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Pictured: Centaurea stoebe — the species. This subspecies isn’t separately illustrated.
Asteraceae family

Spotted Knapweed (subsp. micranthos) Centaurea stoebe subsp. micranthos subspecies

Spotted Knapweed (subsp. micranthos) is an introduced biennial herb, found in Canada, Hawaii, and the lower 48 states.

More about this plant

Centaurea stoebe, the spotted knapweed or panicled knapweed, is a species of Centaurea native to eastern Europe, although it has spread to North America, where it is considered an invasive species. It forms a tumbleweed, helping to increase the species' reach, and the seeds are also enabled by a feathery pappus. Wikipedia →

⚠ Invasive here — plant a native instead USDA + GBIF

Spotted Knapweed (subsp. micranthos) 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.

Part of why it adapts so well: Spotted Knapweed (subsp. micranthos) is a polyploid complex — multiple chromosome races are on record (2n = 18, 36). Spare genome copies give a plant extra raw material to evolve fast, and polyploidy is a documented correlate of successful plant invasions (te Beest et al. 2012). A labelled association from open cytology (ChromoDB), not a prediction for your specific site.

Common Milkweed
Native ★
Common Milkweed
Asclepias syriaca
●●●●●
Swamp Milkweed
Native ★
Swamp Milkweed
Asclepias incarnata
●●●●●
Butterfly Weed
Native ★
Butterfly Weed
Asclepias tuberosa
●●●●●
New England Aster
Native ★
New England Aster
Symphyotrichum novae-angliae
●●●●●
Matched on growth habit · bloom months · mature height · shared U.S. range (USDA + GBIF) — a starting point, not a prescription.

Growing & care

USDA PLANTS · TRY
Conditions
Sources · Conditions
Cold hardiness (derived) — Hardiness
Hardiness
≥ zone 4 derived from its U.S. range
Size & form
Sources · Size & form
USDA PLANTS — Lifespan
Lifespan
Biennial
In the garden
Herb layer — Sits in the herb of a layered food forest or polyculture.Open guide →
derived roles
Species characteristics from USDA PLANTS (public domain) + TRY (CC BY) — general guidance, not a guarantee for your exact site. Deer "browsing" is documented palatability, not a deer-proof claim.

Wildlife & pollinators

How pollinator value is scored →
❧ Caterpillar hosts ~3 caterpillar species

Centaurea supports ~3 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 modest genus.

Recorded feeding on Centaurea in North America, including:

Adaina montana · plume moth Agapeta zoegana · leafroller moth Apterona helix · bagworm moth Hemileuca eglanterina · Elegant Sheep Moth Megalographa biloba · owlet moth Metzneria paucipunctella · twirler moth
+ 4 more species →
Pelochrista medullana · leafroller moth Phyciodes mylitta · Mylitta Crescent Spodoptera praefica · Western Yellowstriped Armyworm Vanessa cardui · Painted Lady
Keystone count (genus-level) from Warren II 2026 (CC0) · Tallamy host-use records. Named species (a documented Nearctic sample, not exhaustive) from NHM HOSTS (CC0).
Species thumbnails re-hosted from iNaturalist — Creative Commons, credited per image (hover for credit). Click any species to see it on iNaturalist. Not exhaustive; many taxa have no openly-licensed photo yet.
Sources for this entry (12) Open & cited
[01] Scientific name & family — USDA PLANTS (DwCA, Zenodo 17903503)
[02] Growth habit & duration — USDA PLANTS (DwCA, Zenodo 17903503)
[03] Native status & distribution — USDA PLANTS (DwCA, Zenodo 17903503)
[04] Common name — USDA PLANTS (via GBIF)
[05] Invasive / introduced status — US-RIIS v2.0 (USGS)
[06] Description — Wikipedia (CC BY-SA)
[07] Ecological value — Warren II 2026 (CC0) · Tallamy host-use counts
[08] Cold hardiness (derived) — Derived from U.S. range × USDA PHZM zones
[10] Caterpillar host count — Warren II 2026 (Dryad, CC0) · Tallamy host-use counts
[11] Caterpillar species — NHM HOSTS (CC0)
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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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