"That's where, I think, I changed for that 'Grande Vallée' subject [a large series of 'natural' paintings, Joan painted during 1982-83], which was really not a subject - the 'Grande Vallée' was a [wild vast] place where this Gisele Barreaux [composer] played with her cousin when they were children, and the cousin, aged 28, died of cancer. And she told me he said to her [when he was dying in 1982], 'If we could only return to the Grande Vallee once again,' as he was dying. I mean, that was what that was all about, so that was a subject of.. .You know, it was the summer my sister died - the same week - and we went to the Manet show. [in '82].. ..when I started the 'Grande Vallée'.. .And I was stuck on a subject, and I thought, 'This is very true and very simple,' and I thought, 'Shit, I'll paint the Grande Vallée for her.' And now, I got her to tell me about it, and it was green and blue, and it was just a vast sort of territory outside Nantes [in Brittany, France]. And so that's how I got started on that whole series."
January 1, 1970
https://en.wikiquote.org/wiki/Joan_Mitchell