All plant material shall conform to the latest version of the American standard for nursery stock (ANSI Z60.1). Plant material shall be of standard quality or better, true to name and type of their species or variety and be free of disease, insects, and or damage. Alternatives to these materials that can be shown to meet both the intent and requirements of this chapter may be approved as part of a landscaping plan. Plant material selection should include consideration of soil type and depth, the amount of maintenance required, spacing, exposure to sun and wind, the slope and contours of the site, and compatibility with existing native vegetation preserved on the site.