Does any know if you can grow a blackberry bush from a cutting. neighbor has a commercial bush that grows really big berries and a lot of them.

Yes cut 8-10” piece and put in good potting soil. Root growth hormone on the stem will help. Plant several and keep them damp. It the vice stay red looking in it’s alive little buds will form. I’ve put cutting in water and have started a few. When you take a cutting keep the bottom the bottom in the ground or water.
This will work …..around his vine put something to hold the vine on the ground and cover with dirt. Leave attached to his vine. The vine will root. Cut it off his vine and dig it in the fall.

good will try tks

root cuttings or tip layering (what Paint Rock described)