Yep that's what it is, a invasive species native to southeastern Eurasia, that has been around in Canada since the late 18th century.
Growing up in southern Saskatchewan, I am very familiar with this field thistle that grew everywhere, and was and still probably is hated by farmers.
The Canada thistle flowerheads are rich in nectar, and are very popular with butterflies, moths, and bees. On this morning, if you expand the photo and look close at the center flowerhead, you can make out several tiny green bugs enjoying their visit.
Once the plant dies out in the early fall, the plant dies and dries out to an attractive light brown color that photographers find attractive.