Friday, October 22

Why do we call them “weeds” if they are essential for urban regeneration | Architecture | ICON Design


With the advance of spring, grasses reclaim their space in cities and make their way into every crack in the asphalt. Although they are known as weeds, their role is essential in urban regeneration, as Ramón Gómez, professor of botany at the Rey Juan Carlos University explains: “If we let the spontaneous weeds that appear on the sidewalks free, the city would become the forest that potentially should be ”.

This return to nature in the city is a chain process, “if we favor the appearance of these plants, or at least respect them, the pollinating insects will soon be attracted by their flowers and these in turn will serve as food for birds and small reptiles ”, explains Ramón Gómez, who considers that these herbs provide great benefits to cities considered as deserts of biodiversity. “The city has its limitations, it is not a forest, but despite this we can turn them into much kinder and lively places.”

The urban botanist expert and technical director of the landscaping studio Herba Nova, is committed to rethinking the model and moving towards more flexible cities where those plants that are born out of man’s control find a place to prosper. Its formula, in line with the approaches of the French botanist Gilles Clément, is as simple and effective as eliminating the use of herbicides and not brushing ruderal herbs at least until they finish their cycle, to allow them to bloom and deposit the seeds that will germinate. the next year.

The herbs common mallow in the center and barley mousetrap in the background, on a street in Madrid.
The herbs common mallow in the center and barley mousetrap in the background, on a street in Madrid.

Alfonso Pérez-Ventana

In the image, the gray mustard grass and the red valerian, two Mediterranean species that are home to more than 50 types of insects.
In the image, the gray mustard grass and the red valerian, two Mediterranean species that are home to more than 50 types of insects.Twitter @morethanweeds

Clement is the author of Third Landscape Manifesto, one of the key texts to understand contemporary landscaping. In it, he encourages the acceptance of the potential of what he calls the Third Landscape, the one that appears in the gutters of the highways, in the residual places of the cities and in the transitional spaces between the city and the countryside.

In urban centers such as Barcelona, ​​initiatives in this direction have emerged in recent years. Living tree pits, developed since 2017 by the City Council, is one of them. This project focuses on the renaturation of the 200,000 tree pits in the city through the planting of a specific mixture of native flowering herbaceous plants that serve to attract beneficial insects for the biological control of pests, as an alternative to the use of chemical phytosanitary products. Other Spanish capitals, such as Burgos or San Sebastián this year have begun to follow the example of the city of Barcelona.

In the opinion of Ramón Gómez, who published the book in June Nearby botany: herbs of towns and cities (Editorial Tundra), “very positive progress is being made but we have to take another step. In Lyon, for example, not only the herbs that grow in tree pits are respected, but also all those that grow in streets and parks ”. Similar measures are carried out in other French cities such as Paris or Nantes and in Ghent (Belgium), where herbicides have been stopped and the free growth of these herbs between cobblestones, in medians and at the foot of streetlights or traffic lights is allowed. , as part of a large urban garden.

Herbs bladder campion, smooth hawk's beard and yellow mignonette, on a street in France.  Plants that house bees and crickets, mainly.
Herbs bladder campion, smooth hawk’s beard and yellow mignonette, on a street in France. Plants that house bees and crickets, mainly.twitter @morethanweeds

Something similar is what Spanish citizens found on the streets at the end of April 2020, after home confinement by covid-19. Thanks to the forced cessation of municipal clearing work, a spectacular proliferation of wild flora took place on public roads. Hollyhocks, dandelions, poppies, chamomiles, dandelions, barnacles, thistles or vividra were part of a new ephemeral urban postcard. Although soon the asphalt returned to win the battle to the opportunistic vegetation. “We must respect those little citizens that are herbs, because not only man inhabits the city,” says Gómez. “The saddest thing is that we pass by their side every day, we step on them and we don’t even know how to name them,” he says.

Precisely, awareness and knowledge on the part of citizens is the objective of Savages of my street (wild plants from my street), an initiative developed in France in 2011 by a group of botanists from the National Museum of Natural History in Paris. Grouped in the research network Botanical Canvas, these experts encourage city dwellers to learn more about the wild herbs that grow on the streets of their neighborhood by developing a participatory census through guides online interactive.

With the same objective, the French botanist Boris Presseq began in 2019 to mark with chalk and identify the plants that grow on the sidewalks of Toulouse. The idea developed by Savages of my street It has also been exported to other countries such as the United Kingdom, where it was born More Than Weeds (more than weeds) that places special emphasis on dissemination through social media, urban itineraries, exhibitions or guides, in order to sensitize citizens and encourage authorities to adopt biodiversity criteria.

Common mallow and wild poppy are born in a crack in the pavement.
Common mallow and wild poppy are born in a crack in the pavement.Alfonso Pérez-Ventana

In Madrid, where some 1,000 species of herbs grow spontaneously, including legumes, composites, grasses or malvaceae, compared to the 300 trees planted by the City Council, initiatives in this field are also beginning to emerge, although outside the municipal government. La Casa Encendida held the second edition of the cycle last April Wild, wild and spontaneous, a conference that proposes an approach to the “most beautiful, wild and resilient” flora of the urban environment through various artistic disciplines such as painting, illustration and the art of walking.

Weeds

“To begin with, we must stop calling them weeds because these plants give us more positive than negative things,” says Ramón Gómez. In extensive dryland herbaceous crops, such as cereals or oilseeds, they perform innumerable ecological functions. They protect the soil from erosion, improve its structure and provide nutrients and organic matter; they provide a more favorable microclimate for crops; They provide biodiversity, harboring beneficial fauna as pollinators or natural enemies of pests, and even become traps for them.

It is precisely agriculture that, in the opinion of the URJC professor, should be the first interested in preserving these weed herbs, since approximately 60% of the plants grown for human consumption depend on pollinators. “Being selfish, we should solve this situation just because it affects our crops and the diet of humanity,” he says.

Climate change and globalization

Climate change has given rise to the appearance of new species: this is the case of the olive grove (Dittrichia viscosa), a native of the Mediterranean which, due to the increase in temperatures, is increasingly found during autumn in the road ditches of the center of the peninsula.

In urban flora there is also a trend towards globalization, the same herbaceous plants appear in different cities of the planet, such as the dandelion (Taraxacum officinale), a European species that has colonized cities and towns all over the world. This is because most urban centers have similar conditions, friendly to certain species, such as high temperatures and the absence of predators. In addition, they are fast-growing species, with high seed production, and nitrophiles, that is, they live in nitrogen-rich environments, such as urban soils.

The Mexican fleabane herb has daisy-like flowers and has become one of the most common plants in cities.
The Mexican fleabane herb has daisy-like flowers and has become one of the most common plants in cities.Alfonso Pérez-Ventana




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