Octogenarian philanthropist and retired banker Henry Buhl is listing his Southampton home — replete with sunflower decor — for $6.4 million. Not surprisingly, it has been the site of his annual fund-raiser, the Sunflower Party, for at least two decades.

The sunlit home — named “Girasole,” the Italian word for sunflower — at 298 Narrow Lane has art, upholstery and furnishings all covered in the flower.

Buhl once said in a 1998 interview with the New York Times Magazine that he slept between sunflower sheets, ate off sunflower plates and even had his two maids wear sunflower aprons.

Built in 1985, the seven-bedroom, six-bathroom residence comes with two woodburning fireplaces and sits on 1 landscaped acre. The property also features a tennis court and a pool.

A community activist, Buhl has helped the homeless for decades, but in 2011, when he discovered 80 people living in the sunflower field behind this home, he founded another nonprofit, the Coalition to Protect American Workers & Returning Servicemen & Women.

The listing broker is Andrea L. Ackerman, of Brown Harris Stevens.