Few thought Paul Schrader would ever match the success of his early scripts for "Taxi Driver" and "Raging Bull" — but suddenly, in his 70s, the writer-director is back at the top of his game.

His fear now, as he appeared at the Venice Film Festival with his latest movie "Master Gardener", starring Sigourney Weaver and Joel Edgerton, is whether he will ever be able to make another.

"I can't breathe," the 76-year-old bluntly told AFP at the festival, visibly struggling. "I couldn't direct a game of miniature golf right now."

The mysterious illness — doctors are unsure whether it is his lungs or his heart — came on earlier this year just as he was finishing "Master Gardener".

"When I got to hospital, it turned out I'd been directing for a week with influenza — at night in Louisiana," he said. "I could be back in hospital tomorrow."

The film follows a gardener with an extremely dark past, trapped in a love triangle with powerful racial overtones.

"We don't think of Paul Schrader as writing big parts for women. But he's created, at this time in his life, two very red-blooded, sexual women," Weaver told AFP.

"It's exciting but also difficult to watch," she added.

"Master Gardener" completes a loose trilogy of films about tough, damaged men seeking redemption, which began in 2017 with "First Reformed" (amazingly, his first to earn an Oscar nomination) followed by "The Card Counter", which also premiered at Venice last year to strong reviews.

Edgerton, an Australian who has quietly become one of the most sought-after actors of the moment, said he was a huge fan of "First Reformed" when it came out.

"Certain directors as they get older, you feel their better work is behind them. But I was watching a guy who had one of his greatest works right there," he told AFP.

"Like a lot of guys in my generation, we all wanted to be De Niro, Pacino… and Paul was very much one of the centers of that era. He's an important guy to me, and then I get to work with him and that felt very special," Edgerton added.

'Forgiveness and rebirth'

The other star — relative newcomer Quintessa Swindell — said "Master Gardener" challenged her ideas about cancel culture.

"I didn't think it would have such an intense theme of forgiveness and rebirth," she told AFP.

"Playing her gave me the emotion of how it truly feels to move on from someone's past, and that was the most insane feeling."

Schrader knows the film's racial politics — which gradually emerge through the film — could cause controversy in "our woke era where everything is examined as to whom it gives offence.

"Maybe it's not realistic, maybe it could never happen, but that's what art is for — to create hypotheticals," he said.

He added that he never planned to make a trilogy.

"When I started writing the third one, a friend said it's a trilogy and I said no, no, it's not. But then I saw it is."

Schrader went through his share of commercial and critical flops until his recent run, and credits new technology with allowing to work more cheaply and therefore free from studio interference.

But the film industry is still in a tough spot, he said.

"The good news is that anyone can make a film now," he said.

"But no one can make a living."