Am I the only one who does not know which Iris has the Peacock Flower? Al

Oh sorry. It's just the label from the nursery that I jotted down. Google search reveals it to be Dietes bicolor (Dietes bicolor (Steud.) Sweet ex Klatt, Family: Iridaceae, Common names: Yellow Wild Iris or Peacock Flower (English), Uintjie or Poublom (Afrikaans)).

I'm not familiar with any of the iris for container planting.

The Dietes would make an excellent plant for your boxes. It does gradually grow a bigger clump and in about 10 years would fit your box pretty well. I would start with about 3 per box and you can always thin them later when needed. The common name for Dietes is usually "fortnight lily" as it tends to bloom in two week cycles. Here without winter protection it will occasionally be frosted back and look bad for a while, in San Francisco that should not be a problem. Al