petunia vs violaceous

petunia

adj
  • Of a dark purple colour, like that of some petunia flowers. 

noun
  • Any of the flowering plants of genus Petunia, of which most garden varieties are hybrids. 

  • a homosexual 

  • A dark purple colour, like that of some petunia flowers. 

violaceous

adj
  • Violet-colored. 

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