Those that we now know as vertical gardens – but it would be more correct to call them technical gardens, even if being aware that this definition is less pleasant – introduce a new operating mode within the contemporary garden design. Critics and public opinion, very impressed by the spectacular nature of these interventions, immediately looked for the origins of this innovation, having the need to search for its creation in the Antique, in order to give a greater meaning to the work of landscape architects. In this sense, in a very fascinating way, the gardens of Babylon were evoked. In this way, the beginning of this new narrative was found in one of the seven wonders of the world, giving back to the contemporaneity the mythical inspiration of history, sinking the roots of the vertical garden in ancient history. This recovered cultural substrate, however, appears to be as comfortable, immediate and easy to communicate as it is incorrect in its enunciation. As often happens, before coming to easy conclusions, a more in-depth contextualization and a larger historical knowledge are necessary, without detracting from the quality and modernity of these plant architectures.
In fact, although it is undeniable that among the values of the garden there has always been a common Edenic aspect in the creation of an artifice of nature, it must be said that, throughout history, the garden has assumed a variegated multitude of meanings and nuances, taking on, in its own design evolution, continuous resemantizations, waiting to be told in a way able to avoid incredible space-time jumps in the succession of events that led to the birth of this innovation. As pointed out by Rosario Assunto in this narration of the history of gardens in the contemporary age, the ontology of the garden radically changes and, like what happened in the history of art, its aesthetics bends to merely functional instances.
The structure of the hanging gardens of Babylon had to be equipped with a highly technological system to supply water at different heights. Over the centuries, its total disappearance has transformed this work into an ideal model of fundamental reference for many gardens. Today, it shares only one of its characteristics with vertical gardens: the distinction between vegetable and natural soil. But the ones of Babylon were precisely hanging gardens. The conformation of this typology consists in planting above an artificial, flat, inclined or terraced structure, which has had its fortune and its continuity in the garden history. On the contrary, in the technological garden plants grow without having any contact with the ground. It works in a different way, as is well stated by Blanc’s patent: «On a load-bearing wall or structure is placed a metal frame that supports a PVC plate 10 millimetres (0.39 in) thick, on which are stapled two layers of polyamide felt each 3 millimetres (0.12 in) thick. These layers mimic cliff-growing mosses and support the roots of many plants. A network of pipes controlled by valves provides a nutrient solution containing dissolved minerals needed for plant growth. The felt is soaked by capillary action with this nutrient solution, which flows down the wall by gravity. The roots of the plants take up the nutrients they need, and excess water is collected at the bottom of the wall by a gutter, before being re-injected into the network of pipes: the system works in a closed circuit. Plants are chosen for their ability to grow on this type of environment and depending on available light». Through an immediate projection in the contemporary world, the constructive principle at the base of the hanging gardens still finds in architecture numerous experiences of international fame.
We are talking about the Vertical Forest (Bosco Verticale, 2009-2014) , the well-known Milanese complex of two residential tower buildings by Stefano Boeri (1956), hosting more than two thousand species – among shrubs and tall trees – distributed onthe façades. An idea born in 2007, when he was editor in chief of Domus, during a trip of the architect to Dubai that generated an intolerance towards mineral steel and glass cities, increased by the fact that 94% of the tall buildings built after the 2000 is covered in glass. Many of his cultural references have thus turned to the Green Architecture trend, which developed in the second half of the 20th century, including the works of his precursor: the Argentine architect Emilio Ambasz (1943) who published the Green over Gray manifesto in the 1980s.
In this context, a particular evolution of hanging garden is highlighted, founding a favorable theory in the Modern Movement: the principle of the roof garden, covering increasingly extensive and characterizing surfaces, gave rise to hypogeal architectures in consolidated landscape contexts, in a kind of post-romantic way due to the mimetic implications inherent in their design, with numerous realizations of great interest and innovation. Lastly, we like to recall an application of the hanging garden principles also on an urban scale in the redevelopment of the High Line Park (2002-2011) in New York. The linear park, like the transformation of the city walls into public promenades happened in the past, was created by architects Diller Scofidio + Renfro and by the landscape architecture firm James Corner Field Operations on a disused section of the elevated railway that runs along the western side of Manhattan.
In the case of Patrick Blanc, to understand the nature of the vertical garden, it is necessary to investigate his personal history, which is linked to the counterculture of the 1960s and 1970s, but also to the principles of Radical Architecture, in a totalizing attention to the environment in function of a global mutation. In 1972, before his PhD in Plant Biology in 1978 at the Université Pierre et Marie Curie in Paris9, Blanc took a trip to the Southeast Asia and, says Diane Ackerman, «as he entered adolescence, his nomadic curiosity drifted from aquariums and birds to aquatic plants, and then, at fifteen, he leapt above the waves to the world’s moist shaded zones, the mysterious understory of tropical forests. A college trip to the rainforests of Thailand and Malaysia brought the revelation that “plants could sprout at any height, not merely from the ground”». The journey in the East slowed time down, expanded spaces, altered distances and brought horizons closer, making the revolution against the profit market feel more real, pushing towards an harmony between man and nature and searching for a fantasy that never would have arrived in the power structure. Starting from his college experience, the young botanist was able to benefit from several other trips around the tropical forests, observing with a disenchanted gaze the nature that still dominates and engulfs ancient architectures, such as the temple of Ta Prohm at Angkor, but also the different vegetation that slowly takes over degraded or abandoned buildings in the suburbs, the green that grows in the smallest interstices of the rock in the most different weather conditions and in other extreme botanical contexts.
