Local species adapted to our fauna
All the vegetables, fruits or ornamental varieties of plants you grow, as well as the animals that live in your garden, contribute to maintaining a healthy natural environment. The greater the diversity, the more the system tends to be balanced. Hosting or maintaining the animals that feed on or parasitize the crop pests in your garden is, therefore, the first step in biological control! Although visually attractive and generous in flowers, the exotic and/or horticultural plants commonly sold in garden centers present (for the most part) very little interest for the local fauna. Our local pollinators are not morphologically adapted to these plants, which are consequently neglected by our fauna. On the other hand, local plant species, which by definition are adapted to their natural environment, have optimal growth. Beyond their development, they have a positive effect on the preservation of local fauna. Indeed, through preserving the fauna’s habitat, local species of plants play an essential role in promoting the return of biodiversity and maintaining a well-balanced natural environment. As you will have understood, if you want to welcome birds, butterflies and other insects in your garden, it is essential to host local plants!
Local plant species are synonymous with ecology and savings
Exotic plants are often ill-adapted to local conditions. Some alien species are more susceptible to diseases, and others will require fertilizers or more water to grow. This will encourage you to use phytosanitary products to control these diseases, fertilizers to enrich the soil and promote the growth of these plants, or to water your garden more. On the contrary, the use of local plant species will allow you to avoid these problems because these plants will be adapted to the soil’s physicochemical and water conditions and will have adapted to fight against diseases… Choosing to use local plants is not only ecologically sound, but it also allows you to avoid the purchase of unnecessary fertilizers and pesticides. It also prevents the need for excess watering.
Exotic plants: beware of invasive species!
While most imported plants are challenging to grow (as explained earlier), other species can find in our climates blooming-friendly conditions that exceed the expectations of the person who brought them in. The absence of competitors and natural predators is a godsend for these plants. You may have heard of invasive plants such as the common ragweed, the primrose-willow, or the pigface… Many nature conservation organizations strongly advocate combating the proliferation of these exotic plants, which can in some cases have a negative impact on health, economic activities, or biodiversity. This is not the case of local plant species. Click here for more information on invasive plants.
How to proceed
Researching and planning ahead of planting will allow you to reduce the possible risks of diseases and parasites significantly. It is necessary to select plants that are adapted to your surroundings and avoid the species that are inconsistent with the local environment. Depending on the environment’s characteristics, it is necessary to ensure that the requirements of the species are met. Select the species that are adapted to the soil (clay, limestone…), the climate (humidity, drought…) and the exposure (shade, sun). This pre-planting planning phase will contribute to healthier plantations and limit the use of phytosanitary products. The cohabitation between natural vegetation and planted vegetation can be very beneficial. Indeed, planting a combination of complementary species on the same site will significantly contribute to protecting plants from parasitic attacks. Some species, such as nasturtiums, for example, attract aphids because of their smell and color. Other species of plants, such as the French marigold, are known to repel many parasites due to the scent of their foliage and flowers. Aromatic plants (lavender, thyme, sage…) also protect neighboring plants against insect pests.
Tips for biodiversity in the garden
Leave a wild, uncultivated area in your garden
Leaving a purposefully “wild” patch of land in your garden will give way to the development of a natural area without the need for fertilizers, brush clearing, or plantations… This uncultivated area will naturally host a large number of animal species that can help you in the process of biological pest control. Insects, birds, frogs, or hedgehogs will be able to use this area to feed or breed. An excellent way to foster biodiversity in your garden!
Rotate your crops
It is recommended to avoid planting the same plant species in the same place each year. This could encourage the proliferation of diseases (bacteria, fungi…). Crop rotation will thus make it possible to eliminate specific diseases which will no longer find the necessary resources to survive.
Encourage the presence of natural predators
Local species are likely to attract natural predators who will feed on organisms that are harmful to your garden: hedgehogs feed on slugs and caterpillars; an adult ladybird can eat up to 150 aphids per day; the earwig also feeds on aphids, small caterpillars, and mealybugs. These predators are adapted to local species, and they will likely be unattracted to exotic species. A diversified garden, both in terms of species and habitats (pond, woodpile, hedge, “wasteland” area, etc.) will accommodate many of the so-called “auxiliaries.” They can be subdivided into three categories: firstly, the decomposers (such as earthworms…) that transform organic matter into a mineral matter that can be assimilated by plants. Secondly, the pollinators (such as the bee, the bumblebee…) which play a fundamental role in plant reproduction and crop production. Finally, the predators that regulate pest populations.
Composting is not only known for its waste-reducing properties, it also helps foster the development of microorganisms in the soil, as well as improve its structure, balance its pH, and provide the nutrients necessary for plant growth.
Don’t “over-clean” your garden!
Plant debris, tree branches, wood chips, tree bark… These natural elements are known to provide excellent shelter for wildlife, including natural predators that will help you in the fight against “harmful” species.
Your best bet? Plant a variety of local plant species!