I've been buying annual phlox from my favorite local greenhouse for a number of years. They bloom all summer. I don't recall them seeding, but that's what they did last year. I'm glad I didn't pull them when I first saw them growing in a circle around the edge of the tub they were in. One of the pansies has come back or else reseeded as well.
The rest of the photos were taken yesterday, 6/7/09. I planted "Spooky" dianthus, also from my favorite nursery, in the center before I knew what was growing on the edges.
The phlox have different colors than their parents. What fun!
None of the phlox are exactly the same colors as each other, either.