Medicinal Trees and ShrubsInformation and resources about medicinal trees and shrubs
Medicinal tree information sheet
Viburnum opulus L.
Common name: Cramp Bark, Guelder Rose, Snowball tree
Description: A deciduous small tree, with showy white flowers and translucent red berries, having stem bark which has anti-spasmodic properties.
Habitat: Cramp bark is found in hedgerows, woodlands, fens and scrubland throughout most of Europe and north and west Asia. It thrives in moist soils and will grow in both moderately acid and alkaline soils.
History: As a medicinal tree, cramp bark may have longstanding use, although few records show this. It was mentioned by Chaucer, and John Gerard described the use of Rose Elder or Gelders Rose in his herbal of 1597. The Guelder Rose form originally from Holland with large round white heads of flowers is mainly seen as an ornamental shrub in gardens. The native form has flatter flowerheads and attractive but intensely bitter tasting red berries. An American variety Viburnum opulus var. americanum, is the Highbush or American Cranberry.
Planting: Cramp bark needs no special treatment if planted in a moist location with plenty of light at the woodland edge. The shrub will survive in shade although it is more productive of flowers and fruits in lighter conditions. It is hardy to zone 3 and is not frost tender.
Cultivation: Regenerates quickly after cutting and is a good candidate for coppice production so a close spacing of plants can reflect this form of cultivation. Cuttings of half-ripe wood can be used to grow additional plants.
Harvest: For medicinal use, the bark can be harvested in the spring, when it will peel away easily from stems several years old and can be used fresh or dry to make a tincture preserved with up to 25-30% alcohol. The bark can also be dried and then powdered for capsules. Dosage of dried bark powder is from 6-12 g per day, dosage of 1:5 tincture from 5-10 ml per day.
Constituents: The bark contains resin, viburnin (bitter glycoside), valeric and isovalerianic acids, salicin, tannins, iridoid glycosides (penstemide, patrinoside and others), coumarins (scopoletin, aesculetin), triterpenes (oleanolic and ursolic acids).
Research: Actions are antispasmodic, astringent, mild sedative, hypotensive, peripheral vasodilator. Constituents such as coumarins have spasmolytic activity and Cramp bark is helpful in conditions where pain arises from muscular tension: such as cramps, menstrual pain, muscle spasm, some kinds of constipation, irritable bowel syndrome. There has been limited clinical research relating to Viburnum opulus. One study found that constituents of Viburnum opulus had antispasmodic effects on smooth muscle (Nicholson, 1972), and Cometa et al. (2009) found that alcohol-soluble constituents of the related North American tree Viburnum prunifolium, such as iridoid glucosides, contributed to muscle relaxant properties.
Contra-indications: For the stem bark of Viburnum opulus there are no reported harmful effects in pregnancy or breastfeeding. However, general advice in pregnancy is to seek professional opinion before taking any medications, and advice should also be taken about use of Cramp bark alongside medications to lower blood pressure.
Sambucus nigra L.
Common name: Black or European elder
Description: A deciduous shrub or small tree growing up to 6 m high and almost as wide, with bunches of edible white flowers and purple-black fruit, widely used in traditional treatments especially of colds and flu.
Habitat: Elder is found in hedgerows and scrubland throughout Europe, northern Africa and central and west Asia.
History: Elder has longstanding use for medicinal purposes, and has been associated in folklore with protection from evil. John Evelyn (1670) wrote ‘if the Medicinal properties of the Leaves, Bark, Berries, &c. were throughly known, I cannot tell what our Country-man could aile for which he might not fetch a Remedy from every Hedge, either for Sicknesse or Wound’. Traditionally the leaves were used to make a green ointment,
Planting: Elder can be planted in a moist location with plenty of light at the woodland edge. It is more productive of flowers and fruits in lighter conditions. It is hardy to UK zone 5 and is not frost tender.
Cultivation: It thrives in moist soils and will grow in both acid and alkaline soils, preferring a rich soil. Elder is prone to suckering and is ideal for hedgerows which can be pruned in winter. The elder is fast-growing and very hardy and will regrow if stems die off. It is suitable for coppice production and plants can be spaced fairly close to each other, cutting to produce stems of one, two and three years of age. Cuttings of one-year-old stems can be used to grow additional plants.
Harvest: For medicinal use, the flowers are harvested in May to June and dried or used in infusion, the purple-black ripe fruit is harvested in August to September and dried or used fresh to make elderberry syrup and other extracts. There are numerous cultivars of the European elderberry for flowers and fruit production, and American elder (S. canadensis) can also be used, having large flowerheads.
