Fertilising guide
How to fertilise Fernleaf yarrow (Achillea filipendulina)— schedule & NPK
Also called Fernleaf yarrow, Fern-leaf yarrow, Cloth of gold.
More about fernleaf yarrow
About Fernleaf yarrow
Achillea filipendulina · also called Fernleaf yarrow, Fern-leaf yarrow · flowering
Achillea filipendulina is a tall, robust yarrow from central and southwestern Asia, distinguished by its rich golden-yellow, plate-like flower corymbs up to 10 cm across atop sturdy stems. The finely divided, aromatic, fern-like foliage is highly ornamental. Exceptional for cutting, dried flower arrangements, and pollinator gardens. Extremely drought-tolerant and easy in full sun.
Growth habit: Upright, clump-forming herbaceous perennial with strongly aromatic, finely cut (pinnately divided), fern-like grey-green leaves and tall, stiff stems bearing large, dense, flat-topped compound corymbs of tiny golden-yellow flowers
Watch for — Flopping in rich soil or shade: Tall stems become lax in fertile soils or with insufficient light. Grow in lean soil with full sun; use grow-through supports if necessary. Deadheading and cutting back hard after the first flush also helps control height.
What fertiliser fernleaf yarrow actually wants — and why
Fernleaf yarrow is an easy, light foliage feeder — a half-strength balanced liquid feed through the growing months keeps it green without forcing weak, sappy growth.
A balanced general houseplant feed (roughly even N-P-K) is exactly right — it is grown for foliage, so steady, moderate nitrogen for healthy leaves is the goal, not a bloom or root formula.
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 fernleaf 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 fernleaf 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 fernleaf yarrow:
Fertilise minimally or not at all in average garden soil. In very poor or sandy soils, one application of a low-nitrogen balanced fertiliser in early spring is sufficient. Rich feeding produces overly tall, floppy stems and increases disease susceptibility. Treat that as sparingly through the growing season between spring through early autumn (roughly March to September); ease off in autumn and stop entirely in the low light of winter.
The dormant-season rule matters more than the exact interval: skip feeding entirely when fernleaf 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 fernleaf yarrow
Half strength is the safe default for fernleaf yarrow — houseplant feeds are formulated strong, and the diluted dose is gentler on the roots while still ample for foliage.
Feeding always goes onto already-damp soil, never dry roots — water fernleaf yarrow first if the soil is dry, then apply the diluted feed. The companion question is when to water at all, covered in the fernleaf yarrow watering schedule.
Signs you are over-feeding fernleaf yarrow
Over-feeding is far more common — and more damaging — than under-feeding for most plants. The classic tells for fernleaf yarrow:
- Brown, crispy leaf tips and edges with no sign of underwatering.
- A white, crusty salt deposit on the soil surface or pot rim.
- Weak, pale, stretched new growth that flops.
- Lower leaves yellow and drop while the soil is correctly watered.
Signs you are under-feeding fernleaf yarrow
- Uniformly pale or yellow-green leaves, oldest first.
- Noticeably small new leaves and stalled growth in good light and season.
- A generally tired, lacklustre look despite correct watering and light.
If the symptoms point at watering, light or roots rather than nutrition, the full fernleaf yarrow care brief covers soil, humidity and the common problems for this species.
Flushing and leaching the salts
Flush the pot of fernleaf yarrow with plain water until it runs freely from the base every couple of months in the feeding season — it washes out the fertiliser salts that cause brown tips.
Organic vs synthetic feeds for fernleaf yarrow
Organic options
A diluted seaweed or worm-casting feed, or fish emulsion if you can tolerate the smell indoors. UK: Westland or Baby Bio Organic, dilute seaweed; US: Espoma Indoor! or Neptune's Harvest fish & seaweed. Slow, gentle and hard to overdo.
Synthetic / liquid feeds
A general-purpose houseplant liquid at half strength — UK: Baby Bio, Westland Houseplant Feed or Phostrogen; US: Miracle-Gro Indoor Plant Food or Schultz. Convenient and fast-acting; the only risk is overdoing it.
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 fernleaf yarrow — frequently asked questions
What fertiliser does fernleaf yarrow need?
A balanced general houseplant feed (roughly even N-P-K) is exactly right — it is grown for foliage, so steady, moderate nitrogen for healthy leaves is the goal, not a bloom or root formula. Fernleaf yarrow is an easy, light foliage feeder — a half-strength balanced liquid feed through the growing months keeps it green without forcing weak, sappy growth.
How often should I feed fernleaf yarrow?
Fertilise minimally or not at all in average garden soil. In very poor or sandy soils, one application of a low-nitrogen balanced fertiliser in early spring is sufficient. Rich feeding produces overly tall, floppy stems and increases disease susceptibility. Fertilise minimally or not at all in average garden soil. In very poor or sandy soils, one application of a low-nitrogen balanced fertiliser in early spring is sufficient. Rich feeding produces overly tall, floppy stems and increases disease susceptibility. Treat that as sparingly through the growing season between spring through early autumn (roughly March to September); ease off in autumn and stop entirely in the low light of winter.
What strength of feed for fernleaf yarrow?
Half strength is the safe default for fernleaf yarrow — houseplant feeds are formulated strong, and the diluted dose is gentler on the roots while still ample for foliage.
What does over-feeding fernleaf yarrow look like?
Brown, crispy leaf tips and edges with no sign of underwatering. A white, crusty salt deposit on the soil surface or pot rim. Weak, pale, stretched new growth that flops. Lower leaves yellow and drop while the soil is correctly watered. Feeding fernleaf yarrow year-round on a fixed schedule, including dark winter months, is the most common mistake — it cannot use the nutrients in low light and the surplus simply burns the roots and crusts the soil.
Should I flush the soil of fernleaf yarrow?
Flush the pot of fernleaf yarrow with plain water until it runs freely from the base every couple of months in the feeding season — it washes out the fertiliser salts that cause brown tips.
Keep reading
- Fernleaf yarrow care — the full brief (light, soil, humidity, problems, pet safety)
- How often to water fernleaf 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 daphne laureola
- How to fertilise clethra barbinervis
- How to fertilise physocarpus opulifolius 'center glow'
- All 6887 fertilising guides in the Growli library