This is one of the Child Ballads (#39), originating in the Scottish Borders. It’s definitely one of the “big” songs.
The story revolves around the rescue of Tam Lin by his true love from the Queen of the Fairies. While this ballad is specific to Scotland, the motif of capturing a person by holding him through all forms of transformation is found throughout Europe in folktales. - Wikipedia
Here’s a great contemporary version from Anaïs Mitchell and Jefferson Hamer.
Tam Lin
Janet sits in her lonely room
Sewing a silken seam
And looking out on Carterhaugh
Among the roses green
And Janet sits in her lonely bower
Sewing a silken thread
And longed to be in Carterhaugh
Among the roses red