Mr Priest has been replaced by Gilbert Vahé, 69, who was head gardener from the start of the site's restoration in 1977 until Mr Priest's arrival. Mr Vahé had retired to a house next door but never, it seems, stopped peering over the hedge.
"It was a problem of communication," said the diplomatic Mr Vahé through an interpreter, as he speaks no English.
"Our philosophy had always been to maintain the garden exactly as Monet planted it at the end of his life. That seemed to us to be honouring the spirit of Monet. But there were other ideas."
He [Mr Priest] wanted to take parts of the garden and return them to the way it was earlier in Monet's life.
"Also, in my opinion, the garden envisaged by James Priest was a bit too much like a town garden."
As the under-gardeners undo Mr Priest's work and reinstate Vahé's designs, a well-placed source in the village said: "After 35 years in charge, Gilbert was furious that an Englishman was undoing all his work. "
"He blackened James's name at every opportunity, making it clear that he didn't consider him an appropriate gardener to look after the Monet legacy.
"Gilbert remained extremely powerful - he never really left Giverny at all - and did everything he could to force a change. Eventually he got what he wanted."
It is possible that Kew Gardens-trained Mr Priest, who has had to leave the half-timbered house on the estate that went with the job, didn't help the entente cordiale after he gave some caustic criticism of the staff in a series of interviews.
Dismissing the staff's protestations that they couldn't understand his accent, he said: "I don't think it was because I was British, it was because I was new. They had been used to doing the same thing year after year, because that was what they had always done.
"Some things were fine. The water lily pond needed hardly any change, but elsewhere other things seemed not right: mechanical blocks of colour, jarring red roses in beds that were supposed to be full of cool blues and purples."
In another interview he went further, saying of the walled Clos Normand garden next to Monet's house: 'It was a hotchpotch. They weren't thinking about it. This is the part of the garden where the artist painted his vibrant studies.
"I am experimenting and opening myself up to criticism, I know."
The Mail on Sunday could not reach Mr Priest for comment, but he was correct on the last point.
Last night a terse spokesman for the Giverny Foundation said neither the organisation nor Mr Vahé wished to discuss Mr Priest's departure. She said: "We don't keep records of Mr Priest. He is gone."