They require little attention, are almost impervious to pests, and disease, are very beneficial to the gardens for their nutrient accumulating abilities, breaking up of the soil, and for their medicinal value as well. In antiquity, yarrow was known as an herb used at military battle fields, due to its use in stanching the flow of bloody wounds. This was also used as part of the classic Gruit recipe for preserving ales, the bittering and flavoring of them before the extensive use of hops. For permatultural techniques, it is invaluable.
