Problem: Thistle (Lawns)
The Canada thistle (Cirsium arvense), bull thistle C. vulgare), musk thistle (Carduus nutans) and several other thistles are common lawn weeds in some parts of the country. Most are biennials that germinate in the spring and grow into a flattened rosette that looks like a large, spiny dandelion and is painful to touch. The rosette dies in the fall, but the thick root survives and sprouts the following spring into an upright spiny plant. Some other thistles are annuals, living only one year and reproducing from seed. Most thistles are problems in new lawns or lawns that are thinning from some other problem, especially drought. Canada thistle, also called creeping thistle, also 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.