Our train station used to have nice wild flowers in the grassy area along the platform only for them to be ripped up and replaced with... nought but untended weeds, really. Someone I know of has tried to get lupins to grow there by hurling pelletts of manure embedded with seeds over the fence - but without success.
I'll have a go with poppies and aqueligia seeds, what else would grow will from seed in an untended patch?
I think that the decorative wildflowers will only survive if the area has been mown recently, as if it were a meadow.
Tesco recently set up shop in Chester Le Street and there was a glorious display of poppies, cornflowers etc all along a bank in year one, but come year two and the area hadn't been mown or cared fro an so went to cr*p. it's a shame too, because simply by mowing and re seeding they could have had a marvelous display, but I think it's council land and therein lies the problem...
I could start a whole other thread on council horticultural services!!!
Poppies and cornflowers are classic weeds of cultivated ground; they're experts at staing in the ground till there's a bare patch of soil, then germinating like mad and colonising it. They can't take the competition as perennials move in though. What you need is tough perennials that can compete. The sort of thing you'd hesitate to plant normally as it's a total thug which just takes over the garden.
foxgloves? they're tough little so and sos!
buddleia?