Yarrow, scientifically called Achillea millefolium, belongs to plant family known as the Asteraceae family. Botanically, Yarrow favors temperate region like the Northern Hemisphere in Asia, Europe, and North America. Yarrow has several names across the world. For example, it is called Old Man’s Pepper, Soldier’s Herb, Knight’s Milfoil. Historically, it was widely used in treating wounded soldiers, hence the name soldier weeds.