Bull Thistle

Bull thistle is Cirsium vulgare, a Eurasian biennial plant that has been introduced around the world. It is considered a noxious weed in many North American states.

Bull thistle produces purple flower heads rich in nectar. That nectar makes the plant attractive to butterflies and bees even though the species is often treated as a weed.

Bull thistle is biennial, meaning it generally completes its life cycle over two growing seasons. It typically grows vegetatively before flowering and producing seed.

Bull thistle has spread beyond its Eurasian native range and is listed as a noxious weed in many North American states. Its weed status reflects its ability to establish in disturbed areas and spread by seed.