A blog about evidence, objects, peculiar aesthetics and cultural remains
There appear to Christmas ornaments mixed in with the greens, is this, perhaps an early version of the Rose Bowl Parade?
The beginnings of the green movement.
Unfortunately the card isn't postmarked, so I don't know where it's from. The image suggests a celebration of fertility and growth, and thanks to your Rose Bowl idea, I found out that that parade was started to celebrate flowers that grew in California's "winter" and the new year. Pretty good guess!