue foliage; grows 5 feet to 7 feet high, with an equal spread, a very hardy juniper.
Juniperus chinensis 'Pfitzeriana Glauca' ('Blue Pfitzer') - Possibly more dense than Pfitzer with mixed leaves, markedly blue in older plants, becoming slightly purplish blue in winter; handsome bluish foliage through the seasons in warmer climates; grows 6 feet high with a spread of 10 feet.
Juniperus chinensis 'Blue Vase' - Vase-shaped form with good summer and winter foliage; dense steel blue foliage; moderate growth rate, 6-10 feet high, 4-5 feet wide.
Upright Growing (Pyramidal)
Juniperus chinensis 'Spartan' - A fast, dense grower of tall, pyramidal or columnar habit, has a deep green color and very formal appearance, may grow to 20 feet high.
Juniperus chinensis 'Hetzii Columnaris' - Medium size, columnar green juniper. Dense tall growth with sharp pointed bright green needles. Grows 10-15 feet tall.
Juniperus chinensis 'Blue Point' - Pyramidal form with a tear drop outline, extremely dense branching, blue-green, needle and scalelike foliage; can grow 7-10 feet.
Juniperus chinensis 'Robusta Green' - Moderately slow grower, upright, rich green, twisted growth to 15 feet tall.
Juniperus chinensis 'Kaizuka' ('Torulosa') - Hollywood Juniper; leaves are scale-like, vivid green, branches slightly twisted; can be grown as a shrub or tree; will grow 20 to 30 feet high; excellent heat and salt tolerance.
Dirr, Michael A. Manual of Woody Landscape Plants. Stipes Publish Co., Champaign, Illinois, 1990.
Whitcomb, C.E. Know It and Grow It. Oklahoma State University Press, 1984.