What is this and how do I kill it? I cleared and area 3 years ago when I bought a piece of property. It was a grown up mess the the people before me had dumped everything known to man . I have sprayed this with cornerstone and 24d. They will wilt it but it comes right back. It seems to be in the area where my dozer guy pushed the pile to burn when he cleared it 3 years ago. I plant this field and am tired of this stuff taking over in that one area.