But someone mentioned, you might find out the county or state comes along once in a while to make sure it is clear to drain, mows everything. Maybe your neighborhood has an association that would know, or find out?
As you said initially, do not consider this a swampy site. It will get bone dry in hot dry weather. All you can count on is full sun.
And don't fill the actual ditch with a lot of plant material, It needs to function.
Maybe something low or that can be mowed for that part, and flowers on the bank / a planting on your side to hide your view. People may park along the street there at times and walk on the grass edge.
