(scientific name Centaurea solstitialis ), more commonly known as Yellow Starthistle , is a highly invasive winter annual or biennial herb native to the Mediterranean region and Eurasia. It is widely recognized for its bright yellow flower heads protected by sharp, straw-colored spines that can reach up to two inches in length. Key Identification Features
Barnaby's Thistle is considered a in many regions, including much of the western United States and Australia, due to its aggressive growth. barnaby's thistle
: The plant typically grows between 1 and 3 feet tall, featuring gray-green to blue-green stems covered in fine, white cottony hairs. : The plant typically grows between 1 and
: Blooming occurs from June through October. The flower heads are topped with yellow florets and surrounded by stiff, sharp spines arranged in a star-like pattern. : It begins as a basal rosette with deeply lobed leaves
: It begins as a basal rosette with deeply lobed leaves. As it matures, the upper leaves become smaller and linear, forming "wings" that run down the stem.
: A single plant can produce up to 100,000 seeds , which are easily dispersed by wind, water, or clinging to animal fur and machinery. Ecological and Agricultural Impact