I know this is an old thread, but I found it through google. I have some brain sedum I've been cultivating myself. 3 years ago I found a single fasciated stem on a patch of my blue spruce sedum (sedum reflexum). I removed it as a cutting and have been letting it grow in a container. I've also been able to start a few other brain sedums by taking cuttings from this one. In order to keep its shape, the reverted stems have to be regularly removed because they will crowd out the mutated growth. They also haven't bloomed for me yet so far, not sure if they do or if what I have needs to be a bit more mature. I'm in zone 8b (Lakewood, wa) and it is definitely hardy. Survives temps down into the teens with no special care other than making sure it has well draining soil.