Hello, everyone. . . thank you all for answering so quickly.
I should have known it wasn't "inch by inch", but couldn't remember, as I only heard it sung once by a friend of mine in the States many years ago.
As for the "experimental iris garden" I referred to, MMario, I have been crossing different varieties of iris germanica for the last few years to try and create new hybrids and now there are over 300 of them to take care of. If you have ever weeded out iris crowns, you can appreciate how much time it requires, as sometimes the only appropriate tool is that wondrous thing on the end of one's arms known as a hand. I can certainly appreciate the "slug by slug" bit in the song, as slugs really love to eat irises!
I don't happen to have RUS and would very much appreciate it if you have time to transcribe it, Mrrzy. Hope the sick twin will be well soon and that the well one won't catch whatever bug it is. . .