blueberry vs bog bilberry

blueberry

noun
  • The shrub of the above-mentioned berry. 

  • A dark blue colour. 

  • An edible round berry, belonging to the cowberry group (Vaccinium sect. Cyanococcus), with flared crowns at the end, that turns blue on ripening. 

adj
  • Of a dark blue colour. 

verb
  • To gather or forage for blueberries. 

bog bilberry

noun
  • A shrub native of the cool temperate areas of northern hemisphere, Vaccinium uliginosum, and the berry of that shrub. 

How often have the words blueberry and bog bilberry occurred in a corpus of books? (source: Google Ngram Viewer )