When I think of folk rock, I think of the Byrds. Turn! Turn! Turn! written by Pete Seeger in the late 1950s became a number 1 hit by the Byrds in 1965. This song has the distinction as being the #1 hit with the oldest lyrics (Book of Ecclesiastes).
"To everything, turn, turn, turn.
There is a season, turn, turn, turn.
And a time to every purpose under heaven."