Italian Thistle

Go to Midwest Weeds and Wildflowers Home Page

Italian Thistle

Carduus pycnocephalus L.

Asteraceae (Sunflower Family)

▲▼ mature, flowering plants

▲▼ leaves, including some basal leaves below

▲▼ winged stems

▲▼ inflorescences

▲ fruit/seed

Carduus pycnocephalus L., ItalianThistle: (Bayer Code: CRUPY; US Code: CAPY2)

· An annual to biennial weed native to Europe found only sporadically in Midwest so far, but potential for greater spread exists

· First year rosette leaves long, narrow, deeply divided and have toothed, spine-edged margins

· Subsequent flowering stem is 1-4 feet tall, slender, slightly-branched with leaf bases extending far down stem, so stem appears to have spiny wings; leaves on flowering stem are smaller than basal leaves

· Inflorescence may be single or in small clusters, smaller than many thistles (usually 0.5 to 1 inch diameter), surround by outspread, spine-tipped, narrow-triangular bracts

· Flowering season is late spring to early summer (May-June), which differs from other invasive thistles (Canada thistle, bull thistle) that tend to bloom in mid to late summer (July-September)

Go to Midwest Weeds and Wildflowers Home Page

Updated 23 January 2019