Milkweed: Food for Butterflies, Food for Your Table, Food for Thought

During the South Texas autumn, if you look outside you’re likely to see an orange flurry of monarch butterflies flitting from flower to flower. They’re busy refueling on the nectar plants in your back yard so they can make the rest of the arduous journey to their wintering grounds in Mexico. How these tiny, fragile creatures can fly up to 3000 miles to a place they’ve never been to before is surely one of the most astounding navigational triumphs of nature.

The Aztecs believed, as did earlier Meso-Americans, that the monarch butterflies returning to the same place at the same time each year were the departed spirits of deceased warriors and relatives that had come back to visit loved ones. As native pre-Hispanic beliefs were merged with Catholic traditions, indigenous ways of honoring the dead were combined with All Souls’ Day and All Saints’ Day observances. The ancient customs of offering ceremonial food and drink on decorated altars and “visiting” with spirits in burial grounds thus came to be celebrated on November 1 and 2 as The Day of the Dead. Coincidentally, early November also happened to be the precise time of year that monarchs reliably reappeared in great orange shimmering clouds. The returning butterflies were welcomed and revered as symbolic embodiments of departed loved ones arriving for their annual visit. Monarch imagery and symbolism continue to be important features of contemporary Day of the Dead festivities, which are being celebrated by hundreds of thousands.

Every autumn, monarchs funnel en masse through the “Texas Flyways” on their way to remote groves of fir trees in the highlands of central Mexico. And every spring, their offspring make the return trip to destinations as far north as Canada.  Suitable habitats in Texas are obviously vital for the survival of the migrating butterflies.  Adequate nectar sources are needed to fuel the long journey south, and appropriate milkweed plants are critical for the multiple reproductive cycles that occur en route as the new generations travel north. In recent years, many organizations and concerned citizens have joined forces to protect the monarch by re-establishing the butterfly habitat that has suffered in recent years from population growth and damaging agricultural practices. 

Many of us are already very familiar with the unique relationship between monarchs and milkweed. Milkweed is widely known as the one and only larval host plant of the monarch butterfly.  There are 73 species of native milkweeds in the United States; and about half of these, each with its unique characteristics and habitats, are found in Texas. These plants are not only challenging to propagate and transplant, but must be well-suited to soil, climate, and other conditions in order to survive and ultimately benefit the monarchs.  The monarch population needs these host plants as it migrates from the United States and Canada to Mexico each fall and returns each spring.  Most big box nurseries in Texas sell tropical milkweed (Asclepias curassavica), which is native to Mexico. The plant blooms later in fall and can trick monarchs heading south then into staying here too long.  The native Texas milkweed, like antelope horns milkweed (Asclepias asperula) or butterfly milkweed (Asclepias tuberosa) shold be planted instead because they bloom at the appropriate time in the butterfly's migration cycle.

Students in beginning biology classes learn how Asclepias species have evolved over millions of years to produce several toxic substances, known as cardiac glycosides, which protect them from herbivores. At the same time, monarch butterflies have developed protective biochemical mechanisms that allow them to ingest, and even concentrate, these toxic substances in their tissues. While not poisonous to the monarchs, the toxin in one bite of a monarch wing causes sufficient distress and vomiting in their avian predators that the birds quickly learn to leave the monarchs alone. The avian learning curve is reinforced by the easily identifiable high-contrast warning coloration brazenly displayed by monarch larvae and adults. As Charles Darwin said, “Evolution is written on the wings of butterflies.”

Milkweed buds for dinner and in medicine

The shoots, stems, buds, flowers, pods, seeds, and “silk” of a toxic plant were converted to nutritious and delicious food by Native American peoples, and milkweed cuisine today is undergoing a revival led by foragers and inventive chefs. My favorite milkweed “recipe” comes from the Chippewa, who stewed milkweed flowers into a type of jam. Not only does this floral jam sound delicious, but, when consumed before a large meal, it was thought to allow one to eat more food than usual!

Unlike many of the foods eaten by Native Americans, the European settlers did not adopt milkweed generally into their kitchens.  A French Canadian communication written in 1760 describes the technique of making a brown sugary sweetener from milkweed flowers: “These are shaken early in the morning before the dew is off of them when there falls from them with the dew a kind of honey which is reduced to sugar by boiling.” I don’t think I will be trying this tedious process anytime soon, but I have certainly been tempted by several less labor-intensive milkweed recipes found on the internet.

What about milkweed as a medicine? The genus Asclepias was, after all, named by Carl Linnaeus (1707 - 1778) after the Greek god of healing, Asklepios, to acknowledge its widespread use in treating illness. Asclepias tuberosa is known by the common name “pleurisy root”, referring to its historical use in treating respiratory disorders. Even Nicholas Culpeper, the great 17th century English botanist, herbalist, physician and astrologer, extolled the medicinal virtues of this herb. “The root,” he wrote, “which is the only part used, is a counter-poison, both against the bad effects of poisonous herbs and the bites and stings of venomous creatures.” Did you notice how Asclepius serves as a textbook example of a plant that can be both toxic and beneficial, depending on dose and preparation? 

While we don’t use milkweed medicinally any more, there is provocative evidence that monarch butterflies “self-medicate” by choosing milkweed plants with varying levels of cardiac glycosides depending on their own health status! Other Asclepias research is currently focusing on chemicals produced by certain milkweed species that may have potential as anti-cancer drugs or as nematocides.

Among the historical uses of this valuable plant are uses ranging from life-saving wartime applications to its utility as fibers for paper, textiles, cordage, and fishing lines. It’s even been used as a poison applied to arrow tips and as soft stuffing for pillows in baby cradles. And if you’re lost in the woods, you can always use milkweed floss to kindle a fire.

Adapted from an article submitted by Karen Cottingham

Milkweed Asclepias spp.