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Understanding Weeds A Better Way to Grow Neighborhood
Originally Published: 2009

This is a chat about cities. It may look like a chat about biological farming, but it’s really about cities. More specifically it’s about understanding several key dynamics in the care and feeding of the human habitat.

I have long held the belief that most of the questions we face regarding culture, society, the built environment, technology, relationships and other facets of the human universe can best be informed and guided by understanding antecedents in nature. That’s a long discussion and I’ve met resistance to the idea over the years.

I stubbornly continue to utilize this view, however, and find that it consistently delivers positive results.

So let’s talk about weeds.

Weeds themselves are controversial. Many people hold the view that a weed is simply a plant that is unwanted in a particular context. This relativistic view is handy and gratifies post modern sympathies but offers little in the way of practical understanding: “One man’s weed is another man’s rose.” A bit of the “Beauty is in the eye of the beholder” argument, a position I also think could stand some scrutiny.

There are positions offered by voices in the environmental community that claim that all plants have purpose and all plants fit into some mechanistic or even spiritual scheme that validates their existence, though we may not understand it yet. This aligns with certain religious positions as well.

Much of the problem in understanding weeds arises out of the fragmented way that we understand environments in the first place. We consider weeds out of context, as we consider most things. But we’ll find, I think, that context, ultimately, is everything and almost nothing can be understood without understanding its relationship to other things.

So I want to offer a simple model for understanding weeds in the context of natural systems

Diversity and Symbiosis

I will claim that there are two fundamental ingredients to any healthy natural system, whether the system being looked at occurs at the scale of a large habitat or a small plot of dirt in the garden. These ingredients are Diversity and Symbiosis. E.O. Wilson has made exhaustive studies and written extensively to both a geek and popular audience on the notion of diversity and will claim that increased diversity is nearly always associated with increased health of a natural place and that a decrease in diversity is almost always associated with decline.

I will also claim that weeds represent a class of plants that will take advantage of a weakened environment and will tend to reduce diversity and symbiosis in very selfish, sometimes self destructive, ways, often preying on the resources of other plants without actually giving much back to the habitat.

The current generation of biological farmers makes a compelling case, backed up by actual practice, that diversity coupled with orchestrated symbiosis in the family farm context is the key to successful, sustainable and dignified farming. The lessons utilized there grow out of traditional knowledge and experience backed up by the more complex understanding of the subtle interrelationships evident in natural settings over the last 50 years of environmental research. We find that most things in nature are interrelated in often less than obvious ways. This is, of course, consistent with older philosophical and religious traditions that seek to unite much of life and universe into single models.

I have outlined this notion of Diversity and Symbiosis as key elements of healthy natural habitats in another article. I have also claimed that diversity and symbiosis are useful metrics for assessing the health of the human habitat, particularly at the neighborhood level, but to some extent at any scale of settlement.

Controlling Weeds

So… there is a little book, memorably titled: “Weeds, Control Without Poison” written by a guy named Charles Walters.

Walters offers strategies for weed control in an organic farming setting. Much of the discussion is familiar as recognized methods for controlling weeds in such a setting. But embedded in his position is a very interesting notion: that weeds are not pests that should be directly eradicated, but are, in fact, useful indicators of the status of the soil in which they grow. Rather than see them as enemies, he makes a good case that they simply reveal a weakness in the soil and that the health of the underlying soil should be the target of weed control, not the weeds themselves.

Walters demonstrates that weakness in the soil prevents many useful plants from growing, limits the numbers of micro-organisms that can grow, and reduces the soil’s ability to support a diversified system of life that works interactively to maintain itself in ways that are, coincidentally, useful to humans. He makes repeated recommendations that the means by which you eradicate weeds, or put them back into their rightful position within a symphony of localized biologic life, is not to attack the weeds themselves, but to improve the health of the soil. The result will be an increase in diversity, the re-emergence of both plant and animal life that better balances needs and opportunities and a return to a localized complex of life that mimics the complexity of nature as a whole.

It’s about delegation. In fact, most plants can fight off their own diseases, and help maintain the diversity of their own habitats, if they are physically healthy. The best way to make them healthy (and in turn to fight off weeds and pests) is to make sure the soil is healthy, full of life and active with complex organic processes that work symbiotically.

