The trees they do grow high is a traditional ballad about an arranged child marriage, also known as The trees they grow so high, My bonny lad is young but he’s growing, Long a-Growing, Daily Growing, Still Growing, The Bonny Boy, The Young Laird of Craigstoun, and Lady Mary Ann. The song was very popular in the oral tradition in Scotland, England, Ireland, and the USA from the 18th to the 20th century. Questions about its true age (medieval?), the basis of its story (describing an actual marriage?) and its original author (Robert Burns?) have attracted conjectural claims. This article investigates the shifting narrative of the story over its lifetime and sifts the repeated assertions from the substantiated evidence.