Common Name: Arnica

General Information

Arnica montana is a herbaceous, perennial plant growing 30 - 60cm tall The plant produces one or more flowering stems, spreading at the roots to form a clump of growth.
Arnica has a long history of herbal use, especially as an external treatment for bruises and sprains. It is commonly harvested from the wild and is also often cultivated to supply material for the herbal maket and also for use as a flavouring.
Arnica montana is a widespread European endemic and is found at hundreds of localities. The populations are stable in some countries and declining in other parts of its range. The reasons for this decline are partly due to collection of the plant for medicinal purposes and partly due to habitat loss. This plant is found mainly in acidic and nutrient poor grasslands and shrublands, a habitat that changes among others due to abandonment of grazing activities or fertilisation to use the land for agriculture. The plant is classified as 'Least Concern' in the IUCN Red List of Threatened Species(2013)[].

Known Hazards

The whole plant is toxic and should only be used for external applications to unbroken skin[, , , ].

Botanical References

Range

Europe - Norway, south to Portugal and east to Ukraine.

Habitat

Montane to alpine meadows and pastures and in light forests to the alpine zone, growing especially on granite or siliceous soils; at elevations up to 2,500 metres. Pasture and open woodland, usually on poorer acid soils[].

Properties

Conservation Status	Least Concern
Edibility Rating
Medicinal Rating
Habit	Perennial
Height	0.30 m
Pollinators	Bees, Flies, Lepidoptera, Self
Self-fertile	Yes
Cultivation Status	Wild

Cultivation Details

Arnica montana is a plant of montane areas in the temperate zone, where it is found at elevations up to 2,500 metres. It grows best in areas where annual daytime temperatures are within the range 8 - 15°c, but can tolerate 5 - 25°c[]. The dormant plant can survive temperatures down to about -25°c or lower[]. It prefers a mean annual rainfall in the range 500 - 800mm, but tolerates 400 - 1,200mm[].
Succeeds in full sun and also in the dappled shade of an open woodland[, , ]. Prefers a moist, well-drained humus rich soil, preferably lime-free[]. One report says that it is often found in calcareous soils in the wild[]. Prefers a pH in the range 5.5 - 7, tolerating 5 - 7.5[]. Prefers a mixture of sand, loam and peat[]. Succeeds in light woodland[] and in a rock garden or border[, ].
This species is declining in the wild, probably because of over-collection as a medicinal herb. It may become extinct in part of its range[].

Edible Uses

The plant is used as a flavour additive to some alcoholic drinks.

Medicinal

Arnica has a long history of herbal use, especially as an external treatment for bruises and sprains[, ] - it is an ingredient of a number of proprietary preparations[]. Arnica increases local blood supply and accelerates healing, it is anti-inflammatory and increases the rate of absorption of internal bleeding[].

Internally, it has been used in the treatment of heart complaints and as a booster for the immune system[].
Generally the plant is nowadays only recommended for internal use as a homeopathic medicine, principally for treating shock, injury and pain[]. 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[].

The flowers are the part most commonly used[, ], they are harvested when fully open and dried - the receptacles are sometimes removed since these are liable to be attacked by insects[].
The root is also used, it is harvested after the leaves have died down in the autumn and dried for later use[].

The whole plant is antiecchymotic, antiphlogistic, nervine, sternutatory, vulnerary[, , , , ]. 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[]. Only take it internally under the supervision of a qualified practitioner.

The freshly crushed flowers cause sneezing if inhaled[].

The leaves have also been smoked as a tobacco[], though it is unclear whether this was for medicinal reasons

The whole plant, harvested when in flower, is used in homeopathic remedies[]. It is especially useful in the treatment of traumatic injuries, sores and bruises[]. 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[].

Other Uses

None known

Propagation

Seed - best sown as soon as it is ripe in pots outdoors. Sow stored seed in early spring in a cold frame[]. A period of cold stratification is helpful[]. The fresh seed can germinate in 3 - 4 weeks at 13°c according to one report[], though it can be slow, difficult and erratic and take 2 years to germinate[]. Prick out the seedlings into individual pots when they are large enough to handle and plant them out into their permanent positions in the following spring.
Division in spring.