Good Natured in St. Charles: How milkweed floss saved lives in wartime

Let’s take a moment, shall we, during this festive time of year, to celebrate a little plant we call milkweed.

Once snubbed as “just a weed,” especially in its common form, this native species – actually a group of native species – became a media darling when we learned its importance in the life cycle of the monarch butterfly. While adult monarchs can take nectar from a wide variety of flowers, monarch caterpillars must feed only on milkweed plants in the genus Asclepias.

Besides precise nutrition, milkweeds offer the little larvae a precious gift: protection from certain predators in the form of cardenolides. You might be able to tell by the “card” in the name that these chemicals affect cardiac processes. While monarch caterpillars have developed means to dodge these effects – which start with gastric unpleasantries and then get worse – birds and mammals that try to eat the chemical-laden caterpillars have not. As a result, these warm-blooded predators tend to leave monarchs alone.

Yet cardenolides are just one of milkweed’s many fine qualities. And monarchs aren’t the only ones who benefit.

If you’ve ever watched milkweed seeds disperse on a breezy fall day, you’ve seen how light – how buoyant – its fluff, or floss, is. Hollow and coated with wax, the floss fibers are lightweight and water resistant, assets that allow milkweed’s seeds to travel far and wide.

Once upon a time, this fluffy stuff also saved countless human lives.

Milkweed’s rise to valor came during World War II, when the United States found itself without a source of kapok. Japan controlled much of Southeast Asia, where the silky fiber was harvested from a tropical tree of the same name. This trade blockage wouldn’t have been a big deal except that kapok fiber, up until then, had been the primary material used to stuff life vests.

With thousands of U.S. servicemen stationed on warships and flying on missions over both the Pacific and Atlantic oceans, life vests weren’t exactly something our country could do without. But thanks to milkweed, we didn’t have to.

Those same qualities that make milkweed floss ideal for dispersing the plant’s seeds also made it ideal for keeping our troops safe. Warmer and lighter than wool and six times as buoyant as cork, milkweed floss provided the homegrown solution that life-vest manufacturers needed.

Dr. Boris Berkman, a Chicago physician and inventor, knew just how to get the floss into their hands. He’d spent many years experimenting with different parts of the milkweed plant, and had devised ways to make more than 20 different products, including insulation, oil, cellophane and dynamite. But his most significant invention was the milkweed gin, a machine that separated the floss from the seeds and pods.

(If we had endless amounts of time and space, we’d do a deep dive into Berkman’s Milkweed Floss Corporation of America and how it, and the milkweed-picking skills of scores of school children, made Petoskey, Michigan, the Milkweed Capitol of the World for a few years in the 1940s. Now that you’re aware, maybe you can check it out for yourself!)

At any rate, in his 1939 milkweed gin patent application, Berkman penned numerous paragraphs that described the plant’s many unique properties. He noted that: “The attributes of milkweed floss, which so admirably qualify it [for many uses], are its elasticity or springiness, which causes it to fill confined spaces and which prevents packing of the floss after long periods of time; its low coefficient of heat conductivity, which is due partly to the air spaces between the fibers, and partly to the air within the hollow fibers themselves; its light weight; and its cellulose content of approximately 60 percent which makes for permanency and freedom from decomposition.”

In 1939, the need for life vests had yet to be determined, but Berkman had brainstormed many other uses for milkweed floss, including “felt and batting, stuffing pillows or upholstery, and as an insulating wool for refrigerator cars, trucks, and trailers, and the hollow walls of dwelling houses.”

Another patent in 1942 thrust Berkman and milkweed into the spotlight – briefly. But then World War II came to an end, and synthetic materials soon took the place of natural materials like milkweed. Today, Berkman’s name isn’t well known – he doesn’t even have a Wikipedia page – and milkweed is a plant known more for its benefits to pollinators than people.

I had to laugh though the other day when I was out for a walk. The setting sun had silhouetted a bird nest in a small tree, just above eye level. But it wasn’t the bird’s handiwork that caught my eye. Piled high above those strips of grass, twigs and bark was a generous quantity of, yup, milkweed floss.

An industrious white-footed mouse had appropriated the empty nest and winterized it with what must have been several mouse-mouthfuls of warm and insulating milkweed fibers. Lightweight, long-lasting and water-resistant, the floss will serve the mouse well this winter and maybe on into spring.

I’m not sure if that Peromyscus mouse instinctively knew to select that weatherproof fluff or if building its snug house was a learned behavior. One thing’s for sure – Dr. Berkman would be proud!

• Pam Otto is the outreach ambassador for the St. Charles Park District. She can be reached at potto@stcparks.org.