spiny plumeless thistle USDA PLANTS SYMBOL: CAAC
Carduus acanthoides L.
Synonym(s): plumeless thistle

Spiny plumeless thistle is an annual or biennial herbaceous plant that grows to 5 ft. (1.5 m) tall. It is an invader of pastures and other disturbed areas throughout parts of the western, central, and northeastern United States, as well as southern Canada. Flowering occurs from May to August. The flower heads are red to purple in color and up to 1 in. (2.5 cm) in diameter. Flower stems are branched with spiny wings extending to the flower heads. Hybridization with musk thistle (C. nutans) has been observed. Spiny plumeless thistle infests open, disturbed areas such as pastures, roadsides, and railroad right-of-ways. It can form dense stands that reduce the forage potential of pastures and suppress the growth of more desirable vegetation. Spiny plumeless thistle is native to Europe and Asia and was first discovered in the United States in Camden, New Jersey in 1878.

Identification, Biology, Control and Management Resources