My outdoor pencil cactus has turned brown after a surprised freeze in South Texas, they are several feet tall. Do I just cut them down almost to the dirt in the pot or what? Never had any dealings with these plants till we moved here. Thanks for any help you can offer.
Cacti are quite sensitive to freeze damage, so the aboveground parts are most likely not going to recover. However, there's always a chance that they could recover or could grow back from the roots. Pruning now could cause more damage if the weather turns cold again, so the best option is to wait and see. If the cacti start growing again in the spring, you will be able to cut out any mushy portions at that point.
If the stems turn mushy all over, though, they are dead and should be cut off at the base in the hopes of saving the roots.