The great milkweed migration
After the cloud-like flocks of blackbirds have departed, swarming like giant amoebas toward points south, and the broad chevrons of geese have mostly disappeared over the horizon, another momentous fall event begins. Yes, it’s time for one more native species to take to the air—the great milkweed migration is on.
By late summer, milkweed pods are bursting with mature seeds affixed to bundles of platinum floss that lie damp and orderly, waiting for autumn emancipation. After a good frost, each pod dries out and splits perfectly along a seam into two boat-like halves to expose a cache of silk. The wind teases this material from the dry-docked pod halves and launches countless puffy, seed-bearing paratroopers to ride its currents.
Many farmers and gardeners are not impressed by such choreography, as milkweed can be a real nuisance in some crops. Not only is it a perennial, it spreads quite effectively through its robust root system as well as its migratory seeds. However, certain butterflies are happy about the white parachutes of autumn.
The survival of monarch butterflies depends on continual access to milkweed from their winter home in Mexico up to the Great Lakes as they move northward each spring. Monarch populations have recently declined sharply, due in large part to habitat loss in Mexico, but also to milkweed issues. Increased use of agricultural herbicides along with continued urban sprawl has resulted in less milkweed. In addition, monarch caterpillars are poisoned when insecticide-tainted corn pollen drifts onto the milkweed plants they eat. Farmers and butterflies may soon be playing for the same team, however, because milkweed is poised to become an economically viable crop. Native peoples and settlers used milkweed for food, medicine, fiber, and even sugar. We’ve all heard how its buoyant floss was gathered during World War II and used by the military in life preservers. But modern research is what has landed our native, latex-bearing “weed” on the economic map. The Agricultural Research Service, a division of the United States Department of Agriculture, has found a number of important new uses for milkweed.
The silky floss is already in use in the textile industry. Companies like the Natural Fibers Corporation of Ogallala, NE use it in comforters and down jackets. One of the main advantages of milkweed floss compared to goose down is that it is hypo-allergenic. It is also 10 percent warmer, 20 percent more durable, and 50 percent more breathable than down. As an added plus, it appeals to consumers who don’t want goods made with animal products. During WWII, schoolchildren gathered floss by hand for life jackets, but today it can be harvested on a large scale with a slightly modified grain combine.
One of the byproducts of floss production is milkweed seed, which cannot be fed to livestock because it’s poisonous. Research done in Illinois and Washington State found a silver lining—its toxicity makes it valuable as a pesticide against fall armyworms and certain nematodes, which can devastate alfalfa, soybeans, potatoes, and many other crops. In one trial, ground milkweed seed tilled into the soil killed 97 percent of destructive nematodes.
The fact that milkweed sap, or latex, is rich in hydrocarbons has been known for decades. Funding from the United States Department of Energy enabled a private Utah-based research firm called Native Plants to investigate latex as a source of crude oil. Native Plants was subsequently financed by an oil company. Before it flowers, milkweed is mowed and baled using conventional farm equipment, and then processed to extract oil. The residue, which is 20 percent protein, can be used as animal feed. Although it is not profitable to extract oil from milkweed at current prices, that could easily change in the future.
More work is needed before milkweed hits the mainstream. It turns out, although patches of milkweed thrive on roadsides and in meadows, when it is grown on a large scale as a monoculture, disease becomes a problem. And then there’s the question of milkweed’s image. According to the founder and CEO of Natural Fibers Corporation, one of his marketing obstacles is that “weed” is in the name.
Paul Hetzler is a horticulture and natural resources educator with Cornell Cooperative Extension of St. Lawrence County.