We had a serious blackberry problem and even worse were the rabbits that had their burrows amongst the black berries we tried every thing including deep rotary howing after mowing used round up an several other brands with limited sucess, then one day the damage the rabbits did to our blue berry seedlings about 500 in a rabbit proof fenced off area they found a spot where the wire was not as deep in the ground and got in .
We got the oxy acetaline on the carry all blocked off all the rabbit burrows we could see and proceeded to fill the burrows with a mix of oxy acettaline lit a short bit of fuse and the whole 50 ft diameter blackburry patch lifted about 2ft in to the air no more rabbits in that patch, then give it another hit with round up that killed it then we pushed it up into a pile on the same ground and burned it, Did that to the other blackberry patches never had a problem again, the explosion airrated the ground made it easy to push in to a pile roots and all
I think burning them on the spot instead of picking them up stopped the spread.
This block was cleared neglected dairy pastures that were broken up and sold as 30 acre lots