I used Dutch rush on a lily petal a few weeks ago, not only to smooth it but to create a subtle texture (p. 230):
For more on Dutch rush, see Grinling Gibbons and the Art of Carving, pp. 202-4.
p. 234. Here is the magnificent lump next the the central area of the carving, of which it is the survivor. The platform with a nail in it once held the bunch of forget-me-nots you can see on the left hand side of the archive photograph:
p. 235. I was able to identify the outline of the middle layer of the carving, here outlined in red. The forward layer of forget-me-nots is outlined in green.
"Sometimes I'd return along the edge of the dizzying cliffs by the sea..." (p. 254):
Near the end of the carving, finishing the bottom layer. "...the creature gives up the ghost and all that's left is the task" (p. 256):
The finished drop, in a niche in the garden wall outside the workroom. A color version of the photo on p. 263.