Thistles can be quite bothersome for wandering pets, unaware humans and hungry browsers. The Canada Thistle, pictured here, is considered invasive of fields and are very widespread. Cattle and other foragers, like deer, won’t eat them because of their spines so their populations aren’t kept in check. Anyone that has tried to remove them from their lawn knows that they have large taproots anchoring them to the ground. Not everyone finds them unpalatable – in their native range, butterflies eat their nectar and some birds like their seeds. This plant is edible for those that are brave enough to pick it.