The creation of Paris born botanist Patrick Blanc, the Vertical Garden (‘le mur vegetal’ in French, which literally translates to ‘plant wall’) is an eye-popping stroke of brilliance that’s been cropping up around the world, from the Musee Du Quai Branly in Paris and the Marithé + François Girbaud store in New York to Saint Tropez's Hotel Byblos and Herzog & De Meuron's Caixa Forum in Barcelona.

With no soil required and just a little water, carbonic gas, light (and some metal construction), the towering gardens thrive with their own self-contained watering system. But just how long do they last? Well, Blanc has been growing one in his home for the past 20 years. Kind of gives new meaning to the term ‘living room.’

Do you regard your vertical gardens primarily as art, green architecture or eco-objects of a scientific nature? 
The Vertical Garden, as it's known in English, is not a real garden for there is no way to walk in it. It's something closer to a living painting than to a garden. Actually, I named it "le mur vegetal.” I'm a scientist, a botanist, and the Vertical Garden is derived from many observations I made in natural places, mostly in tropical areas, for more than 30 years now. The scientific approach is essential for designing the whole system and for selecting the plant species suitable for each peculiar location.
 
Why is it important to study how plants can survive in harsh conditions?
In many ways, studying how plants are living under extreme climatic conditions – for instance, limited light quantity in the tropical forest understory or water shortage for plants growing on cliffs – is essential for the right plant species selection process.
 
Will there be a similar way that humans could adopt this for their own condition?
Plants have been living on earth long before humans; plants physiology has nothing to do with human physiology. Humans should try to develop a way of living using less natural resources like understory plants receiving less than 1% of the sunlight. Humans should also try to limit or reduce their own number. You know, inside a tropical forest there is much space left free, without any plant cover at all. Humans should nots use all the space left free… I also would like to say that, for plants, wherever natural resources are scarce, biodiversity is higher and the competition between individual is lower. Humans should think about this when coping with the lowering of available resources on earth 
 
How do you create these vertical gardens?
The Vertical Garden is composed of three parts: a metal frame, a PVC layer and a felt. The metal frame is hung on a wall or can be self-standing. It provides an air layer acting as a very efficient thermic and phonic isolation system. A 1cm-thick PVC sheet is riveted on the metal frame. This layer brings rigidity to the whole structure and makes it waterproof. A felt layer, made of polyamide, is stapled on the PVC. This felt is rot-proof and its high capillarity allows a homogeneous water distribution. The roots are growing on this felt. The watering is provided from the top. The tap water is supplemented with nutrients. Watering and fertilization are automated. The whole weight of the Vertical Garden, including plants and metal frame, is lower than 30 kg per m². Thus, the Vertical Garden can be implemented on any wall, without any size or height limitation.
 
What about the growing process: A plant takes time to grow and develop roots. How long does that take?
Plants are installed on the felt layer as seeds, cuttings or already grown plants. It depends on whether it has to be densely green at once or not.
 
Is there any soil involved?
Plants don't need soil in any situation. The soil is merely nothing more than a mechanic support. Only water and the many minerals dissolved in it are essential to plants, together with light and carbon dioxide, to conduct photosynthesis. Wherever water is available all year long, as in tropical forests or in temperate mountain forests, plants can grow on rocks, trunk bases and soil-less slopes. In Malaysia, for instance, out of the 8,000 known species, about 2,500 are growing without any soil. Even in temperate parts of the world, many plants are growing on cliffs, cave entrances or fallen rocks. On such very steep places are growing many Berberis, Spiraea and Cotoneaster species. Their naturally curved branches indicate that they originate from natural steepy biotopes and not from flat area like the gardens where man usually grows them. Thus, as seen from nature, it is possible for plants to grow on nearly soil-less vertical surfaces as long as there is no permanent water shortage
 
How did you develop this elaborate device for watering the plants?
Water delivery is automated. Water is going from the top as it would be in any natural situation …on the surface of a cliff or of a rock.
 
How does it survive in an air conditioned environment like a shop or a museum?
Vertical Garden is creating its own specific climate. It has been proved that the Vertical Garden enhances atmospheric humidity of its own vicinity enabling small ferns and mosses to appear and seeds to germinate. Shops and museums turn up to be very suitable places for a Vertical Garden implementation.
 
How often does someone have to look after it?
It’s not like an ordinary garden. Three or four times a year is enough.
 
You created ‘La Robe Végétale’ for Jean-Paul Gaultier. 
That was a wedding dress. I selected the right plant species according to the shape of that dress and to the need of letting the model walk freely. 
 
Any forthcoming projects for ‘green’ skyscrapers?
In Spain and in Abu Dhabi there are current projects involving large Vertical Gardens located inside the top of the building, behind a glass. In Malaysia there is an outdoor project – a Vertical Garden on the wall of a high tower. There are many things to come.

Mar Yvette
Clear Magazine - Summer 2007