devil's nettle vs yarrow

devil's nettle

noun
  • Achillea millefolium or common yarrow, a flowering plant native to temperate regions of the Northern Hemisphere. 

  • Dendrocnide sinuata (synonym: Laportea crenulata), a species of nettle in the family Urticaceae found in Australia and South Asia. 

yarrow

noun
  • Common yarrow, Achillea millefolium, the type species of the genus. 

  • The green woodpecker, Picus viridis. 

  • Any of several pungent Eurasian and North American herbs, of the genus Achillea, used in traditional herbal medicine. 

How often have the words devil's nettle and yarrow occurred in a corpus of books? (source: Google Ngram Viewer )