For the original publication of MacColl's The Gardener, see The Singing Island, 1960, 33. The tune came from Ewan's mother (there called Betsy Henry); her text had evidently been fragmentary, and was bulked out from material collected by Gavin Greig (see Stewie's post earlier in this thread).

I haven't heard Jean Redpath's rendition. If the tune is the same as MacColl's, then he would be her source.