bullace vs damson plum

bullace

noun
  • A small European plum (Prunus interstitia, syn. Prunus domestica subsp. insititia). 

  • The bully tree. 

damson plum

noun
  • A deciduous tree, Prunus insititia, native to Eurasia and related to the plum. 

  • Chrysophyllum oliviforme, the satinleaf. 

  • The edible fruit of these trees. 

  • Syzygium cumini, jambul, native to south Asia. 

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