Have you thought about switching around everything? IE: I would try using your floral where your solids are now, using the solids where the white is and picking up that lavender/purple with the sashing.
I, too, think the white is too stark and is the visual problem you are having with the way it lays out. Even tho it all reads as mediums except the background of the floral, sometimes that makes a very restful and relaxing quilt for a bed. I personally would have no problem with that. I would get a tone on tone purple for the sashing that is also in the range of your peach and green.