Mississippi Highways 63 and 57 are designated as wildflower routes, and the State Highway Department shall take the necessary measures in maintaining rights-of-way along such highways to encourage the growth of native wildflowers. Such measures shall include, but not be limited to, (a) refraining from the use of herbicides, (b) planting native wildflowers, and (c) when mowing becomes necessary, mowing selectively in order to preserve wildflowers during their growing seasons.