Here in SE Texas, we had 3 days of below-freezing weather... practically unheard of around here! Most of the plants have been tucked away for the winter... and I've been trying to protect a couple of palms that are in huge planters. I've had this cactus for around 6 years and never did anything to protect it. It was around 6 foot tall. This is what last weekend's weather did to it. :'( Damaged cactus ( photo / image / picture from cherylad's Garden )
That short stem near the soil surface looks fairly unharmed, maybe it will pull thru. My neighbor has a 4' tall and wide Prickly Pear cactus that appears to have thrived in the 12-15° we had three nights last week.
There's actually a smaller cactus in a pot at the base of the big one. It didn't get any damage. Perhaps because the big one "saved" it?