superweeds

The above graph nicely illustrates what we're up against when it comes to invasive plants. A few species of highly adapted superweeds are being transported across oceans at unprecedented rates. The California Invasive Plants Council estimates that CA spends a minimum of $82million a year on attempting to control these runaway armies of leafy terrorists with very limited success. The plants continue to spread and new species are regularly introduced despite valiant efforts to intercept these illegals at CA's borders ("Any fresh fruits, vegetables, or living plants with you today?")


The top dozen most wanted weeds in california?

Aegilops triuncialis - barb goatgrass
Bromus madritensis ssp. rubens - red brome
Centaurea maculosa - spotted knapweed
Centaurea solstitialis - yellow starthistle
Cortaderia selloana - pampasgrass
Cytisus scoparius - Scotch broom
Delairea odorata - Cape-ivy, German-ivy
Euphorbia esula - leafy spurge
Foeniculum vulgare - fennel
Genista monspessulana - French broom
Hedera helix, H. canariensis - English ivy, Algerian ivy
Lepidium latifolium - perennial pepperweed

in urban areas these are the plants the colonize the cracks and margins where maintenance is minimal. Once established, these plants can be impossible to eradicate. Many of the plants will readily grow in the rugose spaces of architecture and infrastructure, often at edges, seams, or material transitions where an interruption in the impermeable cap creates a micro-swale for collecting nutrients and water. As the plant grows the expansion of roots, stems, and leaves act like small hydraulic jacks slowly and inevitably pushing aside the built environment to increase the potential for growth, survival, and reproduction. The forces at work are enormous, the sun pump driving massive disintegration of urban spaces through the microscopic multiplication of meristematic tissue. If we stopped our constant hacking, poisoning, mowing, pulling, and burning a handful of feral plants would quickly engulf our homes and cities, attacking walls, roofs, rafters, roads, bridges, skyscrapers, freeways, gardens... a smooth green skin appliqued to the city's
bones.



so how do we stop them?

A few options:
manual control: expensive, time consuming, hard, and effective
fire control: dangerous, many invasives surive or are encouraged by fire
chemical control: cheap, fast, easy, and completely ineffective.



broad spectrum herbicide applications for the control of invasive plant species poses the same risks overreliance on antiobiotics does; namely the inevitability of breeding resistance into the target population. This is readily observed in the proliferation of Roundup resistant weeds in areas that rely on Monsanto for their genetically modified herbicide resistant crops. (another reason to buy organic... less risk of GMOs)

the good folks at grist bring us this:

"In the U.S. alone, glyphosate use jumped by a factor of 15 between 1994 and 2005, CFS claims. And this herbicide gusher has given rise to a host of "superweeds" -- weeds that tolerate heavy doses glyphosate. How do farmers deal with superweeds? By jacking up the dose of glyphosate"

Glyphosate... (key ingredient in Roundup) better than atrazine right? Sure, but that's like saying a Hummer is better for the environment than a Hummer limo, not inaccurate but not entirely true. Wikipedia summarizes.
I'm most interested in this paper which suggests that glyphosate may inhibit the ability of soil microbes to protect plants against pathogens, causing higher incidence of plant diseases in fields treated sprayed with Monsanto's magic SAFE weed killer.

uh oh...

There are now confirmed cases of herbicide resistant weeds in 13 states, reporting a total of 63 different weed species. At this rate Roundup ready crops will be completely useless despite the millions of gallons of glyphosate saturating our soil. This points to a larger problem of herbicide resistance in invasive plants and suggests that it's only a matter of time before English Ivy, pampas grass, and japanese knotweed figure out our chemical tricks.

I imagined a sort of high-tech government facility deep in the Ozarks where top-notch plant breeders are hard at work developing the most virulent and unstoppable weeds imaginable. The vigor of Arundo donax, the taproot of knapweed, the rhizome of bamboo, the seeds of a thistle, the thorns of himalayan blackberry, the roundup resistance of Monsanto's weeds, and the speed of kudzu.
Weaponized weeds.



So what can we d0?
biomass production seems like an obvious solution. these plants can be converted into compost or energy (or both via biochar) and used to increase soil fertility in the degraded zones that often have both the absence of maintenance and competition that incubate these over-zealous castaways.