An unconquered, highly evocative nature was combined with the theories developed in France by landscape artists such as Bernard Lassus (1929), Jacques Simon (1929-2015) and Alexandre Chemetoff (1950). These are the years in which the principles of the Jardins Imaginaires, the other landscapes, and the multidisciplinary approach take shape. In the same period also Land art was affirming itself on the international panorama. These are the main theories underlying today’s landscape architecture. In 2006 Blanc published Folies végétales, in which he illustrated the infinite strategies of adaptation of plants. In the meantime, he completed a sort of transference that, since 1985, has made him the contemporary materialization of the man in Habit de Jardinier, depicted by Nicolas de Larmessin in 1695. But was Blanc really the first botanist to invent the vertical garden? Indeed, in a letter from the American writer Elwyn Brooks White, addressed to his wife Katherine in 1937, we read: «I guess everybody has crazy brothers and sisters. I know I have. Stan, by the way, has taken out a patent on an invention of his called ‘Botanical Bricks’, which are simply plant units (like windows boxes) capable of being built up to any height, for quick landscape effects, with the vertical surfaces covered with flowering vines, or the like. He thinks that the idea has great possibilities for such things as World’s Fair, etc., where sudden and transient greenery is necessary, also for sidewalk cafes, small city yards, indoor gardens, and many other projects».
The man he was talking about is Stanley Hart White (1891-1979), a botanist graduated from Cornell University in 1912 and professor of Landscape architecture at the University of Illinois at Urbana-Champaign from 1922 to 1959. The Department of Landscape Architecture was particularly influential in university cultural modernization of the sector, thanks to White’s work. White had patented in 1938 a new structure registered as VegetationBearing Architectonic Structure and System: a vegetal wall that gave way to a new field of work in the architecture of the garden. It was a pioneering method, as stated in the patent itself, «for producing an architectonic structure of any buildable size, shape or height, whose visible or exposed surfaces may present a permanently growing covering of vegetation». An idea that anticipates the current construction programs of artificial wildlife corridors in areas of intense urbanization, as a reaction to the excess of anthropization, promoting interventions aimed at increasing biodiversity and regeneration dynamics of flora and fauna in the contemporary city: a sort of “Blanc effect” that involves various cities, especially within the French context.
White’s 1931 writings, What is Modern?, contained in nuce the principles of the art of creating vertical gardens to respond to the demands of modernity. His botanical bricks consisted of metallic modules that contained the necessary vegetable substrate retained by painted small boards, supported by a water and technological network created to provide water and light for plant life, but in a sculptural form. The modules allowed differentiation and isolation of the root systems of the plants, according to a botanical and artistic logic. This form of abstraction was not isolated in the cultural context of the interwar years, when the dialogue between avant-garde painting and the modern movement was strong. Among the protagonists of rationalism, we recall Gabriel Guévrékian (ca. 1892- 1970), one of the architects present at the first CIAM congress, promoted by Le Corbusier and held in the Castle of La Sarraz in June 1928. Guévrékian is known as the architect who better succeeded in creating a cubist garden, which occurred first in the Jardin d’Eau et de Lumiere for the Exposition Internationale des Arts Decoratifs et Industriels Modernes in Paris (1925); then in the most famous small triangular garden of Villa Noailles in Hyères (1926- 1927); at last, in the hanging garden of Villa Heim in Neuilly (1928). The design of these plants was regulated by severe geometric lines that divided the garden into closed compartments at different heights and built with different materials, using relief borders that were part of the design of the complex. This subdivision, mindful of a medieval cultural tradition, allowed a variegated coloring of the squares precisely closed within their perimeter, without allowing the root system of a flower bed to infest the neighboring module.
In 1948 Guévrékian left for the United States of America and became a professor at the University of Illinois, where he remained until 1969. In 1957 Frank Lloyd Wright published A Testament, in which the project for Mile High Illinois appeared, followed by The living city (1958), the last reflection on the theme of the city and its unstoppable expansion process, to which he had opposed his Broadacre City. In the University of Illinois Guévrékian he collaborated with Stanley Hart White and certainly got to know his patent, just as he must have been familiar with Wright’s environmental utopias. I like to think that the Armenian-born architect, on his return to France in 1970, brought with him the knowledge of certain experimentation that had great impact on some of the main American landscape architects, such as Peter Walker, Hideo Sasaki, Richard Haag, Charles Harris and Philip H. Lewis Jr. Certainly, today we can say that Patrick Blanc is the modern innovator of White’s green wall: specifically, he invented the modern vertical hydroponics garden, distinguished from its predecessors precisely because of the highly technological content behind these spectacular works, which reopen discussions on the ontology of gardens.