Medicinal Trees and ShrubsInformation and resources about medicinal trees and shrubs
Information Sheets for Medicinal Trees
Click on the + in each heading to expand details in each tree information sheet.
You can get a printed set of these sheets with a £10 donation to the Medicinal Forest Garden Trust.
For details on growing and using more trees and shrubs with medicinal actions see The Medicinal Forest Garden Handbook
Medicinal tree information sheet
Cramp BarkViburnum 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.
Medicinal tree information sheetGinkgo 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 sheetHawthorn 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
Tilia cordata Mill.
Common name: Lime, Linden.
Description: The small-leaved lime is a large deciduous tree growing to 30 m by 12 m at a fast rate. It flowers in June-July and the yellowish green fragrant flowers are pollinated by bees. Trees begin flowering at around 15 years of age.
Habitat: The small-leaved lime is native throughout Europe.
History and use: The flowers have been used traditionally as a diaphoretic to promote perspiration.The leaves are mucilaginous and were used in poultices and fomentatons. Lime flowers are widely used for a soothing tea and as a mild sedative to treat headaches and insomnia. About five blossoms will be enough for a cup of tea.
Planting:The small-leaved lime tolerates a range of soils though it prefers moist well-drained soil that is somewhat alkaline. Lime can grow in semi-shade and tolerates strong winds. The location for planting needs to take into account the potential size of this tree and heavy shade that it will cast if it is not regularly coppiced or pollarded.
Cultivation: Lime is very hardy to USDA zones 3-7 and UK zone 3 and does not need frost protection. Coppicing to the ground or pollarding at a height can be carried out in winter.
Harvest: Collect the clusters of lime flowers when some of them are open (recognisable with their stamens), while others may still be closed, including the small leaves or bracts on the flowers. Hang in bunches to dry. Take care when harvesting as the nectar-rich flowers are attractive to bees.
Constituents: The flowers contain 1% flavonoids, alongside mucilaginous polysaccharides, condensed tannins, phenylcarboxylic acids, amino acids, saponins, volatile oils and proanthocyanidins. The leaves are also rich in anti-oxidant polyphenols.
Research: Little significant clinical research has been carried out and lime flower use is based on tradition and knowledge of the constituents. The anti-inflammatory effects of procyanidins in the flowers has been identified to support the traditional use of lime flowers in treating colds and sore throats
Contra-indications: Lime flowers are generally recognised as safe for human consumption. However, it is said that if the flowers are harvested when too old they may produce symptoms of intoxication.
Medicinal tree information sheetPrickly Ash Zanthoxylum americanum Mill. Common name: Northern prickly ash, Toothache tree Description: A deciduous shrub of the Rue family with pinnately compound leaves and thorny branches growing up to 4 m tall and 4 m wide. Inconspicuous flowers are produced May-June and the small black berry-like seeds ripen September-October. A close relative is the Hercules club or Southern prickly ash (Zanthoxylum clava-herculis) and oriental varieties are the Szechuan pepper (Zanthoxylum simulans) and Japanese pepper tree (Zanthoxylum piperitum). In Nigeria the root of Zanthoxylum zanthoxyloides is used as a chewing stick. Habitat: The Northern Prickly Ash is native to central and eastern North America. It does not need frost protection, being hardy to UK zone 4. As an understorey shrub in damp woods in the wild, it can grow in partial shade. It is ideal for a woodland edge and will grow in most soils. History: Members of the Zanthoxylum species group can be found in tropical as well as temperate climates, and often have traditional culinary and medicinal tree uses because of the aromatic spicy foliage, bark and seeds. The edible seeds can be used instead of pepper. The description of ‘Toothache tree’ probably arises from the numbing and tingling sensation experienced when chewing a leaf or seed. Prickly ash has been used for its circulatory stimulant properties in cramps and rheumatism. Planting: Prickly ash should be planted in well-drained soil that does not dry out. For berry production, some advisers say that both male and female plants are needed while others say this is not necessary. Cultivation: Prickly ash can produce suckers to form a thicket if left unpruned, and its growth habit is somewhat like a large gooseberry bush. It can be readily thinned or pruned to a single-stemmed small tree, or shaped in an open goblet style like a gooseberry bush, and this pruning is best done while dormant in winter. Take care to wear thick gloves when pruning as the stems have sharp thorns. Cuttings of half-ripe wood can be used to grow additional plants. Harvest: For medicinal use, fresh young leaves and twigs can be harvested in the spring and used to make a tincture preserved with 25-30% alcohol. The bark and roots can also be used in this way. The bark and berries can also be dried and then powdered. Constituents: The plant contains iso-quinoline-type alkaloids, amides, coumarins, resins, tannins and volatile oil. Research: Some research studies have been carried out, showing anti-inflammatory, anti-fungal, anti-viral and anti-bacterial effects of various parts of the plant and the distilled essential oil. More recent studies suggest that Zanthoxylum species may have a role to play in anti-cancer drug development. Contra-indications: The use of Zanthoxylum species is generally accepted in small amounts in food as a condiment. The safety of use in pregnancy has not been established, and it should be avoided due to the alkaloid content.
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.