Are Weeds Humanity’s Enemies?
— Michael Pollan, Weeds: In Defense of Nature’s Most Unloved Plants
I. Weeds Born in the Shadow of Agriculture
Throughout history, few farms have been free from the bother of weeds. When compared to other farming operations, or even to pest control, weeding remains a weak link in the deployment of machinery and agrochemicals. Consequently, if we seek to view weeds in a positive light, we tend first to consider their culinary or medicinal value. Yet, in my view, for ecological farming, weeds offer something far more significant: a shift in perspective. To borrow the words of anthropologist Claude Lévi-Strauss, they are not only good to eat, but also good to think with. In other words, they prompt us to reflect on what the relationship between humanity and nature ought to be.
The very existence of weeds provides a preliminary answer to this question. Just as waste is merely a resource out of place, weeds are plants whose virtues remain undiscovered, flourishing precisely in the long shadow of agriculture. Among the countless wild species, those successfully domesticated and utilised become crops, while those that go unloved yet compete with them are consigned to the status of weeds. How we draw this distinction ultimately depends on human livelihood and cultural needs. Few realise that barnyard grass—a notorious pest in rice fields—was once a staple food. Centuries of selective pressure have led it to mimic rice so closely, a phenomenon known as Vavilovian mimicry.
When we step away from an anthropocentric viewpoint, weeds shed their moral baggage of impurity or menace. Their emergence is simply a response to disturbed nature and soil, a natural tendency to clear away the old to make way for the new. Consequently, from an ecological agriculture perspective, weeds can rectify soil imbalances, potentially serving as an antidote to the entrenched ailments of modern farming. For instance, weeds growing in compacted soil tend to loosen it, while those in loose soil excel at stabilising it; where essential nutrients are lacking, certain weeds will accumulate them, and others can draw out heavy metal contamination from polluted plots. Once the soil’s balance is restored, they quietly withdraw; conversely, when farmers persist in weeding or constantly disturbing the earth, the weeds refuse to yield.
During a collaborative learning session, an insight from our intern Liangzai stayed with me: “Weeds are mirrors that reflect the condition of my mind.” In traditional agriculture, the conflict between humans and weeds was far from intense. Weed clearance was treated as a routine chore, much like sweeping. Hand weeding itself helped retain soil moisture, and weeds were utilised in myriad ways—from famine relief and medicine to firewood, fodder, and weaving materials. It is only with modern agricultural intensification, which has severely disrupted water, soil, and ecological balance, that weeds have been cast as natural enemies humanity must conquer. Yet force begets resistance: the harder we push, the more fiercely they rebound. In conventional farming, a relentless pursuit of efficiency through chemical herbicides, which entirely ignores the interactive relationship between weeds and the land, has inadvertently bred “superweeds”: Even against potent herbicides like glyphosate, weeds will ultimately develop resistance through mutation or gene flow. By contrast, “weed management” in ecological agriculture requires farmers to truly immerse themselves in a diverse ecosystem. It is not merely about tolerating or exploiting weeds, but about fostering nature through a dynamic, continuously unfolding interplay of life where cooperation and competition coexist.
II. How Ecological Agriculture “Dances” with Weeds
The first tier focuses on directly eliminating established weeds, employing physical methods (hand weeding, mechanical cultivation, mulching, etc.) or biological controls. However, any singular weeding technique inevitably exerts evolutionary pressure, ultimately fostering a homogenised weed population.
The second tier draws on ecological principles to suppress weed emergence, utilising practices such as crop rotation, intercropping, false seedbeds, drip irrigation, and even using certain weeds to manage others. The essence of these techniques lies in introducing unpredictability in timing and diversity in the environment, preventing weeds from exploiting predictable niches.
The third tier embraces weeds as a constructive force in building farmland ecology. As ecological balance matures and crops grow more resilient, weeds naturally cease to be a problem. This philosophy echoes an ancient Chinese maxim: “The supreme physician heals the state, the competent physician heals the individual, and the lesser physician treats the disease.”
