I had some poppies last winter/spring that did well. Can't remember exactly what kind they were but they were single and red.

I don't know if it would be so great for winter but Nasturtium are good flowers for neglect.

I've also had some snapdragons survive all summer being pretty ignored but they would probably be happier in a sunny winter situation.

Many of the standard northern annuals will do fine down here in winter. Pansies, violas and violets but they probably want a little more attention and richer soil than sand.

There are probably many edible plants that would also make lovely winter "ornamentals" Stuff like Red Kale, and ornamental cabbage would probably be worth a look. There was one variety of Kale in the package of Mesclun mixed greens I planted once that was really pretty and I tended to leave it growing for the visual interest more than I wanted to eat it.

Here is a link that might be useful: TCLynx

Thanks, Tclynx. Good to hear you had luck with the poppies. I'm leaning more and more towards a patch of shirley poppies or corn poppies with corn flowers.

I grow kale (the Russian types)and violas in the vegetable garden, in heavily ammended soil. I even grow my nasturtiums with vegetables. (Everyone always says nasturtiums like poor soil but they don't like soil as poor as mine.) Now I'm looking for something wildflowery and easy for sandier beds. I especially like flowers that have petals so thin the light shows through, which is one of the main reasons I'm leaning towards poppies.
Bill

Here's a tip: Try growing some perennial flowers instead pf seasonal or annual. They will last a whole lot longer, and are more cold and heat hardy.