The men traveled Highway 101 in budget rental cars, stopping at remote state parks with stunning vistas as they snaked their way along the Northern California coast. To a casual observer, Byungsu Kim, 44, Youngin Back, 45, and Bong Jun Kim, 44, might have seemed like yet another group of road-tripping tourists on the famously scenic highway, marveling at the towering redwoods and the waves crashing against dizzying bluffs.

But wildlife detectives who had been tracking the three South Korean nationals since they arrived at Los Angeles International Airport in October 2018 noticed that their rented minivan was full of boxes and rubber totes — not the typical gear for a week-long vacation. The men chatted on handheld radios as they explored the parks and always seemed to wear bulky backpacks. Watching from a distance, wardens saw what they were stuffing inside: Dudleya succulents, which have spiky blue-green leaves immediately recognizable to anyone on Pinterest and Instagram.

On Friday, the three men were charged with stealing more than $600,000 worth of wild succulents from public lands and attempting to smuggle them into Asia, where a lucrative black market for the trendy houseplants is flourishing. The bust, which led to the seizure of more than 3,700 plants, was part of a larger crackdown on succulent poachers who are believed to be part of international smuggling rings. Overseas, the plants retail for as much as $50 each, according to wildlife officials, and are a highly prized consumer good among the growing middle class.

“Right now these plants are a boom in Korea, China and Japan,” Pat Freeling, a game warden with the California Department of Fish and Wildlife, told the Guardian last year. “It’s huge among domestic housewives. It’s a status thing.”

Frequently found in third-wave coffee shops, on top of wedding cakes or alongside mid-century modern furniture in millennial-chic apartments, succulents are ubiquitous enough to be considered a design cliche. But rather than dying down, the succulent craze has gone global, with potentially disastrous effects. According to the Guardian, the plants have become so popular in Korea and China that they are sold in stores the size of multiple basketball courts.

Dudleya, a genus encompassing dozens of species native to the West Coast, plays a crucial role in the delicate ecosystems of California’s wind-battered cliffs, where they help to fight erosion. Some of those species are considered threatened or endangered, and the population has recently been devastated by wildfires. Now, experts worry that the rarest types of Dudleya could be driven to extinction if poachers keep ripping out thousands at a time.

Though Dudleya can be grown in nurseries, they take years or even decades to mature, and commercial growers have struggled to keep up as succulent mania spreads from South Korea to China. Kang Suk-Jung, who owns a nursery in Hojawon, South Korea, told NPR last year that once Chinese customers started buying succulents, “even tens of thousands of plants would not meet the demand.” Besides, he said, it was tough to replicate the look of the most sought-after species.

“Those plants had survived in their natural habitats for decades through rain and wind,” he said. “That’s what makes them beautiful. You can’t grow succulents like them with artificial measures.”

Until December 2017, authorities had no idea that thousands of succulents were being stolen from state parks. Then, a frustrated postal customer called the California Department of Fish and Wildlife’s hotline with an anonymous tip. The woman had grown exasperated while waiting to mail a Christmas package at the tiny post office in Mendocino, Calif., the Mercury News reported. A man ahead of her was shipping 60 packages to China, and the line snaked outside the door. Curious, she asked what was in the boxes.

“Shhhh, something very valuable,” the man responded, putting one finger to his lips.

“Where did you get them?” the woman asked. The man pointed to the ocean.

Freeling, the game warden who received the tip, asked U.S. Customs and Border Protection to X-ray the packages. The tipster had suspected that the boxes held abalone, a type of edible sea snail often illegally harvested by divers in Northern California. Instead, they turned out to contain dozens of succulents, he told NPR. That on its own wasn’t necessarily illegal, but Freeling had a hunch he had stumbled onto something bigger. Sure enough, within a month, he got a call about a suspicious man wandering the cliffs with a backpack. It was the same man he had seen on surveillance footage from the Mendocino post office, and the pack was stuffed with succulents.

“I confronted him and asked what he was doing, and he said it was for his garden. He had another person as a lookout,” Freeling told the South China Morning Post’s magazine. “This was my first time dealing with plant poaching and I didn’t know what I was doing, and I didn’t search his vehicle for more plants. I believe now that there were more.”

Other busts followed, though the fact that poachers typically work in remote and isolated spots gave them plenty of cover. A woman who was on a day trip to Big Sur with her family pulled over in a highway turnout, noticed a couple climbing up a cliff with bags full of succulents and jotted down their license plate number. Another tipster reported a suspicious minivan parked along the highway, which turned out to be filled with plants. And after postal workers in Trinidad, a seaside community in California’s Humboldt County, noticed an unusually large number of packages that traveled through their office were headed to Asia and seemed to be leaking soil, authorities raided a rental cabin and seized thousands of Dudleya from suspected smugglers.

In 2018, as they became aware of the scale of the threat to natural succulent habitats, wardens started looking closely at Byungsu Kim, who operated a nursery in San Diego County, and who they suspected was exporting Dudleya plants to Korea. Customs officials tipped them off to his arrival when he flew into Los Angeles International Airport in October 2018, and investigators began conducting surveillance as he drove north with the two other men, according to a criminal complaint filed in the U.S. District Court for the Central District of California.

The trio allegedly made repeated trips to three state parks in Northern California, filling up their two rental cars with Dudleya plants before returning to the nursery to unload their harvest. They had just dropped off approximately 3,715 succulents at a commercial exporter’s warehouse when the wardens pulled them over.

When questioned, Back and Bong Jun Kim admitted to illegally collecting wild plants, according to a probable cause statement. But while Bong Jun Kim is in federal custody, prosecutors said on Friday that Back and Byungsu Kim fled the country after their arrests and are considered fugitives. The men also face charges in Del Norte County Superior Court in California, and it wasn’t immediately clear how two of them had been able to leave the United States.

If convicted on federal charges of conspiracy to export plants that were taken in violation of California law, and attempting to export plants in violation of state law, each of the men faces 10 years in prison.

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