I'm in So Cal, and we just had a freeze too! In the past, I've had
good luck - as a last ditch efffort - using compost to save plants. I
put a shovel or two of compost at the base of the plant (cover the
rootstock) so you have a small mound covering the bottom half of the
plant. The compost protects the bottom part from frost and keeps it
just slightly warmer. I'm sure this won't help if we have snow!
Aren't we supposed to cover roses with burlap if you're expecting snow?

If you have obvious frost damage on plants I would leave them alone for
now. The top half of all my succulent plants, especially the jades,
are all wilted and frozen. By leaving the damaged foliage you are
(hopefully) protecting the undamaged plant underneath. When it is warm
again, I'll have to go out and start cutting back the damage.

You can check to see if the wood is ok by scraping the bark off with
your nail. If it is still green you're ok. If not, I would still wait
until spring before I did any trimming. Good Luck, Laura