There is a sense in which the average gardener is like the motorist who tools along year after year in blissful ignorance of what goes on under the hood of his car. If the mechanism works, well and good. If it doesn’t, consult an expert. Don’t try to understand it. That, at any rate, has been my way. Incurious, for the most part, about the private lives of plants except as they impinge on my plans for them, I haven’t often asked myself why milkweed attracts butterflies or whether garlic is immortal; and still less have I been concerned with the larger matter of the environment that surrounds me. All I know is that my soil is on the acid side, and full of rocks. I have, to be sure, had my occasional suspicions that more is happening out there than meets the eye—going so far as to speculate that a vine reaching out horizontally toward a holdfast might have eyes or even a brain, and that those who claim to have witnessed the power of prayer on beans may have something. But these wanderings have more to do with superstitious magic than with an interest in science, which I am not, as they say, good at.

For all these reasons, a book apparently devoted to weeds didn’t promise to exert a spell. In my view, weeds have been something to get rid of, not study. Weeds, the catchall term that Stein has chosen to describe all plants not currently under cultivation, are fascinating—far more various and full of quirks and disguises than their domesticated counterparts. Or at least they become so under the scrutiny of an insatiably curious mind.

Here I should say that this isn’t a how-to book. Though it describes some of the innumerable uses to which so-called weeds have been put over the centuries, it isn’t a guide to concocting dyes or wild salads. Nor does it disclose any secret for eliminating weeds from the garden. Sara Stein hoes and hacks and curses like the rest of us, with no more and no less success. The difference is that she asks questions as she goes along, and having asked them goes to books and neighbors and old records to find the answers. She wants to know her enemies: where they came from, how long they plan to stay, and what their personal habits are.

Though we all know how quickly an untended garden will return to what is called a state of nature, few of us, I think, realize that the state of nature is no more permanent than the garden itself. A garden is an interregnum, an artificially induced pause in the inexorable march of occupying armies. But so, too, is the landscape beyond it unless by some remarkable chance it happens to be a forest primeval or a virgin prairie. These are stable plant communities that have reached what is termed the “climax,” meaning that they will undergo no further transformation without outside interference, and no weeds grow in them. Weeds appear in the wake of disasters, fire and flood that sweep clean, or that most persistent of all disturbances to the natural order: agriculture. It is the plow (and by extension the gardener’s hoe) that by clearing the land restarts the process of colonization. Weeds are therefore and very largely our creatures, our very own monster children.

Were I as well-informed as Stein, I would have realized that I have a perfect example of how it all works right here in the scraggy, ill-conditioned woods of shoreline Connecticut. I knew that most of this land had been farms and orchards only a few generations ago (broken stone walls, strangling in wild grape and poison ivy, are everywhere in the undergrowth), but failed to make the connection. The inferiority of our woods must, I thought, be due to some deficiency in the environment, or simply human failure to clear the brush, as was regularly done by the peasantry where I used to live in Eastern Europe. It isn’t so. Our woods are weed woods, in a transitory stage, and if left alone will, in another hundred years, give way to a noble forest like the one the early settlers cut down.

Stein, who lives about a hundred miles down the road from me in country very like this, has explored it like an archaeologist, noting the stages of growth as though they were the strata of a lost city. Here she is on a bank of the Mianus River:

The stages of succession are palpable in a place like that, where the forest-to-be is barely shoulder high, and the meadow-that-was is dying. The dominant trees will never amount to much. They are fast-growing but short-lived, and lack the stature of trunk or wealth of crown valued in specimen and shade trees. Such species as poplar, sassafras, and wild cherry are considered weed trees, and I would cut down every one of them as so much woody ragweed were it not for the part they play in plant succession. In every stage, from bare earth to beech grove, weeds both cull the old and nurse the new.

Grasses are the earliest arrivals on cleared land, as everyone knows who has let a vegetable garden lie fallow for a season; and they in turn are invaded by goldenrod, milkweed, daisies—plants whose roots are strong enough to penetrate turf and make a meadow. But not for long. All these are sun-lovers, and soon they will be shaded out by the advancing thickets and weed trees whose seeds do not need sun to germinate. But these, too, are doomed. Mining the soil with their roots, depositing their annual mulch of leaves, they unwittingly prepare the conditions in which the forest giants can take their stand at last—terminating the cycle.


Weeds are the proletariat of the vegetable world. Teeming in their ghettos, thriving on neglect and adversity, they are a continuous threat to the cultivated plants that like a spoiled and passive aristocracy wait for their needs to be met. Because the traits we desire are precisely those that nature discriminates against, cultivars depend on us for their very existence. Wild yams, for instance, are poisonous, wild beans purgative, wild carrots bitter and tough. Thousands of years of cultivation have bred out these protective characteristics in favor of sweetness, tenderness—edibility, in short, which insects, too, prefer. Natural selection, moreover, culls the weaklings from the wild population, leaving the survivors more resistant to plagues. What gardener hasn’t noticed the spectacular health of weeds as opposed to his rusted beans and mildewed phlox?

