At the intersection of two streets, no shrubbery, hedge or other natural growth, fence or wall over three feet higher than the apex at the center line of the street shall be located within the triangular area shown shaded in Sketch A below nor shall any such shrubbery, hedge or other natural growth, fence, or wall be permitted which shall obstruct vision or line of sight regardless of height, nor shall the limbs or foliage of any tree obstruct vision or line of sight or be permitted to grow nearer to the ground than eight feet, where such limbs or foliage overhang or are over or upon land within the triangular area as shown in Sketch A.