I am not really sure how this happened, but i was training my Pokemon for the Pokemon league, when i stumbled upon a Drapion. Behind it was a tree with berries on it. I thought i was crazy, but at the end of the battle, it says i received a berry. This happened on route 19. I am not really sure if it happens on any other route, but let me tell you first hand, it takes quite a while to find the tree, but when you find it the first time, it appears more often. If you find just a normal tree, you get no berry. I think that the tree has to have a berry on it. Tell me if you have something like this happen to you in a different route!