The Story of Common Milkweed
Author: Mary Nelson
Ralph Waldo Emerson once wrote, “What is a weed? A plant whose virtues have not yet been discovered.” Say hello to common milkweed (Asclepias syriaca), a plant that, through the years, has been branded as a noxious weed, invasive plant, aphid magnet, and other not-so-appealing names. Of the thirteen species of milkweed that are native to Wisconsin, common milkweed is the most abundant and the one that most people associate with the word “milkweed”. It is found throughout the state in fields, meadows, and along roadsides. Gardeners who have dealt with common milkweed know that it is not a very well-behaved plant. It grows readily from seed and spreads rapidly by rhizomes, frequently forming large colonies that can overwhelm small landscapes. While generally safe if not ingested, its toxicity to livestock and pets is a concern for some farmers and animal owners. All parts of common milkweed, just like other native milkweeds in Wisconsin, contain toxic cardiac glycosides which, when ingested in small doses, can cause nausea, vomiting, abdominal pain, diarrhea, weakness, lethargy, and confusion. When large amounts are ingested, symptoms may include seizures, heart rhythm changes, severe slowing of the heart rate and, in some cases, death.
In the 1940’s, common milkweed was classified as a “noxious weed” by the US Department of Agriculture, largely due to its toxicity to grazing animals. At that time, farmers used all sorts of eradication methods to eliminate common milkweed from their fields, including plowing it under in spring, pulling it during the growing season, and burning it. However, since the plant is unpalatable to livestock due to its bitter taste and milky sap, most animals will not eat it. According to the United States Department of Agriculture (USDA), livestock will only eat milkweed if there is no other available forage; in other words, if they are very hungry. A major risk to livestock occurs when milkweed plants are inadvertently harvested and dried into hay. The drying process causes milkweed to lose its bitterness, resulting in animals willingly ingesting it.
So, how exactly did common milkweed become a war hero? It all boils down to military life jackets.
Around 1915, the US military began using a substance called kapok to fill life vests. Kapok is a buoyant, cotton-like fiber harvested from the seed pods of the ceiba tree growing on the island of Java, present day Indonesia. When the Japanese invaded Java in 1942 during World War II, the supply of kapok was cut off from the US military and the supply of life jackets for soldiers was threatened. The US War Department desperately needed a substitute for kapok. A man by the name of Boris Berkman, a Chicago physician and inventor, advocated the use of common milkweed floss as a filling for life jackets. He also devised a “milkweed gin” for separating the milkweed floss from the seeds.
Kapok, courtesy of Wiktionary, the Free Dictionary
The U.S. Navy conducted extensive tests to determine if the floss from common milkweed would provide adequate buoyancy and water-repellency to keep soldiers afloat in the event they ended up in a body of water. Test results showed that a little over a pound of floss could keep a 150-pound man afloat for more than 40 hours. Based on this evidence, the status of common milkweed was elevated from lowly “weed” to “strategic wartime material” and the government quickly appropriated money to build a milkweed processing facility in Petosky, Michigan. According to surveys conducted by the USDA, the 12-county area surrounding Petosky, located along the shores of Lake Michigan, was home to the largest concentration of milkweed in the country. When the first crop of milkweed in Petosky was ready to be harvested, the military started a campaign to recruit the help of volunteers. The campaign spread quickly, resulting in the participation of hundreds of thousands of families, community organizations, and especially schoolchildren across 25 US states and two Canadian provinces.
Common milkweed, courtesy of Xerces Society for Invertebrate Conservation
Volunteers used mesh onion bags to collect pods and were paid about 15 cents per bag. Each bag held approximately 600 to 800 pods, and two bags provided enough milkweed floss to make one life jacket. The government coined the slogan “Two Bags Save One Life” to promote pod collection. Reports estimate by the end of the entire war effort, over 12 million pounds of milkweed pods were collected, which is estimated to be 1.5 billion pods in total. At the end of World War II, when the supply of kapok was restored and other synthetic materials were being developed as alternatives, the US military stopped using milkweed floss for life jackets.
Today, common milkweed is still a hero but for different reasons than in the 1940’s.
As a host plant for the monarch butterfly, it is one of the easiest and fastest of our thirteen native milkweeds to establish in Wisconsin and is the most abundant milkweed in the Midwest. It is not picky about where it grows and thrives in a wide range of soil environments. According to research conducted by the USDA Agricultural Research Service (ARS), it also happens to be one of the most popular milkweeds for monarch egg laying. Laboratory analysis of tissue samples from monarchs overwintering in Mexico revealed that most monarchs fed on common milkweed as caterpillars.
Planting common milkweed is a great way to support monarch butterflies. But remember to choose the area carefully so that common milkweed can do its thing without becoming a nuisance.
References
Albert, Kaitlyn, Michigan and Milkweed: An unsuspected plant aided in the War effort
during World War Two. Little Traverse History Museum (2022).
Borders, Briana and Eric Lee-Mader, Milkweeds: A Conservation Practitioners Guide. Xerces
Society for Invertebrate Conservation (2014).
Kahler, Kathryn A., Back in the Day: When Picking Milkweed was a Patriotic Pursuit. Wisconsin.
Michigan History Magazine (February 4, 2014)
Podurgiel, Bob, How Collecting Milkweed Saved Lives in World War II. Veteran’s Breakfast Club,
16-20.
Wykes, Gerald, Natural History Magazine (Fall 2019). A Weed Goes to War, and Michigan Provides the Ammunition.