ashen hue vs etiolation

ashen hue

etiolation

noun
  • Paleness produced by absence of light, or by disease. 

  • Blanching of plants, accomplished by excluding the light of the sun; the condition of a blanched plant. 

  • Growth process of plants grown in the absence of light, characterized by long, weak stems, fewer leaves and chlorosis. 

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