In short, you don’t need to kill the weeds; you just need to feed the soil. The plants that grow well in diverse neighborhoods will in turn kill the weeds for you.

This is a simple notion, though it can get deep into soil chemistry, the critical role of trace elements and the equally critical role of diverse species of predators and prey that make a localized system sustainable. But it’s a notion that has precedent in other patterns in which man attempts to tinker with nature.

It’s also a very interesting notion, consistent with a class of realizations in which the common understanding of the problem is found to be incorrect and that decades of focus on that problem have been wasted by aiming solutions at the wrong target. It’s kind of like widening freeways and providing more parking as a means to relieve congestion.

In fact, in the world of farming, we have spent decades, and mountains of chemicals, trying to eradicate weeds with little result other than the specific degradation of overall habitats coupled with the general degradation of the whole of diversity of life. We have used chemicals to kill weeds that do so temporarily, then fail to do so, then turn out to have damaged other key species sometimes thousands of miles away. In the meantime, the weeds themselves get stronger as a result of the selection pressures accelerated by the use of poisons in the first place. Antibiotics offer the same pattern.

Certainly, in a natural setting, the onslaught of weeds could be seen as simply a step in a largely natural process. However, true weeds are rarely present in natural settings unless those settings have been somehow upset by human actions. In fact, there are no weeds in nature. In a natural habitat we may find all of the species that we call weeds, but in healthy natural settings all species tend to achieve a balance, usually via tension, that maintains diversity and exhibits symbiosis.

Weeds tend to occur in places unnaturally disturbed by humans. When diversity and symbiosis are lacking, when weeds appear to dominate and a healthy diversity is not present, we should look for what is missing, not just what is present.


Controlling Weeds in Cities

So let’s look at this model in the context of making healthy cities.

Much of the cause of sprawling big box suburbia can be traced to codes and policies created over the last 75 years. We have not simply made a choice to spread our cities out over the landscape and kill their interiors. Instead, we have created a body of law, in reaction to a wealth of forces, both social and industrial, that have defined the limited choices available.

The result has been fundamentally depleted soil. Our codes have discouraged diversity and actively attacked symbiosis such that our soil is sick and little grows that can be considered a “natural” city. The landscape has been scraped and only weeds grow well. These weeds take the form of strip malls and big boxes and sprawling mono cultures of houses, factories and other “unnatural” patterns of human habitation.

In recognition of the problems associated with this depletion of the urban soil, we have responded with additional regulation designed in the spirit of pesticides and herbicides: codes written to prevent specific occurrences and to eradicate specific, usually isolated, elements.

We have, essentially, sprayed poison all over the ground where we wish for cities to grow.

Consider a big box store such as Wal-Mart or Safeway and consider them as weeds in the urban environment. We are justified in doing this based on our definition of weeds as entities that exhibit, or generate, reduced diversity and symbiosis in a neighborhood. Big box stores tend to do this by monopolizing one of the key resources in a neighborhood: transactions. By stealing transactions from other businesses, usually smaller ones, they attack diversity and symbiosis. They limit competition and seek to isolate their customers from other businesses, attempting to keep transactions for themselves, much the way an invasive species seeks to monopolize nutrients and moisture in a natural setting.

It is no accident that the barren strip mall habitat that surrounds most of our cities actually resembles a vacant lot that has been allowed to return to weed, where the native species and accompanying diversity were long since bladed away.

It’s also no accident that the mechanism by which both are realized is similar in both spirit and craft. The forces that generate big box malls are specifically focused on wiping out the former competition offered by smaller, more diverse and more integrated “species” of business.

Recognizing the problem of big boxes (or any other pattern of typically sprawling America) we seek to control it to some extent in the same way that we attack weeds in natural settings: by aiming herbicides directly at the subject with little understanding of the larger setting, the failing soil in which these businesses grow.

We write codes, draft polices, instigate discretionary review on project after project in an attempt to force that project to behave as a good neighbor. We make national retailers jump through all kinds of hoops to shape them into a friendlier form, yet those businesses continue to capture transactions, the key resources in a healthy neighborhood. We add ordinances that require more land, more parking, more roads, more lights, more water, more fertilizers, more poisons so that our cities will look pretty while eliminating the very thing we love about cities: Locality, diversity, commodity, delight.

