Common yarrow (Achillea millefolium) is a familiar weed with an ancient history in folklore and traditional medicine.
Yarrow’s scientific name relates to its mythological connection to the Greek god Achilles, who used the plant to treat wounded soldiers during the Trojan war. And millefolium (“thousand-leaved’) describes yarrow’s finely divided leaves.
Native to North America and parts of Eurasia, yarrow has been used in diverse cultures to reduce inflammation, pain, infection, and bleeding. Other common names for the plant also evoke this therapeutic history: soldier’s woundwort, bloodwort, nosebleed, knight’s milfoil, sanguinary, staunchweed.
The flowers, leaves, and stems of yarrow have also been put to use as a medicinal tea, diuretic, stimulant, mosquito repellent, contraceptive, sedative, expectorant, anti-oxidant, food flavoring ... The list goes on and on.
Scientific analyses have identified dozens of biologically active compounds in common yarrow and its close relatives. Many of these substances may have future medicinal and commercial value.
More research is still needed, though, on safe dosage and side-effects before yarrow can be widely used therapeutically. Common yarrow is found throughout the U.S. in a variety of habitats — from fields and grasslands to open forests, farmlands, roadsides, and vacant lots.
The plant stands about one to three feet tall, with large flat-topped clusters of small, whitish flowers and aromatic, fernlike leaves. If you look closely at a yarrow in bloom, you’ll see that its basic floral structure resembles that of sunflowers, asters and other members of the Daisy Family.
What seems like a single small flower is actually a tight grouping of even smaller flowers: tubular “disc” florets in the center and white, strap-like, “ray” florets surrounding them.
The flowers produce nectar and pollen attractive to native bees and a variety of other pollinators. And the pungent, feathery leaves, though apparently repellent to deer, are food for the caterpillars of many moths. Yarrow is amazingly tolerant of hot sun, drought, and nutrient-poor soils. Because of this resilience, and despite its tendency to spread via rhizomes, the plant is favored for butterfly and wildlife gardens.
There are also dozens of colorful cultivars available at plant nurseries.
Yarrow is useful to birds, as well. European Starlings gather the plant, among other materials, to construct their nests. Studies suggest that anti-microbial substances in yarrow may provide therapeutic benefits, protecting the nestlings from feather-degrading, bacterial infections.