Google Books shows the text:

Folk Song of the American Negro by John Wesley Work (Nashville: Fisk University, 1915), page 11.

Frankly, the song doesn't sound like a true "folk" song to me. Despite the dialect, it feels a little too genteel. The imagery, the sentiment, and especially the carefully constructed parallelism of the 4 stanzas, make me think this was written by someone who had read and admired a lot of published poetry.

--Which is not to say it couldn't have been written and sung by an African-American. I only mean, it didn't pass through many hands from poet to publisher, and wasn't much affected by oral tradition.