hickwall vs soldier's woundwort

hickwall

noun
  • A European green woodpecker, Picus viridis. 

  • A lesser spotted woodpecker, Dryobates minor. 

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 hickwall and soldier's woundwort occurred in a corpus of books? (source: Google Ngram Viewer )