Cirsium vulgare

Bull thistle can cause large infestations and drive out native plants. It is mostly a prominent issue in disturbed areas including hay fields and pastures, and along trails, roads and vacant fields. Overgrazed pastures are susceptible to bull thistle invasion, and it can sometimes form dense stands that reduce productivity and stocking levels. These thistles may also dominate forest clear cuts and reduce growth of tree seedlings. Although the seeds are short-lived, they can persist in the soil for many years, making them hard to eradicate.