Hi Kenrussell and welcome to Goy. You will need to cut them back first and then dig up the roots.

You may need to use SBK brushwood killer, following the instructions keenly. Wait a while for results and then do like we did with one property. We had a series of 'parties' and got it cleared. We were lucky that there were some very large productive pear trees and a cherry tree on the property. So the rewards for helpers were clear, Plus cultivated berry fruits in season, which they could just turn up and pick!

I would recommend combining the two above. Go through and cut and dig. Then keep an eye out for new growth and blast it with Roundup or some other systemic weed killer. It is going to take a couple of years to eradicate this vicious weed. And welcome to GoY!

Unfortunately it's a long and hard job to clear blackberries but once you have got the top growth off it is a lot easier to clear the roots and any new growth that will inevitably re-appear. As others have said, don't expect to be having a lovely lawn next spring.

I cleared a 1/3 acre plot of 10ft high brambles by first spraying. Once more or less dead I then cut back the branches (in 3ft lengths to go in the wheelbarrow) down to about 6 inches. I then loosened the soil around the stem and found the main roots which I then tried to follow back (they can be 2/3 ft in length) and cut them. You need to cut several of the roots so that the stem can be pulled out. You just need to be methodical and eventually you will clear the plot. You then need to keep an eye out for seedlings or new growth and pull it up. Good luck!