artichokey vs when Hell freezes over

artichokey

adj
  • Resembling, or having a flavor of, artichokes. 

when Hell freezes over

adv
  • Never; not in this lifetime or a time in the unforeseeably distant future; not a chance. 

How often have the words artichokey and when Hell freezes over occurred in a corpus of books? (source: Google Ngram Viewer )