The Monarch Butterfly

"There is drama in every bush, if you can see it," wrote the naturalist Aldo Leopold. Few species embody that drama as well as the monarch butterfly. Behind its orange wings veined with black hides one of the greatest travellers in the living world: every fall, monarchs born in Quebec fly to a handful of Mexican mountains nearly 4,000 km away, without ever having been there.

This wonder is now under threat. But its fate rests almost entirely on a plant we long looked down on, milkweed, and on an idea that unsettles people: what if the best way to protect the monarch was not to put milkweed under glass, but to grow it, harvest it and sell it? That is Lasclay's bet, and that is the story this page tells.

Recognizing the monarch (and its look-alike, the viceroy)

The monarch butterfly (Danaus plexippus) has bright orange wings, veined and edged in black with white dots, and a wingspan of 9.3 to 10.5 cm (about 3.7 to 4.1 inches). It is one of the largest day-flying butterflies in Quebec.

Those vivid colours are not just for show: they are a warning sign. Biologists call it aposematic colouring, a way of telling predators "I am toxic, move along." The monarch even has an imitator, the viceroy, which copies its livery to profit from its bad reputation. To tell them apart: the viceroy is slightly smaller and carries a thin black line across its hind wings, which the monarch lacks.

A life in four acts: metamorphosis

The monarch goes through a complete metamorphosis, in four stages:

• The egg, laid one at a time on the underside of a milkweed leaf.
• The caterpillar, which devours the leaves and moults five times (five larval instars) while growing at a spectacular rate.
• The chrysalis, a jade-green case trimmed with gold, from which the adult emerges after 8 to 15 days.
• The adult, which feeds on nectar, reproduces and starts the cycle over.

Over the summer, four to five generations follow one another. These summer monarchs are short-lived: they survive only two to six weeks. Except one.

The super generation and the great migration

The last generation of the season, born in late summer, is different from all the others. It is born in diapause, meaning its sexual development is put on hold to save energy. The result: instead of a few weeks, it lives up to eight months. It is sometimes called the "super generation" or the "Methuselah generation."

This generation, and this one alone, undertakes the great journey. The monarch is the only butterfly in North America that migrates in both directions, the way birds do. Eastern monarchs head for the oyamel fir forests of Michoacán, in central Mexico, where they cluster by the millions, often on the same trees year after year. Western monarchs overwinter on the California coast. In spring, the great return begins, and the relay of generations starts again.

Monarch and milkweed: an alliance sealed by poison

It is nearly impossible to talk about the monarch without talking about milkweed. It is the only host plant of its caterpillars: the female lays her eggs exclusively on milkweed, and the caterpillar eats nothing but its leaves. Their bond probably goes back tens of millions of years of co-evolution.

The most fascinating part is that this dependence rests on a poison. Every part of the milkweed plant holds a white latex loaded with cardenolides, molecules that are toxic to most animals. Rather than avoiding it, the monarch caterpillar sequesters these toxins in its tissues and keeps them even after metamorphosis. The butterfly thus becomes toxic itself, and its bright colours warn predators off. The plant that should kill it makes it untouchable.

The caterpillar has even learned to outsmart the plant: before feeding, it notches the leaf's main vein to "cut the latex line," then feeds downstream, where the sap no longer flows, a detail observed by the naturalist Craig Holdrege in his beautiful monograph on common milkweed. In exchange for the feast, the adult monarch pollinates the milkweed. A fair trade.

A species at risk: where does the monarch stand?

The monarch's trajectory worries scientists around the world.

• In July 2022, the International Union for Conservation of Nature listed the migratory monarch as "Endangered" on its Red List.
• In Canada, the species went from "Special Concern" to "Endangered" in December 2023 under the Species at Risk Act.
• In the United States, the Fish & Wildlife Service proposed, in December 2024, to list it as "Threatened".

The numbers tell of a dizzying fall. The eastern population is measured by the area it occupies each winter in Mexico:

• Winter 2022-2023: 2.21 hectares (5.5 acres)
• Winter 2023-2024: 0.90 hectare (2.2 acres), the second-worst year on record
• Winter 2024-2025: 1.79 hectares (4.4 acres), an encouraging rebound, but still below the decade's average (2.81 ha) and very far from the levels of the 1990s

The western population, for its part, counted barely 9,119 butterflies in the winter of 2024-2025, one of the lowest totals ever recorded. Overall, the monarch has lost more than 80% of its numbers since the 1980s.

