Is the quote liberty when it begins to take root is a plant of rapid growth also proverb?

No, the quote "liberty when it begins to take root is a plant of rapid growth" is not a proverb. It is a quote from Thomas Paine, an English-American political activist, philosopher, political theorist, and revolutionary. The quote is from his pamphlet "Common Sense", which was published in 1776 and was influential in the American Revolution.