In December 1941, the U.S. was bombed by Japan and pulled into World War II. During the weeks that followed, Americans were told to get ready to give something up: rubber. The U.S. was cut off from 90% of the world’s rubber supply, tapped from rubber trees in Southeast Asia. So everything from men’s work boots to car tires became tightly controlled commodities.
It’s why if you look back at news coverage from that month, you’ll notice a furtive excitement about a strange idea: making rubber from the milky white substance—which is actually latex—inside a dandelion. The New York Times declared “DANDELION LOOMS AS RUBBER SOURCE; Farm Research Council Asserts Kok-Sagyz, Russian Plant, Would Ease Our Shortage.” By 1943, dandelions were planted across 48 states. By 1944, we successfully made tires out of them.
But then the war ended, rubber supplies normalized, and dandelion rubber never took off.
Eighty years later, as the world turns toward sustainability, dandelion rubber is back. While the concept has been percolating in laboratories for years, dandelion rubber has reappeared for the first time in a new casual shoe from Cole Haan called the Generation Zerogrand II ($130). Cole Haan used a patent-pending process to convert dandelions into rubber that’s mixed into its EVA foam midsole (the chunky, bouncy bottom of a sneaker made of high-tech plastics). This “FlowerFoam” makes up at least 25% of the shoe’s midsole.
“The extraction process is not dissimilar from rubber,” says David Maddocks, brand president of Cole Haan. “With rubber, you tap a tree like making syrup. With this . . . you take the plant. There’s a heat process to extract [latex], and what’s left is biowaste—old plants.”
While much of the rubber found in shoes today is synthetic, you’ll still find considerable amounts of natural rubber, farmed from trees, listed in the environmental reports from companies like Nike. Farming this rubber is not an issue unto itself, but rubber trees are clones, making them particularly susceptible to disease. And the rubber plantations have been among the greatest drivers of deforestation. Between 2000 and 2016, land dedicated to rubber plantations doubled to 12.9 million hectares.
The shoe industry has been aggressive in chasing down more sustainable practices to lower its ecological footprint on every material, including rubber. Both Nike and Adidas have developed processes to grind up old shoes and use the material in new ones. Nike calls its rubbery substance Grind, while Adidas calls its process Loop.
Maddocks admits that Cole Haan’s sustainability programs have not reached the level of maturity needed to support circular product lines, yet. However, he’s reasonably excited about the adoption of dandelion rubber into the company’s supply chain.
“The neat thing about dandelions [is that] they’re a renewable resource that grows dense and fast,” Maddocks says. “They grow in areas where you couldn’t farm other products. You don’t need to cut down big groves of trees to grow them.”
Adding the rubber allows the company to cut down on its use of EVA polymer. And depending on the actual performance and experience Cole Haan wants out of its FlowerFoam midsole, it can incorporate more or less dandelion rubber into the EVA mix. In fact, Maddocks claims that the dandelion content in Generation Zerogrand II’s FlowerFoam “is much higher than 25%,” but that the company is rounding down for marketing purposes of its new sustainability initiatives.
“We want a simple reference point, that a sustainable product from Cole Haan has 25% by weight of either naturally derived or recycled content,” Maddocks says. “We exceed that in many places. But we want a threshold that’s easy to understand for consumers. So when they see ‘sustainable’ they know what that means.”