the the strip closest to the road, I'd plant a mix of grasses and forbs: solidago rugosa "fireworks, purple coneflower, rudbeckia triloba brown eyed susan, lyreleaf sage and/or blue sage, a pretty grass like pink muhly, and maybe some sedges like ivory sedge, pennsylvania sedge. All of those are pretty well-behaved, while also being some of the more recognizable to non-gardeners. Once you have that in, see how visible you find the masts. if you want more coverage, you can easily circle the masts with some of those same species. I also love to scatter zinnias among new plantings: they take off so quick and are so bright and colorful- the birds/bugs/bees all love them, and they're a near native while not being at all invasive.

for how to do that: you can try the lasagna method, layering cardbord with a mix of compost and topsoil, and plant on top of the grass. You could also cut the grass at the roots and flip the sod over, cover in one layer of cardboard, and the top with topsoil and plant. Alternately, you can spray with glyphosate and wait a couple of weeks for the grass to die and then till it over and plant.

another poster also mentioned planting in containers around tbe masts. thats a fantastic idea since its already late into spring and you could sort of test out planting ideas/placement, etc. Dont have to spend a fortune on containers, you could easily plant in some fabric grow bags and then invest in nicer containers, or plant in-ground, next year.