Hi ssaxe, I have noticed mine gets black spots every fall but I don't worry about it, I dont even cut them off anymore! Come spring theres new leaves that look healthy and green and stay like that until fall arrives again, I believe its called tar spot, a fungal infection that causes premiture leaf drop but does not affect the long term vigour of the plant. I live beside a forest and the sycamore trees are heavily infected with tar spot at this time of year and they will still be there this time next year so I wouldn't worry about it too much! But just incase you may actually have a problem you should post a pic!
