hawthorn tree vs mayblossom

hawthorn tree

noun
  • A tree 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 tree and mayblossom occurred in a corpus of books? (source: Google Ngram Viewer )