Western Yarrow

Achillea millefolia

Asteraceae

• Spokane Native
• Sun - Shade
• 1'-3' tall x 2'-3' wide
• Drought Tolerant: Yes
• Evergreen: No
• Flower Color: White, occasionally pink; May through September
• Wildlife: Attracts butterflies, bees, and beneficial insects; deer resistant

Western yarrow is a hardy, aromatic herbaceous perennial widespread across Canada and the northern United States, including Washington's Spokane region. This vigorous plant spreads by rhizomes to form colonies in open meadows, grasslands, prairies, and disturbed areas from sea level to alpine elevations. Native yarrow grows from an extensive fibrous root system that allows it to thrive in a wide range of soil conditions, from sandy to clay to rocky substrates. The finely divided, fern-like foliage is aromatic when crushed, releasing a distinctive, somewhat pungent fragrance. The soft, feathery leaves give the plant an attractive texture even when not in bloom.

The flowering display consists of numerous tiny white flowers arranged in dense, flat-topped or slightly dome-shaped clusters called corymbs, typically one-half to one inch wide. Each flower head contains ten to one hundred individual florets with white ray flowers (occasionally tinged pink or yellow) surrounding a central disk. The flowers bloom prolifically from late spring through early fall, with deadheading encouraging continuous flowering. The erect flowering stems rise well above the foliage, reaching heights of one to three feet. The leaves are bipinnately or tripinnately divided into hundreds of tiny segments, giving rise to both the common name milfoil and the species epithet millefolium, meaning thousand-leaved. The foliage remains attractive throughout the growing season and turns bronze in fall.

Yarrow provides exceptional value for pollinators and beneficial insects. The flat-topped flower clusters serve as landing platforms for butterflies, native bees, parasitic wasps, and other beneficial insects, making it an essential component of pollinator gardens. The flowers are particularly attractive to small native bees and hover flies that help control pest populations. While deer and livestock generally avoid the aromatic foliage, bighorn sheep, pronghorn, and deer occasionally browse the flower heads. The plant has an extraordinary history of medicinal use spanning millennia. Named after the mythical Greek hero Achilles, who reportedly used it to treat soldiers' wounds in the Trojan War, yarrow has been employed by countless cultures for its astringent, anti-inflammatory, and wound-healing properties. Native American tribes including the Navajo, who called it life medicine, used it for toothaches, earaches, wounds, burns, fevers, and numerous other ailments.

In garden and landscape settings, yarrow is remarkably versatile and low-maintenance. It thrives in full sun to part shade in well-drained soils and is exceptionally drought-tolerant once established, though it grows more vigorously with occasional moisture. The plant tolerates poor soils, making it ideal for challenging sites, and its spreading rhizomes provide effective erosion control on slopes and banks. Yarrow naturalizes readily and can become aggressive in rich garden soils, so site selection is important. Use it in meadow plantings, cottage gardens, perennial borders, and naturalistic landscapes where its informal habit is welcome. It combines beautifully with other drought-tolerant perennials and native grasses. The flowers have excellent vase life and are prized by floral designers for fresh and dried arrangements. While yarrow is generally tough and pest-free, it can cause contact dermatitis in sensitive individuals, and it is toxic to pets if consumed in quantity.