area used for drainage? put wetland plants in them instead of trying to grade out a giant funnel that dumps water into a drain pipe as quickly as possible. it'll absorb excess floodwater and filter out pollutants. if it's the southeast USA, PUT RIVER CANE OH MY GOD IT'S PERFECT. Arundinaria gigantea, you can look it up. Rushes. Cattails. Horsetails. Sedges.
roadside or other area that needs to be kept relatively low? short native grasses and flowers. there's a billion of them.
Awkward leftover land next to a building? trees. if there's plumbing or power lines to worry about? more native grasses and flowers. pollinator gardens. Or grow fiber plants that can be harvested yearly and turned into fabric/baskets/mats/whatever. If the soil doesn't have anything toxic in it, you could grow food plants. Grow sunflowers, they're allelopathic and keep the weeds down. Walking paths. Solar panels. Walking paths with solar panels. Put solar panels above your parking lot while you're at it. Did i mention Arundinaria gigantea.
flowers...fruit trees...native sedges...infinite possibilities