I have a lot of what seems to be Canadian Thistle. I am unsure because some of the stems are spiny, rather than smooth. See photos. Also, it does not necessarily grow in clumps. The partly-opened lavender-colored flowers are 1/2 inch across now, near the end of June. The infestation took hold long ago, on sunny ground below a pine and a spruce tree. It has extended well into my yard which is grass and other plants. I followed my city's recommendation to pull the plants and put thick newspaper down below surface level. I find now, through experience and reading, that this is far from the correct approach. I hesitate greatly to buy the array of chemicals recommended, and to apply the ones that require (to my knowledge) expert handling. Your advice would be much appreciated.