A sweet grabber

Milkweeds protect butterflies and entertain children.

Milkweeds are among the great toys of nature, known to almost any kid who grows up in the country. “The common milkweed needs no introduction,” wrote naturalist F. Schuyler Mathews in 1894. “Its pretty pods are familiar to every child, who treasures them until the time comes when the place in which they are stowed away is one mass of bewildering, unmanageable fluff. Then there are vague talks about stuffing pillows and all that sort of thing; but the first attempt to manipulate the lawless airy down usually results in disastrous confusion, and whole masses go floating away on the slightest zephyr.” He adds: “Of course, there is more fun in chasing milkweed down than in patiently stuffing a pillow; so the milkweed has its own way and goes sailing off to scatter its seeds hither and thither.”

Alice Morse Earle had fond memories of milkweed in her 19th-century childhood. “That exquisite thing, the seed of milkweed, furnished abundant playthings,” she wrote in Old-Time Gardens. “The plant was sternly exterminated in our garden, but sallies into a neighboring field provided supplies for fairy cradles with tiny pillows of silvery silk.”

Wild Cotton

The references to stuffing pillows were no joke. Both pillows and mattresses were filled with milkweed down from the Europeans’ earliest settlement of North America. “The poor collect it and with it fill their beds, especially their children’s, instead of feathers,” wrote Peter Kalm in 1772. The silky hairs, or “pappus,” gathered before the seam of the pod splits and spreads the seeds, were mixed with flax or wool, and woven to create a softer thread than either fiber yielded alone. Take a microscope, said Mr. Mathews, and “place some bits of white sewing silk beside [this] sheeny silk of Nature, and the former will look like a coarse white rope.”

A 19th-century magazine article reported that milkweed’s “chief uses were for beds, cloth, hats, and paper. It was found that from eight to nine pounds of the coma [seed hair] . . . occupied a space of from five to six cubic feet, and were sufficient for a bed. . . . A plantation containing 30,000 plants yielded from six to eight hundred pounds of coma.” That seems an awful lot of plants and trouble to go through for about 100 mattresses, which may explain why milkweed mattresses are a thing of the past. However, during World War II, when all sorts of imported raw materials were in short supply, milkweed down was used extensively as a substitute for Asian kapoc in life preservers and for the linings of airmen’s outfits. All these uses of the silky fluff have earned the plant such names as cottonweed, cottontree, silkweed, and wild cotton.

For a weed, this was a pretty handy plant in other ways. The French in Canada as well as some New Englanders in the 18th and 19th Centuries ate the tender shoots like asparagus. French Canadians also made a “very good, brown palatable sugar,” according to one 18th-century author, by gathering and processing the flower heads in the early morning when they were covered with dew. Paper and even cloth could be made from the fiber in the stalks of the common milkweed (Asclepias syriaca). The fiber of swamp milkweed was so strong, it was made into twine and cord (see the chapter on butterflyweed, page 142). American Indians made dyes from the juice, and one modern expert on herbal dyes says milkweed can produce a wide range of colors. Rubber has been produced from the juice of various milkweed species, though commercial production has not been feasible.

American Indians made other good uses of milkweeds. Chippewas cut up and stewed the flowers of common milkweed, eating them like jam. They believed that consuming the flower-jam before a big meal would allow a person to eat more food than usual. The Sioux, or Dakotas, used to boil the tender young seed pods and eat them with buffalo meat. (Esclepain, a constituent of milkweeds, is supposed to be a good meat tenderizer.) Some Indians used the buds as food. Hopi mothers who were nursing ate milkweed to increase the flow of milk.

Incidentally, unless properly prepared, any part of the milkweed is bitter, and it may be poisonous. Cooking requires several changes of boiling water, and the water must be boiling when it comes in contact with the plant. Putting the plant parts in cold water and then turning on the heat will only serve to make them permanently unpalatable.

The root of A. syriaca has been used to treat typhoid fever, scrofula, and, in general, to help relieve inflammation of the lungs caused by a variety of ailments, especially asthma. Milkweed was imported to Europe by the early 17th century. Nicholas Culpeper, who called it swallow-wort, wrote, “the root, 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.” As late as the 1930s, the tuberous roots of common milkweed could be sold to commercial concerns for six to eight cents a pound, about the same price paid at the time for butterflyweed, which was long listed as an official drug in the U.S. Pharmacopoeia.

