Common Yarrow
Achillea millefolium
Also called: Western Yarrow
Common Yarrow. Achillea millefolium, the common yarrow, is an aromatic herbaceous perennial native to most of the Northern Hemisphere and present as native or naturalized throughout the United States. Flat-topped clusters of small white (or pink, yellow, red in cultivars) flowers bloom from late spring through summer above feathery fern-like foliage. A pollinator magnet, host plant for many beneficial insects, and historic medicinal herb.
Growing & care
- Sun: full sun, minimum 6 hours. Shade produces flopping leggy growth and reduced bloom.
- Water: very low once established. Drought-tolerant; overwatering produces lush foliage at the expense of flowers.
- Soil: lean, well-drained, average to poor. Rich garden soil produces flopping growth.
- Hardiness: USDA zones 3–9 — exceptionally cold-hardy and broadly adapted.
- Spacing: 12–18 inches; clumps spread aggressively by rhizome.
- Cutback: shear spent flowers after the main bloom flush to encourage rebloom and prevent excessive self-sowing.
Propagation
Divide established clumps every 2–3 years in spring or fall to control spread and rejuvenate vigor. Stem cuttings root easily in moist sand in summer. Seed germinates readily but produces variable color and habit; named cultivars must be divided. Yarrow self-sows freely in undisturbed sites.
Common problems
Flopping mid-season is universal in rich, irrigated beds — relocate to lean dry conditions or cut back by half early in summer. Powdery mildew appears in humid summers with poor airflow. Rust occasionally affects foliage in wet years. Yarrow can become aggressive in lawns and small beds — choose carefully where to introduce it. CAUTION: yarrow contains volatile oils and alkaloids that cause vomiting, diarrhea, and dermatitis in dogs and cats per ASPCA listings. Skin contact can cause photosensitivity dermatitis in sensitive humans.
Common Yarrow — seeds, tools & books
Native range
Native to 49 states
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