Let's show-off those mailbox gardens. I need some ideas for next year. For my MB garden I have a red mandevilla in the large pot behind the mailbox, there are 2 purple kales at each corner behind the pot, marigold between the kale, brown and green coleus in front of the MB, ganzia on each side of the coleus. there also a couple of geraniums out there.
Dianthus superba would look good. Dianthus, for me, blooms all season and is pretty versatile.
Red petunias would look good too.
Angelonia would be good also. Red Celosia. Red Pelargoniums. White Pelargoniums.
Just some ideas.