- Let the grass grow. For several years, the landscaper Eric Lenoir has been having this regular rant. It undoubtedly has more echoes today, at the end of a health crisis which invites to review its relationship with nature.
- The challenge ? Greater biodiversity in our private gardens, which is favored by tall grass and other honey plants that we tend to cut immediately. "A real pantry for insects", invites to see the director Sylvain Lefebvre
- And behind, very often, the rest follows. If there are signs that tend to show better consideration of these considerations, much remains to be done, supporters of green spaces cut to the millimeter remaining dominant today.
Let the grass grow, damn ... The recommendation should please more than one teenager who often has the chore of mowing the lawn in the garden. This is what has been repeated in any case, for several years now, Eric Lenoir, author of the Little Treatise on Punk Garden [ed. Living Earth], which he puts into practice at Flerial, his 14,000 m² experimental garden in the Yonne.
He is not the only one to ask to take it easy on the mower. The same animal documentary director Sylvain Lefebvre or Jean-Louis Hemptinne, professor of ecology at the University of Toulouse and CNRS research director of the laboratory "Evolution and biological diversity", give the same advice.
"Less often or more at all on a part of the garden"
The idea is not so much never to mow again, but to do it less often, if ever on a part of your garden, they temper. “There is a compromise to be found in the layout, calls Jean-Louis Hemptinne. Between a part regularly mowed so that the children can play it, and another where the grass is allowed to grow or which is cut only twice a year. "Yves Verilhac, director of the Bird Protection League (LPO), abounds and adds another recommendation:" That of no longer pruning hedges or pruning trees between mid-March and end of June, until the end of the nesting period, ”he says.
Recently, all four have felt more audible. The two months of confinement linked to the Covid-19 health crisis should help a little more. "Suddenly, people discovered what an uncultivated lawn was," says Eric Lenoir in any case. Something rough, not clean? This is often the remark that leaks into the mouths of supporters of gardens cut to the millimeter. The current still largely dominant today. "What does clean mean?" Says Eric Lenoir. If you have the chance to observe a natural space not shaped by man - there is not much left in France - you will find just that beautiful. It will never occur to you that it is not clean and that you would need a good mower stroke. "
A nature that makes you a hundredfold?
We would quickly arrive at the same observation, leaving more freedom to Nature. Wild flora and fauna will give you back a hundredfold, assures Sylvain Lefebvre, who wants as proof "Wild Garden", animal documentary filmed in his garden, in Acigné near Rennes. We follow the passage of a red squirrel, the first flight of great tits, the metamorphosis of a dragonfly, the reproduction of spotted salamanders ... The whole gives 50 minutes of documentary that Sylvain Lefebvre could have completed with the many meetings made during containment. "For the first time, a family of robins settled in one of my nest boxes," he says. The little ones stayed in the garden for ten days with their parents. "
The reward for a process that has as its starting point, among other things, to leave patches of tall grass. It is always the same virtuous circle which is described. The grass grows and with, many melliferous flowers. Blueberries, poppies, Damascus nigella ... "Not only is it magnificent, but it is also an essential pantry for insects," says Sylvain Lefebvre. Even dandelions and nettles, for which the first reflex is often to remove them, play an essential role. The former constitute an abundant food for bumblebees at the end of winter. The latter are the exclusive food of many species of caterpillars. And if there are bugs in abundance, the birds will not be far away. Yves Verilhac invites you to see them as nature's thermometers. "If they like your garden, it is rich in biodiversity," he says.
One of the answers to the fall in biodiversity?
Eric Lenoir invites us to see even further the virtuous chains that are quickly being set up in a wild garden. "A lady pointed out to me that since she no longer mows the lawn, she no longer has aphids on her roses, since they are eaten by the auxiliaries present in her tall grass," he illustrates. The latter also provide shade at the foot of the trees, prevent evaporation, promote dew. At Ferial, in any case, my trees are much more resistant to drought. "
Not a detail in these times of climate change and biodiversity crisis. It is in this perspective that Jean-Louis Hemptinne plans to convince gardeners to change their practices. He cites in particular the study published in October 2017 in PlosOne and which had caused a great stir, by estimating at 80% the reduction in the biomass of insects in thirty years in Germany. Scientists pointed to intensive agriculture as a likely cause of this loss of biodiversity. "It will take time to achieve massive change in these practices, as the economic interests at stake are important," he begins. On the other hand, there are a large number of areas which are not subject to these constraints and which could easily be transformed into a biodiversity reservoir. "
Private gardens in mind: 63% of French people say they have them, according to the 2019 survey of Ifop and Unep (National Union of Landscape Companies). Jean-Louis Hemptinne adds public gardens and other green spaces managed by local authorities. Roadside, cemeteries, the outskirts of craft areas, roundabouts, "spaces still too often artificialized". Even if they do not form a continuous whole, "the multiplicity of these oases of biodiversity would make it possible to form ecological corridors, allowing the species to pass from one medium to another, to mix their populations", estimates Eric Lenoir.
Let the grass grow, just a front door
All the same, there has been better in recent years. Both for communities (see box) and for individuals. Yves Verilhac has as proof the 30,000 LPO refuges existing today in France. Or as many gardens in which the owners set up facilities promoting the return of nature. "The community is now growing by 10% per year, and the whole now covers 40,000 hectares," he says.
It's not just about letting the grass grow there. "It is only a gateway," recalls Sylvain Lefebvre. Having a wild garden will require a little more effort, diligence and compromise with nature. Even if it means cutting down a bit on the football field. "A small pond is the development that brought me the most biodiversity," says the director, who also invites to regularly leave seeds for the birds, "but only in winter". "Recover your green waste," insists Eric Lenoir too. Just a bunch of branches left at the bottom of the garden can turn into a biodiversity treasure. "
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Towards a better consideration of nature in public spaces?
In the 5th arrondissement of Lyon, only two hectares of parks and gardens will be mowed out of the usual 7.5. In the 9th district, barely one hectare out of the usual 3.5 ... In Gerland Park, an additional five hectares will be left in the meadows. At the end of the confinement, the city decided to set up a frugal mowing management and to intervene at the bare minimum on the parks and gardens according to the size and their frequentation, reported on May 18 last Le Progrès . Other major cities in France have opted for similar strategies, starting with its neighbor, Grenoble.
Simple com operation during an election period? "In recent years, more and more communities have changed their practices to take better account of biodiversity," notes Yves Verhilac, director of the LPO. They are practicing more and more, for example, late mowing [which consists in leaving grassy areas as much as possible to respect the natural cycle of plants]. "
But the margin of progress is very often still colossal and the municipal teams just named or in the process of being will have a primordial role to play. "It is now or never to review our conceptions of gardening," says Jean-Louis Hemptinne. Maud Lelièvre, general delegate of Eco-Mayors, an association of elected officials who supports municipalities in a sustainable development approach, also draws attention to this. "Precisely, in early July, we will distribute to all mayors of France a guide to good practices to promote biodiversity, produced jointly with the LPO," she announced. Among the advice, "those of reintroducing orchards in public spaces, in particular in medium-sized cities, to leave hollow teeth - these temporary vacant spaces in a city - with biodiversity - to use permeable materials in urban 'spaces ... Without forgetting that of leaving wild grass in town. Eco-Maires had already published a similar guide ten years ago. "This time, there will be a monitoring of practices with a barometer that we hope to publish in January," says Maud Lelièvre. Proof that the tone has changed.
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