Fernleaf Yarrow Achillea filipendulina
Fernleaf Yarrow is an introduced perennial herb, found in Canada and the lower 48 states. It grows to 1.3 ft and blooms May – Aug.
More about this plant
Achillea filipendulina, the yarrow, fernleaf yarrow, milfoil, or nosebleed, is an Asian species of flowering plant in the sunflower family. Wikipedia →
Fernleaf Yarrow is flagged invasive in the U.S. These natives fill a similar niche — same growth habit, bloom season, height, and region — so you keep the look and feed local wildlife instead of spreading a problem.
Growing & care
USDA PLANTS · TRY- Hardiness
- ≥ zone 5 derived from its U.S. range
- Height
- 1.3 ft
- Lifespan
- Perennial
- Foliage
- Broadleaf
- Flower colour
- Yellow AI AI image-analysis of community-science photos (~87% expert agreement) — not a botanical record
Wildlife & pollinators
How pollinator value is scored →❧ Caterpillar hosts ~21 caterpillar species
Achillea supports ~21 caterpillar species.
Native butterfly & moth caterpillars are the base of the terrestrial food web — most songbirds rear their young almost entirely on them. As a host for native Lepidoptera this is a moderate genus.
Recorded feeding on Achillea in North America, including:
+ 8 more species → ↑ show fewer
✦ Bees specialist-bee host · 88 bee visitors
Specialist native bees depend on it.
Some native bees are pollen specialists (oligolectic) — they raise young only on pollen from particular plant genera. Achillea is a recorded specialist-bee host, so losing it can mean losing the bee that relies on it.
88 native & managed bee species are documented visiting Fernleaf Yarrow — the 12 most-recorded:
Wildlife & visitors 54 birds · 13 nectaring
Open records of who else uses Fernleaf Yarrow — a generalist food-web signal, kept separate from the keystone Ecological Value.
Recorded eaten by 54 birds species (fruit, seed, browse) — the most-recorded:
13 adult butterfly & moth species are recorded nectaring at its flowers — the most-recorded:
Related plants
More Achillea →
How we know this (3) Methods & honest limits
A recorded categorical fact: each species is tagged C3 (standard), C4 (heat/water-efficient) or CAM (succulent, night-time CO₂ uptake) — or a facultative combination. We only show a trait card for the noteworthy C4/CAM cases; C3 is the unremarkable majority, kept in the data but not surfaced as a card.
We take the plant’s U.S. county range and look up each county’s long-term climate, then summarise: native rainfall = the median annual rainfall across its counties; heat tolerance = the warm end (90th percentile) of average temperature across its range (mirroring how our cold-hardiness floor uses an extreme). Counties + medians blunt the roadside/observer bias that makes point-level climate unreliable. Needs at least five placeable counties.
Honest limits: A realized, sampling-biased niche (where it has been recorded, not its physiological optimum), and county climate is coarse — large Western counties span deserts and mountains. Derived guide, never a measured fact.
McKenzie et al. assigned each species a flower colour with a GPT-4V vision model over iNaturalist photos. We use the confident tier plus a separately-labelled lower-confidence top-up (mostly inconspicuous green/brown flowers), and render it as a small tint — never as an asserted fact, and kept out of the written synopsis.
Honest limits: AI image inference (~87% expert agreement on the confident tier); a decorative, confidence-tiered indicator, not a measured trait.
Sources for this entry (22) Open & cited
Cite this page Open data, please attribute
PlantKey’s data is open under CC BY-SA 4.0 — free to reuse and adapt, with attribution and the same licence. Photos keep their own per-image licence + credit (see Sources above).
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