Persian lilac vs chinaberry

Persian lilac

noun
  • Syringa × persica, a shrub in the olive family (Oleaceae) 

  • Melia azedarach, a tree in the mahogany family (Meliaceae) 

chinaberry

noun
  • Actaea rubra, a poisonous herbaceous flowering plant in the family Ranunculaceae, native to North America. 

  • The bead tree or azedarac, Melia azedarach, a deciduous tree in the mahogany family Meliaceae, native to India, southern China and Australia, or its fruit. 

  • The soapberry (genus Sapindus, especially Sapindus saponaria), native to the Americas. 

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