Yet the ideal of ecological restoration is often forced to yield to the practical pressures of farm profitability. Organic yields frequently lag behind conventional ones. Compounding this, many ecological farms begin on ‘sick soil’—lands depleted or contaminated by chemical agriculture—that require extended periods to rehabilitate. Some farms therefore turn to more direct, quick-acting weed control methods, even when they demand greater labour and resources. At Guilong Farm in Dali, Yuhu argues that ecological farms that rely exclusively on such interventions have not truly broken free from conventional agricultural paradigms; nature’s innate capacity for self-repair remains neither trusted nor harnessed.
If our focus remains solely on yield, we overlook ecological agriculture’s true ‘inexhaustible treasury’: sustainability and resilience—qualities that enable crops to better withstand adverse environmental conditions. At Guilong Farm, rose bushes are spaced considerably wider apart than on typical plots, intercropped with various fruit trees and shrubs, while weeds are permitted to grow unchecked. Yet do not underestimate these weeds: part the lush stems and creeping vines, and you will find fallen leaves and a mycelium-rich humus layer carefully safeguarding the topsoil. A rich, brown, soft, damp, and refreshingly earthy atmosphere greets you.
Yu Hu recalled that when Dali recently suffered through consecutive droughts, neighbouring rose gardens took heavy losses, while the plants at Guiling Farm weathered the crisis. What proved equally unbelievable to other growers was that the pests running rampant in their fields were almost entirely absent here. It was the biodiversity fostered by the weed communities that balanced the food chain, preventing any single pest from dominating.
Ecological agriculture has brought us another welcome surprise: the flavour of food. For consumers who have tasted ecologically grown produce, this needs no explanation. Yet, visiting healthy land to taste its bounty firsthand offers a more vibrant and holistic form of nourishment. Yu Hu casually plucked a few fruits from a plum tree for us. The sweet-tart, juicy delight made it hard to imagine the bitterness the tree produced when it first took root on the farm. Originally discarded by its previous owners and rescued by the farm, the fruit it bore for the first two years was nearly inedible. Yu Hu decided to wait another year, reasoning that if it remained just as bitter, she would simply dig it up. To her surprise, by the following year, perhaps after the farm’s soil and water had “detoxified” it, the fruit’s flavour had transformed remarkably. The patience invested then has yielded the connection we enjoy today.
III. The Scope of ‘No-Weeding’
First, there is a conscious step back from the relentless pursuit of intensification. If maximum yields and absolute uniformity are no longer the overriding goals, a scattering of weeds is hardly a cause for concern. At Guiling Farm, three small plots are dedicated to different rice varieties. When it comes to common weeds such as barnyard grass, Sister Yuhu simply says: leave them be. In effect, she has come to view a moderate presence of barnyard grass as a natural component of the agroecosystem. They grow alongside the crops, undisturbed, without detracting from a bountiful rice harvest.
Second, farmers can allocate alternative spaces for weeds. Large-scale ecological farms cultivating staple crops, such as Lüwo Farm in Xi’an and Yuefeng Island in Kunshan, may opt for a season of fallowing. This allows the land to be ‘replenished’ with weed species that aid in restoring soil health. For both crops and weeds, as well as for the land and the farmers, this fallow period offers a chance to catch their breath and reach an equilibrium: heading into the next season, crop succession pressures ease, and the demands for fertilising and weeding diminish accordingly. At Xiqing Farm in Beijing, weed-free cultivation is maintained within the strawberry beds, yet the surrounding margins are planted with cruciferous species designed to attract beneficial insects. In this way, the ecological pest-control benefits typically associated with weeds are still harnessed.
Beyond the dimensions of time and space, the line between weed and crop can also be blurred through variety diversity. Yuefeng Island plays a key role in conserving heritage varieties. Out of several hundred rice cultivars, roughly twenty are propagated in neat rows, while around forty are maintained in small, one-metre-square conservation plots. These delicate squares require additional reinforcement with bamboo stakes and twine, alongside the timely installation of bird-proof and shade netting. The sheer diversity of rice temperaments encountered here is eye-opening: early and late maturing types, tall and dwarf stalks, paddy and upland varieties, to name but a few. Certain tall cultivars, in particular, stand out: their leaves droop and tangle like unruly hair, and their panicles splay out in a casual, untamed fashion. In virtually any other rice field, such plants would be classified as ‘wild rice’ or ‘weedy rice’ and promptly ripped out.
