Mowing your lawn, trimming hedges, pruning a tree… These activities can harm garden wildlife. But we can limit the impact.
“My father lives in a rural area and, every two weeks, the town hall mows with ardor, tells us Cécile. Instead of field flowers, there are mowed lawns. » To his father’s protests, the municipality replied that “people want clean lawns”.
“It’s mostly dead lawns”takes offense at our reader, who reminds us of the danger represented by mowing the grass in green spaces and shoulders for hedgehogs and ground-nesting bird species (such as the skylark, which appears on the red list of threatened species in France).
An observation illustrated by the League for the Protection of Birds (LPO) with this tweet showing the sad end of a blackcap:
The same goes for hedges and trees: their maintenance can considerably disturb the fauna that find refuge there. And this concerns both public spaces and our gardens. Here are some tips for mowing, trimming and pruning while sparing biodiversity.
• A hairy lawn
Conserve patches of wild grass
In addition to being a nesting place for some birds, tall grasses “form the habitat of insects, and allow passerines and their broods to be fed with caterpillars, flying insects, butterflies…”, explains Nicolas Macaire, animator of the Refuge LPO program. He therefore recommends keeping islands of wild grasses in your gardens, to create a “mosaic of backgrounds”.
“Les Herbes Folles” is precisely the name that Caroline Caironi, landscape gardener in the Gard within the Terracoopa cooperative, has chosen for her company – “to give them a place in the gardens”. For this, it practices differentiated mowing. “The idea is to keep unmowed areas, such as the edges of the garden, or around trees, which are spaces less used by individuals. »
When you stop mowing, you will see grasses, daisies, clovers, dandelions, poppies… without having to sow, because these flowers are “from seeds fallen from the beaks of birds or from pollination”according to the LPO. “You can also plant bulbs in the fall, sow wildflowers…suggests Caroline Caironi. It’s another way of looking at the garden, giving it a more rural feel. »
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Mow, yes, but as little as possible in the spring
If you still want to clear certain areas of your garden – under a swing, for example – don’t panic: just follow a few precautions. “We recommend late mowing methods, advises Nicolas Macaire. From the end of July, once the flowers have seeded. »
It is better to avoid taking the mower out on the first days of good weather, in March or April, because you would thus cut all the first wild flowers: dandelions, primroses, daisies… which are the food pantry of many insects.
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The clean cut, to avoid!
Another precaution: “You must not mow close”recommends Caroline Caironi. “It’s not good for the soil or the grass”adds Nicolas Macaire, who recalls that a cut of at least 7 centimeters makes it possible to preserve a certain biodiversity, in particular among insects, snails and other invertebrates.
If you have a small garden, prefer shears and small scythes to mechanical or motorized mowers, which could crush small animals. The latter can be used on the largest surfaces, provided that centrifugal mowing is carried out – from the center of the plot outwards – in order to let the fauna escape on the sides.
Finally, you must at all costs avoid running robotic lawn mowers at night, as they can kill nocturnal animals, especially hedgehogs.
In the garden, beware of ticks!
Ticks move on animals: birds, rodents… As a precaution, it is therefore better to leave tall grass in the less frequented places of the garden. And mow at children’s play areas, deck chairs… Another possible solution: leave chickens, fond of ticks, in semi-freedom in your garden if they are not confined because of avian flu.
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• Country hedges
Prune in winter to protect the nests
Hedges form shelters for pollinating insects, birds and small mammals. Their size therefore represents a danger for all this fauna. This is why the French Office for Biodiversity advises against intervening on hedges between March 15 and July 31, as this would jeopardize the broods of birds.
Not pruning during this period not only protects the birds, but also the shrubs that make up your hedge: “To respect the biological cycles of plants, pruning is usually done at the end of autumn and in winter, before the spring sap rises”explains Nicolas Macaire.
As far as possible, prefer the manual method, using sharp shears, because mechanical hedge trimmers tear off the branches, thus encouraging the development of fungi and diseases… For the largest branches, opt for a tree saw.
Choose the right plant species
But the best thing is still to prune as little as possible. This is what “free-port” pruning allows, which consists in letting the shrubs grow freely rather than constraining their morphology. This involves carefully choosing the species upstream: “If you put species that become very large in adulthood, you will have to prune them a lot, warns Caroline Caironi. The habit of the species must be adapted to the size of the garden. »
The right choice of species not only limits the size as much as possible, but also attracts birds, hedgehogs, insects, etc. “For this, we must favor native shrubs, rather than exotic species”, blows Nicolas Macaire. Similarly, prefer feeder species that produce berries for birds (sea buckthorn, blackthorn, arbutus, pistachio lentisk, etc.), rather than ornamental trees.
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In contrast, ” cedars are plants to be avoided completely, because they are not shelters for fauna and they acidify the soil, which prevents the installation of micro-organisms “warns Olivier Bedouelle, founder of Sauvaje, a landscaping company in Île-de-France.
The ideal, to make a country hedge, is to choose four to six species, as indicated in the LPO tutorial. This makes it possible to develop three strata: the herbaceous stratum, the bushy stratum and the shrubby stratum. Each of them is associated with a very specific fauna. “The turtle dove nests more from 4 or 5 meters in height, while other birds nest between 1.5 and 3 meters, explains Nicolas Macaire. And certain species of animals use the herbaceous bench, such as the European hedgehog, rabbits…”
• Refuge trees
Leave dead wood for animals
Like the size of hedges, the pruning of trees must take into account the nesting periods of birds. “You have to be really careful between mid-March and mid-July, underlines Sophie Valat, founder of the company Sophie Élagage, in Montpellier. For the felling of trees, it is absolutely necessary to avoid this period because birds lodge in the cavities and you cannot see them. » The ideal is therefore to wait until the end of summer, autumn or winter… or even not to cut down the tree at all.
Indeed, if it does not present a danger, you can very well leave a dead tree at the bottom of your garden. “All cracks and cavities are natural habitats for wildlife, and this helps attract animals like squirrels and birds”adds the pruner.
In addition, dead wood is a food source for many insects, which then feed on other animals, such as woodpeckers, according to the LPO. Hence the interest of leaving the piles of cut branches in a corner of your garden. And why not use them to develop a dry hedge? The hedgehogs will be delighted!
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Ivy, an ally of trees and biodiversity
Another tip: don’t pull the ivy that grows on the trees! “It does not hinder them at all in their development, and protects them from the heat in summer”, reassures Sophie Valat. By pulling on them, you could on the contrary damage their bark.
It is also a habitat for wildlife, thanks to its evergreen and dense foliage. According to the LPO, it has the advantage of flowering in September-October, a time when pollen is scarce, and of offering fruit all winter long to blackbirds and thrushes.