perennial vs shrub

perennial

noun
  • A plant that is active throughout the year, or has a life cycle of more than two growing seasons. 

  • A thing that lasts forever. 

  • A person or thing (such as a problem) that appears or returns regularly. 

adj
  • Lasting or remaining active throughout the year, or all the time. 

  • Appearing or recurring again and again; recurrent. 

  • Continuing without cessation or intermission for several years, or for an undetermined or infinite period; neverending or never failing; perpetual, unceasing. 

  • Of a plant: active throughout the year, or having a life cycle of more than two growing seasons. 

  • Appearing again each year; annual. 

shrub

noun
  • A woody plant smaller than a tree, and usually with several stems from the same base. 

  • A word mispronounced by replacing some consonant sounds with others of a similar place of articulation due to interference from one's knowledge of an indigenous Kenyan language. 

  • A liquor composed of vegetable acid, fruit juice (especially lemon), sugar, sometimes vinegar, and a small amount of spirit as a preservative. Modern shrub is usually non-alcoholic, but in earlier times it was often mixed with a substantial amount of spirit such as brandy or rum, thus making it a liqueur. 

verb
  • To mispronounce a word by replacing some consonant sounds with others of a similar place of articulation due to interference from one's knowledge of an indigenous Kenyan language. 

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