mandarin orange vs orange grove

mandarin orange

noun
  • A small citrus tree (Citrus reticulata) with fruit resembling the orange. 

  • The fruit of this tree, smaller than an orange and oblate. In daily usage, it may include other similar citrus fruits like Citrus unshiu (satsuma or mikan) Citrus tangerina (tangerine). 

orange grove

noun
  • A group of cultivated orange trees 

How often have the words mandarin orange and orange grove occurred in a corpus of books? (source: Google Ngram Viewer )