Silvery Yarrow (Clavenna's Yarrow) care

Light

Aim for at least 4-6 hours of direct sun on the leaves. Requires full sun for at least 6 hours daily. In its native limestone rockface and scree habitat, it grows in open, exposed positions. Full sun intensifies the silver colouration of the foliage. In shade, plants become lax, the silver colour fades, and flowering is severely reduced. If your only bright window faces south, that's perfect for silvery yarrow — same window any aroid would fry on.

Watering

Watering silvery yarrow: every 10–14 days; very drought-tolerant once established. The number that matters isn't the day of the week — it's how dry the top 2-3 cm of the pot feels. A finger in the soil tells you more than a watering app. After every watering, tip the saucer. Water sparingly and allow the soil to dry completely between waterings. This species is highly adapted to summer drought on sun-baked limestone. Overwatering is the primary cause of failure — it causes root rot quickly. Established plants in open ground often need no supplemental irrigation.

Soil and pot

Silvery Yarrow grows best in poor, alkaline to neutral, very well-drained stony or gritty soil. Thrives in lean, gritty, alkaline or neutral soil (pH 6.5–8.0) reflecting its limestone origin. Use a mix of 50% horticultural grit with 50% loam. Rich, fertile, moisture-retentive soils cause rank growth and rot. Excellent drainage is the single most important requirement. A pot with a working drainage hole is non-negotiable for this species — even free-draining mix will turn soggy in a closed planter. If you love the look of a decorative pot without a hole, use it as a cachepot around an inner nursery pot you can lift out to water.

Humidity and temperature

Silvery Yarrow sits happiest at around 25–50% humidity and -20–30°C (-4–86°F). Prefers dry to moderately humid air. The silvery tomentum (fine hairs) on the leaves is an adaptation to dry, sun-exposed conditions. High humidity promotes fungal disease in the foliage. Avoid enclosed or damp positions — open, breezy exposures suit this plant perfectly. If you keep the room above year-round and avoid placing the plant near a cold draught, a hot radiator, or an air-conditioning vent, you have already handled the two biggest indoor stressors.

Fertilising

Feed silvery yarrow sparingly. Little to no feeding required. Achillea clavennae grows naturally in nutrient-poor limestone soils. An annual topdress of grit around the plant is more beneficial than fertiliser. If growth appears very weak, a single application of a low-nitrogen slow-release granular feed in spring is sufficient. Skip fertiliser entirely on a stressed, recently-repotted, or actively wilting plant — fertiliser salts make damage worse, not better. Wait for a round of healthy new growth before resuming a feeding rhythm.

Common problems

Below are the issues we see most often on silvery yarrow in the Growli community. Each is annotated with the most common cause so you know where to start.

• Root rot in wet or heavy soil — The number one cause of death in cultivation. Achillea clavennae cannot tolerate waterlogged or poorly drained soil, especially in winter. Plant in raised beds or troughs with gritty, lean soil, and avoid overwatering at all times. Winter wet is far more damaging than frost.
• Powdery mildew — In humid conditions with poor air circulation, powdery mildew (Erysiphe spp.) can colonise the foliage. Improve ventilation and avoid overhead watering. Planting in full sun with good air movement is the best preventative. Affected leaves can be treated with a sulphur-based fungicide.
• Spreading too aggressively — While more restrained than many yarrows, A. clavennae spreads by rhizomes and can outgrow its allotted space in loose, open soil. Divide every 2–3 years in spring to maintain a tidy clump and rejuvenate flowering. Excess runners can be pulled away and replanted.

Propagation

Easily divided in early spring — lift and separate rooted sections of the spreading mat and replant directly. Stem cuttings (5–8 cm) taken in late spring root readily in gritty compost. Seed can be sown on the surface of gritty compost in a cold frame in autumn or early spring; seedlings are variable. Propagation is the cheapest, most satisfying way to expand a collection — and it doubles as insurance against losing a mature plant to an accident. Take a backup cutting once the parent is established and healthy.

Toxicity to pets

Silvery Yarrow is mildly toxic to pets. Achillea species contain achilleine, sesquiterpene lactones, and volatile oils that can cause contact dermatitis in sensitive individuals and mild gastrointestinal upset if ingested in quantity by pets. ASPCA does not individually list Achillea clavennae but lists the genus Achillea (yarrow) as toxic to dogs, cats, and horses, causing vomiting, diarrhoea, increased urination, and potential dermatitis. Treat as mildly to moderately toxic to pets. If you keep cats, dogs, or curious children in the house, weigh placement carefully — a high shelf or a hanging planter is enough for casual safety. For severe ingestion incidents, call your local vet and the ASPCA Animal Poison Control Center (in the US, 888-426-4435).

Pet-safety status is sourced from the ASPCA Toxic and Non-Toxic Plant List, which catalogues the most-asked-about plants for cats, dogs, and horses.

Silvery Yarrow deep-dive guides

Every aspect of silvery yarrow care, each with its own calibrated guide:

• Common silvery yarrow problems & fixes
• Silvery Yarrow watering schedule
• Silvery Yarrow light requirements
• Best soil mix for silvery yarrow
• Silvery Yarrow fertilizing guide
• When to repot silvery yarrow
• How to propagate silvery yarrow
• How to prune silvery yarrow
• What's eating my silvery yarrow?
• Silvery Yarrow growth rate & size
• Silvery Yarrow cold hardiness
• Silvery Yarrow temperature & humidity
• Is silvery yarrow toxic to cats & dogs?
• Is silvery yarrow toxic to cats?
• Is silvery yarrow toxic to dogs?
• All 12 Achillea varieties
• Getting silvery yarrow to bloom

Featured in these plant shortlists

Silvery Yarrow qualifies for 4 curated Growli shortlists — each one filtered objectively from our structured plant-care library, so the selection is consistent and checkable:

• Best drought-tolerant houseplants — Houseplants that prefer to dry out — forgiving of forgotten watering and ideal for travel or busy weeks.
• Best flowering houseplants — Indoor plants grown for their blooms — selected from the flowering species in Growli’s plant-care library.
• Best houseplants for full sun — Houseplants that want direct sun — the species for a hot south or west-facing windowsill where shade-lovers scorch.
• Best houseplants for a cool room — Houseplants that tolerate cool conditions down to about 10°C — for an unheated spare room, hallway, porch or a home kept cool.
• Browse all 29 plant shortlists — pet-safe, low-light, drought-tolerant and more

Related guides

Silvery Yarrow is also known as Silvery Yarrow, Clavenna's Yarrow, and White Yarrow.

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