How do I handle a neighbor issue?

My neighbor keeps an impecable yard. She has recently however adopted the practice of tying her dog's waste into the plastic bags you get at the supermarket and she piles them up at the foot of the tree that is in front of her house OUTSIDE her fence! Between trash pickups they aculate and by the time regular trash day comes there can be about 12 - 15 knotted bags of poop sitting there. I asked her about them and she shrieked in my face, "WHO ELECTED YOU KING OF THE STREET!?" and walked away. What would you suggest as a next step?