Yarrow

How to recognise it

Growth habit

Perennial with creeping rhizomes; forms mats of leaf rosettes and upright flowering stems of 20–60 cm.

Leaf

Narrowly lance-shaped in outline but two to three times finely divided into hundreds of narrow segments; softly hairy and aromatic when crushed.

Flower

Small heads of 4–6 mm, usually with five white or pink ray florets around a yellowish centre, gathered in a flat-topped cluster. From June to October.

Stem

Sturdy, grooved, often woolly and branched at the top.

Fruit/seed

Small, flat, grey-brown seeds without a pappus.

Confusion with

Sneezewort (Achillea ptarmica) has undivided, finely toothed leaves and larger heads. Umbellifers such as wild carrot or the highly poisonous hemlock look like yarrow from a distance, but have true umbels with spokes rather than heads with ray florets.

Flowering: June–October · Pruning: March, July and September

Why grow it?

• Flowers from June into October, providing nectar and pollen for months.
• The flat flower clusters are landing pads for hoverflies, soldier beetles, tiny parasitic wasps and small solitary bees.
• Stays green in dry summers, even in the lawn when the grass is already turning yellow.
• The faded flower heads stand through winter, giving structure and shelter to insects.
• The leaves were once used to flavour beer, and a few young leaves add bite to a salad.

Yarrow: where does it grow best?

• In the wild: grassland, verges, dykes, dunes, roadsides and lawns, on almost any soil.
• Full sun is ideal; in shade it barely flowers.
• Dry to normal, well-drained soil; poor soil keeps the stems sturdy.
• Suits a flower meadow, a dry border, a gravel garden or a flowery lawn.

Goes well with

• Oxeye daisy: Together the classic picture of a flowery verge in June.
• Bird’s-foot trefoil: Yellow pea flowers on the same poor, dry soil, and food plant of the common blue.
• Knapweed: Purple knobs among the white flower heads, a favourite of butterflies.
• Wild marjoram: Pink, fragrant flowers for insects in a sunny, dry spot.

Yarrow: when and how to plant it?

1. Buy plants from a native plant nursery or sow your own: yarrow is also in many wildflower meadow mixes of native seed.
2. Sow in March–May or in September on bare, weed-free ground. The seed needs light to germinate: scatter it on the surface and press it in, but do not cover it.
3. Keep the seedbed moist until the seedlings appear, usually after one to two weeks.
4. Plant pot-grown plants in March–April or September–October, 30–40 cm apart, or in groups of three among grasses.
5. Water well after planting; after that, water only during long dry spells in the first year.
6. Never dig up plants from the wild: buy them or grow them from seed.

Care

Water

Only in the first year during long dry spells. Established plants cope well with drought.

Feeding

Not needed. In rich soil the stems become floppy and fall over.

Mowing

In a flower meadow, mow in July and in September and remove the cuttings. In a flowery lawn it simply survives mowing.

Spreading

In a border it creeps with rhizomes; slice off the runners at the edge with a spade each spring.

Faded flowers

Cut back the first flush after flowering for a second flush; leave the last flower heads standing for winter.

Tip: In May, cut back some of the stems by a third: they flower a little later and stay sturdier, so the display lasts longer.

Pruning and mowing

Pruning months: March, July and September.

When: Remove the old stems in March; in July, cut back after the first flush if you like.

How:

• In March, cut last year’s dead stems just above the new leaf rosette.
• In July, cut the faded stems back to the leaves: you will get a second flush in September.
• In autumn, leave some of the flower heads: insects overwinter in them and they look lovely with frost.
• In a lawn or meadow, mowing is all it needs.

Pruning: when and how · Pruning calendar and basic rules

Propagation

Division

In March–April or September, split a clump with a spade and replant each rooted piece elsewhere.

Seed

Collect seed in September–October and sow on the surface in spring. Seedlings of coloured varieties seldom resemble the parent.

Yarrow: how does it get through the winter?

Hardy to −30 °C.

• The flowering stems die back, but a green leaf rosette often stays visible all winter.
• Fully hardy, to about −30 °C.
• Leave the dry flower heads: they shelter insects and look lovely with frost.
• It copes less well with waterlogged soil in winter than with frost.

Diseases and pests

• Flopping: In rich or wet soil the stems fall over. Do not feed, and shorten the stems by a third in May.
• Spreading: Creeps between other plants in a border. Slice it off with a spade or install a root barrier.
• Powdery mildew: White powder on the leaves in dry, warm summers. Give plants space and cut back affected stems.
• Aphids: On the flowering stems in early summer. Ladybirds and hoverfly larvae deal with them.

Through the year

• March: Cut off old stems. Plant or divide.
• April: Sow on bare ground. Slice off runners in the border.
• May: Shorten some stems by a third for sturdier plants, if you like.
• June: Flowering begins. Hoverflies and beetles on the flower heads.
• July: Cut back after the first flush. Mow the flower meadow.
• August: In flower. Water only young plants in dry spells.
• September: Second flush. Mow the meadow again and remove the cuttings. Sow or divide.
• October: Last flowers. Collect seed.
• December: Leave the dry flower heads for insects.

Did you know?

• The name Achillea refers to the Greek hero Achilles, who according to legend treated his soldiers’ wounds with this plant. Millefolium means a thousand leaves.
• Before hops became widespread, yarrow was one of the herbs in gruit, the herb mixture used to flavour beer in the Middle Ages.
• According to an old English folk custom, you put yarrow under your pillow to dream of your future love.