It’s pretty but,

it’s poisonous to animals and a noxious weed. Ragwort appears to be everywhere this year. It contains alkaloids that are toxic to cattle, horses, dogs, and cats. In susceptible animals, the toxins cumulatively cause irreversible liver damage. The toxic properties of tansy ragwort continue after the plant is cut or baled in hay. Human poisoning can also occur.

Spaying with WeedMaster® herbicide will kill this weed. Pulling should only be considered an option on new or small infestation sites. If you pull, get the entire root.