When low temperatures are associated with high level of humidity, shrub like Sage or Lavander suffer till to die.
The water inside of branches cannot evaorated and become ice and when this physical phenomenon happens the volume increase till to hurt the wood itself.
Here some photos of this irreversible event on a Sage:
To avoid or prevent this damage it’s important to have a well drained soil without water collect.
Useful it’s to put plants little elevated, compared to the ground level, and, in any case, choosing plants in according with our area, temperatures and humidity.