Carduus nutans (Nodding Thistle)
|Also known as:||Nodding Plumeless Thistle, Musk Thistle|
|Habitat:||sun; fields, along roads|
|Bloom season:||June - October|
|Plant height:||2 to 7 feet|
|Wetland Indicator Status:||GP: FACU MW: FACU NCNE: FACU|
|MN county distribution (click map to enlarge):|
|National distribution (click map to enlarge):|
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Flower heads are 2 to 3 inches across, purple to pinkish and often nod down, hence the common name. The showy bracts are rather large and generally triangular, in many layers spreading out away from the flower head, and are green or tinged purple. Flowers are single at the end of branching stems.
Leaves and stem:
Leaves are up to 15 inches long at the base of the plant and deeply lobed, the lobes on lower leaves further divided into several smaller lobes, and becoming smaller and less deeply lobed as they ascend the stem. There are numerous spines along the wavy edges. Leaves are stalkless, mostly hairless except for the main veins on the underside, and may have a white cast on the edges, especially early growth rosettes.
Goldfinches are quite fond of Nodding Thistle (and all other thistles) for both the seed and the silks from the seed heads, which they use to line their nests. The large flower heads and broad, showy bracts make this species stand out from the rest, though closely related is Plumeless Thistle (Carduus acanthoides), whose flower heads are rather smaller, with narrow bracts. Nodding Thistle is on the noxious weed list for Minnesota, a common pasture/roadside pest. While not as obnoxious or as widespread as Plumeless Thistle, this species can invade high grade native habitats and is no doubt under-reported in the state. Of note is the MN Weed Advisory Group is recommending this species, currently a Prohibited-Control species, be removed from the noxious weed list because they have determined "infestations [are] primarily caused by human disturbance". The decision seems illogical, since that doesn't make it any less of a pest.
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Where to buy native seed and plants ↓
- Nodding Thistle plants
- the bracts of a flower just starting to bloom
- a roadside infestation of Nodding Thistle
- early growth rosette
Photos by K. Chayka taken at Long Lake Regional Park, Ramsey County. Photos courtesy Peter M. Dziuk taken at various locations around the Metro.
Have you seen this plant in Minnesota, or have any other comments about it?