Yellow Star Thistle
I recently wrote about both Canada Thistle and Bull Thistle, but neglected to mention Yellow Star Thistle.
This plant is certainly more of an issue out west than it is here on the east coast, but it has been spotted in Chester County, so it is worth mentioning. I found this image from a website in California that give some insight into what a major issue this plant is in CA. At this point of the game, we are still in the "early detection" stage, so let's beat this plant before we have to put up "wanted" signs for our thistles as well!