Arnica (Arnica Montana) is native to the mountains of central Europe. Arnica is also called Leopard’s bane, Mountain tobacco, Mountain Arnica, and Wolfbane. It is an upright, perennial herb. It has a flowering stem that can grow to two feet in height. The leaves are downy and lance-shaped. They are aromatic and the lower ones are raised in a rosette. The flowers are orange-yellow and there is usually only one per stem. Arnica flowers in late spring through mid-summer. It is often used for decorating grassy banks in the garden. Arnica has been used for a long time in folk medicine. It is said to help bruises and sprains when spread as a poultice on them. Arnica is poisonous and should not be taken internally. The poultice should not be used on broken skin as that may lead to internal bleeding. Arnica grows in zones five to nine. It prefers a pH range of 6.0 to 8.0. If your pH is too acid for arnica, you can adjust it by using ground agricultural limestone.
Arnica can be grown from seed or by division. To grow from seed, you must first chill the seed for ten to twelve weeks in your refrigerator. After they have been chilled properly, sow the seed indoors in flats of a good potting mix consisting of equal parts peat moss, sand, and loam. After the arnica has true leaves, and after all danger of frost, you can transplant the arnica plants into a well drained, loamy flower bed. To make sure the flower bed is draining well, till it up to a depth of six inches. Spread three inches of compost on the tilled area. Till the compost into the soil until it is mixed throughout. The compost raises the nutrient level of the soil and improves the drainage of it as well. The disadvantage of growing arnica from seed is that it will not bloom the first year. It will, however, bloom the second year and every year after that.
To get plants that bloom their first spring, you can dig up an arnica plant and divide it. You can then replant the divided plant and the baby plants you took off of that plant. Divide arnica in the fall.
Arnica needs to be planted in full or partial sun. It does best in full sun. Arnica should be watered once a week. It is best to water it all at once with an inch of water. If you have a sprinkler, you can find out how long to run it by placing a small can, such as a tuna fish can or cat food can, by the plant. Run the sprinklers until an inch of water is in the can. In the future, run your sprinklers that long each week.
Arnica generally does not need much fertilizer, particularly if you tilled in compost before planting. A good general all purpose fertilizer such as 10-10-10 can be applied at the beginning of the growing season and will last all year.