Spiny broadleaf rosettes appear in the lawn in late summer or fall, or upright spiny plants appear in the spring where rosettes grew last fall. Canada thistle, bull thistle, musk thistle, and several other thistles are common lawn weeds in some parts of the U.S. Most thistles are problems in new lawns or lawns that are thinning from some other problem, especially drought. Canada thistle, also called creeping thistle, spreads by underground runners and can spread over a large area in a single growing season.
It is difficult to control thistles by digging because any pieces of root left in the soil will re-sprout.