common yarrow vs soldier's woundwort

common yarrow

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

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