IV. The Unknown Fate of ‘Invasive Alien Weeds’
Of all the weeds I have encountered, Canadian goldenrod is the only one that still resists my efforts to shed my preconceptions. Introduced to Shanghai and surrounding regions in 1935 as an ornamental, it has steadily colonised the wild, driven by its formidable reproductive capacity and tolerance for nutrient-poor soils. At the Lexian Valley farm in Fengxian, Shanghai, several fallow plots have, within just a few short years, fallen entirely to this alien invader. Standing taller than a person with tough, woody stems, the plants proliferate in dense, unruly thickets. Their allelopathic exudates stifle every neighbouring herbaceous species before they can take root, making them veritable fascists of the botanical world. Each year, Yuan Qinghua organises crews to cut the stands down before flowering, yet such interventions merely offer temporary reprieve from their explosive spread.
For those few days, our main task was weeding. The mower could only manage the shorter grass; the dense patches of Canadian goldenrod had to be dealt with by hand, using sickles or chainsaws. Teacher Yuan patiently corrected the finer points of my technique. As I gradually gained proficiency, a single swing would send a whole row of plants crashing down. A surging fighting spirit, disregarding the sweat and exhaustion, drove me to push steadily deeper into the wasteland, stepping over the fallen stalks. This was a far more resolute us-versus-them dynamic than in conventional farming: a practical production need elevated to a sense of moral mission.
My experience was not an isolated one. In conversations, even those partners who hoped to weed less or not at all found themselves harbouring a certain hostility towards the more pernicious weeds. This perhaps stems from an underlying principle: life governed by reciprocity and tolerance can coexist, while life characterised by aggression and exclusivity must be checked. Consequently, clearing noxious weeds becomes a “necessary evil” in the pursuit of a healthier agricultural ecology.
The issue of “alien invasive weeds” is not merely a matter of conflict between humanity and nature; human activity is intrinsically woven into it. First, from early colonial history to the human migrations and territorial expansions of the globalised era, certain species have simply hitched a ride. Second, the regions most severely affected by invasive weeds are often lands already heavily disturbed by large-scale land clearance, chemical agriculture, and industrial or urban development. The weakening of native ecosystems has, objectively, cleared the field for outsiders by eliminating what limited competitors and natural predators remained.
Even with this understanding, we can only accept the reality of Canadian goldenrod’s arrival on this soil, and no one can predict its ultimate fate. Perhaps native weeds can be harnessed to outcompete it; perhaps new natural predators will emerge to keep it in check; or perhaps humans will yet discover a new use for it. But this will take time, and inevitably, local people and other species will suffer in the process. The only certainty is that, on land perpetually disturbed by human activity, it is highly unlikely to simply vanish.
Perhaps the three-leaved beggar-ticks, which arrived earlier, might give us a little more confidence. Ecologically, it is not an ideal successional species, yet it objectively helps rehabilitate disturbed and polluted land, and through its varied uses, has woven itself into people’s daily lives. In Shitou City, Lijiang, Yunnan, much like its native relatives, it has become embedded in local knowledge systems through its wide range of applications (medicine, fodder). Its Naxi name no longer readily conjures its invasive origins. In Sister Yan Ping’s herb garden, beggar-ticks even found their way onto the table as a wild vegetable. It turns out that traditional farming communities and ecological farmers do not draw rigid boundaries between native and alien species, nor do they elevate so-called “noxious weeds” into an us-versus-them conflict. These weeds may bring trouble, but they also leave room for transformation: at the very least, they are edible.
Having come full circle, ‘thought’ leads us back to ‘eating’. As anthropologist Anna Marie Moore illuminates, the interplay of eating and feeding forges the foundational bonds between the lives of different species. We nourish crops and weeds in opposing ways, and we consume them in equally contrary fashions. After all, no finite life is self-sufficient. Whether grass or human, we must ultimately learn to coexist with other beings in our environment, continually giving and taking. Watching the farm’s sheep heartily relish a meal of Canadian goldenrod, my preconceptions against this particular weed began to dissolve.
