I'm sorry you are having these issue with your neighbor. Good fences are supposed to make good neighbors but that's not always true, as you can see in your own case.
Your best bet is to get a real estate lawyer who deals with property issues, including walls and fences, all the time. In this case, there are plants and trees, living things that are encroaching on the wall but that are damaging the wall. The damage will only get worse.
I would suggest that you get a real estate lawyer for this and sometimes you won't have to go to court -- sometimes a threatening letter from a real estate attorney will do the trick. If that doesn't work, then the lawyer will want to discuss with you the option to take her to court but will also see if she can pay some $ towards your legal fees if it has to go to court. Legal fees are never guaranteed by the court but it's always good to ask for it anyway because sometimes litigants get them.
Let me know if you want me to find real estate lawyers for you in your area. I would need to know the biggest city/town near you so I can find lawyers for you. I do this free of charge for my customers here, and while we're not allowed to recommend a specific attorney, I can point you in the right direction. I also have a guide that I made to explain how to pick lawyers from the list that I will send you. It's easy to follow and short, to the point, so it will help you when deciding which lawyers might be right for you. Just let me know and I'll be happy to give you the information about lawyers in your area.
I'm happy to help you with this so please let me know if you need this information about real estate lawyers in your area.
Does this answer your question? I'll be back to check in the late morning so I can finish answering the question then and find some lawyers for you.