Legal Question in Civil Litigation in Maryland

You have the right to trim any portion of the trees that protrude into your "air space". A good neighbor would have taken the responsibility for this, especially given the damage to your gutters, but obviously you don't have one. If their trees displayed obvious signs of disease or rot which made it likely that protruding branches would fall onto and damage your property, you would possibly have a claim against them for ignoring that issue.