Vertical gardens or green walls describe are artificial ecosystems, designed either as aesthetic elements, as part of a so-called urban gardening, sometimes as works of art using the plants or with specific intention of retaining sound or regulate heat.
In the latter case, these walls, such as vegetated terraces or fences, helps to improve the characteristics of a building, and perhaps to restore green areas, particularly in the city.
They can serve as a refuge for birds, insects, but they can also play a role in the microclimate, water purification, sound control and urban air quality. Its horizontal equivalent is a green roof.
History of the vertical garden
Natural colonization by plants on walls is usually considered a problem, the roots damaging the foundations of the building when they are wet. This, under certain conditions, can take off the bricks or contribute moisture to the wall. In the humid areas, some trees can quickly colonize and cover architectures -such as for example the temples in Thailand.
There are some artificial architectural structures, concrete or stone masonry units covered with moss and plants that have existed for over 200 years. These are mainly found in a few large parks typically surrounded with fountains or waterfalls.
This construction is especially found in French gardens in the nineteenth century.
Green walls were then developed in some zoos, and for the set of terrariums, generally using tropical species. This is before the French botanist and scientist Patrick Blanc created, tested and developed his concept of green wall.
Some other techniques of walls where plants grow independently, were developed by designers and landscape architects as new methods for interior spaces.
For instance, Fedor van der Valk has invented mini indoor hanging garden (“String Gardens”) that seem to float in the air supporting cascades of greenery. The New Zealand Patrick Morris was able to give the impression that the ceiling is covered with plants. Many examples of interior walls are now available.
Several Principles of green wall
Green walls or vertical garden can be arranged both outside and inside buildings, with or without artificial source of light.
The principle relies on the fact that without human intervention, in the presence of clean air and sufficient moisture in the air, plants will develop by themselves. In the case where the wall is dry, or a drier atmosphere, it can also be colonized by vines and ivies
Several approaches exist, from the insertion of plants adapted to dry environments which create a structure like a “rock garden” to very sophisticated techniques optimizing the colonization and growth of plants with substrates capable of absorbing and releasing water like coconut fibers.
Or with plastic in which water circulates enriched with nutrients.
In the latter two cases, irrigation works in a closed circuit, and must be adapted to the context and seasonal climate, the watering system is more or less automated depending on the case, as well as the nutrient. An automatic watering systems is one of the core elements of your vertical garden or green wall.
Many tropical plants grow in the shade and need few nutrients, but require soft, pure water (eg rainwater).
Increasing biodiversity also increases the presence of birds. However, glass surfaces are a visual trap for birds that hit windows during day or night.
The bird may be the victim of a mirror where the glass reflects the sky.
At night, birds frequently hit the window of a lighted room, a victim of the effects of light pollution.
In the latter case, the frequency of collisions can be reduced by 80% by using a heavy curtain. Such a simple measure to make your green wall more bird friendly.
By day, it greatly reduces the risk of collision by affixing a black silhouette of a bird of prey, even more effectively if it is hanging by a thread that allows it to move. These figures are marketed by various associations and institutions. They do not interfere with local wildlife adapts and prevent collisions with migratory birds passing through.
The ivy is particularly well suited to the greening of facades. The plant is a strong climber, however this plant does not damage the walls, although it can damage the paint when its roots leave traces.
A green wall all year round
Ivy is suitable for outdoor green walls as it is resistant to harsh weather conditions (flood, frost, drought …). It stays green all year, allowing it to continue to absorb carbon during the winter when most plants have lost their leaves.
The pollination period of ivy is in late summer. The fruits of ivy appear very early in the year (March), and are a wanted food for fruit-eating birds.
In addition Ivy has an aesthetic value, need for your outdoor green wall. Other species commonly used are the Virginia creeper, honeysuckle, wisteria.
Maintenance green wall plants
The maintenance of facades can not be at all times of the year to meet the rhythms of wildlife and flora who have found refuge. Avoid nesting periods or periods of cold winters during which the vegetation provides shelter for many animals.
To facilitate vegetation and maintain natural processes, retain islands of vegetation (moss, ferns) in the maintenance of facades.
The developer must take into account the problems that can appear when installing a green wall in our outside the building:
Be cautious with moisture, such as humidity penetrating the wall of your home. It may damage paint work. Also be aware of any possible short circuits in case you have artificial lighting installed and / or a water pump.
The increasing weight of your green wall is also something to consider. Is your construction strong enough to support the weight of the vertical garden?
To avoid any of these problems and to keep your green wall in good shape, maintenance and regular checks are needed.
When using exotic plants for your vertical garden, avoid importing unwanted organisms or pathogens, it is recommended to work with specialist growers who can recommend you on the origin of the plants used and can offer your advise concerning legality of the plants used.
The green wall or the vertical garden is a new process plant on façade or building which differs from a wall as it is simply covered in vines.
At the aesthetic side the green wall improves the beauty of a building.
It enriches architecture by creating small rainforest in constant motion – seasonal appearance, colors …, it also offers designers unprecedented opportunities to integrate a building to its environment or to make the urban areas greener.
Flexible and easy to implement, the vertical garden is therefore not only decorative: it prevents the building from graffiti, it also improves the acoustic performance and heat performance.
The vertical garden absorbs sounds
A full grown green wall offers an absorbing surface. The green wall is a sound insulating material which can be used for the construction of noise-shields. Such as Airports, Highways, Structures, Circuits motor sports, industrial sites, Home, Office Buildings …
The vertical garden regulates heat
Green wall is part in the ecological revolution. It regulates heat gain and losses of buildings as well as humidity, improve air quality. Moreover it protects the walls of solar radiation and reduces the temperature of a wall directly exposed to the sun of 10 ° C to 15 ° C.
The green wall is colorful
The green wall is changing with the seasons and the growth of the plants, it is composed of colors, different textures changing according to season.
The composition of the plant colors depends to the site location and direction North / South / East / West.
The green wall releases pleasant smell
In addition to the decorative wall, the plants can have odor properties:
Cassis, mint, lemon, pineapple or vanilla smells can be released by the wall by making the right selection of herbs …
You can smell it by walking by or even to crush a few leaves in the fingers to release a perfume.
Low Water consumption
You can make your green wall water efficient by irrigating it at regular intervals, and not too often.
Also using different materials for the bases can be extremely hydro retaining and form an integrated natural water reserve. In my case, I had few choices of materials due to my location. I advise to ask a gardening shop about their specific innovative water-retaining materials.