Sustainable gardening includes the more specific sustainable landscapes, sustainable landscape design, sustainable landscaping, sustainable landscape architecture, resulting in sustainable sites. It comprises a disparate group of horticultural interests that can share the aims and objectives associated with the international post-1980s sustainable development and sustainability programs developed to address the fact that humans are now using natural biophysical resources faster than they can be replenished by nature.

Included within this compass are those home gardeners, and members of the landscape and nursery industries, and municipal authorities, that integrate environmental, social, and economic factors to create a more sustainable future.

Organic gardening and the use of native plants are integral to sustainable gardening.

The objectives
The objectives are multiple:

rationalize the management of green spaces by allocating the necessary resources;
improve the quality of life and use by diversifying landscape qualities and amenity offerings;
restore, preserve and manage biodiversity, by limiting artificialization, pollution (fertilizers, pesticides, pollution and / or mortality of gear-induced fauna), by limiting disturbance and promoting the diversification of habitats and species, as well as the expression of the natural processes of maintenance and healing of biodiversity. It is a means of developing the ecosystem services and amenities offered by green spaces or semi-natural environments;
make a teaching environment: the work of municipal or private gardeners to local authorities is also a model, or a support to eco-citizenship for the public who sees the work or talk to them.
This management can benefit from an ecological network approach, sometimes referred to as a green network, where the natural fauna will then be considered as a management aid that one seeks to circulate on the spaces. In a context that is often very artificial, the manager is also careful to limit the expansion of invasive or invasive species.

Introduction
Any artificial urban or peri-urban development calls for a follow-up for its durability. As the vegetation evolves constantly and naturally towards a theoretical climactic stage or in response to local constraints (including pollution, over-crowding, etc., the control of its development is necessary, and the managers seek to maintain or improve the aesthetic value. space and respond to a growing demand for naturalness, but also accessibility.To
meet these sometimes contradictory objectives, a differentiated management plan can emerge from a reflection on the functions of green or semi-natural spaces and the scenarios of future maintenance.

This new management mode – differentiated management – appeared in the 1990s, is a more ecological management and alternative to horticultural management intensive, trivialized and banal. It incorporates elements of defense and restoration of the environment and involves another technicality, as well as the diversity of management responses to respect the different environments and needs of the flora, uses in green public spaces, while maintaining a concern for the aesthetics of plant forms and successions.
Are concerned on a daily scale the management of the resources, the limitation of the induced pollution, the recycling then, from the point of view of the biodiversity, the recognition and the expression of the ecological potentials, the taking into account elements of flora and wildlife and / or spontaneous, the revaluation of spaces and environments so far neglected, even polluted.
This new mode of management calls upon the skills of various actors (professionals, organizations, associations and more recently public in the framework of a participative democracy), such as ecologists, landscape architects, local communities, regional natural parks…

This article presents:

the methods for setting up such a management plan,
the organization of differentiated management according to the types of spaces,
some examples of parks managed this way.

On the other hand, the choice of plants greatly influences the maintenance of the developed space. Indeed, plants that are endemic or that adapt to the conditions of the environment will not need to be helped by humans to develop properly and stay in good health, while species that require additional benefits (water, matter organic, phytosanitary products…) are absolutely not part of the research of adequacy with the environment.
For example, it can be said that landscape gardener Beth Chatto built a garden at White Barn House (Essex), including various types of habitats, without any watering. Located on a fallow land with a spring, this garden immediately seduced the designer, who has kept most of the trees in place and added others to protect all the strong winds. She planted appropriate species at the site, associating them in an ecological way.

Since the 1970s, the concept of “ecological gardening” has evolved from the use of native plants to the association of plants from different regions, but sharing identical needs.

Thus, towards the end of the twentieth century, a new approach to landscaping came to maturity. It results in fact from an uninterrupted evolution, which connects some great landscapers of the time and leads to sustainable experiments at the University of Weihenstephan (Germany), on herbaceous and perennial plants. These personalities were interested in the development of a habitat favorable to plants and, more recently, their autonomy. This idea was especially applied to perennials that were often avoided, especially in the second half of the twentieth century, when maintenance became a central issue in public and private gardens.

Principles and concepts
Managing global biophysical cycles and ecosystem services for the benefit of humans, other organisms and future generations has now become a global human responsibility. The method of applying sustainability to gardens, landscapes and sites is still under development and varies somewhat according to the context under consideration. However, there are a number of basic and common underlying biological and operational principles and practices in the sustainable sites literature.

