May blossom vs hawthorn

May blossom

noun
  • A species of flower-bearing hawthorn with edible berries, Crataegus monogyna. 

hawthorn

noun
  • Any of various shrubs and small trees of the genus Crataegus having small, apple-like fruits and thorny branches 

How often have the words May blossom and hawthorn occurred in a corpus of books? (source: Google Ngram Viewer )