Constituents: Flavonoids, lectins and anthocynanins are found in the flowers and berries.
Research: The elder has antioxidant activity, antiviral and antiinflammatory, diuretic, laxative actions (Porter and Bode, 2017). The flowers and berries contain key constituents which reduce the replication of viruses (Chen et al., 2014). A study in air travellers (Tiralongo et al., 2010) has shown that elderberry extract significantly reduced the duration and severity of cold symptoms in air travellers. Commercial extracts of the elder are sold for colds and flu.
Contra-indications: The bark, leaves, stem and unripe fruit of elder should not be used internally as they are considered toxic due to the content of alkaloids and cyanogenic glycosides. The cooked fruit can cause digestive upset in some people.
Medicinal tree information sheet
Ginkgo biloba L.
Common name: Maidenhair tree
Description: A deciduous tree growing up to 30 m tall and 9 m wide, with fan-shaped leaves. The ginkgo is regarded as a living fossil, related to tree ferns and cycads. Trees may be male or female, although this may not be determined until the tree is old enough (35 years) to produce seed. Many cultivars exist, particularly for the striking golden yellow leaves in autumn.
Habitat: The ginkgo is a native of China, growing in silty soils along stream banks, but is endangered in the wild. It is widely grown in Europe and America. It can grow in a wide range of soils, and can tolerate drought and pollution, though preferring well-watered and well-drained soil. The ginkgo is a hardy tree and does not need frost protection.
History: Ginkgo has longstanding use in traditional Chinese medicine, and extracts from this medicinal tree are widely sold as supplement throughout the world.
Planting: Ginkgo can be grown on, in a container, using good quality multi-purpose compost with 10% grit added. Keep moist but ensure that the pot drains freely. Water well when in leaf as rain will tend to be shed away from the pot by the leaves. For potted plants a little slow-release fertiliser can be added to the surface of the soil in spring, plants in the ground do not need additional fertiliser.
Cultivation: Ginkgo is a slow growing tree, averaging less than 30 cm per year. The young trees are slender with few branches, and have few pests or diseases. It can be readily coppiced or pruned, best done while dormant in January or February.
Harvest: For medicinal use leaves are harvested in the late summer, just as they start to turn yellow, and can be dried for later use. Female trees eventually produce edible fruit containing butanoic acid which smells like rancid butter.
Constituents: The leaves contain flavonoids and terpenoids which have anti-oxidant effects in the body.
Research: Many trials have been carried out with standardised extracts containing around 24% flavone glycosides and 6% terpene lactones. Some studies have found evidence of improvements in circulation to the eye and brain and decreases in intermittent claudication (poor circulation in legs). Studies have considered possible benefits in dementia, memory and tinnitus.
Contra-indications: Can increase bleeding and so caution is needed in using ginkgo alongside blood thinners or anti-coagulant medication. Discontinue taking ginkgo at least two weeks before if you are having dental or surgical treatment.
Medicinal tree information sheet
Crataegus monogyna Jacq.
Common name: Hawthorn, also known as May or Whitethorn.
Description: A small deciduous tree with pinkish-white flowers in May, and red berries in autumn. This shrubby plant with small toothed leaves grows up to 10m tall by 6m wide and the branches carry thorns.
Habitat: Hawthorn is native to northern temperate parts of Europe, and has become naturalised in parts of North America as a garden escape.
History: Hawthorn has considerable historical association with magic and folklore beliefs. Historically, the fruits or haws were known as a diuretic, although more recent sources focus on use as a sedative or for heart complaints.
Planting: Hawthorn can be obtained in many ornamental varieties but for medicinal purposes the common Hawthorn used for hedging is appropriate. It can be planted on a woodland edge or in full sunshine.
Cultivation: It can grow in a wide range of soils, and can tolerate drought and pollution, though preferring well-watered and well-drained soil. The Hawthorn is a hardy tree and does not need frost protection. Seedlings will start to fruit after 5-8 years. Rate of growth is fairly fast and if space is limited then pruning will be needed to maintain shape and to avoid the thorny branches straying across paths. Removal of suckers at the base is also advised.
Harvest: The parts used are the flower and leaves harvested in May and fruits when ripe and red in autumn. These can be used fresh to make tinctures, or dried and later used for infusions. Caution in harvesting as this is a thorny plant.
Constituents: The Hawthorn flowers and leaves contain flavonoids and oligomeric procyanidins which have anti-oxidant and cardioprotective effects in the body.
