My neighbor claims that 3 feet of property that sits in my backyard is theirs. If that’s true, and they want to build a fence, legally do I have to remove all my plants, trees, and planter? How do I know if the property is theirs?

The situation you’re describing is surprisingly common in areas that are subdivided. People assume that the existing fences are on the property line, which may or may not be true.

Unfortunately, the only way to be certain where the property line is, is to have a survey done. You can either agree with the neighbor to split the cost, or if you aren’t getting along that well, get your own.

If it’s true that your landscaping is on the wrong side of the property line, technically that’s a trespass. However, you may be able to work something out for mature trees or other things which are difficult to move. The law does recognize the balance of interests, here, but you’re both better off coming to an agreement rather than rolling the dice on how a judge will determine that balance.