Are weeds the enemy of mankind?
— Michael Pollan, *Weeds, Roses, and Groundhogs: How the Garden Educated Me*
I. Weeds Born in the Shadow of Agriculture
Since time immemorial, almost no farm has been free from the nuisance of weeds. Compared to other production stages, and even compared to pest and disease control, weeding remains the weak link in the application of machinery and agrochemicals. In this context, when people attempt to view weeds in a positive light, they often first think of their edible or medicinal value. However, I believe that for ecological agriculture, the true significance of weeds lies in a shift in perspective: to borrow the words of anthropologist Claude Lévi-Strauss, they are not only tasty, but they also help us think. In other words, weeds prompt us to consider: what should the relationship between humanity and nature look like?
The very existence of weeds provides an initial answer. Just as waste is merely a resource in the wrong place, weeds are simply plants whose virtues have yet to be discovered; they are born precisely in the shadows of agriculture. Among thousands of wild species, those successfully domesticated and utilised became crops; those unfavoured, yet competing with the former, were relegated to ‘weeds’. Which is which depends entirely on human livelihoods and cultural needs. Few realise that barnyard grass—a common ‘noxious weed’ in rice paddies that, through long-term selection pressure, has evolved to closely mimic rice (a phenomenon known as ‘Vavilov mimicry’)—was once a staple food for humans.
When we move away from an anthropocentric perspective, weeds lose their moral connotation of being ‘unclean’ or ‘dangerous’. Their appearance is simply a response to disturbed nature and soil—a natural tendency towards renewal through disruption. Therefore, from the perspective of ecological agriculture, weeds can rectify the imbalances of the land, potentially serving as an antidote to certain chronic ailments of modern farming. For instance, weeds growing in compacted soil often help loosen it, while those in loose soil are adept at binding it; where the soil lacks essential elements, certain weeds can enrich it, and where there is heavy metal pollution, weeds can help absorb and deplete it. Once the soil balance is restored, they step aside; conversely, if we persist in weeding or disturbing the soil, they will never cease their efforts.
During a collaborative learning session, an insight from an intern named Liangzai left a deep impression on me: ‘Weeds are a mirror; they reveal my heart.’ In traditional agriculture, the struggle between humans and weeds was not so fierce. Weeding was seen as a daily chore, akin to sweeping, and manual hoeing itself helped conserve soil moisture. Weeds were utilised in various ways, from famine relief and medicine to firewood, fodder, and weaving. In the modern era, the intensification of agriculture has exacerbated the disturbance of water, soil, and ecological balance, turning weeds into natural enemies that human civilisation felt it must conquer. Yet, for every action there is a reaction; in conventional agriculture, a chemical weeding approach that pursues efficiency at all costs while ignoring the interaction between weeds and the land has instead forged ‘super-weeds’. Even when faced with powerful herbicides like glyphosate, weeds will eventually develop resistance through mutation or genetic exchange. In contrast, ‘weed management’ in ecological agriculture requires farmers to truly immerse themselves in a diverse ecosystem. It is not merely about tolerating or utilising weeds, but about fostering nature through a dynamic, ever-evolving relationship where cooperation and competition coexist.
II. How Agroecology ‘Dances’ with Weeds
First is the direct removal of weeds that have already appeared, using physical methods (hand-weeding, mechanical weeding, mulching, etc.) or biological means (biopesticides). However, any single method of weeding exerts some evolutionary pressure on the weeds, leading to the formation of homogenised weed communities.
Second is the use of ecological principles to reduce the occurrence of weeds, such as crop rotation, intercropping, false seedbeds, drip irrigation, or even using certain plants to suppress others. The essence of these techniques lies in creating uncertainty in timing and diversity in the environment, making it harder for weeds to establish a consistent survival strategy.
Finally, there is the approach of allowing weeds to become a positive force in constructing the farmland ecosystem. When the ecological balance becomes refined and crops grow hardier, weeds cease to be a problem. This perhaps mirrors the old proverb: “The highest physician heals the state, the middle physician heals the person, and the lowest physician heals the disease.”
