Arnica Montana, also called Leopard's bane, Wolf's bane and Mountain Tobacco, is a perennial herb indigenous to the mountain pastures of Central Europe. Arnica has been harvested for medicinal purposes sing the 1500s. Arnica's daisy-like flower and rhizome are dried or made into poultices, tinctures, powders or gels and used to treat skin ailments. Arnica plants grow well outdoors in USDA plant-hardiness Zones 5 to 8, which means these plants can withstand temperatures as low as -20 degrees Fahrenheit. You can grow arnica plants from seed in the spring, germinating them indoors and transplanting them outdoors in May.
Sow your arnica seeds in early spring. Plant the seeds in a shallow dish filled with a moist mixture of equal parts loam, peat and sand. Push the seeds just below the surface of the mix.
Keep the arnica seeds in a cold frame or a greenhouse at 55 degrees Fahrenheit until May. Mist the potting medium with a water spray bottle to keep it moist. Place the dish in bright indirect sunlight.
Transplant the seedlings outdoors in May, after the last frost has passed and the seedlings have germinated. Choose a planting site that receives good indirect sunlight and has well-drained soil.
Water your arnica plant once per week or as needed to keep the soil moist. Because arnica plants thrive in nutrient-poor soils, you do not need to fertilize them.
Pick off the whole flowers in mid- to late summer. Dry the flowers on a tray lined with paper towels placed in an airy room. Dig up and collect the root after the leaves have died in autumn.