All this is bad enough. Most serious of all is the loss among many cultivated plants of the ability to disperse their seeds, delay their germination, or in some cases to make seed at all. The domestic pea is a prisoner in its pod, which no longer splits to release it. The cultivated tomato, unlike its little wild cousin, is too big to be swallowed by birds, who spread seed far and wide. Wild grains have heads that shatter easily, releasing seed that is barbed to catch at passing animals. Domesticated cereals have shatter-proof heads and the seed, ripening all at the same time, stays on the stalk. In each case, a plant has been deprived of its capacity to multiply and must depend on us for its propagation and ultimate survival.

Some cultivated plants do, in fact, seed themselves, but only in their own immediate vicinity. Few are independent travelers. Weeds, on the other hand, are invincible wanderers. They may be powered by their own fiendish devices: burrs that float or grab; winged seed that flies before the wind. Tumbleweeds roll themselves into a ball and cover vast distances like miniature tornadoes. But most weed seed is moved, unwittingly, by men and animals. In cattle guts and packing materials, attached to hoofs and wheels, weeds have crossed oceans and continents. A few have even spread by invitation. Rosa multiflora, a pervasive nuisance, was imported to control erosion and fence highways. But one way or another weeds move. They move and they flourish, often by means that are close to unbelievable.

One of these is mimicry, whereby a weed changes its shape and size as circumstance requires. In alternate stands of winter and spring barley, a weed form of the genus Arena is a rosette among the rosettes of winter barley, grows tall among the taller spring barley, with which it also blooms simultaneously. Doppelgängers like these have been with us, it seems, since the dawn of agricultural history, and we won’t be rid of them soon. Indeed, it is hard to know what action could be taken, since every effort to eliminate them actually has the opposite effect. Sieving the grain to remove weed seeds naturally selects for those that are the same size as the crop—guaranteeing that they will be replanted. Pulling or otherwise trying to get rid of the plants themselves further intensifies selection for mimicry: those weeds that most resemble the farmer’s crop are just the ones he will miss. With some crops the situation is almost hopeless. A rice mimic, for example, is so like cultivated rice that the farmer, unable to tell them apart, must trample his crop in order to “weed” it. (Researchers tried to solve this one by breeding purple rice. No good. Within a few years, the weed had turned purple, too.)

There is more. Some weeds are parasites. A beautiful member of the snap-dragon family called Striga asiatica, more perniciously known as witchweed, is such a one and it threatens to engulf whole provinces in India and Africa, reducing everything in sight—corn, cultivated cereals, cotton, soybean, and tobacco—to stubble. Its method is as devastating as it is simple. Even before it has thrown a shoot, the almost invisible seed has plugged itself into the root of the host plant, which it proceeds to inject with poisons that will sabotage the plant’s hormone balance and clog its circulation. This lethal beauty was first noticed in the United States in 1956, and nobody seems to know quite what to do about it, other than to try quarantine. The seed, however, is wind-borne, making this an unlikely cure.


Some plants may as well be called immortal—at least from the human perspective. There are bristlecone pines that germinated four thousand years ago, sequoias that were full grown when the Normans invaded England. The life span of all plants is genetically determined, and in these the genetic instructions apparently didn’t include information about how to get old and die. We can be thankful that weeds, which are fast-growing and generally short-lived, don’t fall into this category. Nevertheless, there are those that do achieve a kind of immortality in other ways. Any plant that reproduces itself by cloning—that is, by throwing off bulblets—or that has the power to sprout from root or stem cuttings, is perpetuated in identical form, more or less indefinitely. No clone or cutting of this kind knows its own age: in each, the genetic clock has been set back to infancy, and in effect the plant begins all over again from scratch. This characteristic can be useful—as when cuttings from antique apple trees are grafted to new rootstock to reproduce valued old species no longer grown—and no one is sorry to see a stand of ancient lilies renewing itself year after year.

But with weeds the results can be appalling. Cuttings from a single prickly pear plant introduced to Australia in 1839 have multiplied to cover sixty million acres. Most of us have encountered weeds whose response to being hacked at is to spread like something out of a horror film. Many of the bindweeds have this characteristic, and it is futile to hoe them out unless you remove every last fragment. And in the case of Ipomoea pandurata even this won’t serve. Known to folklore as “man-under-ground,” this fearsome thing, which looks like a morning glory, has a root as big as a man’s leg that weighs up to thirty pounds and is buried “at the depth at which we store corpses.” Digging it up would be like unearthing a coffin, and the only way to get rid of it is to pluck its stems weekly for two summers, when all the food stored underground will be used up and no new shoots appear.

A passionate determination to survive is always moving, even in a plant that man (as opposed to nature, whose agenda often differs) has no earthly use for. When weeds sprang up in the ruins of bombed-out London, they were greeted as a sign of hope, proof that life would go on. And rightly, too. The arrival of weeds on the slopes of Mt. St. Helens after a volcanic eruption signaled that the long process of reforestation had begun. We need weeds, or call them wild plants since that is what they are, and not only because they are the colonizers of blasted heaths. Just as important is their genetic diversity, which is vital to the famous gene pool. Though necessary to agriculture no less than to the home garden, the incessant breeding of “new and improved” varieties poses the same threat to health (and perhaps to the green equivalent of sanity) as the inbreeding of human beings. The over-hybridized plant becomes a kind of vegetable idiot. The perfect ear of corn ripening in unison with its identical neighbors has been purged of the recessive genes that might make it resistant to drought, say, or high winds, or certain pests and diseases; and if these should strike it can’t cope. Worse, neither can any of the other plants in the field, or for that matter in the whole country—if the condition is widespread and the crops are of the same variety. This has happened. In 1970, one third of the American corn crop was wiped out by an attack of fungus on a single strain of corn.