Research: Clinical evidence supports the benefits of the Hawthorn for the circulation, particularly extracts of the flowering tops, as a cardiac tonic, including therapy for congestive heart failure. Tassell et al. (2010) reviewed trials which showed few minor adverse effects and much potential for use in treating cardiovascular disease.
Contra-indications: Since Hawthorn can affect blood pressure, it should not be taken alongside prescription drugs without medical supervision. If used for making preserves, the seeds, like apple pips, should not be eaten in quantity as they contain cyanogenic glycosides.
Medicinal Tree Information Sheet
Salix daphnoides Vill.
Common name: Violet willow.
Description: Violet willow is a large shrub or small tree growing to 6-8 m in height and 2-3 m wide. Supple branches carry leaves which are narrow and hairless. The leaf buds are characterised by a single scale. It flowers in early spring producing attractive furry buds.
Habitat: The violet willow is native to central Europe and widely naturalised elsewhere.
History and use: Willow has been used since ancient times to treat pain and fever. The leaves can be used as an infusion for a gargle or in the bath for rheumatism. Willow bark is used mostly as an anti-inflammatory for symptomatic relief in back pain, joint pain, headache and toothache.
Planting: It is fairly fast growing in sandy areas but does not tolerate competing plants well and needs weed-suppressing mulch. The location for planting needs to take into account the potential of this tree for breaching drains or pipes in seeking moisture, and planting away from buildings is essential.
Cultivation: Violet willow is hardy to USDA zone 4 (UK zone 5). Coppicing to the ground or pollarding at a height can be carried out in winter, to produce new stems for harvesting as a sustainable source of willow bark.
Harvest: The bark of 2-3 year old violet willow branches is harvested during the spring, when it readily peels off stems for drying. Leaves can be used fresh or dried for later use.
Constituents: Violet willow bark and leaves contain glycosides, salicylates, tannins, aromatic aldehydes, acids, salicyl alcohol and flavonoids. Studies suggest that violet willow is one of the richest sources of active ingredients in the willow family.
Research: Limited studies have been carried out and willow use is based on tradition and knowledge of the constituents. The anti-inflammatory effects of flavonoids and polyphenols support the traditional use in conditions of back and joint pain.
Contra-indications: Adverse effects appear to be minimal apart from irritant effects on digestion, so willow is best combined with food. Unlike manufactured aspirin, willow does not have significant blood-thinning effects and it should not be used as a substitute for other anti-coagulant medications such as warfarin.
Medicinal tree information sheet
Hamamelis virginiana L.
Common name: Virginian Witch Hazel
Description: A deciduous shrub or tree with alternate leaves and arching branches growing up to 6 m tall. Spidery yellow fragrant flowers are produced in late autumn. Seed capsules are produced which stay on the branch until the following year and then burst open to project the small shiny black seeds over 3 m.
Habitat: The witch hazel is a native of the eastern half of North America. It is a hardy tree and does not need frost protection. As an understorey tree in damp woods in the wild, it can readily grow in partial shade. It prefers a rich moist soil which is on the acidic side.
History: Witch hazel extracts were first brought to wider attention in the nineteenth century, when settlers identified potential uses of medicinal trees from the North American Indians. It is now widely used in eye drops, skin creams, toners, and cosmetics. The Virginian witch hazel is also the basis for grafts of Asian cultivars with larger flowers.
Planting: Witch hazel can be readily grown on, in a container, using good quality multi-purpose compost. Keep moist but ensure that the pot drains freely. Water well when in leaf as rain will tend to be shed away from the pot by the leaves. For potted plants, a little slow-release fertiliser can be added to the surface of the soil in spring, while plants in the ground do not need additional fertiliser.
Cultivation: Witch hazel has a branching habit. It can be readily thinned or pruned, and this is best done while dormant in January or February. As a large shrub, witch hazel provides attractive autumn colour with small but unusual late autumn flowers.
Harvest: For medicinal use, fresh young leaves and twigs are harvested in the spring and a distilled extract is preserved with up to 15% alcohol. The bark is also used to make a distillate and in North America, whole trees are used to make the distillate in large manufacturing operations.
Constituents: The plant contains tannins, phenolic acids, flavonoids and other constituents which are astringent and anti-inflammatory.
Research: Few research studies have been carried out, although witch hazel extracts are considered effective in traditional use against inflammation. The distilled extract has longstanding use for calming skin conditions ranging from insect bites to acne, eczema and haemorrhoids.
Contra-indications: Witch hazel extracts are regarded as safe and well-tolerated on the skin, but not for internal use due to the tannin content.