Several species are cultivated as ornamentals for their flat-topped clusters of flowers and scented foliage. Native Americans also used the plant medicinally, particularly as a treatment for earache. The use of yarrow in folk medicine is based on its apparent anti-inflammatory and coagulatory properties.
Some yarrows are among the plants imparting a disagreeable taste to milk when grazed by cows.
Water milfoils are unrelated freshwater aquatic perennials of the genus Myriophyllum, sometimes grown in aquariums and ponds. Yarrow is classified in the division Magnoliophyta , class Magnoliopsida, order Asterales, family Asteraceae.