Can't agree with Brad's ID, unfortunately. The spines are different, for one thing. Judging by the newer growth, I might go with whatever Cereus peruvianus is currently called.

Christopher

Christopher, I don't recall that C. p. is that blue.

Thank you all. I love it no matter what it is and if I can get it to bloom someday then we'll know fore sure. I've always wanted a blue cactus and the slightly different growth that some areas of this one made it all that much more interesting to me.

This other pot was also there. Not sure if it's the same plant or not, but could help identify.

Nicholas, what does that plant tag say?

Said the same as mine just Cereus monstrose. Then a bunch of vague care directions.

Jeff...indeed they can be, my friend. Saw some big blue C. peruvianus beasts in Florida, where they thrive.

Christopher