Any student of modern planning, particularly in the last twenty years, shares an increasing awareness that the codes and laws we have written to protect our cities are the very thing that is screwing them up. Just like the chemicals we apply to the soil as poisons and fertilizers are slowly depleting our ability to conduct sustainable agriculture.

Ultimately, we have made it so hard for local businesses to thrive that they die and blow away. We have robbed the soil of key ingredients; we have allowed diversity to slip away, symbiosis to fragment. While spraying the weeds we have inadvertently sprayed everything, with the net effect that we have actually favored the weeds.

So…Let’s consider a different approach. Rather than seeing the onslaught of big boxes and national chains at the outskirts of town as inevitable economic forces, suppose we see them as indicators of poor soil. And let’s consider the city as a habitat that quite likely behaves in very similar ways to natural habitats.

How do we build back the soil of community, how do we get the microorganisms of local and fine-grained commerce going again? We have very few codes that are actually aimed at the health of a city as an organism, as a living thing that requires nourishment and a reasonably supportive habitat. We tend to have a mechanical view of cities that catalogues uses and configurations, but we don’t often understand the organic way these things work together. We lament the loss of local businesses and historic neighborhood patterns while we do nothing to grow the actual soil that will, in turn, allow those forms to grow.

Were we proper organic farmers we would spend less time worrying about individual plants and more time ensuring that we had great soil capable of growing nearly anything (and intended to grow many things at once in close association.)

The answer is surprisingly simple, though it requires courage. We don’t have to force it; we just have to stop preventing it. We don’t have to increase the complexity of codes and regulation; we have to dramatically reduce that complexity.

This means that we need to remove the codes that actually discourage small businesses. We have to remove the codes that discourage small lot development and small scale redevelopment. We have to remove the regulations that discourage adaptive re-use, incremental density increases and simple increases in affordable business space. This means that a lot of interests may have to give up pet concerns because the codes that deplete the soil represent beloved and emotional issues to many.

For starters, city governments need to get back into the street business. Regardless of the size of a development, a connected grid of public streets, forming human scaled blocks, will create tremendous habitat for small businesses, human scaled mixed use and a “natural” evolution of settlement.

Next, cities have to get out of the parking business. Parking needs to become the property owners’ problem, not a problem for the public to solve. By backing off of parking requirements, and allowing a business owner or developer to determine whether parking is necessary, greater opportunities for diversity will occur, greater opportunities for small scale development will emerge, and affordable business spaces will increase in supply. At the same time, streets will become necessarily walkable as diversity and symbiosis favor trip combination and reveal the benefits of human interaction.

We may need to see a much more rational approach to accessibility codes so that older buildings and smaller projects are not overburdened by draconian lawmaking.

We need affordable business policies to accompany affordable housing. These will support increases in the supply of small business spaces and resulting rent competition, as well as fined grained mixed uses that encourage live-work and house-over-shop patterns.

We also need to get out of the business of use-based zoning and instead favor form-based coding that encourages great streets and great neighborhoods and offers wider choice and greater competition for the big box out by the freeway.


This is not the place to explore the answers in depth. I am more interested in the idea of seeking positive actions for growing healthy cities, rather than simply considering city planning as an exercise in the treatment of disease. I’m interested in growing cities the way nature grows complex organisms: through leverage and by allowing the “natural” forces of  human scaled commerce to once again drive the decision making process.

Rather than continue trying to beat sprawl by affecting it directly, I am more interested in simply undermining it by growing civilization downtown where the vacant land is waiting.

Rather than decorate sprawl with pretty landscaping, or attempt to kill it by overloading it with regulation, I’d rather steal back the transactions with irresistible urbanism in neighborhoods and let sprawl die a natural death.

The process has already started in most downtown’s in America.  People have discovered great neighborhoods, chosen to visit them and, eventually chosen to live in them. Downtown America is in better shape that it has been in 90 years.

But we still build sprawl and every city that has a great downtown still sprays poison around the edges where the next generations of neighborhoods need to grow.