However, the ideal of ecological restoration often has to give way to the practical pressures of farm revenue. Yields from organic farming are often lower than those of conventional farming; moreover, many ecological farms begin on “sick land” that has been polluted or exhausted by chemical agriculture, requiring a longer period of rehabilitation. Some farms opt for more immediate weeding methods, even if they require greater manpower and resources. Yuhuzhou, from Gui Ling Farm in Dali, believes that ecological farms that rely solely on such methods have not truly broken free from the mindset of conventional agriculture; the natural restorative potential of the land has neither been trusted nor activated.
If we focus only on yield, we miss the “inexhaustible treasure” of ecological agriculture: sustainability and resilience—meaning crops are better equipped to handle adverse natural conditions. At Gui Ling Farm in Dali, the spacing between rose bushes is significantly wider than in typical farms, with other fruit trees and shrubs intercropped among them, and weeds allowed to grow without restriction. But do not underestimate these weeds: pushing aside the lush stems and vines, one finds a layer of humus, dead leaves, and mycelium carefully protecting the topsoil, bringing a sensory rush of brown, soft, moist, and fresh earth.
Yuhuzhou recalls that during a period of prolonged drought in Dali, other rose gardens suffered heavy losses, yet the plants at Gui Ling Farm weathered the crisis. Equally unbelievable to other farmers was the fact that pests, which ran rampant in their fields, were almost nonexistent here. It was the biodiversity created by the weed communities that completed the food chain, preventing any specific pest from becoming overwhelmingly dominant.
Ecological agriculture also brings another surprise to our lives: the flavour of the food. For consumers who have tasted ecological produce, this needs no explanation. Yet, visiting healthy land to taste its gifts provides an even more vivid and holistic form of nourishment. Yuhuzhou plucked a few fruits from a plum tree for us. The sweet and sour delight was such that it was hard to imagine the bitterness the tree possessed when it first arrived at the farm. The tree had been salvaged from someone who no longer wanted it, and the fruit it bore in the first two years was almost inedible. Yuhuzhou thought she would wait one more year; if it remained that bitter, she would simply dig it up. Unexpectedly, by the following year—perhaps after being “detoxified” by the farm’s soil and water—the flavour of the fruit had improved immensely. Yesterday’s patience created today’s kinship.
III.The Scope of ‘No Weeding’
Firstly, this involves reducing the obsession with intensification. If one does not strive for absolute perfection in yield and uniformity, a few weeds are harmless. At Gui Ling Farm, there are three small plots growing different varieties of rice; regarding common weeds like barnyard grass, Yu Hu believes there is no need to pull them. In essence, she has accepted a moderate amount of barnyard grass as a member of the paddy system; they grow as they will, without hindering the rice harvest.
Secondly, it involves providing alternative spaces for weeds. Ecological farms that grow grain crops on a larger scale—such as Green Me Farm in Xi’an or Yuefeng Island in Kunshan—will choose to leave the land fallow for a season, allowing weeds that help restore soil fertility to ‘replenish’ the earth. This offers a moment of respite and reconciliation for the weeds, the crops, the land, and the people: by the next season, the cropping pressure is reduced, and the requirements for fertilisation and weeding are lessened. At Xiqing Farm in Beijing, the strawberry patches are kept weed-free, but the surrounding areas are planted with Brassicaceae and other crops that attract insects, thereby leveraging the ecological control functions of weeds.
Beyond time and space, the boundary between weeds and crops can also be blurred through varietal diversity. Yuefeng Island is tasked with the conservation of heirloom varieties; among hundreds of rice varieties, about 20 are propagated in rows, while around 40 are conserved in small one-square-metre plots. These conservation plots require additional reinforcement with bamboo poles and ropes, and the timely installation of bird nets and shading nets. Here, the diverse temperaments of the rice were an eye-opener for me: early-maturing and late-maturing, tall-stalked and short-stalked, lowland and upland rice, and more. In particular, some tall-stalked varieties have leaves that bend like wild hair and panicles that splay haphazardly—in the vast majority of other rice fields, these would be pulled out as ‘wild rice’ or ‘weedy rice’.