The main cause is a matter of broad consensus: the loss of its breeding habitat, in other words the disappearance of milkweed. In the American Corn Belt, field milkweed declined by nearly 81% between 1999 and 2010, largely because of the massive use of herbicides tied to genetically modified crops. Let's be honest: the phenomenon is more complex than that single factor, and the decline partly began before GMOs arrived. Urban sprawl, intensive farming, the loss of fallow land and the climate all add up. But the common thread stays the same: less milkweed, fewer monarchs.

Why planting in your garden is not enough

The logical reaction is to plant milkweed. It is an excellent reflex, and we come back to it below. But let's be clear-eyed: a few plants in a backyard, an urban lot or a roadside will not reverse the trend.

Why? Because migrating monarchs travel in large groups. Scattered, tiny patches are either never found, or too small to feed the migrating swarms. And the large wild colonies, in pesticide-free rural fallows, are getting scarce. Worse: for decades, milkweed was actively pulled out, deemed a nuisance because it is toxic to livestock and "invades" fields. As the horticulturist Eric Lee-Mäder tells it in his book The Milkweed Lands, we "waged chemical warfare" against it and even "fined people for growing it."

To recreate the abundance the monarch needs, we therefore have to change scale: the agricultural scale.

Farming and selling milkweed: a lifeline for the monarch

Here is the idea at the heart of our mission, and the angle almost no one else defends.

Large-scale milkweed farming will only happen if it is profitable. And it will only be profitable if there is a commercial outlet for the plant. That outlet is milkweed floss: a remarkable plant-based insulation. The reasoning comes full circle: buying products insulated with milkweed finances the planting of vast fields, which recreate the massive breeding habitat the monarch needs. Passive conservation does not create habitat at scale. The market can.

The orders of magnitude are dizzying. To bring the population back to its conservation target, scientists estimate that 1.3 to 1.6 billion milkweed stems would have to be added across North America, or between 10,500 and 13,000 hectares (26,000 to 32,000 acres) under cultivation. In 2017, there were about 1,400 hectares (3,500 acres) in Quebec and Vermont. The road is immense, but it has a clear engine: demand.

There is an elegant virtuous circle here. Milkweed's pollination is so intricate that it depends entirely on pollinators. No insects, no pods; no pods, no floss; no floss, no industry. In other words, the industry has a direct economic interest in banning insecticides and protecting the whole insect community of its fields. For once, conservation is not a cost: it is a condition of production. Milkweed growers do in fact flatly refuse insecticides.

One clue, to be handled with care: large-scale milkweed farming started in Quebec and Vermont around 2014, at the very moment the monarch population in Mexico began climbing again. That Quebec adventure (the boom from 2013, the bankruptcies of 2017, then the relaunch) deserves its own telling: we tell it in the history of the milkweed industry in Quebec. Correlation is not causation, and we say so honestly. But a University of Guelph study published in the Journal of Animal Ecology points precisely to the loss of breeding habitat as the driver of the decline. Everything converges.

We insist on transparency, because it is our cardinal value. The mechanized late-season harvest raises a real question: could it kill chrysalises or late butterflies? We debate it frankly among ourselves. The answer lies in the calendar and the latitude: we harvest as late as possible, once the migration is well under way and the plants are senescing, and we take only the pods, not the green plants. Under those conditions, farming remains a net benefit for monarch populations, a hypothesis we stand behind and that science keeps refining.

It is very rare for the use of a raw material to be a net gain for its ecosystem. Think of down, cotton or petroleum-based synthetic insulation. Hand-picked milkweed seems to belong to that rarest of categories: a resource whose use supports the balance of its environment and the survival of the species that depend on it. That is what drives us.

Milkweed, much more than "the monarch plant"

Reducing milkweed to the monarch would be a mistake. As Eric Lee-Mäder explains, a former pollinator conservation director at the prestigious Xerces Society, milkweed shelters "an almost infinite universe of associations," from soil fungi to the tiny insects on its leaves, and even their parasites. A "natural history that connects the life of the soil to the life of the clouds."

