having trouble killing off our my weeds in the yard. first bought some ortho wed b gone. did nothing. then bought some round up, same result. its like i'm shooting them with miracle grow , not weed killer! any suggestions. have a lot of area to cover. below is small area I treated. was all dirt and weeds. I trimmed them as low as I could applied generous round up and covered in bark. few days later, weeds are poking thru arrrggg!