US agriculture is based on ideas that make me scratch my head. We typically grow plants that are not native to North America, we grow them as annuals, and we usually only care about one product from the crop, like the tomatoes that give us ketchup and pizza.
And we don’t like weeds. Why would we? They take resources away from our crops, reducing yields more than insect pests or disease, they’re hard to get rid of, and they might give you a rash. But there are few plants more useful, easy to cultivate, and environmentally friendly than the milkweed. The milkweed takes its ill name from the sticky rubbery latex that oozes out when you break the leaves, it’s the monarch butterflies only food, and it is a native meadow plant. Milkweed has sometimes received a bad rap, and perhaps for good reason, they can be poisonous to livestock, they are hard to get rid of, and they do reduce crop yields. But what about milkweed as a crop?
Thomas Edison showed that milkweed’s milky latex could be used to make rubber. The oil pressed from the seed has industrial applications as a lubricant, and even value in the kitchen and as a skin balm. And as a specialty item, acclaimed for its hypoallergenic fibers, milkweed’s seed fluff that carries milkweed seeds in the wind, is being used to stuff pillows and blankets. Perhaps more surprising, the same fluff is highly absorbent of oils, and is now being sold in kits to clean up oil tanker spills. The fibers from milkweed stems make excellent rope and were used by Native Americans for centuries of years. More than two hundred years ago, the French were using American milkweed fibers to make beautiful cloths, said to be more radiant and velvety than fine silk. And chemically, milkweeds were used medicinally by Native Americans since the dawn of civilization, with a potential for use in modern medicine. This is a diverse plant with a lot to offer. Why wouldn’t we cultivate this plant, not only for its stem fibers, seed oils, pillowy fluff, rubbery latex, and medicines, but also in support of the dwindling populations of monarch butterflies?
Ever since the four lowest years of monarch butterfly populations 2012-2015, planting milkweeds for monarchs has been on the tips of a lot of tongues. For most insects that eat plants, however, their populations are not limited by the availability of leaves. Instead, their predators typically keep them in check, or as in the case of monarchs, there may be constraints during other parts of their annual cycle. Monarchs travel through vast expanses from Mexico to Canada, tasting their way as they go. They tolerate poisons in the milkweed plant; indeed, they are dependent on milkweed as their only food source as a caterpillar. Nearly all mating, egg-laying, and milkweed-eating occurs in the United States and Canada. And each autumn monarchs travel to Mexico, some 3,000 miles, fueled only by water and flower nectar.
All parts of the monarch’s unfathomable annual migratory cycle should be observed and studied. My own research has suggested that habitat destruction in the USA, lack of flower resources, and logging at the overwintering sites in central Mexico are all contributing to the decline of monarch butterflies. Lack of milkweed does not seem to be causing the decline of monarchs. Read more about this in my book on Monarchs and Milkweed.
Planting native milkweeds can only help the cause of conserving monarch butterflies, but it is not the only answer. And of course we humans need our corn and soy, and we love our broccoli and strawberries, so is cultivating milkweed really something to consider?
We humans, with our highly sensitive pallets, do the one thing that monarch butterflies don’t do. We cook. And the invention of cooking foods has been deemed one of the greatest advances in human evolution. Cooking certainly reduces the time spent chewing and digesting, and perhaps more importantly, cooking opens up much of the botanical world for human consumption, because heat can break down plant poisons.
Euell Gibbons, the famed proponent of wild plant edibles in the 1970s, was a huge advocate of eating milkweed. The shoots of new stems of the eastern “common milkweed” are my personal favorite. I simply pull them up when they are about 6-8 inches tall and eat them like asparagus. Gibbons recommended pouring boiling water over the vegetables in a pot, then heating only to regain the boil, and pouring off the water before sautéing. You can pick several times and the shoots keep coming. With some preparation, the other parts of the milkweed plant can be eaten too, and enjoyed like spinach, broccoli and okra. Only do this with common milkweed, and if too bitter, listen to your tongue and don’t eat it!
At the end of summer, many insects have enjoyed the benefits of eating milkweed, especially the monarch butterfly. Any boost we could give to the monarch population may help use preserve it in perpetuity. But the real value in cultivating milkweed as a crop is that it has a lot to offer, from medicines to fibers to oils. It is native and perennial, and can be grown locally and abundantly. Let’s give this weed a chance.
