A biennial herb of European origin with pink flowers on prickly stems. It is established across most of North America and is regarded as a noxious weed nearly everywhere.
- ‘The spotted knapweed is a European invader that, over the last hundred years, has spread throughout the pastures and rangeland of western North America, often out-competing native species.’
- ‘The weeds, spotted knapweed and leafy spurge, are native to Europe.’
- ‘Recently, as part of a school project, two teenagers have been coming out to the farm to raise beetles that selectively attack spotted knapweed.’
- ‘Invasive plant species, such as spotted knapweed, may out-compete native grasses.’
- ‘Sheep are efficient foragers and, unlike cattle, can thrive on a fair number of invasive weeds, such as leafy spurge and spotted knapweed.’