Biological principles
Sustainable management of man-made landscapes emulates the natural processes that sustain the biosphere and its ecosystems. First and foremost is the harnessing the energy of the Sun and the cycling of materials thereby minimising waste and energy use.

Running within, and dependent on, the natural economy there is the production and consumption of goods and services in the “human economy” which has now significantly altered, in a detrimental way, natural biogeochemical cycles (notable here are the water cycle, carbon cycle and nitrogen cycle so sustainable practices maximise support for ecosystem services.

Native plants
The use of native plants in a garden or landscape can both preserve and protect natural ecosystems, and reduce the amount of care and energy required to maintain a healthy garden or landscape. Native plants are adapted to the local climate and geology, and often require less maintenance than exotic species. Native plants also support populations of native birds, insects, and other animals that they coevolved with, thus promoting a healthy community of organisms.

Plants in a garden or maintained landscape often form a source population from which plants can colonize new areas. Avoiding the use of invasive species helps to prevent such plants from establishing new populations. Similarly, the use of native species can provide a valuable source to help these plants colonise new areas.

Some non-native species can form an ecological trap in which native species are lured into an environment that appears attractive but is poorly suited to them.

However, in Britain research by the University of Sheffield as part of the BUGS project (Biodiversity in Urban Gardens in Sheffield) has revealed that for many invertebrates – the majority of wild animals in most gardens – it is not just native plants which can sustain them. The findings were published in popular form in Ken Thompson’s book ‘No Nettles Required: The truth about wildlife gardening’. He confirms the approach which Chris Baines had promoted in ‘How to Make a Wildlife Garden’.

Operational principles
Enhancement of ecosystem services is encouraged throughout the lifecycle of any site by providing clear design, construction, (operations), and management criteria. To be sustainable over the long term requires environmental, social and economic demands are integrated to provide intergenerational equity by providing regenerative sustainable systems. Operational guidelines will link to and supplement existing guidelines for the built environment (supplementing existing green building and landscape guidelines), the wider environment, and they will include metrics (benchmarks, audits, criteria, indexes etc.) that give some measure of sustainability (a rating system) by clarifying what is sustainable or not sustainable or, more likely, what is more or less sustainable.

Scale
Impacts of a site can be assessed and measured over any spatio-temporal scale or context.

Direct and indirect environmental impact
Impacts of a site may be direct by having direct measurable impacts on biodiversity and ecology at the site itself or indirect when impacts occur away from the site.

Alternative methods to plant protection products
The words of biological struggle
The official definition (of OILB-SROP) states that biological control is “the use of living organisms to prevent or reduce damage caused by pests”. The principle is simple: The biological fight is based on the exploitation by Man and for his benefit of a natural relation between two living beings:

the target (of the fight) is an undesirable organism, pest of a cultivated plant, weed, parasite of the cattle…;
the control agent (or auxiliary) is a different organism, most often a parasite, a predator or a pathogen of the first, which kills it more or less quickly by feeding on it or at least limits its development.
If the auxiliary is an animal, it is biological control, or fight by entomophage. The auxiliary can be a vertebrate (Bird or Insectivorous Fish) or a Nematode; in most cases it is another insect. The predators (which kill and eat more prey during their development) differ from parasites, which live at the expense of a single host, who died after completion of the development of the parasite. There are parasites of eggs, larvae, nymphs. Their biologies are extraordinarily diverse and host-parasite relationships are very complex, including hormonal exchanges and interspecific chemical messages.
If the antagonistic organism is a microorganism, it is called microbiological control. The auxiliary pathogen can be a fungus, a bacterium, a virus, a protozoan. It infects the host in general by ingestion and has a form of resistance allowing it to pass – and stay – in the middle (soil, foliage, litter).

The pathogen multiplies in the host and causes its death by tissue destruction, sepsis, sometimes by the emission of a toxic substance (case of Bacteria). The corpses of the host release pathogens into the environment.

If the antagonistic organism can, as a result of its contribution by humans in contact with the target insect, develop and maintain itself at the expense of this insect, without requiring a new intervention, it is in the case of the fight against biological by acclimation. This is the case when an entomophagous or an exotic pathogen is used against a previously introduced or naturally occurring pest from another region of the world.

