Yarrow
Achillea millefolium
Care
full sun
very low
adaptable; tolerates clay, poor soils, and drought
1–3ft tall , 1–3ft wide
Apr-Sep · white
Semi-Deciduous
Resistant
Friendly
Throughout California in many habitats
Flat-topped clusters of small white flowers
Medicinal herb; spreads by rhizomes; extremely adaptable native
Care Guide
Planting
Plant yarrow in full sun in spring or summer. It thrives in nearly any soil type - clay, poor soils, and even slow-draining conditions are fine - so don't worry about amending. Space plants 1–3 feet apart depending on whether you want them to fill in quickly as a groundcover. Yarrow's deep roots make it excellent for erosion control on slopes.
After Planting
Water weekly during your first summer, then gradually reduce watering as the plant establishes; once established, it needs no more than once-weekly irrigation even in summer heat. After the first year, let yarrow do its thing - it's semi-deciduous and will handle our Bay Area winters down to -10°F. The #1 mistake is overwatering; this plant wants dry conditions and will rot in consistently wet soil. Deadhead spent flowers to encourage more blooms throughout spring and summer, or let it reseed if you want it to spread naturally.
Endangered & Threatened Species Supported
California Species of Special Concern; monarch populations declining
Wildlife Supported
Insects
Critical fall migration fuel source Sep-Oct during southbound migration to Mexico
Adult nectar source Jul-Sep in California foothills and mountains
Mid-elevation California butterfly Jul-Sep
Adult nectar Jun-Aug in California grasslands
Mammals
Opportunistic foraging on tender foliage and dried material in chaparral/grassland