According to the Internet source given below, Margarete Jehn (nee Rollny) is a German author and songwriter born in Bremen.
She studied music in Bremen (violin, voice and guitar). At the age of 15 she wrote her first song cycle Im Jahrkreis,. She sang in a Bremen- Vegesack youth choir and then lived in Sweden for some time . In 1962 she wrote her first radio play Der Bussard über uns.From 1968 to 1982 Jehn was editor and translator of Scandinavian plays for Südwestfunk. In the 1980's she performed with the folk group Simplex as a singer and instrumentalist.
She wrote the words and music of Grün, Grün, Grün (M. Jehn).

Websites:
	Margarete Jehn	Biography by wikipedia.org.