The Vertical Garden: From Nature to the City
About this book
"The Vertical Garden: From Nature to the City," published in French in 2008 and in English translation by W.W. Norton in 2008 and in a revised edition in 2012, is the principal theoretical and documentary work of French botanist Patrick Blanc, who invented the modern vertical garden—known in French as the mur végétal (living wall)—and whose patented system has enabled the construction of living plant walls on the facades and interiors of buildings across the world. The book presents Blanc's work on multiple levels: as scientific explanation of the botanical and ecological principles that underpin vertical growing; as technical description of the system he developed and patented; as a photographic catalogue of his most important projects worldwide; and as a philosophical argument for the reintegration of nature into the built urban environment.
Blanc's scientific starting point is botanical observation. As a researcher at the French National Centre for Scientific Research, specialising in tropical forest plants, he observed that many plant species in tropical and subtropical environments grow naturally on vertical surfaces—cliff faces, tree trunks, rocky outcrops—without any soil at all. These plants, which botanists call epilithic or epiphytic species, obtain their water and nutrients entirely from the moist rock surface or bark on which they grow, relying on the thin film of water and dissolved minerals that runs down vertical surfaces after rain.
Blanc's insight was that the ability of plants to grow without soil on vertical surfaces could be replicated artificially, using a lightweight system of mineral wool substrate and continuous nutrient solution delivery, to allow virtually any plant species to be grown on any vertical surface in any climate. The patented system that Blanc developed consists of a simple but ingenious layered structure mounted on a metal frame that can be attached to any wall or free-standing structure. A sheet of rigid PVC provides structural support and a moisture barrier.
On this are fixed two layers of polyamide felt, a material that is resistant to rot, capable of absorbing and distributing water by capillary action, and strong enough to support the weight of the plant roots that grow into it. A network of irrigation pipes, controlled by programmable valves, delivers a dilute nutrient solution to the top of the wall at regular intervals; the solution soaks into the felt layers and flows downward by gravity, bathing the roots of all the plants in the wall with water and dissolved minerals before being collected and recycled at the base. The botanical knowledge required to make this system work is as important as the engineering.
Blanc draws on his research in tropical forests—where he has documented plant species growing in light conditions and on substrate types that would be impossible to replicate in conventional horticulture—to select plant communities capable of thriving in the specific conditions of each installation: the light intensity, the temperature range, the humidity, and the aspect of the wall. In shaded north-facing walls in Paris, the plant palette is drawn from shade-tolerant species from forest understoreys. On sun-exposed south-facing facades in Kuala Lumpur or Bangkok, it includes species adapted to high solar radiation.
The result, when successful, is a genuinely naturalistic composition that recalls the texture and complexity of natural ecosystems. The book documents in detail some of Blanc's most celebrated projects. The most prominent is the vertical garden on the exterior of the Musée du Quai Branly in Paris, designed by architect Jean Nouvel and opened in 2006: a 15,000-plant composition covering 800 square metres of the museum's north-facing riverside facade, comprising some 150 species from Europe, America, Asia, and Australia.
This project established the vertical garden as a serious element of contemporary architectural expression and demonstrated that large-scale living walls could be maintained in a temperate urban climate. Other projects documented in the book include the exterior of the Caixa Forum Madrid (2007), designed by Herzog & de Meuron; the exterior of the Siam Paragon mall in Bangkok; vertical gardens in hotel interiors in Singapore and Tokyo; and domestic installations of various scales. Each project illustrates a different aspect of the design and botanical challenges involved.
The environmental dimensions of the vertical garden are explored in the final sections of the book. Blanc argues that living walls provide measurable benefits in terms of building energy performance: the layer of vegetation shades the wall surface from solar radiation in summer, reducing heat gain; in winter, the vegetation and trapped air layer provide additional insulation. The evapotranspiration of the plants also contributes to the cooling of the surrounding air during hot weather, reducing the urban heat island effect in densely built environments.
In terms of biodiversity, vertical gardens provide habitat for insects and birds in environments otherwise dominated by impermeable surfaces. Sources: W.W. Norton; Wikipedia – "Patrick Blanc"; Amazon; Homeli; Hotel Icon.