Common Name: Juniper.
Known Hazards: Although the fruit of this plant is quite often used medicinally and as flavouring in various foods and drinks, large doses of the fruit can cause renal damage. Juniper should not be used internally in any quantities by pregnant women.
Habitats: Chalk downs in S. England but only where there is least sunshine and most rain, heaths, moors, pine and birch woods in the north of Scotland on acid peat, often dominant on chalk, limestone and slate.
Range: Northern temperate zone, including Britain, south to the mountains of N. Africa, Himalayas and California
Juniperus communis is an evergreen Shrub growing to 9 m (29ft) by 4 m (13ft) at a slow rate. It is hardy to zone 2 and is not frost tender. It is in leaf 12-Jan It is in flower from May to June, and the seeds ripen in October. The flowers are dioecious (individual flowers are either male or female, but only one sex is to be found on any one plant so both male and female plants must be grown if seed is required) and are pollinated by wind. The plant is not self-fertile.
The plant prefers light (sandy), medium (loamy) and heavy (clay) soils, requires well-drained soil and can grow in heavy clay and nutritionally poor soils. The plant prefers acid, neutral and basic (alkaline) soils and can grow in very acid and very alkaline soils. It can grow in semi-shade (light woodland) or no shade. It requires dry or moist soil and can tolerate drought. The plant can tolerate maritime exposure.
Fruit – raw or cooked. It is usually harvested in the autumn when fully ripe and then dried for later use. It has soft, mealy, sweet, resinous flesh. The fruit is often used as flavouring in sauerkraut, stuffings, vegetable pates etc, and is an essential ingredient of gin. The aromatic fruit is used as a pepper substitute according to one report.
An essential oil is sometimes distilled from the fruit to be used as flavouring. Average yields are around 1%. The cones are about 4 – 8mm in diameter and take 2 – 3 years to mature. Some caution is advised when using the fruit; see the notes above on toxicity. The roasted seed is a coffee substitute. A tea is made by boiling the leaves and stems. A tea made from the berries has a spicy gin-like flavour.
Plants For A Future cannot take any responsibility for any adverse effects from the use of plants. Always seek advice from a professional before using a plant medicinally.
Medicinal Actions: Antiseptic; Aromatherapy; Aromatic; Carminative; Diaphoretic; Diuretic; Rubefacient; Stomachic; Tonic.
Juniper fruits are commonly used in herbal medicine, as a household remedy, and also in some commercial preparations. They are especially useful in the treatment of digestive disorders plus kidney and bladder problems. The fully ripe fruits are strongly antiseptic, aromatic, carminative, diaphoretic, strongly diuretic, rubefacient, stomachic and tonic. They are used in the treatment of cystitis, digestive problems, chronic arthritis, gout and rheumatic conditions.
They can be eaten raw or used in a tea, but some caution is advised since large doses can irritate the urinary passage. Externally, it is applied as a diluted essential oil, having a slightly warming effect upon the skin and is thought to promote the removal of waste products from underlying tissues. It is, therefore, helpful when applied to arthritic joints etc.
The fruits should not be used internally by pregnant women since this can cause an abortion. The fruits also increase menstrual bleeding so should not be used by women with heavy periods. When made into an ointment, they are applied to exposed wounds and prevent irritation by flies. The essential oil is used in aromatherapy. Its keyword is ‘Toxin elimination’.
A decoction of the branches is used as an anti-dandruff shampoo. The essential oil distilled from the fruits is used in perfumes with spicy fragrances. In hot countries the tree yields the resin ‘Sandarac’ from incisions in the trunk. This is used in the production of a white varnish. The stems were at one time used as a strewing herb to sweeten the smell of rooms.
The whole plant can be burnt as an incense and fumigant. It was used during epidemics in the belief that it would purify the air and cleanse it of infection. Fresh or dried juniper branches also make a good insect repellent. Many forms of this species are good ground cover plants for sunny situations. Forms to try include ‘Depressa Aurea’, ‘Dumosa’, ‘Effusa’, and ‘Repanda’. ‘Prostrata’ can also be used. The bark is used as cordage and as a tinder. Wood – strong, hard, fragrant, very durable in contact with the soil and very close-grained, but usually too small to be of much use. It makes an excellent fuel.
An easily grown plant, it succeeds in hot dry soils and in poor soils. Succeeds in most soils so long as they are well drained, preferring a neutral or slightly alkaline soil. Does well in chalky soils. Grows well in heavy clay soils. Tolerates a pH range from 4 to 8. Succeeds in light woodland but dislikes heavy shade. Established plants are very tolerant of drought. Although the fully dormant plant is cold-tolerant throughout Britain, the young growth in spring can be damaged by late frosts. All parts of the plant are very aromatic.
Juniper is a very polymorphic species that has a long history of culinary and medicinal use. It is frequently grown in the ornamental and herb garden, there is a huge range of cultivars of widely diverse habits. At least some forms tolerate maritime exposure, there is a thriving colony in an exposed position at Land’s End in Cornwall. The fruits take 2 – 3 years to ripen on the plant. Plants are usually very slow growing, often only a few centimetres a year. Resists honey fungus. Plants are sometimes attacked by a rust, this fungus has an aecidial stage on hawthorn (Crataegus spp.). Dioecious. Male and female plants must be grown if seed is required.
The seed requires a period of cold stratification. The seed has a hard seedcoat and can be very slow to germinate, requiring a cold period followed by a warm period and then another cold spell, each of 2 – 3 months duration. Soaking the seed for 3 – 6 seconds in boiling water may speed up the germination process. The seed is best sown as soon as it is ripe in a cold frame.
Some might germinate in the following spring, though most will take another year. Another possibility is to harvest the seed ‘green’ (when the embryo has fully formed but before the seedcoat has hardened). The seedlings can be potted up into individual pots when they are large enough to handle.
Grow on in pots until large enough, then plant out in early summer. When stored dry, the seed can remain viable for several years. Cuttings of mature wood, 5 – 10cm with a heel, September/October in a cold frame. Plant out in the following autumn. Layering in September/October. Takes 12 months.