Yarrow grows along roadsides, fields, try open woods and alpine meadows. It is a weedy plant with finely dissected, fern like leaves. They have a flat-topped cluster of small white (sometimes pinkish) flowers. Medicinally, Yarrow has been used for centuries as a means of stopping the flow of blood from wounds.
The genus Achillea is named after Achilles, who used the plant to stop the bleeding of his soldiers wounded in the Siege of Troy.