While on the Losee Lake Trail at Pinckney State Recreation Area in Michigan, I came across this common yarrow (Achillea millefolium, Asteraceae) in a forest opening. Widespread across the northern hemisphere, this plant is highly variable and is separated into at least a dozen subspecies.
Yarrow has been used for centuries in a variety of medicinal applications. It’s been used to prevent bleeding and infection of wounds and to treat fevers, gastrointestinal trouble, hypertension, and a whole host of other pains and diseases. Over one hundred chemicals have been identified in this plant, and recent research has started to discover exactly what compounds are useful for treating certain ailments and why. Yarrow was found to produce an alkaloid known as achilleine, for example. This is a known hemostatic compound that would explain the plant’s use as a blood-stopping agent. It’s also been discovered that essential oil extracts from the plant possess antioxidant and antimicrobial properties (Candan et al. 2003). These are just a couple of examples; there are literally hundreds of research papers detailing the chemical and pharmacological properties of compounds found in yarrow.
As if that wasn’t enough, yarrow also produces compounds that help repel mosquitoes (Tunón, Thorsell, and Bohlin 1994). This common and widespread plant is a literal factory for the production of useful chemicals.
Candan, F., M. Unlu, B. Tepe, D. Daferera, M. Polissiou, A. Sökmen, and H.A. Akpulat. 2003. Antioxidant and antimicrobial activity of the essential oil and methanol extracts of Achillea millefolium subsp. millefolium Afan. (Asteraceae). Journal of Ethnopharmacology 87:215-220.
Tunón, H., W. Thorsell, and L. Bohlin. 1994. Mosquito repelling activity of compounds occurring in Achillea millefolium L. (Asteraceae). Economic Botany 48(2):111-120.