Yarrow
蓍草 Achillea millefolium · Asteraceae
A flat-topped meadow flower with a short harvest window: cut the heads when they are fully open, before they brown, and keep the patch in bounds.
The flat-top harvest
Yarrow flower heads open into a flat, dense corymb. The best harvest is short: fully open, before the outer flowers begin to brown. Cut the top 15–20 cm in dry weather, in the morning, and leave some heads for pollinators.
The plant is a spreader, so the harvest is also a management tool. Cutting back after flowering keeps the patch tidy and can encourage a late flush, but it will not stop the rhizomes. If you want a compact clump, divide it in spring and replant the vigorous edges.
| Stage | What you see | Action |
|---|---|---|
| Buds | Tight, green heads | Wait |
| Fully open | Flat head, strong colour | Peak harvest |
| Browning | Outer flowers fade | Cut for drying only |
| Seed | Dry, brown heads | Collect or deadhead |
Growing it
PFAF gives USDA zone 4–8 and describes yarrow in meadows and pastures on all but the poorest soils (PFAF). It wants full sun, lean soil and sharp drainage. Rich, irrigated beds make it floppy and invasive.
Sow seed in spring or autumn, or divide clumps in spring. The plant spreads by rhizomes and can become a thug in a small border; a root barrier or a dedicated patch helps. Cut back after flowering to keep it tidy and encourage a late flush.
Harvest and drying
Cut the flowering tops when the heads are fully open but before they brown. Harvest in dry weather, in the morning. Take the top 15–20 cm of stem.
Bundle the stems and hang them in a dark, airy place, or dry them on a rack. The feathery leaves dry quickly. Store the dried tops in an airtight jar away from light and use within a year.
- Cut the top 15–20 cm at full flower.
- Harvest in the morning, in dry weather.
- Dry in bundles, in the dark.
- Store airtight; use within a year.
Identifying it
Yarrow has finely divided, fern-like leaves with a strong, slightly bitter scent and flat-topped clusters of tiny white or pale pink flowers. The stems are stiff and ridged. The plant spreads by creeping rhizomes.
Other white-flowered umbellifers and daisies can look similar at a distance. The combination of feathery leaves, flat flower heads and rhizomatous growth is distinctive, but do not harvest from a wild mixed sward without certainty.
Traditional context
Yarrow has a long folk history in Europe and Asia, including use as a wound herb and a bitter tonic. The Latin name refers to Achilles, and the plant appears in many traditional herbals.
PFAF warns that extended use can cause allergic skin rashes or photosensitivity, and that yarrow may enhance the effect of sedatives. This site does not recommend home treatment of wounds or any other condition; use proper medical care.
Cautions
Safety notes for yarrow
- Asteraceae allergy is common; avoid if you react to daisies, ragweed or chamomile (PFAF).
- Extended use can cause allergic skin rashes or photosensitivity in some people (PFAF).
- Yarrow may enhance the sedative effect of other herbs or sedative drugs; ask a pharmacist before combining (PFAF).
- Large amounts may have sedative and diuretic effects; avoid medicinal doses without professional advice.
- Avoid medicinal use in pregnancy and breastfeeding unless a qualified clinician advises otherwise.
- This is horticultural information, not medical advice or a dose recommendation.
A starting point for a conversation with a qualified practitioner or pharmacist — not a diagnosis, dose or treatment plan. See the full safety page.
Questions this plant raises
Does yarrow spread aggressively?
Yes, by rhizomes. Give it a dedicated patch or a root barrier, and divide clumps every few years.
Why is my yarrow flopping?
Rich soil and too much water. Yarrow is a meadow plant; lean, dry conditions keep it upright.
Can I grow yarrow in a pot?
Yes, in a large pot with gritty compost. It is drought-tolerant but needs repotting every few years.
Sources & further reading
- Plants for a Future — Achillea millefoliumPFAF
- NC State Extension — Achillea millefoliumNC State Extension
Accessed for horticultural and safety context. Traditional-use statements are historical and are not evidence of effectiveness. Written and edited by the Herb Ledger editorial team. Read the editorial policy.
More flowers & flowering tops
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