Achillea millefolium
Yarrow
Family: Asteraceae
Perennial, almost evergreen in Tucson, but needs cutting back after blooming as new growth emerges below. Growing to about 3x3’ when it blooms, but is below a foot tall when not blooming. Flowers are usually white but some cultivars sport other colors.
Grow in full sun (avoid reflective heat) to full shade, more water in the sunnier locations, hardy to -40° F. Improved soil recommended.
Larval food plant for the painted lady butterfly (Vanessa cardui) and numerous moth species. Nectar rich flowers are a favorite of butterflies and other nectar-seeking insects. Many beetle species use yarrow as habitat and food. Several nesting birds use yarrow to line their nests. Experiments conducted on the tree swallow suggest that adding yarrow to nests inhibits the growth of parasites. Yarrow is considered an especially useful companion plant, attracting beneficial insects and repelling some pests. It attracts predatory wasps, which drink the nectar and then use insect pests as food for their larvae. Similarly, it attracts ladybirds and hoverflies.
Yarrow was once an important bittering agent for beer (before hops were used) and is sometimes used now, especially by creative microbreweries and home brewers. The entire plant is reportedly edible and nutritious, but it is advised not to consume much. The foliage is pungent; both its leaves and flowers are bitter and astringent. The leaves can be eaten young; raw, and are often added to salad. The leaves, with an aniseed-grass flavor, can be brewed as tea.
Yarrow is an important medicinal plant and is used in traditional medicine, in part due to its astringent properties and the mild laxative effect of its leaves. It is used since ancient times to heal wounds and stop bleeding. Yarrow and its North American varieties are traditionally used by many Native American nations. Many Navajo consider it a "life medicine" and chew the plant for toothaches and use its infusions for earaches. The Miwok in California use the plant as an analgesic and head cold remedy. Many Native American nations traditionally use the plant for healing cuts and abrasions, relief from earaches and throat infections, as well as for an eyewash. Common yarrow is used traditionally by Plains indigenous peoples to reduce pain or fever and aid sleep. Some Ojibwe people use a decoction of yarrow leaves on hot stones and inhaled it to treat headaches, or apply decoctions of the root onto skin for its stimulating effect.
Yarrow can be used for dying wool as it contains apigenin and luteolin. Depending on the mordant the color may be green to yellow.
Native in our mountains in Arizona, but occupying various niches, this is a cosmopolitan plant, native all over the world.