Thanks funnyperson I think the plants are growing as weeds along the streets, but that could be just what I imagined when I heard the story. Oh i wish my baby brain would fade so I could remember properly.
I wonder where I've got it from though - maybe a Peter Ackroyd book. I have emailed Gardeners Question Time, maybe someone on there might have heard of something. I would love it to be true too - a little bit of living history. Thanks for your help though - will keep you posted.