General. The placement of natural landscape materials (e.g., trees, shrubs, and hedges) is the preferred method for buffering differing land uses, for providing a transition between adjacent properties, and for screening the view of any parking or storage area, refuse collection, utility enclosures, or other service area visible from a public street, alley, or pedestrian area. Plants may be used with fences or berms to achieve the desired screening or buffering effect. Plant material should be mature enough at the time of planting to provide an effective buffer or screen, and should be planted in an appropriate location to allow for desired growth within a reasonable period of time. When used to screen an activity area such as a parking lot, landscaping shall not obstruct the visibility of motorists or pedestrians or interfere with public safety.