Yarrow

Sun

Full sun; tolerates light shade, but stems may lean and flowering is reduced.

Water

Water regularly while establishing. Once established, water during prolonged drought rather than keeping the soil consistently moist.

Soil

Well-drained soil, including sandy, gravelly or chalky ground. Tolerates poor soil and a broad pH range; avoid waterlogged ground and heavy feeding.

Height

1-3 ft (0.3-0.9 m)

Spread

1-2 ft (0.3-0.6 m) initially; spreads farther over time by underground stems and seed.

Flowers

Early summer to early autumn, depending on climate; usually white, sometimes pale pink. Named selections offer additional colours.

Foliage

Aromatic, finely divided, fern-like green to grey-green leaves. Basal leaves may persist through mild winters; plants usually die back in cold climates.

Growth

Fast once established.

Care needed

Low

• Water new plants when the root zone begins to dry; reduce watering once they are established.
• Avoid routine feeding: rich soil encourages soft, floppy growth.
• Keep heavy organic mulch away from the crown, especially in wet winters.
• Divide congested clumps every two to three years in spring.
• Pull or dig out spreading shoots while small, and remove seedheads if unwanted seedlings are a concern.

Pruning. After the first flush, cut spent flower stems back to leafy growth to encourage another flowering. Cut dead stems near ground level in late winter or early spring, or sooner if seedlings are unwanted.

Late winter

Cut down remaining dead stems before new growth starts, leaving any occupied insect stems undisturbed where practical.

Spring

Plant or divide clumps in well-drained soil; remove runners extending beyond the intended planting area.

Late spring

Water establishing plants during dry spells and check young shoots for aphids.

Summer

Cut back faded flower stems to leafy growth for possible repeat flowering.

Early autumn

Remove seedheads before seed sheds if you want to limit self-sowing.

Autumn

Clear fallen debris from around crowns where winters are wet; leave some sound stems standing for insects.

• Repeat small groups through sunny perennial borders, pairing the flat flowerheads with upright salvia spikes.
• Combine with ornamental grasses for a loose, meadow-like planting; allow space for its spreading habit.
• Use in gravel gardens with lavender and catmint, where lean soil helps keep growth compact.
• Plant in sunny wildlife borders to provide accessible flowers for small pollinators and predatory insects.

Garden styles it suits: Cottage garden, Wildflower, New perennial (prairie), Pollinator garden, Dry gravel garden and Desert / xeriscape.

Plant it with: Catmint, Lavender, Perennial salvia, Coneflower, Globe thistle and Little bluestem.

Wildlife: Flowers attract bees, hoverflies, butterflies and small beneficial wasps. Foliage supports some moth larvae; standing stems provide shelter for overwintering insects.

• Powdery mildew: improve spacing and airflow, avoid drought stress, and remove badly affected foliage.
• Rust: remove affected leaves and dead debris; divide crowded clumps to improve airflow.
• Aphids: rinse colonies from young shoots with water and encourage ladybirds and other predators.
• Crown or root rot: avoid waterlogged sites, keep mulch off the crown, and replace badly rotted plants in a better-drained position.

Toxic to cats, dogs and horses if eaten. Leaves and flowers contain compounds that can cause vomiting, diarrhoea, drooling or loss of appetite; larger amounts are more concerning. In people, sap and foliage can cause contact dermatitis, particularly in those sensitive to the daisy family, and ingestion can cause adverse effects. Do not treat it as an edible garden herb.

Where it spreads. Can spread aggressively by underground stems and seed in gardens and lawns across the United States, Canada, the United Kingdom and Australia. In southeastern Australia, including Victoria and Tasmania, introduced yarrow can invade grassland and other open vegetation. Its native status varies across North America; local native status does not prevent it from becoming a garden nuisance.

• Queen Anne's lace (Daucus carota)

  Its flowers form true umbels, with stalks radiating from a shared point, and conspicuous divided bracts beneath. Yarrow has dense clusters of tiny daisy-like flowerheads rather than true umbels.

• Poison hemlock (Conium maculatum)

  Usually much taller, with hollow, hairless stems often marked by purple blotches and white flowers in true umbels. Yarrow has narrow, finely divided leaves and compact clusters of tiny daisy-like heads.

• Feverfew (Tanacetum parthenium)

  Has broader, lobed leaves and obvious little white daisies with prominent yellow centres. Yarrow's leaves are finely feathered and its individual flowerheads are much smaller.

Achillea refers to Achilles and the plant's traditional association with treating wounds, while millefolium means 'a thousand leaves', describing its finely divided foliage.

Propagation. Divide clumps in spring, keeping rooted shoots and replanting promptly. The species can also be raised from seed sown shallowly in spring; seedlings from named selections may not retain the parent's colour or habit.

Accepted botanical name

Achillea millefolium

In the US and Canada

Native in Alaska, Canada, Greenland, the lower 48 states and St. Pierre and Miquelon. Introduced in Canada, Hawaii, the lower 48 states and St. Pierre and Miquelon.

Native range

Northwest Territorie, Norway, Nunavut, Ohio, Oklahoma, Ontario, Oregon, Pakistan, Poland, Portugal, Primorye and Prince Edward I..

Measured

Soil pH 6 to 8. Average height 16 cm.

Sources: GBIF (CC BY 4.0), USDA PLANTS and Trefle (CC BY 4.0). The care and design notes are LandscapeGPT's own.