NOXIOUS WEED
CO, NM, UT

Carduus nutans (Musk Thistle)    
Asteraceae (Sunflower Family)

Semi-desert, foothills, montane, subalpine.  Meadows, disturbed areas.  Summer.
Mesa Verde National Park, Knife Edge Trail, July 17, 2004 (with Zachary and Spencer).

Carduus nutans is a prickly-beautiful, common, foreign invader of lawns, farm fields, roadsides, and disturbed mountain fields.  It reproduces by seed which it produces prodigiously, resulting sometimes in a spiny, impenetrable thicket of Thistle.  During its first year, Carduus nutans grows a basal rosette (sometimes several feet in diameter  --  see below) and in its second year it produces a stout, tall flower stalk armed with sharply pointed leaves.  Cutting the rosette off just below ground level usually kills the plant.

Linnaeus named this genus and species in 1753.  "Cardus" is Latin for "Thistle" and "nutans" is Latin for "nodding", referring to often nodding flower.

Semi-desert, foothills, montane, subalpine.  Meadows, disturbed areas.  Summer.
Navajo Lake Trail, August 30, 2007.

Semi-desert, foothills, montane, subalpine.  Meadows, disturbed areas.  Summer.
Navajo Lake Trail, August 30, 2007.

Semi-desert, foothills, montane, subalpine.  Meadows, disturbed areas.  Summer.
Near Yellowjacket Canyon, October 8, 2010.

A thick taproot produces a large, spreading, basal rosette of sharply armed leaves.  In the second year, this basal rosette will sprout a thick stem which will branch and produce many flowers, each of which will produce a prodigious number of seeds.

Range map © John Kartesz,
Floristic Synthesis of North America

State Color Key

Species present in state and native
Species present in state and exotic
Species not present in state

County Color Key

Species present and not rare
Species present and rare
Species extirpated (historic)
Species extinct
Species noxious
Species exotic and present
Native species, but adventive in state
Eradicated
Questionable presence

Range map for  Carduus nutans