Urban Jungle logo

Fall 2012

Urban Jungle

The changing natural world at our doorsteps | Illustration and text by Patterson Clark      

September 25, 2012

Milkweed fruits: Pods of plenty


As September winds down, milkweed pods dry out and split open, releasing flat, brown seeds carried aloft by a white, silky fuzz known as milkweed floss.

The hollow fibers are coated in wax, making them waterproof and buoyant, a quality exploited during World War II after the Japanese occupation of Java cut off supplies of kapok, a fluffy plant fiber used in life vests. (Today's vests use synthetic fibers.)

To fill the gap, defense contractor War Hemp Industries enlisted American schoolchildren to scour the September landscape for ripe milkweed pods, paying kids 15 cents to fill an onion bag with pods. Each open-mesh bag held about a bushel, or 600 to 800 pods. Two bags provided enough floss for one life vest. More than 1.5 billion pods were collected to make 1.2 million life vests.

Francis Joey Wilson Jr., who was 10 years old in 1944, remembers his father tipping him off about a poster promoting the pod harvest near their home in Upper Marlboro. "All my friends jumped on our bikes and took off for the post office to read the notice for ourselves," writes Wilson. Later, his bags full of pods were collected behind the post office and hauled away by a big truck. "They were paying about 5 cents a pound," says Wilson.

These days, milkweed pods are worth about 55 cents a pound, and they are still collected by people toting onion bags through the North American countryside. The floss is harvested to help fill pillows, comforters and stuff into jackets.

Milkweed floss is best used in combination with goose down. Floss by itself clumps together after being washed, but when mixed with down, floss smoothes out the texture of down without compromising down's other qualities. Floss is about half as costly to produce as down.

Milkweed pods provide more than just fibers: Their seeds yield an omega-7-rich oil. The Nebraska company Natural Fibers extracts the oil for a balm it sells as an anti-inflammatory. Although the FDA has not evaluated the balm's claimed benefits, the agency did reject a proposal by Natural Fibers in 2009 to recognize milkweed-seed oil as a new dietary ingredient, noting the presence of toxins in milkweed and questioning the safety of a proposed use of organic solvents to extract the oil.

Herb Knudsen, president of Natural Fibers, says the balm isn't extracted with organic solvents. "We cold-press the oil," mashing 200 pounds of seeds an hour in a seed press at room temperature.

Knudsen, 71, former vice president of new ventures at Standard Oil of Ohio, acquired the energy company's experimental "Milkweed Project" in 1987, making it his own. He downplays presumed toxins in milkweed-seed oil: "Their amounts are at such low levels that they do not harm anyone," but proving that to the FDA would be prohibitively expensive.

"Topical applications do not need FDA approval," says Knudsen, who rubs milkweed balm into his osteoarthritic hip that was due for replacement. "But the benefits of the oil have kicked that can down the road for now."

Sources: The Erie County Independent, Toxicological Sciences, New Crops, University of Nebraska

Common Milkweed pod, Asclepias syriaca

Asclepias syriaca