Nodding Thistle / Carduus nutans

The large Nodding, or Musk, Thistle (Carduus nutans) is my favourite thistle. I was surprised to see this one growing mid-September near one of the newly built stormwater ponds at Burnsmead, Fish Creek Park. Unfortunately, this quite spectacular and beautiful flower is on the list of Restricted, Noxious, and Nuisance Weeds In Alberta. It is a biennial that spreads rapidly by seed forming extremely dense stands, though when I have seen this species growing in several places within the city, there are usually only a few of them. However, if they are left ....