Common Name: Southern Redcedar

General Information

Juniperus virginiana silicicola is an evergreen tree with a conic crown when young, becoming flattened with age; it usually grows around 10 metres tall[].
The plant is harvested from the wild for local use as a food, medicine and source of materials. It can be grown as an ornamental in gardens, where it can make a very useful screen and windbreak in maritime areas.
Although confined to coastal areas and northern Florida, Juniperus virginiana silicicola is wide-spread and abundant and regenerating well. The plant is classified as 'Least Concern' in the IUCN Red List of Threatened Species(2013)[].

Known Hazards

The essential oil in this plant contains thujone[]. Thujone is a GABA receptor antagonist which allows neurons to fire more easily. In larger doses this can cause muscle spasms and convulsions, and can also be toxic to brain, kidney, and liver cells.
There has been a lot of negative press regarding thujone, particularly in the mid 19th century when thujone was reported to be more dangerous than alcohol - since shown to be exaggerated; and reports in the 1970’s that it might have a similar effect on the brain to THC (found in cannabis) – since found to be incorrect.
Thujone is probably best known for its use in the alcoholic drink ‘Absinthe’. It is also found in the essential oils of many other plants that are used in herbal medicines and foods, including Arborvitae (Thuja species), some Junipers (Juniperus species), Wormwoods (especially Artemisia absinthium) and Sage (Salvia officinalis). There are some legal restrictions in various countries on the quantity of thujone that can be added to foods and drinks and these vary between countries.
Side effects from consuming thujone can include sleeplessness and anxiety but, unless the pure essential oil is used, the quantity of thujone found in plants is well within safety levels. Pregnant women, however, may be advised to restrict their use of thujone-containing plants.
Juniper should not be used internally in any quantities by pregnant women[, ].

Botanical References

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Range

South-eastern N. America - South Carolina to Florida, west to Louisiana

Habitat

Mainly restricted to a narrow coastal strip near sea level, often bordering tidal marshes or occurring in old dunes, sometimes a minor component of pine forests further inland; usually found in limestone soils and prehistoric shell middens[]

Properties

Conservation Status	Least Concern
Edibility Rating
Medicinal Rating
Other Uses Rating
Habit	Evergreen Tree
Height	20.00 m
Growth Rate	Slow
Pollinators	Wind
Self-fertile	No
Cultivation Status	Ornamental, Wild

Cultivation Details

Juniperus virginiana silicicola is not a very cold-hardy plant, able to tolerate short-lived temperatures down to around -8°c when dormant. The climate is subhumid to humid, with a mean annual precipitation in the range 1,000 - 1,600mm and very mild winters[].
Requires a sunny position. Succeeds in most soils if they are well drained, preferring a neutral or slightly alkaline soil[, ] and succeeding on chalk[]. Tolerant of saline soils, salt-laden winds, and urban pollution[, ]. Established plants are drought tolerant, succeeding in hot dry positions[].
This species is only hardy in the milder areas of the country, requiring a warm sunny sheltered position[].
A very ornamental tree, it is moderately fast-growing for a juniper and is long-lived in the wild[, ]. Seed production is cyclic, a year of high yields being followed by some years of low yields[].
This southern variety of Juniperus virginiana appears to be restricted mainly to coastal foredunes but differs little in morphology or leaf terpenoids from upland Juniperus virginiana and appears to intergrade with that variety in Georgia[].
The crushed foliage has an aroma like soap or paint[].
Plants are resistant to honey fungus[]. In America this tree is a host of a gall-like rust that at certain stages in its life-cycle also attacks the leaves of apple trees[].
Plants are dioecious, male and female plants must be grown if seed is required.

Edible Uses

Fruit - raw or cooked. A thin, sweetish resinous flesh, the cones are about 7 - 10mm in diameter and have a thin skin[, ].
Seed cones 3--4 mm, pollen cones 4 - 5mm in diameter[].

Medicinal

The leaves are analgesic, antirheumatic, diuretic and febrifuge[]. An infusion has been used in the treatment of fevers, stiff neck, backache, headaches, low fever, coughs, colds and diarrhoea[]. A decoction of the leaves has been used as a body rub and steam bath in the treatment of rheumatism[].

The following reports are for the closely related J. virginiana, they probably also apply to this species.

The leaves are anthelmintic, diuretic, rubefacient and stimulant[, ]. A decoction has been used in the treatment of coughs and colds, general weakness and as a medicine for convalescents[].
The berries are anthelmintic, diaphoretic, emmenagogue and mildly antiseptic[, , , ]. They have been chewed as a treatment for mouth ulcers[, ] or made into a tea to treat colds, rheumatism, worms etc[, ].
The fresh young twigs are used as a diuretic[]. An infusion has been used both internally and as a steam bath in the treatment of rheumatism[].
The essential oil from the wood is an abortifacient, in some cases it has caused vomiting, convulsions, coma and death[, ].
The plant is said to contain the anticancer compound podophyllotoxin[].
The essential oil from the berries is used in aromatherapy. Its keyword is 'Composing'[].

Agroforestry Uses:

A fairly wind-resistant tree, it can be grown to form windbreaks around houses, succeeding even by the coast. It can also be used in hedges and screens[, , ].

Other Uses

The wood is straight-grained, very durable, light, brittle, soft, easily worked, very fragrant, insect-resistant[]. The wood does not shrink much on drying and weighs 30lb per cubic foot[]. The reddish wood is highly prized for cabinet making[], it is also used for fencing, the casing of lead pencils etc[]. This tree has been over-exploited and large trees suitable for commercial exploitation are now rare[].

Various extracts of the plant, especially the essential oil, are used as ingredients in commercial cosmetic preparations for perfumery, as skin and hair tonics, and to mask the aroma of other ingredients[].

The following reports are for the closely related J. virginiana, they probably also apply to this species.

An essential oil is obtained from the wood[, , , ]. Composed of cedar camphor or cedrol[], it is used in soaps, as an insecticide and moth repellent[, ], a deodorant, in polishes, perfumery etc[, ].
The leaves are used as an incense[, ] and are also either burnt or crushed and then scattered around as an insect repellent[, ].
The crushed bark can be used as a soft base in cradles[]. The bark has also been used to make mats[].
Some cultivars of this tree are suitable for ground cover when spaced about 90cm apart each way[]. 'Tripartita' and 'Chamberlaynii' have been recommended[].

Propagation

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/early autumn in a cold frame. Plant out in the following autumn[, ].
Layering in September/early autumn. Takes 12 months[].