The danger of genetic impoverishment hasn’t gone unnoticed. An international effort to set up gene banks of seeds garnered from antiquated varieties hidden away in primitive communities (mostly in third world countries) may work if it is carried out before the old strains become extinct—and if the rage for high-yield, high-profit crops can be slowed if not halted. But as Stein says, “The miracle of fat new corn is understandably spreading faster than any multinational urge to collect old shrunken kernels,” and anyway can we really demand that the half-starved peasant stick to his meager crop of corn and beans in order to preserve the genes that we have lost to progress? Obviously not. A burgeoning world population is waiting to be fed by the new “miracle” grains. But the future looks cloudy. Efforts to outwit the corn-killing witchweed, for example, by developing corn strains resistant to it, foundered on the limited number of corn genes available to researchers as opposed to the nearly limitless reservoir the witchweed has to draw on—in human terms, an army of millions to overwhelm a tiny fighting force. There is an alternative: a sophisticated control system that includes huge doses of nitrogen, an exacting regime of herbicides, and the injection of ethylene gas. But it is so ruinously expensive as to rule it out for general commercial use, even in developed countries. In places like Kenya, where the witchweed scourge is endemic, there would seem to be no conceivable way to finance an eradication program.

There is another catch to solving the problem of genetic diversity. Many seed companies that were once privately owned have been swallowed up by petrochemical conglomerates whose business is the marketing of the herbicides, pesticides, and fertilizers that modern hybrids depend on for their very lives. Clearly, they aren’t interested in developing plants that can do without their costly products. I mention this because Stein doesn’t, and the omission seems to me indicative of her book’s only serious flaw. In my view, she is too lenient by half with the chemical manufacturers—has too much faith in their good intentions, and is downright credulous about the asserted harmlessness of their products. Thus, she gives “guilt-free grades” to the herbicide Round-up, and says she feels “safest” with systemic insecticides while acknowledging that they are “imperfect.” She would use Sevin if she had a vegetable garden. Well, I have a vegetable garden and I wouldn’t at any price. (Doesn’t she know that among other hazards it is lethal to honeybees?) She seems to think it’s enough to read labels carefully, and if still unsatisfied to ask the companies for more precise information—as though their claims to safety hadn’t been disproved, over and over again. Finally, she appears to believe that because many plants are themselves in the business of producing poisons we are somehow entitled to follow their example.

It is true that the record of depredation by plants is impressive and that some of their methods read like the inventory of a medieval torture chamber. In herbivores, plants can cause death by hemorrhage, asphyxiation, kidney failure, enzyme destruction, respiratory paralysis, heart disease, and hypothyroid derangement. Against insects they employ poison gas, and various forms of strangulation, flaying, and burning alive. Still other plants manufacture their own herbicides, inhibiting the growth of anything around them. Not an attractive list, but part of the intricate and delicately calibrated system known as the balance of nature. Stein ought to understand this, just as she should know how easily (and sometimes fatally) it can be disrupted by the introduction of man-made toxins.

For a start, plants kill selectively. Most chemicals don’t. Again, nearly every predator has been provided with a natural enemy. Most insecticides destroy them both—upsetting the whole process. And does she seriously believe that plants are capable of contaminating the waters of the earth as chemicals have done? (That idea would be uncomfortably close to Ronald Reagan’s deathless assertion that pine trees pollute the atmosphere.) Or that any natural herbicide is the equivalent of 2,4,5-T, the weedkiller used on American lawns until, eight years after the Vietnam War, the public woke up to the fact that it was an ingredient of the infamous Agent Orange? There is something of naughty defiance in her confession that her toolshed contains a number of products deadly to people, pets, and pests alike, and I was not amused by the childish statement, “I zap, I like it, Poisoning is fun.”

This considerable caveat aside, Stein has written a fine and original book. Most importantly, she has taught me to look carefully where once I was blind. “It’s the weeds,” she says, “whose peremptory statements are commanding enough to make the gardener, gritty from his struggles, wonder if maybe plants are more than the dumb greens they appear to be. For me, the intimacy has been of a higher order than I could have guessed when I first set out to understand the catbrier’s underground anatomy.” I don’t think I have any cat brier in my garden. But I do have quack grass among the parsley, and when I pulled it up the other day, I remembered Stein’s remark that a rhizome, inching through a flower bed, slows the growth of anything in its way. That didn’t seem to have happened. The parsley looked fine. But it is early in the season, and I remembered that in other years the parsley planted in this same spot and subject to the same invasion did mysteriously yellow and wither. So I have decided to trust her—and to look harder in future.

This Issue

September 29, 1988