Question
My neighbor has a berry tree (blue berries) in her backyard right up against our adjoining fence.  She had it cut back but it is beginning to grow back and so fiercely that it is making the fence lean badly!!! Can I use something like vinegar to kill the beast?

Answer
The bush can be killed with a herbicide called Roundup BUT if the neighbor does not want it killed you could lose a good neighbor and start a feud. If the neighbor want to keep the bush I would cut the branches that are on my side of the property and keep them cut back.
Roundup if sprayed on the foliage will kill the bush. Be aware that any plant that is green if the roundup gets on the foliage during the spraying will be killed. So only spray the plant that you want to kill.