Common Name: Carolina Hemlock

General Information

Tsuga caroliniana is an evergreen tree with a narrow conic crown; it can grow up to 30 metres tall. The straight, cylindrical bole can be up to 200cm in diameter[, ].
The tree has a wide range of traditional uses as a food, medicine and source of materials. It is little harvested on a commercial basis for its wood. It is often grown as an ornamental, especially within its native range, where it can be used as a hedge.
The area of occupancy of this rare and scattered species probably falls below the threshold for Endangered (500 km²) but there are no reports of overall decline of the population. Individual stands may be damaged or mature trees wiped out by a storm, but there appears to be regeneration on such sites. Decline of more permanent or widespread nature could occur as a result of death of trees from infestation with the hemlock adelgid insect, but so far this has been of limited impact. The plant is classified as 'Near Threatened' in the IUCN Red List of Threatened Species(2013)[].

Known Hazards

None known

Botanical References

, ,

Range

South-eastern N. America - Tennessee to Virginia, south to Georgia.

Habitat

Usually found growing singly or in small scattered groves of a few individuals on the rocky banks of streams; at elevations from 750 - 1,200 metres[].

Properties

Conservation Status	Near Threatened
Edibility Rating
Medicinal Rating
Other Uses Rating
Habit	Evergreen Tree
Height	20.00 m
Growth Rate	Slow
Pollinators	Wind
Cultivation Status	Ornamental, Wild

Cultivation Details

Tsuga carolina grows in the temperate regions of southeastern N. America where the climate is humid and cool, becoming relatively warm at lower elevations. The annual precipitation exceeds 1,000mm and falls throughout the year; there is much cloudy weather in all seasons[].
An easily grown plant, it thrives best when growing in a deep well-drained soil in the more humid regions of the temperate zone, where it appreciates the higher rainfall[]. However, it succeeds in most soils and positions, being especially good on acidic sandy soils[] but also tolerating some lime[] so long as there is plenty of humus in the soil[]. Grows best in cool woodland conditions in a partially shaded position[]. Typically, in the wild most soils are very acid, with a pH in the range 3.5 - 4.5[]. Plants are very shade tolerant when young, but need more sunlight as they grow older[, ]. Plants are thin and poor when grown in dry or exposed places[]. This species is more tolerant of atmospheric pollution than Tsuga canadensis[].
The tree is often slow growing when cultivated outside its native range. It is very cold tolerant, buit requires hot humid summers if it is to thrive[, ].
It begins producing seed when about 20 years old, but good crops do not occur until the trees are 25 - 30 years old[].
The wood is of little commercial importance because of the combination of mediocre quality and the relative rarity of the species in nature[].
The root system is shallow and spreading[], which makes trees highly susceptible to wind-throw when exposed through timber cutting or planted in open sites. Plants should be staked for the first two or three years following transplant in order to prevent wind-throw[].
Tsuga caroliniana is valuable as an attractive ornamental; a number of cultivars, mainly of compact form, have been developed[, ].
Plants in this genus are notably resistant to honey fungus[].

Edible Uses

Inner bark - raw or dried, ground into a powder and then used as a thickening in soups etc or mixed with cereals when making bread[, , ].

The leaves and twigs yield 'spruce oil', which is used commercially to flavour chewing gum, soft drinks, ice cream etc[].

A herbal tea is made from the young shoot tips[, , , , ]. These tips are also an ingredient of 'spruce beer'[].

Medicinal

The bark is astringent, diaphoretic and diuretic[]. A tea made from the inner bark or twigs is helpful in the treatment of kidney or bladder problems, and also makes a good enema for treating diarrhoea[]. It can also be used as a gargle or mouthwash for mouth and throat problems or externally to wash sores and ulcers[]. A poultice of the bark has been used to treat itchy armpits[].
The powdered bark can be put into shoes for tender or sweaty feet or as a remedy for foot odour[].

An infusion of the stem tips has been used to treat kidney problems[].

A decoction of the roots has been used as a birthing aid to help expel the afterbirth[]. The roots have been chewed in order to treat diarrhoea[].

Agroforestry Uses:

Tolerant of light trimming, plants can be grown as a hedge[]. This species does not make a good hedge in Britain[].

Other Uses

The inner bark has been used to make baskets[].

A rosy-tan dye can be obtained from the bark[].

The bark is a source of tannin[, ].

Hemlock wood is moderately strong and pliable and lacks resin ducts[]. It can be used for lumber or pulpwood[].


All the uses listed below are based on the uses of Tsuga canadensis and reports in [, , ] that this species has similar uses:-

Yields a resin similar to Abies balsamea, it is gathered by incisions in the trunk or by boiling the wood[, , ].

A pitch (called hemlock pitch), is obtained by distillation of the young branches[]. 'Oil of Hemlock' is distilled from the young branches according to another report[].

The boiled bark has been used to make a wash to clean rust off iron and steel, and to prevent further rusting[].

Wood - coarse-grained, light, soft, not strong, brittle, not durable outdoors[, , , , , ]. Difficult to work because it splits easily[]. The wood weighs 26lb per cubic foot[]. The trees do not self-prune and so the wood contains numerous remarkably hard knots that can quickly dull the blade of an axe[]. A coarse lumber, it is used occasionally for the outside of buildings[, , , , , ].
The wod is used for fuel. It should be used with caution as a fuel for outdoor fires because it can project embers and burning wood several metres from the fire[].

Propagation

Seed - it germinates better if given a short cold stratification[, ] and so is best sown in a cold frame in autumn to late winter. It can also be sown in early spring, though it might not germinate until after the next winter. If there is sufficient seed, an outdoor sowing can be made in spring[]. Pot-grown seedlings are best potted up into individual pots once they are large enough to handle - grow them on in a cold frame and plant them out in early summer of the following year. Trees transplant well when they are up to 80cm tall, but they are best put in their final positions when they are about 30 - 45 cm or less tall, this is usually when they are about 5 - 8 years old[]. Larger trees will check badly and hardly put on any growth for several years. This also badly affects root development and wind resistance[].