This native biennial is our tallest thistle. It is well-behaved and grows to 6 feet or more in height. The leaves are lance shaped and up to 10 inches long near the base of the plant. They become much shorter further up the stems and branches, but all are very spiny on their edges (C). The purple flower heads are up to 2 inches across, with short spines on their urn-shaped bases (A,B). The seeds are borne on feathery disks (D). Differentiated from the Bull Thistle (Cirsium vulgare) in that the Tall Thistle blooms later, has lance-shaped basal leaves and short spines on its flower head.