Nodding plumeless thistle (Carduus nutans) is an invasive plant. It is a native of Eurasia and was first detected in North America in 1800.
This thistle has a long history as an invasive species. It has been declared a noxious weed in Australia, many U.S. states and Canadian provinces. Some farmers spend many hours attempting to rid them from farm ground, mostly pastures.
For more information about this plant pest, see the CABI data sheet.