I haven't found that they grow as well unattached (for me anyhow)
I have super-glued them to rock or just recently started using the 2 part epoxy for mounting to larger rock in the tank, and I like what I can do with it.
This is what I did:
My frag was all healed edges so I just picked a side and embedded it, it's not beautiful but it will cover with corraline soon enough. My only suggestion would be to use the purple epoxy, the stuff I used is clay-coloured and a friend asked me why I had put silly-putty in my tank!