Hoary Ragwort

Sometimes I leave an unknown weed alone, to let it grow and flower, so I can find out what it is.
Like with this one, which grew huge (about 120 cm) and just started to flower. My curiosity is satisfied now, and I won't let it seed.
Workwise, my day was about as pleasant as the name of this plant. I am looking forward to the day after my current project is finished!