It’s no accident that the generic name, Asclepias, comes from Asclepius, the Greek hero of the medical arts. On the other hand, syriaca, meaning “of Syria,” is probably an accident. This species is a native of America. Perhaps Linnaeus mistook the country of origin while classifying and naming the plant in 1753. Or perhaps the plant had already been imported to Syria for a crop experiment, and Linnaeus examined a specimen that had come from there. The rules of taxonomy require that the first name applied to a plant, even if based on mistaken assumptions, is the proper name. Some authorities haven’t accepted this, preferring to use Asclepias cornuti, which was concocted in 1844. Cornuti means “horned,” probably referring to the shape of the flower crowns.

North America can lay claim to 75 or more native species of milkweeds, some of them very difficult to tell apart. They represent more than half the known species in the world. A. syriaca, perhaps the most famous, is the type species for the genus and is found from Oregon and Saskatchewan and Kansas eastward, and down into the highlands of Georgia. The milkweed genus is in turn a member of the Milkweed family (Asclepiadaceae) of some 220 genera and more than 2,000 species, mostly tropical. In fact, only a half-dozen genera are found in North America. Several go by the name of milkweeds, though they are not of the Asclepias genus.

Milk Trap and Saddlebags

As the name suggests, milkweeds are known for their milk. In common milkweed, this white juice, which oozes out of the stems and leaves when broken, contains sugar, gum, fat, and other compounds. It is both acid and somewhat poisonous to animals. And it clots, like blood, soon after exposure to air.

Few creatures, including livestock and insects, will eat the plants because of the acrid fluid. What is more, since milkweed depends on flying insects for pollination, it doesn’t want ants and other crawlers robbing its nectar supplies. When larger ants start creeping up the plant, tiny spikes in their feet pierce the green flesh, the flesh exudes the sticky fluid, and the fluid tangles up the ant’s feet. As an ant struggles to clean off the goo, it gets even more glued and either becomes permanently stuck to the plant or falls off. No system, however, is perfect. I have seen small ants, probably light-footed enough to avoid breaking the skin, make it to the top and dine on the sweets.

To attract the kinds of insects they need, many milkweeds offer both color and extraordinarily sweet scent. The visitors are then given a little task to perform before obtaining their rewards. Although milkweeds come in various colors, common milkweed tends toward a hue that is difficult to describe—Mathews insists it’s “lavender-brown”; Mrs. William Starr Dana says it’s “dull purplish-pink”; Neltje Blanchan calls it “dull pale greenish purple-pink or brownish-pink”; Lawrence Newcomb describes it as “brownish pink or greenish purple”; and Roger Tory Peterson said it varies “in subtle shades of dusty rose, lavender, and dull brownish purple.” Whatever the color, it and the strong sweet fragrance, attract a wide variety of bees, butterflies, and moths. Often a half-dozen insects will roam the umbels at one time. Once the insects have landed, the plant plays a reproductive trick.

Each flower has a slippery surface. When an insect lands, its feet slide around—often down between one of the five nectar-filled points in a flower’s crown. If a foot gets briefly caught in a little slit, tiny pollen-coated devices, called pollinia, attach themselves. Ms. Blanchan said that these pollinia look like saddlebags, but they might also be likened to minuscule gnats with long amber wings. The pollinia drop off pollen as the insect visits other plants; eventually they fall away. If you watch closely as an insect crawls and often struggles around a freshly opened milkweed flower head, you may see one or several pollinia dangling from its legs.

It’s hard to imagine a cleverer device for plant reproduction, and you must inspect a flower with a needle and magnifying glass to really appreciate it. Ms. Blanchan, a great admirer of the milkweed, said that “After the orchids, no flowers show greater executive ability, none [has] adopted more ingenious methods of compelling insects to work for them than milkweeds.”

This system, like the sticky juice, is not perfect. Occasionally, bees, butterflies, and other insects can be found hanging dead from the flowers. Trapped in the pollinia-holding slit, they were attacked by spiders, ants, or beetles, or they were killed by heavy showers while struggling to get free.

