achillea vs thousand-leaf

achillea

noun
  • Any of various plants of the genus Achillea 

thousand-leaf

noun
  • Achillea millefolium or common yarrow, a flowering plant widespread in the temperate Northern Hemisphere, featuring finely divided leaves. 

How often have the words achillea and thousand-leaf occurred in a corpus of books? (source: Google Ngram Viewer )