I have a corner of my yard that the previous owners put down 2-3 inches of wood chips and didn't maintain. There is now small buckthorn (pencil thick) and some stinging nettle growing there. There are 5 medium trees there as well. I am hoping to turn this area into grass. What would be the best way to accomplish this? Remove the wood chips? Till everything? Put topsoil on top? Any suggestions are appreciated!