hawthorn vs mayblossom

hawthorn

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

mayblossom

noun
  • The flower of the hawthorn, Crataegus, especially the common hawthorn, Crataegus monogyna. 

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