A whole procession of species depends on this plant: the milkweed longhorn beetle and leaf beetle, the large and small milkweed bugs, the milkweed tussock moth, weevils, bumblebees, and even goldfinches, which line their nests with its floss. A milkweed flower produces more nectar than its visitors could ever consume. It is, quite literally, a gold mine for pollinators.

And that famous floss? Each fibre is a hollow tube. The air trapped between the fibres and inside each one makes it, weight for weight, an insulator that often outperforms down. A waxy coating makes it naturally water-repellent, and its cellulose nature makes it hypoallergenic. This is exactly the milkweed floss that Lasclay turns into warm products. Once again, the loop closes.

How to actually help the monarch butterfly

Good news: even modest actions count. Lee-Mäder tells of turning a paved Seattle parking lot into a tiny meadow; within a year, rabbits, an owl, a rare bumblebee and sparrows had moved in. Here is where to start.

• Plant native milkweed, the single most useful thing. Our planting guide explains everything. To get going: native milkweed seeds, and in season, seed bombs to drop on the ground or seedlings already on their way, in our garden collection.
• Add native nectar flowers, to feed the adults on their way south.
• Ban pesticides and herbicides from your property.
• Do you own a large lot or farmland? Our milkweed planting service creates habitat at a larger scale while generating income.
• Take part in citizen science, for example with Mission Monarch or Journey North, to help track populations.
• Support the milkweed industry. Every product insulated with milkweed is a boost for the growers, and potentially one more hectare for the monarchs. It is not a purchase that "saves a butterfly," but a demand that makes habitat possible.

Frequently asked questions

Why is the monarch butterfly endangered?

The dominant cause is the loss of its breeding habitat in North America, that is, the decline of milkweed, its only host plant. That decline comes from intensive agriculture and herbicides (up to 81% less milkweed in the Corn Belt between 1999 and 2010), urban sprawl, the disappearance of fallow land and the climate. Add to that the hazards of migration and the fragility of the overwintering sites. The result: a population down more than 80% since the 1980s.

Isn't the decline caused by deforestation in Mexico instead?

This is the objection we hear most, and it deserves an honest answer. Illegal logging in the Mexican overwintering forests was indeed a serious threat in the 1990s and 2000s. But thanks to monitoring by WWF, the Mexican government and local communities, large-scale deforestation of these forests has fallen sharply since the mid-2000s, without the population recovering for good. When researchers take the monarch's annual cycle apart, as the University of Guelph team did in the Journal of Animal Ecology, it is the loss of breeding habitat (milkweed, in the north) that stands out as the driver of the long-term decline, ahead of overwintering conditions. Science is not unanimous, and some put more weight on mortality during the fall migration; the debate is real and healthy. But milkweed remains the lever we can act on directly, and the most promising one.

What does the monarch caterpillar eat?

Only milkweed leaves. It is an absolute dependence: the female lays her eggs only on milkweed, and the caterpillar eats only its leaves, sequestering their toxins (cardenolides) to protect itself from predators. No milkweed, no monarch.

Where do monarchs go in winter?

Eastern monarchs, including those from Quebec, travel up to 4,000 km (about 2,500 miles) to overwinter in the oyamel fir forests of central Mexico, where they gather by the millions on the same trees from one year to the next. The western population overwinters on the California coast.

How long does a monarch butterfly live?

Summer generations live only two to six weeks. The "super generation" born in late summer is the exception: thanks to diapause, it can live up to eight months, long enough to migrate to Mexico, spend the winter there and begin the return trip in spring.

How do you tell a monarch from a viceroy?

The viceroy mimics the monarch to profit from its reputation as a toxic butterfly. To tell them apart: the viceroy is smaller and carries a thin black line across its hind wings, which the monarch does not have.

Does planting milkweed in my garden really help?

Yes, every plant counts, and it is a fine gesture for the monarchs passing through. But to reverse the trend across a continent, vast areas of milkweed also have to be recreated, which only profitable farming makes possible. The garden and the field complement each other.

A final word

The monarch has come through millions of years by leaning on a plant we learned to despise. Giving it back its habitat means rehabilitating milkweed, not by putting it under glass, but by giving it a useful place again in our fields and our lives. That is, on our humble scale, what we are trying to do, one plant and one pair of mittens at a time.