In case of successful acclimatization and sufficient efficacy, biological control is carried out by itself, the auxiliary becoming an effective and permanent agent (over many years at least) of the suppression of the pest. The initial effort is particularly valued. We are sometimes told of natural biological control.

If the antagonistic organism is to be released or inoculated (in large numbers) each time the pest population grows dangerously, it is in the case of flood control. It is then necessary to master the techniques of multiplication of the entomophage (in insectarium) or of the pathogenic germ (in fermenters for Bacteria, on the living for the Viruses), of storage conditioning and spreading, while maintaining constant the quality of the product. Such auxiliaries, so-called biopesticides, intended for repeated applications in a current agricultural practice are the subject of multiple controls to ensure their safety for non-target living beings. Their range of hosts (in principle very limited) is examined as well as their possible toxic or allergenic properties.
By selection and by genetic engineering operations, it is sought to improve these auxiliaries, for example by giving them resistance properties to extreme climates, insecticides or fungicides.

At the frontiers of biological control: the autocide struggle (still called sterile male struggle).
It is based on the introduction in large numbers into a natural population of modified male individuals (rendered sterile by the application of ionizing radiation) but to intact sexual behavior. These manipulated males will, once released, compete with wild males. If they are (for example) 9 times more numerous than their “natural” congeners, and if females only allow mating, 9 out of 10 females will have no offspring. After a few generations, the supply of sterile males continues, the target population is destroyed. The autocide struggle is based on a very clever principle but its use seems restricted to a few very well adapted cases.

Beyond biological control… The use of toxins from fungi and entomopathogenic bacteria is being developed, either as a phytopharmaceutical active ingredient to be stored alongside conventional insecticides, or as substances made by the genetically modified plant (a maize-resistant maize resistant transgenic maize is in principle available).

Reasonable protection of crops
Respectful of the environment, it involves the introduction of auxiliaries, the use of microbiology, or mechanical or thermal methods.
The so-called mechanical or thermal means can be used against weeds (or weeds), or against certain predators of plants, or unwanted organisms of the soil.

Hoeing is loosening the soil around a cultivated plant by the action of a manual tool (the hoe) or mechanical (the mechanical hoe). It allows, among other things, to uproot weeds.
Thermal weeding involves burning weeds with a machine designed for this purpose.
Solarisation is a technique of weeding the soil by means of the heat of the sun.
Soil steam disinfection, used in greenhouses or on some farms to kill germs, including pathogens in the soil.

Site principles
The following are some site principles for sustainable gardening:

Do no harm
Use the Precautionary principle
Design with nature and culture
Use a decision-making hierarchy of preservation, conservation, and regeneration
Provide regenerative systems as intergenerational equity
Support a living process
Use a system thinking approach
Use a collaborative and ethical approach
Maintain integrity in leadership and research
Foster environmental stewardship

Measuring site sustainability
One major feature distinguishing the approach of sustainable gardens, landscapes and sites from other similar enterprises is the quantification of site sustainability by establishing performance benchmarks. Because sustainability is such a broad and inclusive concept the environmental impacts of sites can be categorised in numerous ways depending on the purpose for which the figures are required. The process can include minimising negative environmental impacts and maximising positive impacts. As currently applied the environment is usually given priority over social and economic factors which may be added in or regarded as an inevitable and integral part of the management process. A home gardener is likely to use simpler metrics than a professional landscaper or ecologist.

Three methodologies for measuring site sustainability include BREEAM developed by the BRE organisation in the UK, Leed, developed in America and the Oxford 360 degree sustainability Index used in Oxford Park and developed by the Oxford Sustainable Group in Scandinavia.

The Sustainable Sites Initiative is producing recommendations for the American Landscape Industry. The standards and guidelines finally adopted will lead to a uniform national standard, which does not currently exist. Sustainable Sites is currently in the pilot program stage, and will formally introduce its first rating system by 2013. The U.S. Green Building Council supports the project and plans to adopt the Sustainable Sites metrics into future versions of its Leadership in Energy and Environmental Design Green Building Rating System. Sites are rated according to their impact on ecosystem services: The following ecosystem services have been identified by the study group:

Local climate regulation
Air and water cleansing
Water supply and regulation
Erosion and sediment control
Hazard mitigation
Pollination
Habitat functions
Waste decomposition and treatment
Global climate regulation
Human health and well-being benefits
Food and renewable non-food products
Cultural benefits

INPUTS

Fossil fuels
Embodied energy and water
Compost
Mulch
Ecology & biodiversity
Fertilizer
Hard landscape materials
Equipment
Products

OUTPUTS

Energy & water
Food
Green waste
Ecology & biodiversity
Chemicals
Old hard landscape materials
Old equipment
Old products

PROCESSES

Constraints
Any kind of auditing or benchmarking will depend on the selection and weighting of the metrics chosen; the depth and detail of analysis required; the purpose for which the figures are required; and the environmental circumstances of the particular site.

