Arnica chamissonis

Arnica chamissonis is native to the American West. It is both a botanical treasure and a robust rhizomatous perennial with large basal leaves in a rosette. This medicinal plant, closely related to the famous Arnica montana, displays a radiant flowering in the summer with golden yellow heads. It is easier to cultivate in lowland areas and offers a better yield than its European cousin.

The Plains Arnica belongs to the Asteraceae family. It is native to the mountains of the American West. It is found in the wild, growing along prairies and streams. This perennial plant has a rosette habit, reaching 50 cm (20in) when in bloom, and spreads rapidly to a diameter of 50 cm (20in). Flowering occurs in June-July. The stems, with opposite leaves, bear intense yellow heads resembling small sunflowers. Deeply rooted and spreading through rhizomes, the plant develops clusters of reasonably narrow, hairy, bright green leaves in spring. After a nectar-rich flowering, the plant produces seeds commonly used in herbal medicine, similar to the seeds of Arnica montana. Arnica is apomictic, which means that the formation of seeds is initiated through asexual reproduction by spontaneous division of the gametes before the flowering phase. This implies that pollination is not necessary for the production of viable seeds, and each seed is capable of giving rise to a plant that is identical to the mother plant.

Arnica chamissonis thrives best in soil that is light and occasionally damp, enriched with humus, and slightly acidic to neutral. However, it cannot tolerate limestone. It can be grown in regular soil lightened with turf and coarse sand. For abundant flowering, it requires full sun exposure.

American Arnica is a highly ornamental medicinal plant that thrives in herb gardens, near water sources, and turf moors.

Arnica chamissonis and Arnica montana are two plants that have similar chemical compositions and are used for therapeutic purposes. German and European pharmacopoeias consider Arnica chamissonis as effective as Arnica montana. However, Arnica chamissonis is easier to cultivate and more productive. As a result, in the future, it is likely that Arnica chamissonis subsp. foliosa will be grown instead of relying on Arnica montana for herbal medicine.