The Spaniards who colonized the archipelago more than 300 years ago called it Isla del Fuego (Island of Fire) because of the eerie glow cast by millions of fireflies that swarmed around the molave trees at night.
Feared by many Filipinos for its sorcerers, known locally as "mambabarangs," the island has also earned a reputation for the apparently incredible powers of its local healers, or "mananambals."
A 30-minute ferry ride from Dumaguete City on central Negros Island, the tiny, pristine island skirted by white beaches and surrounded by clear blue water has become a major draw card for believers and the curious alike.
Among Siquijor’s better known clients is said to be Imelda Marcos, the former first lady and widow of the late dictator Ferdinand Marcos.
Locals tell of how a curse was put on her in the 1970s during the building of the San Juanico bridge that connects the central islands of Samar and Leyte and which was a pet project of the late dictator.
The story goes that a "mermaid" was injured during the construction work and in retaliation Imelda was cursed with a spell that made scales grow on her legs.
Imelda sent a helicopter from the presidential palace in Manila to fetch a powerful Siquijor healer called Boscia Bulongon, who cured her and was paid handsomely.
Bulongon returned to the island and buried the money but about two decades later was beaten to death by her grandson because she refused to give him the money. Locals say he used a piece of wood to kill her because the woman was invulnerable to bullets and knives.
From the rich and famous to the curious Siquijor is attracting Filipinos and foreigners – especially around Easter – for what is commonly referred to as the "Witches Festival" when people buy potions for everything from improving their sex life to curing terminal illnesses.
The healers begin collecting the herbs, plants and sea creatures that go into their potions each Friday after Ash Wednesday, 40 days before Good Friday.
On Good Friday they will have gathered everything they need to make potions for the coming year, and on Saturday they start to chop and mix the ingredients.
Nothing will be collected again until Ash Wednesday the following year.
While the Philippines is majority Catholic, it remains a mystery why the rituals of a craft often associated with the darker arts should be so closely linked to Christian tradition.
"The process of making potions is tied in with the resurrection of Christ. It’s a rebirth of power," explained Pedro "Endoy" Tumapon, a respected local herbalist who, at 80, is still fit and has customers from all over the Philippines who buy his herbal medicines.
"That is why it is done during Holy Week."
Asked why, he answered simply: "That’s just the way it is."
Ponce learned his craft from his father, who had learned it from his father, who learned it from his.
"Nothing is written down," he said, his daughter Diosdada acting a translator.
Sitting outside his modest bamboo hut as women grated cassava and his grandchildren played nearby Ponce said he had never visited a "real" doctor.
"They come to me," he said smiling through his few remaining teeth.
He told the story of a Danish doctor with an incurable rash on his hands who read about the healers of Siquijor and flew from Denmark for treatment.
"He found me and asked if I could do anything for him. I told him I have everything here.
"I rubbed oils into his hands and within a month the rash had gone. He could not explain what happened but he was a doctor."
Then there was the woman from New Jersey who had a bloated stomach.
"Doctors could not help her," he said sitting under a crucifix with Christ bleeding from the hands and feet. "She read about me in a magazine and flew out. I cured her too. That was in 1992. She still sends Christmas presents."
The day AFP visited Endoy in his nearby village home, Girlie Maing, 48, from Zamboanga was visiting. Diabetic since her early 20s she said she had spent much of her life on daily insulin shots just to stay alive.
A believer in magic, she said her mother died from a curse placed on her by an adversary in a land dispute. "She was told that her stomach would grow when the tide goes out and settle when it comes back in again," said Maing.
"This went on for months and months. Doctors could do nothing and she eventually died."
Four years ago a friend from Siquijor told her about the healers and suggested she visit. "So I came to see Endoy to see what he could do. Today, I am cured and my doctors say it is a miracle. They can’t explain it."
Breaking off part of the woody, brown nest he rubbed it between his fingers, squeezing out a wet, bright green substance which he said was good for breast cancer among other things.
His son-in-law, Noel, who was a non-believer but is now learning from Endoy, said he had cysts on his eyes but after using the green substance from the nest they disappeared.
Endoy who has been practicing herbal medicine most of his life is now cataloguing many of the herbs he uses for the Department of Environment and Natural Resources.
"It is wrong to call us white witches," he said. "We are herbalists. And we cure. Everything you want is here in the forest or in the sea."
But does he believe in sorcerers and black magic?
"Yes, because the people who have been cursed come to me for help," he said, telling the story of a man who passed live beetles and another who vomited bumblebees after being cursed.
"I know science can’t explain these things, that is why some people call it witchcraft. But what we practice is natural medicine."
No one on the island will admit to being a sorcerer or a black witch but for P6,000 ($110) and upwards, depending on what harm you want to inflict, one can be found.
These so-called witches guard their privacy and refuse to give interviews. But in the hills are said to be caves where pictures of the victims of curses can be found.
Adultery and land disputes are common reasons for hiring the services of a black witch.
Their rituals are conducted at night usually during the full moon.
"There were a lot on the island but during the war (World War II) most of them fled," Endoy said. "Locals found an excuse to burn their homes." – AFP