Water a plant that has a recurring pattern of 4 or more letters in its name

You may define a pattern where some text is repeating word-by-word throughout the string. Once captured, the text in a capturing group can be then referenced in a regular expression with \N where N is an order of the capturing group numbered from 1. E.g. \1 will match literally the text captured with the first capturing group:

console.log(!!"foo foo".match(/(\w*)\s\1/gi)) // true 

console.log(!!"bar bar".match(/(\w*)\s\1/gi)) // true 

console.log(!!"foo bar".match(/(\w*)\s\1/gi)) // true 

console.log(!!"foo bar foo bar".match(/(\w*)\s(\w*)\s\1\s\2/gi)) // true 

console.log(!!"foo foo bar bar".match(/(\w*)\s(\w*)\s\1\s\2/gi)) // false