Protection of fire-sensitive areas
Wildfires pose a growing risk in hot, dry areas and sometimes in temperate areas. The explanations often produced are:

agricultural abandonment leading to a decrease in the regular maintenance of fire-sensitive natural areas;
to a sprawl of the landscape with implantation in the dry forest of new inhabitants ignoring the risks related to fire. This inexperience leading to imprudences, often a source of fire;
speculation on tourism development, considerable financial stakes explaining some deliberate fires;
repeated drought, possibly exacerbated by drainage of wetlands. Increasing dead and dry wood in areas vulnerable to fire, and less exploited, can increase risk.

Faced with this situation, regulations, collective means of prevention and defense, and public information are associated to encourage more thoughtful development, more cautious behavior, and a more rigorous management than these spaces.

The flammability of organic matter and plant tissue changes with their water content and terpenes. It varies with the amount of surfaces exposed to dehydration and the stage of plant development (by age, species and water availability). Its knowledge helps to draw the attention of the manager at certain times of the year, or may guide the choice of species during development or guide development so that the watershed retains more water rainy winter.

A table which lists all the species of grass, shrub and tree stages, allows to know the degree of flammability of each species, month by month. The degree is noted from 0 to 5, respectively from “low flammable” to “extremely flammable”. These data were derived from tests conducted on samples at the same stage of development and on criteria of frequency, ignition delay and burning time.

There are several methods of protection:

brushing: this consists of destroying the herbaceous layer and the lower shrub to reduce the risk of fire.
manual: ensures quality work, allows the selectivity of species, expensive for low yields, provide for the disposal of waste;
mechanical: the slope limits the interventions, the investment is heavy but the yields are important, the shredded waste remain on the spot;
chemical: application of products with root or foliar absorption, the water supply is sometimes difficult, the phenological and climatic conditions reduce the period, the plants dry out and stay in place.
controlled burning (or burning): this consists in burning the herbaceous and shrub layer at a date that limits the damage on the tree layer, in order to create an area with less fuel, slowing the progression of the fire and favoring the means of fight against fire. The intervention is fast and the cost price low, but it must be done by specialists.
Controlled grazing: this involves grazing a flock of sheep or goats to limit the phytomass in areas to be protected (sylvo-pastoralism). It makes it possible to fight against desertification to a certain extent, but sometimes causes damage to the plants to be preserved. This requires the establishment of fences and the presence of specialized shepherds.

Differentiated management by type of space

Maintenance of support areas
Management of shrubby areas
Protection against animals: In particularly vulnerable areas, game can cause irreversible damage, particularly in the case of bark, on young plantations. In this case, it is essential to place protective nets around the shrubs, with a light hilling to avoid the passages below. Three bamboo stakes are driven 30 cm into the ground and hold a polyethylene net sleeve (60 cm high).
Watering: in areas without an irrigation system, it will be necessary to water the young shrubs using, for example, a tank.
Size of shrubs with flowers: consists of removing the branches having bloomed to obtain new branches well flowering. (Intervention periods: immediately after flowering for spring-flowering shrubs, during the rest of vegetation for summer-flowering shrubs).
Size of hedges: consists of keeping the shapes and volumes of regular hedges. The best time depends on the growth and frost resistance of the young shoots.

Roadside management
The road network has changed considerably in recent decades. With the increase in traffic, the road allowance widened. Roadside was mowed manually by the roadmenders once but today it requires a high-performance equipment. Faced with increasingly heavy maintenance tasks, road authorities are turning to greener management. It consists in reconstituting the plant structures favoring a biological equilibrium. These create a natural space and easier maintenance.

Landscape integration: Generally, infrastructure works profoundly alter the soil. It is therefore important to facilitate management:
to favor the integration of the structure by the choice of heterogeneous local essences,
to use easier installation species adapted to the soil and the climate,
to reconstruct natural structures such as meadows, thickets or hedges that are characteristic of the environment and that are useful as refuge areas for wildlife.

