Fertilising guide
How to fertilise Yarrow (Achillea millefolium)— schedule & NPK
Also called yarrow, common yarrow, milfoil.
More about yarrow
About Yarrow
Achillea millefolium · also called yarrow, common yarrow · herb
Yarrow is a tough, drought-resistant perennial with finely divided ferny leaves and flat-topped clusters of tiny flowers from summer into autumn. A magnet for pollinators and beneficial insects, it spreads by rhizomes to form weed-suppressing mats. Ideal for dry meadows and gravel gardens, it is toxic to pets and grazing animals if eaten.
Growth habit: Rhizomatous, mat-forming herbaceous perennial with upright flowering stems, soft feathery aromatic foliage, and dense flat corymbs of small flowers; spreads steadily to form colonies.
What fertiliser yarrow actually wants — and why
Yarrow is a soft, fast leafy herb that you harvest hard — a modest balanced feed keeps tender growth coming without tipping it into bland or bolting.
A balanced general feed (even N-P-K) at modest strength — enough nitrogen to keep replacing the leaves you pick, but not so much that flavour thins or it bolts to seed.
For the language behind the three numbers on the bottle — what nitrogen, phosphorus and potassium each do — see the NPK ratio explained entry. The short version for yarrow: match the feed to the job the plant is doing right now, not to a generic “plant food” on the shelf.
How often to feed yarrow, and which months
Feeding only earns its keep while the plant is in active growth and can use the nutrients — pour feed into a dormant or low-light plant and it simply builds up as root-burning salt. For yarrow:
None to minimal. Yarrow performs best in unimproved soil and rarely needs feeding; fertiliser produces weak, floppy stems. Skip feeding in average ground. In practice: a balanced liquid feed every few weeks through the main growing and harvesting season (spring through early autumn), more often the harder you are picking it.
The dormant-season rule matters more than the exact interval: skip feeding entirely when yarrow is resting. For the wider context on indoor feeding rhythms across the seasons, the houseplant fertiliser schedule walks through the year month by month.
What strength to mix for yarrow
Half strength is a sensible default for yarrow — enough to fuel regrowth after cutting, gentle enough that the leaves stay aromatic rather than watery.
Feeding always goes onto already-damp soil, never dry roots — water yarrow first if the soil is dry, then apply the diluted feed. The companion question is when to water at all, covered in the yarrow watering schedule.
Signs you are over-feeding yarrow
Over-feeding is far more common — and more damaging — than under-feeding for most plants. The classic tells for yarrow:
- Fast, soft, pale growth with diluted, less aromatic flavour.
- Early bolting (running to flower) and a bitter edge.
- Salt crust and scorched tips on container plants.
Signs you are under-feeding yarrow
- Pale, slow regrowth after cutting and small leaves.
- A tired, stalled plant that cannot keep up with harvesting.
- Yellowing older leaves in a long-spent pot.
If the symptoms point at watering, light or roots rather than nutrition, the full yarrow care brief covers soil, humidity and the common problems for this species.
Flushing and leaching the salts
Pot-grown yarrow builds up feed salts quickly — water until it drains each time and flush the pot with plain water every few weeks, especially on a sunny windowsill.
Organic vs synthetic feeds for yarrow
Organic options
A diluted seaweed feed or worm-casting tea keeps soft growth coming without overdoing it. UK: dilute seaweed or Westland; US: Espoma Garden-tone or Neptune's Harvest. Gentle, hard to overdo, flavour-friendly.
Synthetic / liquid feeds
A balanced liquid feed at half strength through harvesting — UK: Phostrogen, Baby Bio or Westland; US: Miracle-Gro all-purpose at half strength. Fast regrowth; just do not overdo the nitrogen.
Brand names are examples, not endorsements, and UK and US ranges differ — check the label’s own NPK and dilution rate, since formulations change.
Fertilising yarrow — frequently asked questions
What fertiliser does yarrow need?
A balanced general feed (even N-P-K) at modest strength — enough nitrogen to keep replacing the leaves you pick, but not so much that flavour thins or it bolts to seed. Yarrow is a soft, fast leafy herb that you harvest hard — a modest balanced feed keeps tender growth coming without tipping it into bland or bolting.
How often should I feed yarrow?
None to minimal. Yarrow performs best in unimproved soil and rarely needs feeding; fertiliser produces weak, floppy stems. Skip feeding in average ground. None to minimal. Yarrow performs best in unimproved soil and rarely needs feeding; fertiliser produces weak, floppy stems. Skip feeding in average ground. In practice: a balanced liquid feed every few weeks through the main growing and harvesting season (spring through early autumn), more often the harder you are picking it.
What strength of feed for yarrow?
Half strength is a sensible default for yarrow — enough to fuel regrowth after cutting, gentle enough that the leaves stay aromatic rather than watery.
What does over-feeding yarrow look like?
Fast, soft, pale growth with diluted, less aromatic flavour. Early bolting (running to flower) and a bitter edge. Salt crust and scorched tips on container plants. Over-feeding yarrow with strong nitrogen is the usual mistake — it grows fast and lush but the leaves turn bland and it bolts to flower sooner, ending the useful harvest early.
Should I flush the soil of yarrow?
Pot-grown yarrow builds up feed salts quickly — water until it drains each time and flush the pot with plain water every few weeks, especially on a sunny windowsill.
Keep reading
- Yarrow care — the full brief (light, soil, humidity, problems, pet safety)
- How often to water yarrow — the watering schedule
- The houseplant fertiliser schedule — feeding through the year
- NPK ratio explained — what the three numbers on the bottle mean
- How to fertilise basil
- How to fertilise herb garden
- How to fertilise mint
- All 2464 fertilising guides in the Growli library