As a comment about
Canada Thistle (Cirsium arvense),
cwhitt wrote:
This Canada Thistle is pretty invasive and can really take over an area very quickly. It can choke out other plants and wildflowers quickly. They are growing at at the condo where I live (Ohio), but they just happen to be growing in a small area contained on all sides by asphalt. Otherwise, they would probably need to be removed as too invasive for our condo setting. But even though the plant is invasive, I can see that it has it benefits in its contained area. The goldfinches love them, and it might not be an accident that the goldfinches showed up at the same time the thistle started growing. Also, tons of bees are attracted to the masses of light purple flowers. In the fall, they do tend to lose their appeal a little and start to look a little weedy. Even so, it is nice to have this little area of wildness in a formal condo setting.