On my property there are several heap piles where the previous owner had the timber cut and the leftovers pushed into piles scattered about the property. He never got around to burning the dead piles and they have all been taken over by privy hedge and other greenery that refuses to burn. Is there anything that will kill this growth so that I can get the piles dry enough to burn? Roundup will kill the small stuff, but it will not kill the hedge and some of the small trees that have started to grow.