• Juniperus communis
• (Joo-NIP-er-uss kom-YOU-niss)
• Family Cupressaceae
• Hardy tree
The genus Juniperus contains about seventy species of evergreen trees or shrubs in the Northern Hemisphere, some thirty of which are native to North America. Common juniper (J. communis) is an erect or prostrate shrub or small tree to 35 feet tall. Native to much of North America and Eurasia, this species is said to have a wider distribution than any other tree or shrub.
Juniper’s berries are relished by cedar waxwings, quail, squirrels, chipmunks, and raccoons; its dense, prickly foliage has made it useful as a shelter for birds and small mammals. Legend has it that juniper branches sheltered Mary and Jesus in their flight from King Herod. Some people have thought that planting a bush by the front door would repel witches, who, however, might still get in if they could correctly count its needles. The smoke of juniper burned during childbirth was once believed to keep fairies from substituting a changeling for the newborn and was also reputed to protect against plague and leprosy.
The red-brown or gray-brown bark is smooth at first but later becomes fibrous and shreddy. Young shoots are triangular in cross section with longitudinal ridges. The sharply pointed, pungent needles, 3/8 to 1 inch long, grow in whorls of three at right angles to the twig. They are typically gray-green with a white band on the upper surface. A green midrib may divide the white band in two at the base of the needle. In spring, yellow male and female flowers are borne singly in the leaf axils, usually on different plants. They are wind-pollinated. The male cones are cylindrical and about 1/3 inch long. The round or oval female cones, 1/4 to 1/2 inch in diameter, take two or three years to ripen from green to blue or black three-seeded “berries”. The species has many natural and cultivated varieties that vary in habit and color. The wood is hard and resists insects.
Juniper berries, eaten raw or in tea, have been used to treat inflammation of the bladder, flatulence and other digestive disorders, respiratory ailments, intestinal parasites, venereal disease, and scurvy. Native Americans drank a twig tea for colds and stomachaches, and they applied hot packs of twigs and boiled berries to sores and aches. Juniper also has been used externally to treat snakebite and cancer.
Juniper is an ingredient of some commercial diuretics and laxatives. The essential oil is antiseptic but can cause blistering when used undiluted. Terpinen-4-ol, its principal active constituent, works by irritating the tissues of the kidney and intestine. Overdoses can cause kidney failure, convulsions, and personality changes. Although it contains vitamin C and is therefore effective in preventing or treating scurvy, long-term use of juniper tea can interfere with the absorption of iron and other minerals. Research has not supported its effectiveness in treating flatulence. Do not take juniper during pregnancy or if you have kidney disease, and don’t give it to children. The oil is most abundant in ripe, freshly picked berries, although it also occurs in the wood and the needles.
Relatively safer ways to use juniper include soaking in a tub of warm water to which you have added a few aromatic sprigs (watch the prickles) or simmering berries in olive oil and then rubbing the cooled oil on sore limbs.
The best-known nonmedicinal use of juniper berries is probably as flavoring for the Dutch invention, gin (the name comes from the Dutch word jenever, “juniper”). The dried berries and oil have also been used in liqueurs and cordials as well as in French and Swedish beers. The berries have served as a pepper substitute and, roasted, as a coffee substitute. They add piquancy to meats, especially game, sauerkraut, and stuffings. Crush three or four berries to simmer in chowder or steep in an herb vinegar, but remove them before serving. Juniper berry tea is spicy with a flavor reminiscent of gin, but it’s also diuretic.
Maud Grieve, in A Modern Herbal (1931), notes that juniper is “readily eaten by most animals, especially sheep, and is said to prevent and cure dropsy in the latter.” Oil of juniper mixed with lard was at one time applied to wounds of animals to keep off flies.
The early European settlers in America spread their sheets on juniper bushes to dry. The fibrous bark has been made into rope. The branches may be used for wreaths.
Common juniper is hardy to USDA Zone 2 but may not do well in the Deep South. It withstands drought and wind, and it grows in all kinds of poor soils. Its extensive root system is well equipped to hold soil on slopes. Low kinds are good for ground cover in sandy soils and waste places, taller ones for hedges and windbreaks. Those with drooping branch tips may take root and form new plants, eventually growing into an impenetrable thicket—nice for a wildlife preserve but less appealing for a small backyard.
The foliage of common juniper has an unfortunate tendency to brown in winter. Other juniper species such as J. chinensis, horizontalis, or virginiana may be better choices for good winter color. The numerous cultivars of J. communis include dwarf, upright, spreading, conical, vase-shaped, pyramidal, and columnar forms with green or yellow foliage, one or more of which is probably suitable for your landscape. J. communis ‘Berkshire’ makes a flat mound 1 foot high, ‘Compressa’ is a 3-foot-tall narrow columnar spire, and ‘Repanda’ is a prostrate cultivar that holds its color in winter better than most.
Common juniper can be grown from seeds, although they may take two to three years to germinate. To speed germination, try dipping the berries briefly in boiling water. Giving the planted seeds moist warmth for sixty to ninety days followed by ninety days of moist chilling is said to promote germination within twenty to thirty days.
Grow plants in full sun. Seedlings transplant readily. Plant several to increase the likelihood of having both male and female plants, which you’ll need for the production of berries.
You can harvest berries all winter, but remember to wear gloves and work from below the branches to avoid being pricked by the needles. Pick only the mature (blue or black) berries, dry them slowly indoors, and store them in a tightly closed container.
• J. L. Hudson, Seedsman, PO Box 1058, Redwood City, CA 94064. Catalog $1. Seeds of J. communis.
• Roslyn Nursery, 211 Burrs Ln., Dix Hills, NY 11746. Catalog $3. Plants of J. communis ‘Berkshire’, ‘Compressa’, ‘Gold Cone’, ‘Pencil Point’, and ‘Repanda’.