(example showing Jean Pain's biomass experiments)

This requires, like always, a ton of maintenance and given the tendency for machines to make the problem worse via incomplete removal and meristem shattering, it will probably have to be done the old fashioned way, by hand. This, of course, is radically expensive and would seem to encourage more creative incentives for invasive control, such as exchanging space for time (the homestead approach).

There is the possibility that the proliferation of exotic invaders that destroy our human-made environment are a sort of built-in mechanism for biosphere regulation. Invasive plants are the land's attempt at fighting back against the suffocating cap of impervious surface, a bioclimatic reflex. Combined with crazy rasberry ants: eating electrical devices throughout the southern U.S.(!), H1N1, and zebra mussels it would appear that the control we believe we have over our environment is a wayward delusion persisting from the mechanistic roots of enlightenment science. Maximum control only pushes the inherent energy of the system into other channels (why fences are always hopped). We exist at the mercy of our fellow lifeforms and rather than fighting them we need to focus more of our energy towards developing complex probiotic solutions to our abiotic actions.

on weeds

working as much as possible with, and as little as possible against the natural forces already present there.


a weed, like wilderness, nature, beauty, evil, and a perfectly clean shirt are all cultural constructs, a second order sign used to corral an ever changing set of beliefs, like herding cats. generally, a weed is a plant that grows better than the plants you would prefer to see growing in a particular area at a particular time. weeds are a constant ecological pressure exerted on the order & human usefulness of a given garden, pasture, or lawn. we want the system to grow like we imagined it would, and weeds often disrupt that idealized vision. so we pull them out, poison them, and curse the curse that kicked us out of the garden where apparently the noxious weeds were nil. of course sometimes weeds actually do some damage. they get stuck in our livestock's feet, poison the ground, smother the fruit trees, and grow through cracks in walls like they just don't care. billions of dollars in damage & lost revenue, a worldwide epidemic of virulent invasive species literally bringing down our homes around our heads. yet you don't hear the candidates talking about this problem do you?


well i have a solution to all your weed struggles. it's called reframing the weed debate and it's simple; instead of dividing up all the plants into two categories, weeds & non-weeds, just use one category, plants. as far as evolution goes, plants have been at it for much longer than we have and really have some pretty powerful tricks up their sleeves to avoid eradication. various government & private agencies spend millions of dollars each year attempting to remove targeted plant invaders from the landscape; arundo reed, knotweed, scotch broom, star thistle, english ivy, and as it turns out it doesn't work. the plants come back, or they will soon enough.

reframing weeds is championed by one of my favorite landscape architects, a frenchman by the name of Gilles Clement. this is a quote from the book enviro(ne)ment

This approach assumes that the garden and the gardener are totally interdependent, with the gardener keeping an attentive eye on the wanderings of the plants and animals and insects that enter into the garden. He follows the 'movement' of 'traveling' plants like Digitalis, the Mulleins, Spurges, and Hogweed, instead of confining them to "beds," which are traditionally employed to highlight flowering. This approach relativizes the notions of plants and weeds, allowing everything present in the garden to play an equal role in producing a dense and richly overlapping whole in which each development is treated as an evolutionary event

this reframing of weeds isn't just fun & games. if we were to recontextualize our notions of beauty in a designed landscape to include the wooliness of weeds & the process by which a bare patch of land becomes a forest we could save billions of dollars a year & untold consumption of resources.

This project by Clement included a large elevated island of bare dirt surrounded by a 30ft concrete wall. over time weeds & trees colonized the bare dirt and now there is a young forest floating above the rest of the ground plane, untouched & unmaintained.

another of my favorite projects is by Hans Hollein, a Pritzker Prize winning Austrian architect, where he took a good number of colored buckets, filled them with dirt from an industrial site outside town, put them in front of the local government buildings and let the weeds banked in the soil just grow.

but for the most part weeds are eschewed in landscape design, have been for 4000 years, and i doubt it's going to change anytime soon. but i believe in a guided evolution of a site where product, process, and design form three sides of a triangle, and if any side changes length the other two must shift in response.

this creates a dense pattern of ecological form & function, overlapping and changing in time. something i call ecological bricolage. François Jacob uses the term bricolage to describe the apparently cobbled-together character of much biological structure, and views it as a consequence of the evolutionary history of the organism.

i think this is applicable to site design.