It shall be the duty of the public works director to notify in writing the owner, the agent of the owner, or the lessee, or the occupant of the property whereon is located any illegally maintained tree or shrub as defined herein to remove such tree or shrub or portion of such tree or shrub within ten days from the date of such notice. If at the expiration of the date set forth in such notice such illegally maintained portion of such tree or shrub has not been removed and no extension of time has been granted, the public works director shall report such refusal or neglect to the city attorney, who shall file charges against such owner, agent or the lessee or occupant of such premises for violation of this chapter.