She was not getting back at you - that is a human thing to do. Dogs don't have the capacity to plot revenge. I'd say she was bored, it was simply - I'm out here, I'm bored, gee these things look interesting, gee this is fun

. If it was an upset tummy she would have gone for grass. If she has taken a liking to plants and flowers it might be a good idea to check the ones in your yard aren't toxic to dogs