Extensive management of green dependencies: Ecological engineering interventions stem from the observation of ecosystems. It is a question of putting in place a strategy favoring the relations between the natural actors of a site by applying certain rules:
ensure the balance and stability of biotopes;
maintain the recycling of the basic elements by respecting the minimal surfaces necessary for the autonomy of the biological system;
control the natural evolution while maintaining networks of biological corridors and refuge zones, including for caulicultural species of the herbaceous layer, which do not support mowing;
choose the least traumatic material for the vegetation and wildlife that takes refuge there.

Management of grasslands
There are two main types of grassland areas: wet meadows and dry grasslands.

The wet meadows are natural and near-natural ecosystems characterized by vegetation and dominated by grasses, sedges, reeds, rushes and low perennial grasses. They are home to specific wildlife and biological diversity, including rare and threatened species and communities of plants and animals, including internationally important bird populations, mammalian diversity, invertebrates, reptiles and amphibians. They are periodically flooded or saturated with water and maintained by cutting, burning, grazing (natural or man-made), or by an assortment of these factors.
Dry meadows provide habitats for many animal and plant species, but tend to become rare, as can be seen with the example of Switzerland. This is why the Federal Office for the Environment, Forests and Landscape (FOEN)) of this state is currently compiling an inventory of dry grasslands and pastures of national importance. At the end of 2000, employees of private ecology offices completed this assessment in half of the cantons. In order to determine which areas to protect as a priority, a method of assessment and classification has been put in place. Each meadow is evaluated according to its quality; this value is based on six criteria: vegetation, area, important structural elements for animals, possible presence of rare plant species, diversity of vegetation, and ecological networks including corridors located outside the grassland.

The flora that covers the grassy areas consists of annual, perennial and sometimes semi-woody plants. Grasses are the most numerous in lawns and meadows; for the most neat, they are even the only vegetation. It is therefore very important to know their vegetative cycle in order to determine the periods of human intervention. Knowing this cycle, we understand that the intense period of intervention is between the “rise of the ear” and the “fruiting”, deliberately limited interventions will start at the “rise of the ear”, and that the mowing, reduced to an annual intervention, must naturally take place at the ‘rise of the ear’.

Mowing, a largely dominant cutting method in differentiated management, involves cutting grass from a height; the waste is either left on the spot, raked and loaded. It is usually annual but can be renewed several times for reasons of safety (roadside visibility) or aesthetics. Three types of material are used:

the cutting bar on tractor
the tiller-cutter bar (for smaller surfaces with fewer obstacles and possibly sloping, but a quality cut)
the mower (for large areas and a cut without finishing).

In order to reduce interventions on these areas, it is also important to choose species adapted to the natural qualities of the site and the soil, in order to limit watering (which will have to be calculated according to the natural precipitations and the evapotranspiration of the ground), fertilization and phytosanitary treatments. As for weeding, it can be considerably reduced by the choice of highly combative species, which will not leave much room for weeds.

Management of water bodies and their surroundings
A body of water is a living element just like the vegetated parts, and as such it must receive regular monitoring and maintenance. In the aquatic ecosystem, each element of the food chain must keep its place and develop normally, otherwise this set will change rapidly and die.

There are six different controls to ensure the preservation of these environments:
upstream controls help protect flood-prone areas (contributing to water quality), check wastewater discharges (sanitation, industries, etc.) and have an impact on farming methods (no excess nitrates);
the control of the luminosity aims at limiting the development of the plant vault to favor the action of the light on the immersed vegetation (photosynthesis = oxygenation of the water), and to limit the plants and suspended matter (the excess of nitrates favoring floating plants);
the limitation of the aquatic vegetation is done by cutting, so as not to cut too much at the same moment (to avoid the stop of the reproduction of the fish);
the control of silty deposits, which are signs of asphyxiation and poor water quality; this disadvantage can be limited by a contribution of chalk of Champagne;
the control of the fish population makes it possible to keep a good proportion between the quantity of fish and the reserves of food and oxygen of the water body;
the control of the chemical equilibrium of the water makes it possible to detect accidental pollution quickly and to remedy it.

Good knowledge of ecosystems linked to wetlands will lead to a reflection favoring interventions more respectful of the biological balance of flora and fauna: the irregularity and the greening of the outlines multiply the ecological niches, and a level of water constant and gently sloping shoreline development favor important fauna and flora along the banks.

Source from Wikipedia