Knapweed is a group of flowering plants belonging to the genus Centaurea. These plants are often found in fields, meadows, and disturbed areas, and they can be recognized by their distinctive purple or pink flowers. Knapweed species, such as spotted knapweed and diffuse knapweed, are known for their ability to spread rapidly and outcompete native vegetation. Knapweed is considered an invasive species in many regions, particularly in North America. Its aggressive growth can lead to reduced biodiversity and altered ecosystems. Efforts to control knapweed include mechanical removal, herbicides, and biological control methods, such as introducing natural predators.