Pink, Rose, Red, or Purple Flowered Forbs

Pink, Rose, Red & Purple Flowered Forbs
Alfalfa
Black henbane
Blue Mustard
Bull thistle
Canada thistle
Common burdock
Diffuse knapweed
Hounds-tongue
Iberian knapweed
Meadow knapweed
Musk thistle
Purple loosestrife
Purple starthistle
Red clover
Redstem filaree
Russian knapweed
Scotch thistle
Spiny plumeless thistle
Spotted knapweed
Squarrose knapweed
Tall morning-glory
Teasel

 

Musk Thistle
Carduus nutans L. (Aster family, Asteraceae)
 

Description

Erect, single-stemmed annual or biennial forb; 1 to 7 feet tall; often forming dense patches; stems glabrous to wooly, spiny-winged from leaf bases; taprooted.

Leaves: Basal and cauline, alternate, lance-linear to elliptic, 4 to 16 inches long, 1/4 to 8 inches wide; upper blades smaller, surfaces glabrous above, undersides furry—primarily along main veins, margins 1 to 2 pinnately lobed and spiny-toothed; basal leaves taper to winged petioles while cauline leaves are sessile.

Flowers: Flowers June to September; purple flower heads spherical 3/4 to 2-3/4 inches in diameter, nodding, solitary on stalks more than 3/4 inch long; flower head bracts glabrous to sparsely wooly, tips erect to spreading; flower head receptacles flat, densely covered with cream-colored bristles.

Fruits: Glossy golden to brown achenes elliptic, greater than 1/8 inch long; curved, slightly compressed; cream-colored, 1/2 to 1 inch long, pappus bristles are numerous; united at the base to form a ring, and are deciduous as a unit.

Habitat

Moist cultivated and disturbed or degraded sites in meadows, grassland, chaparral, woodland, forest, and riparian communities, and roadsides within elevations that generally range from 4,200 to 8,100 feet.

Propagation/Phenology

Plants appear to require a period of chilling to induce flowering; first flower heads can produce large numbers of seeds, sometimes 1,500 or more seeds per head; later flower heads produce fewer seeds. Most seeds are dispersed within 165 feet of the parent plant; typically, seeds are dispersed 1 to 3 weeks after flowering. Seeds typically germinate during the winter/spring months and exist as a rosette until flowering in the spring/summer of the following year.

Comments

Native to Europe; serious infestations are often associated with sandy, fertile soils. This species and spiny plumeless thistle readily hybridize with one another, and plants with intermediate characteristics may be found where their ranges overlap. New Mexico Class B noxious weed and Oklahoma noxious weed.

Collage of 4 images of Musk thistle

 

 
Forest Service Shield
Invasive plants and weeds of the national forests and grasslands in the southwestern region
Musk thistle flower heads Musk thistle flower heads Musk thistle stems and foliage Musk thistle basal rosette