If the neighbour from hell is going round punching elderly neighbours in the face and harassing people generally, the police should be dealing with it.
"He is likely to pick on something else . . . ." Yes, but two wrongs don't make a right. The hedge is a hazard in itself, separately from the parking row. The OP says that there is no pavement, so the hedge must stick out a metre into the road. That will narrow the road by a metre and be dangerous to motor traffic and to passers-by.
If the OP can get it seriously narrowed down it will improve her own parking choices, improve the road for everyone, and put her firmly into the "good guy" list with her other neighbours - that is worth doing.