hewhole vs soldier's woundwort

hewhole

noun
  • The European green woodpecker. 

soldier's woundwort

noun
  • Achillea millefolium or common yarrow, a flowering plant widespread in the temperate Northern Hemisphere, formerly and sometimes used to stanch the flow of blood. 

How often have the words hewhole and soldier's woundwort occurred in a corpus of books? (source: Google Ngram Viewer )