Salt and vinegar sort of works on blackberries.
Those are Himalayan blackberries though, and are pretty robust. Round up works great, but glyphosates make frogs gay.
Best solution is to get a weed whacker and cut it all down to the dirt, and keep doing that every couple months till the blackberries die off and grass takes over
>>2610138Don't want anything growing on your fence if it can be helped, it speeds up rot, especially in the PNW where these nasty bitches like to grow.