We also have a ground hog problem................we filled the hole in with glass bottles and then rocks and dirt......I saw something in a book that you stick in the ground and it hums. Try the bananna peels.....I use them to keep dogs away from my trees....they also work on the base of the rose bush the gas from the bananna makes the roses have beautiful blooms. You also could use a save--a-heart trap and move them 10 miles from your property.