I'm pretty sure this is the original version, extant in medieval England and still used by folk singers as a round (ie song which, sung by different voices starting the same melody at different times, provides its own harmony). Every line ends with the same rhyme, which makes for a pleasing choral blend when sung.

Rose, rose, rose red,
Will I ever see thee wed?
"I'll marry you", she said,
"When thou art dead".

DCDA
DDEEFGFE
aBaBCBa
FEDA

Those are the pitches for each line. It's in 2/4 and lines 1 and 4 both only contain crotchets (quarter notes). There are 2-note melismas on "thee" in line 2; and on the second syllable of "marry" in line 3. Small case "a" stands for the higher octave. Any musician worth his salt ought to be able to work the rest out from this!

Enjoy.