I have a 5 foot tall pencil cactus. I put it outside and was unable to bring it in when temperatures dropped to freezing. It is so severally frostbitten. What to do?
It can take days or even weeks for frost damage to appear.
Keep the plant in a normal indoor environment.
You can prune away the dead or damaged plant material. Use gloves, as the sap can cause irritation and reactions can be serious in some people.