The Butterflies

A few insects make use of the milkweeds in a different fashion. The caterpillars of the milkweed butterflies (Danaidae)—the most common of which is the orange-and-black monarch—feed on the leaves, usually in small enough quantity so as not to harm the host. The ingested acrid juice of the plant makes both the milkweed caterpillar and the subsequent butterfly distasteful to hungry birds. Some species of butterflies that are not milkweed eaters—such as the viceroy—mimic milkweed butterflies in color and design to take advantage of this strategy for survival.

Recent research has found that many common milkweeds contain potent, often poisonous, substances known as cardiac glycosides. Digitalis, a cardiac glycoside obtained from the foxglove, has been widely used to make heart muscles perform more efficiently after a heart failure. Various plants containing these substances have been used since ancient times to poison the tips of arrows. The glycosides in milkweed are strong enough to induce a heart attack in some grazing animals dumb enough to eat the bitter leaves.

It is probably these powerful cardiac glycosides that make monarchs unpalatable. Birds almost immediately become nauseous and vomit for up to a half hour after eating a monarch. After such an experience, most birds will simply bypass the monarch (and the look-alike viceroy). Some crafty birds, however, will catch a butterfly and sample a bit of a wing to see if it tastes bad, letting it go if it’s a monarch. In Mexico and Central America, where our monarchs spend the winter, there are birds such as grosbeaks and orioles that have learned which parts of the monarch contain the smallest doses of poison and eat only those parts.

The monarch is the best known of the milkweed butterflies, recognized by almost every schoolchild and frequently seen fluttering around patches of milkweed. The monarch caterpillar lives most or all of its life on the plant and then constructs its bright green chrysalis under a leaf. Once the butterfly emerges, it feeds on the flower’s nectar—a good reason for the caterpillar to refrain from overeating the host.


Milkweed uses the most convenient and available method of dispersing its seeds: wind. The seeds are topped with fuzz, or pappus, and breezes can carry these packages for miles. When the seeds land, they have a high rate of germination. Survival is also aided by the roots, which sink themselves deep in the earth and are hard to destroy. “Our milkweed is tenacious of life,” wrote John Burroughs. “Its roots lie deep as if to get away from the plow.” Moreover, common milkweed has a “mother plant,” with the deepest roots, which sends out underground runners that sprout other plants nearby.

In some states milkweeds are considered field pests, hard to eradicate and a threat to stock. Farmers find it particularly annoying because few herbicides can harm it without repeated applications.

Many people would just as soon have a patch of milkweed. They are handsome plants, the flowers have a sweet scent (Mathews said too sweet), and the blossoms attract beautiful butterflies and sometimes hummingbirds. The French, in fact, imported them to their gardens in the 19th century. Many people have found the open dried pods attractive additions to dried flower arrangements or wreaths. The pods are sometimes gilded, and often the insides are painted in a bright color.

Because of the deep roots, successful transplantation of mature plants is difficult. Attempt it only with small offspring of the mother plant in the spring. Better yet, grab a few pods in late August or September and plant seeds in fairly dry soil that gets plenty of sunlight. Seeds may be planted in the fall or spring.

There are many varieties of milkweed, and some others should be mentioned. The swamp milkweed (A. incarnata), which is widespread from the Rockies eastward, was once commonly used as a source of fiber for twine and cord. While smaller and less fragrant than those of common milkweed, its flowers are more beautiful. The specific name means “flushed with pink,” but the color is often deeper—purplish red or magenta. It can be planted in gardens with moist soils. Also rich in color is purple milkweed (A. purpurascens), common from the Plains eastward. Four-leaved milkweed (A. quadrifolia), unusual in that it favors shady forests instead of sunny fields, swamps, or roadsides, has pretty pink to lavender flowers. It, too, is found eastward of the Plains. A variety so red that it’s called bloodflower (A. curassavica—“of Curacao”) is common in the Gulf coastal states and in southern California. White-stemmed milkweed (A. albicans) favors the dry rocky deserts of the Southwest, while the showy milkweed (A. speciosa), with big, starlike, pinkish flowers, is found in a wide range of terrains from the central United States and Canada to British Columbia and California.

There is also the bright orange butterflyweed, a variety so handsome and interesting that it gets a chapter of its own -- the next.

This is a chapter from The Secrets of Wildflowers. 
Text and photo Copyright 2003 Jack Sanders. All rights reserved.

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