Milkweed: More than just a food for the monarch butterfly

Lisa Kucinskas

            In doing research on milkweed for my Master Gardener training presentation, I learned quite a few interesting facts about these plants beyond their best-known role as food for the larvae of the monarch butterfly.

Milkweed comes from the genus Asclepias, consisting of 130 species, of which all are herbaceous perennials. They are found in the Americas, with most living from Mexico on northward to Canada. There are 11 varieties that are native or naturalized in Pennsylvania. Milkweed is not self-pollinating; it needs another milkweed plant to pollinate with it. Common milkweed (Asclepias syriaca), the variety that serves as host for the larval stage of the monarch butterfly, is clonal and can be considered aggressive. Butterfly weed (Asclepias tuberosa) is the milkweed plant most commonly found for sale at garden centers and in our gardens. 

Common milkweed (Asclepias syriaca); Photo credit: David Taylor, https://www.fs.fed.us/wildflowers/plant-of-the-week/asclepias_syriaca.shtml

Milkweed contains cardenolides, a steroid that acts as an emetic (a substance that causes vomiting). This is why the plant is considered toxic. Symptoms of cardenolide toxicity are depression, dizziness, labored breathing, and seizures. However, there are beneficial modern medical uses for milkweed as well, such as to treat heart failure, to relieve inflammation of the lung, and as a promising new anti-cancer drug.        

There are many other diverse uses for milkweed. The oil from the seeds is used as an industrial lubricant; Thomas Edison developed rubber from milkweed latex; and the fiber from milkweed seed pods is used as stuffing for pillows and comforters. During World War II, school children across America gathered 25,000,000 pounds of seed pods for the United States Navy to fill life vests with the seed fibers (called coma), since the kapok from Asia was no longer available. The plant fibers have been used for hundreds of years by the Native Americans for rope, string and cloth, and presently farmers in Vermont are growing milkweed for Canadian clothing companies.

Butterfly weed (Asclepias tuberosa); Photo credit: www.missouribotanicalgarden.org

Milkweed nectar was used by the early French Canadians as a sweetener. Euell Gibbons wrote in his book Stalking the Wild Asparagus of the many other food uses for the plant: New shoots up to 6" can be served like asparagus and newly opened top leaves like spinach; unopened flower buds are similar to broccoli, and the young pods cook like okra. Though milkweed is extremely bitter, boiling the water and changing it several times during the cooking process will take care of this. To quote Gibbons, milkweed is a "very acceptable vegetable if properly cooked.”

For more on milkweed, see another recent Master Gardener post here.

SOURCES:

Anurag Agrawal, Monarchs and Milkweed: A Migrating Butterfly, a Poisonous Plant, and Their Remarkable Story of Coevolution

Euell Gibbons, Stalking the Wild Asparagus

Mary Joy Haywood, Phyllis Testal Monk, and Members of the Botanical Society of Western Pennsylvania, Wildflowers of Pennsylvania

Jennifer Levitz, “This Winter's Hot Fashion: Parkas Stuffed With Vermont Weeds,” The Wall Street Journal (September 28, 2017)