Flash Company, I'm assuming that the "Wallflowers, wallflowers growing up so high" song that you mentioned asking the Girl Guides and Brownies about was this one that is in the DigiTrad: @displaysong.cfm?SongID=7605

If so, was this in England? And if so, when {meaning what decade}?

I'm interested in knowing this because imo most Girl Scouts and Brownies in the USA nowadays wouldn't know that Wallflower song.
I didn't know it when I was in a Brownie troup more than five decades ago and I don't get a sense that "Wallflower" is known in the general US children's population.

I guess that another point that could be added to the 30 minute talk about folk songs that Raggytash has been asked to give-folk songs that may be very familiar to one person may be totally unfamiliar to others, or may have different words. {It's interesting though that tunes appear to be more stable than lyrics. Do others agree that this is so?}

But back to that Wallflowers song- I'm trying to think of what song would be one you could use as a substitute for the Wallflower song {as an example of a folk song that they would know}. Maybe "Found A Peanut"? Another song that might work for American kids would be the way children and youth have changed "Rudolph The Red Nose Reindeer" [adding a response to the end of the line such as "Ruldolph the red nose reindeer/had a very shiny nose-like a like bulp}...That same thing is done for the song "She'll Be Coming Round The Mountain"...

And even if the audience made up of older folks, these types of songs might be fun additions to your presentation.   

Anyway, best wishes on your talk, Raggytash!