meadow saffron vs pencil tree

meadow saffron

noun
  • Colchicum autumnale, a fall-blooming colchicum. 

pencil tree

noun
  • Euphorbia tirucalli, a tree found in semi-arid tropical climates 

How often have the words meadow saffron and pencil tree occurred in a corpus of books? (source: Google Ngram Viewer )