Arnica, Mountain arnica

Arnica montana

Physical Characteristics

Arnica montana is a PERENNIAL growing to 0.3 m (1ft) by 0.2 m (0ft 8in). See above for USDA hardiness. It is hardy to UK zone 6 and is not frost tender. It is in flower in July. The species is hermaphrodite (has both male and female organs) and is pollinated by Bees, flies, Lepidoptera (Moths & Butterflies). The plant is self-fertile. Suitable for: light (sandy), medium (loamy) and heavy (clay) soils, prefers well-drained soil and can grow in nutritionally poor soil. Suitable pH: mildly acid, neutral and basic (mildly alkaline) soils and can grow in very acid soils. It can grow in semi-shade (light woodland) or no shade. It prefers moist soil.

Distribution

C. Europe.

Habitats

Woodland Garden Sunny Edge; Dappled Shade; Cultivated Beds;

Edible Uses

None known

Medicinal Uses

Antiecchymotic Antiphlogistic Antirheumatic Epilepsy Nervine Sternutatory Vulnerary Arnica has a long history of herbal use, especially as an external treatment for bruises and sprains[232, 238] - it is an ingredient of a number of proprietary preparations[238]. Internally, it has been used in the treatment of heart complaints and as a booster for the immune system[238]. Arnica increases local blood supply and accelerates healing, it is anti-inflammatory and increases the rate of absorption of internal bleeding[254]. Generally the plant is nowadays only recommended for internal use as a homeopathic medicine, principally for treating shock, injury and pain[254]. If used as a decoction or tincture it stimulates the circulation and is valuable in the treatment of angina and a weak or failing heart, but it can be toxic even at quite low doses and so is rarely used this way[254]. The flowers are the part most commonly used[4, 232], they are harvested when fully open and dried - the receptacles are sometimes removed since these are liable to be attacked by insects[4]. The root is also used, it is harvested after the leaves have died down in the autumn and dried for later use[4]. The whole plant is antiecchymotic, antiphlogistic, nervine, sternutatory, vulnerary[4, 7, 9, 46, 165]. Although a very valuable remedy, it should be used with caution. It has been known to cause contact dermatitis when used externally and collapse when taken internally[238]. Only take it internally under the supervision of a qualified practitioner. The freshly crushed flowers cause sneezing if inhaled[232]. The leaves have also been smoked as a tobacco[232], though it is unclear whether this was for medicinal reasons The whole plant, harvested when in flower, is used in homeopathic remedies[232]. It is especially useful in the treatment of traumatic injuries, sores and bruises[232]. The homeopathic dose has also been used effectively in the treatment of epilepsy and seasickness, and it might be of use as a hair growth stimulant[268]. The German Commission E Monographs, a therapeutic guide to herbal medicine, approve Arnica montana for fever and colds, inflammation of the skin, cough/bronchitis, inflammation of the mouth and pharynx, rheumatism, common cold, blunt injuries, tendency to infection (see [302] for critics of commission E). The essential oil has to be diluted before being used externally [301].

Known Hazards

Deadly in large quantities. The whole plant is toxic and should only be used for external applications to unbroken skin[9, 14, 65, 172]. Alcoholic extracts of arnica can cause toxic effects on the heart and raise blood pressure [301].