See Comparison of spiny-leaved thistles .
Severe infestations can form tall, dense, impenetrable stands, especially in fertile soils.
To date, biological control agents have been unsuccessful in the United States. Introduced from Europe and the Mediterranean region. Leaves elliptic to oblanceolate and irregularly spiny-toothed. Scotch and Illyrian thistle leaves covered with white woolly hairs , with the lower surface more densely covered than the upper. Taurian thistle leaves typically covered with glandular hairs.