Rock wool and potted plants.

The question on rock wool brings up something I've wondered about for 
years. I've thought plants come in planters so that shops could charge 
more for them. Is there a recommended way to handle these potted plants? 
Bury the whole plant, remove immediately, remove after a while?

-Don Pickerel- 

P.S., for those wondering about my palludarium construction project, it's
been on hold because of almost constant travelling for the past 4 months.
Hopefully this weekend....