It shall be the duty of every outdoor advertiser to keep all grass and weeds, and other growths except trees and ornamental shrubbery, cut down so that the same shall not grow to a greater height than ten inches within six feet of any billboard or signboard used by him; provided that this obligation shall extend only to property controlled by the advertiser.
('70 Code, § 2.2.21.8) Penalty, see § 111.99