Aaron's rod vs king's crown

Aaron's rod

noun
  • Hylotelephium telephium (syn. Sedum telephium; orpine, livelong, or live-forever). 

  • A rod-shaped molding decorated with an entwined snake, and sometimes leaves, vines, and/or scrolls. 

  • Goldenrod, the Solidago genus of North American plants with yellow flowers. 

  • Verbascum thapsus, the great mullein, common mullein, or hag-taper. 

king's crown

How often have the words Aaron's rod and king's crown occurred in a corpus of books? (source: Google Ngram Viewer )