devil's nettle vs hickwall

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. 

hickwall

noun
  • A European green woodpecker, Picus viridis. 

  • A lesser spotted woodpecker, Dryobates minor. 

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