Collect enough petals from the petal scheme, and you would either receive an outfit or Rosemary wearing this outfit.
There are a few petal scheme outfits that are all collected from various peoples' memories. It's hard to verify all of the petal scheme outfits,
as they're not listed in any catalogues.
This outfit is probably the nicest of the petal scheme outfits, the yellow ribbon is sewn onto the suit.