Hello George,
VFT, temperate Drosera (most sundews are Drosera and most are *not*
temperate), Sarracenia, and Darlingtonia all have just about the
same dormancy needs. As Kevin Snively pointed out these plants
can be frozen as long as they are ready for dormancy *and* are
insulated from freeze drying air. Snow is really the best for
this but a mulch of leaves will work very good too. Nepenthes
don't really have dormancy at all and grow year round. They tend
too flower in the spring, if large enough. Cephalotus likes to
stay warm but can rot easily during the winter so it should be
kept drier (but not dry!) and a light application of Maneb
fungicide will help.
Dave Evans