allheal vs bishop's-wort

allheal

noun
  • Stachys, a genus of plants in the mint family, heal-all, self-heal, woundwort, betony, lamb's ears, hedgenettle. 

  • Valeriana officinalis, a species in the valerian family. 

  • Prunella vulgaris, a species in the mint family. 

bishop's-wort

noun
  • wood betony (Stachys betonica, now Stachys officinalis) 

  • fennel flower or devil-in-the-bush (Nigella damascena) 

How often have the words allheal and bishop's-wort occurred in a corpus of books? (source: Google Ngram Viewer )