IV.The Unknown Fate of ‘Invasive Alien Weeds’
Of all the weeds I encountered, the only one that made it difficult for me to cast aside my prejudice was the Canadian Goldenrod. Introduced to Shanghai and other regions as an ornamental plant in 1935, it gradually spread into the wild thanks to its extraordinary reproductive capacity and tolerance for poor soils. At Lexian Valley Farm in Fengxian, Shanghai, some idle plots have become the domain of this invasive alien species in just a few short years. Plants over a person’s height, with woody stems, grow in dense thickets; their allelopathic effects stifle surrounding herbaceous plants in the cradle, making them the fascists of the plant world. Every year, Teacher Yuan Qinghua leads a team to cut them down before they flower, but such measures can only temporarily control their outbreak.
Our primary task during those few days was weeding. Mowers could only handle low-growing grass; the swathes of Canadian Goldenrod required manual labour, using sickles or chainsaws. Teacher Yuan patiently corrected the details of my technique; once I became proficient, a single stroke would send a row of plants crashing to the ground. A spontaneous surge of battle spirit, ignoring the sweat and exhaustion, drove me to push deeper into the wasteland, stepping over broken stems. This was a more absolute ‘us versus them’ relationship than in conventional agriculture: practical production needs were sublimated into a sense of moral mission.
My feeling was not an isolated case. In our discussions, some partners who hoped to reduce or eliminate weeding also inevitably harboured hostility toward these malignant weeds. This perhaps stems from the following principle: life based on reciprocity and inclusion can coexist, while life based on aggression and exclusion must be halted. Therefore, eradicating malignant weeds is a ‘necessary evil’ in improving the agricultural ecology.
‘Invasive alien weeds’ are not just a matter between humans and nature; they embody the factors of human activity. Firstly, from early colonial history to the human migration and expansion of power in the era of globalisation, certain species have hitched a ride. Secondly, the regions where alien weeds are most severe are often lands significantly disturbed by large-scale reclamation, chemical agriculture, and industrial or urban construction. The weakening of native ecosystems has objectively cleared the way for outsiders by removing their limited competitors and natural enemies.
Even understanding this, we can only accept the fact that Canadian Goldenrod has arrived on this land, and no one can predict its future fate. Perhaps native weeds can be used to compete with it, perhaps new natural enemies will emerge to tackle it, or perhaps humans will develop new uses for it. But this takes time and inevitably results in harm to local people and other species. The only certainty is that on this land, continuously disturbed by humans, it is unlikely to simply disappear.
Perhaps the earlier arrival of the beggar’s tick can give us more confidence. From an ecological perspective, it is not an ideal successional species, but it objectively repairs disturbed and polluted land, weaving itself into daily life through its many uses. In the Stone City of Lijiang, Yunnan, like its native relatives, it has become embedded in the local knowledge system due to its wide utility (medicinal, fodder); its Naxi name no longer evokes its invasive origins. In Yan Ping’s Herb Garden, the beggar’s tick has even become a wild vegetable on the dining table. As it turns out, traditional agricultural communities and ecological farmers do not mechanically draw a boundary between native and alien species, nor do they elevate so-called ‘malignant weeds’ to a state of enmity. These weeds bring trouble, but there is room for transformation: at the very least, they are edible.
Coming full circle, ‘thought’ returns to ‘eating’. As anthropologist Anna Marie Moore has revealed, the relationships of eating and feeding shape the fundamental connections between different species. Humans have fed crops and weeds in opposite ways, and we eat them in opposite ways. After all, no finite life is self-sufficient; whether grass or human, one must ultimately learn to coexist and give and take with other lives in the environment. When the farm sheep gladly accepted a feast of Canadian Goldenrod, my prejudice toward this weed diminished.
