832 Achillea millefoliumCommon Names: common yarrow, milfoil, sneezewort, soldier's friend Family: Asteraceae (aster/daisy Family)
The 100 or so species of yarrows are herbaceous perennials, most with fragrant lacy foliage and small daisy-like flowerheads borne in rounded corymbs. Common yarrow has leaves that are grayish green, aromatic, and very finely dissected, like soft dainty ferns. The plant forms dense spreading mats of lacy leaves from rhizomes that creep beneath the ground surface. In summer yarrow sends up erect, grayish, usually unbranched stems, 1-3 ft (0.3-0.9 m) tall. The fifty or more small, about 0.25 in (0.6 cm) across with whitish flowerheads are borne in flat to domed clusters, 2-3 in (5-7.6 cm) in diameter.
Although wild yarrow is a troublesome weed in fields and gardens, horticulturists have created, selected and hybridized many outstanding cultivars which are beautiful flowering perennials. Many of these have branched flowering stems and larger flower clusters. Some are selected for stronger stems that don't require staking. Among the many cultivars of A. millefoilum, are these beauties: 'Cerise Queen' with vivid pink flowerheads; 'Fire King' red; 'Lilac Beauty' lavender; 'Paprika' orange-red; and 'White Beauty' with snow white flowerheads. There are hundreds of cultivars that have been created by crossing and backcrossing among a dozen or so species of Achillea. The Galaxy hybrids, of which A. millefolium is a parent, have much stronger stems, larger, 4-5 in (10.2-12.7 cm) flower clusters and come in many different flower colors. They are usually identified with the genus and cultivar name. A. 'Apfelblute' has an upright, open habit and gets 2-3 ft (0.6-0.9 m) tall with purple-pink flowers. A. 'Fanal' has bright red flowers with yellow centers. A. 'Hoffnung' has creamy yellow flowers. A. 'Taygetea', with pale yellow flowers, is the other parent of the Galaxy hybrids and is itself believed to be a hybrid between A. millefolium and A. clypeolata, a small species from Romania. A. X 'Moonshine' is a popular yellow-flowered yarrow with 'Taygetea' and A. clypeolata in its parentage.
Some authorities recognize one or more native American species of yarrow (A. lanulosa and A. occidentalis, for example) which can be distinguished from A. millefolium only by microscopic techniques. The group is a complex of variable polyploids whose taxonomic status is uncertain.
Common yarrow is a cosmopolitan weed originally native to Europe and western Asia. Today it grows in temperate regions worldwide. In the U.S. it occurs in disturbed areas, road shoulders, meadows and fields from Texas to Florida and north to southern Canada. In Europe, yarrow is a ubiquitous weed in hedgerows, pastures and fields, and seldom allowed near respectable gardens.
CultureEven the horticultural selections of yarrow are vigorous and strong growers, adaptable to a wide variety of soils and growing conditions, and likely to spread. Yarrow does best on poor soils and longevity and flowering are likely to suffer if fertilizer is used. Divide every couple years to maintain vigor and to keep the plants in bounds. Common yarrow may require staking. Light: Full sun. Moisture: Grow yarrow in well drained soil but water regularly. The species and many of the cultivars are resistant to drought once established. Hardiness: USDA Zones 3 - 9. Many of the cultivars are listed as useful only in zones 4-8. Flower colors often fade and stems tend to be weaker when temperatures are above 80ºF (26.7ºC). Propagation: Propagate yarrow by division in early spring or autumn. Seeds can be planted, but even those available from the seed companies are likely to yield plants with great variability in flower color and other characteristics.
Yarrows are well suited to the wildflower garden where they can be allowed to spread a little, as they surely will. In fact, they are often used along highways in wildflower plantings. The taller cultivars are good in the mixed perennial border, and are excellent when massed. Spaced at 2 ft (0.6 m) intervals, a stand of yarrow should produce an unbroken mat within one year. The soft, lacy foliage makes an interesting and beautiful groundcover. The flowerheads are used in arrangements, fresh and dried. If picked at their peak and dried quickly, they will retain their color. Dry on a bed of silica gel in the microwave at half power for best results.
Common yarrow has been used as a salad green, beer additive, snuff, poultice, wound dressing, astringent, antidepressant, stimulant, antispasmodic, fever reducer, blood pressure reducer, perspiration inducer and baldness preventer for centuries, and Grieve's A Modern Herballists 17 different English common names. In Roman times it was called herba militaris and much valued for treating wounds. Linnaeus, the father of botanical nomenclature, coined the generic name Achillea, in honor of Achilles, the Greek hero of the Trojan War in Homer's Iliad, who used yarrow to treat his soldiers' war wounds. (But, alas, yarrow couldn't save Achilles himself when he was shot with an arrow through his heel.) Yarrow has been called "nose bleed" because it was used to induce nose bleeding as a way to cure a headache, but it also was used to stop bleeding, including nose bleeds! Held against a wound, yarrow is supposed to stem the bleeding and disinfect. It also has been assigned magical properties and used to determine the nature of another's true love. Yarrow actually may be useful in treating circulatory problems, fever, colds, flu, high blood pressure and hay fever, but, despite its long history of use, there has been surprisingly little research into its efficacy and safety.
Some people may develop an allergic reaction from contact with the foliage or sap of yarrow. Prolonged use is said to make the skin sensitive to light. Floridata does not advocate the use of any herb or medicine without your doctor's knowledge and supervision. In the garden, common yarrow can be invasive and out compete other less aggressive plants.
Steve Christman 10/17/00; updated 5/24/02, 10/23/03, 5/30/12