I live in Houston, Texas and my daughter has seven chrysalis and 2 more caterpillars in her garden. This is July and I thought the Monarchs would have migrated north by now. Why do you think they are still around at this late date?
Hi Anurag – Happy Solstice.
I’ve been meaning to write you for some time, since I attended your “Monarchs and Milkweed” book talk at the Arnold Arboretum several weeks ago.
As you know, in your talk, you mentioned the “toxic cardiac glycosides” that are present in milkweed plant tissues, which the Monarch caterpillars and butterflies use to deter predators.
Hearing that a plant contains significant amounts of “toxic cardiac glycosides” might lead one to reasonably assume that such a plant would not be safe for human consumption.
Nevertheless – this (Asclepias syriaca) is a species I have eaten many times (after boiling for seven minutes). I devote a chapter to eating the Common Milkweed in my book, Wild Plants I have Known…and Eaten. Many other people I know have also eaten this species, some with even less pre-cooking than my standard practice.
Expert forager Sam Thayer also includes an extensive chapter on eating Common Milkweed in his book,The Forager’s Harvest.
And now I see, via this blog posting, that you have eaten Milkweed too, and have in fact fed it to your unsuspecting family.
I imagine, with your extensive experience with Asclepias syriaca, you might have an explanation for why the toxic cardiac glycosides present in this species don’t seem to adversely affect people who eat this plant. On the other hand: should we (who have been eating this plant) all worry that we have been poisoning ourselves and/or endangering our heart rhythms?
Thanks for letting me know –
— Russ Cohen
Dear Russ,
Thanks for coming to my talk and your email! Yes, of course you are correct that A. syriacs is edible… my favorite of the articles about this Euell Gibbon’s: Milking the milkweed from Organic Gardening in 1972. In Chapter 7 of my book, I detail this stuff and how I have prepared milkweed for consumption. Most of the cardenolides in A. syriaca are highly polar and not absorbed by our vertebrate guts. Also, the boiling does washout some of them (although they are heat stable).
I hadn’t seen some of these other articles about eating milkweed, so thank you! Many other milkweeds are more toxic and it would not be advisable to at them. I hope you have an excellent holiday. –Anurag
It can’t be vertebrate guts. See https://www.aspca.org/pet-care/animal-poison-control/toxic-and-non-toxic-plants/milkweed and of course water is highly polar, so your response to Russ doesn’t hold water ;>)
Yet I have eaten a single flower bunch of common milkweed raw, many times, to no bad effect, so I don’t know what the answer is on the vertebrate toxicity.
There are probably a few different things going on here. First, some milkweed species are more toxic than others, and often the information available on the web isn’t super reliable, since milkweeds aren’t always correctly identified, etc. Second, the latex of milkweed contains many other toxins and defenses that can cause problems. Eating less latex is better for most consumers! For both cardenolides and the other poisons in milkweed, “dose makes the poison”. So how much we consume (and over what time period) is critically important. As for polarity, the the fact that some cardenolides are water-soluble makes it easier for our vertebrate guts to prevent the compounds from seeping into our bloodstream. So, overall, my best guess is that the fact that we eat small amounts of common milkweed relative to our big bodies, typically with low levels of latex and mostly polar cardenolides, makes it all okay. Hey, it makes it more than okay, it makes it a tasty treat!
Wouldn’t growing milkweed as a crop harm Monarchs? That’s lay their eggs on the plants and the caterpillars would start munching away. The farmer would then spray insecticide. Or perhaps l harvest the plants. Either way no butterflies.
Farming milkweed would be complex, I agree
Most people don’t understand that it is not just about the monarchs! Dont forget the rest of the pollinators and all the wildflowers. Without them we won’t have food! How can we as humans spray and mow everything and then complain we didn’t have a bumper crop plus go to the store and complain again about the high price of food. It’s all about ecology. Insects got to eat too! It’s not just about milkweed. I just bought 4 more mums to plant on my 2 acre pollinator plot. There are already milweed plants there. I released 33 monarch butterflies since August 9. My daughter, who has a monarch waystation has released Almost 100 this year so far. I harvested 32 eggs just ONE DAY before the farmer mowed the ditch for the second time this year.
I couldn’t agree more!