I've tried dried peony and rose petals. Both turned black, as do lavender buds. I think there are only two dried flowers that don't discolor, those are calendula petals (yellow) and cornflowers (blue). It's a shame, because I have so many things in my garden that would look great in soap...if it weren't for that lye monster! Similarly, the lovely pink pomegranate tea, and other things I've tried along the way, don't work either.