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The idea for this post came to me last summer, when Mr. Best
in Show and I were in Avignon. The central market's north façade is a stunning
living wall. Living walls and living roofs have been around for a long time.
Sod roofs, the original living roofs, date back to prehistory [insert URL] in
Scandinavia. The Hanging Gardens of
Babylon might be mankind's initial stab at living roofs and walls. Gardeners have
created green facades, formed when plants grow on a structure like a trellis or
an arbor, for centuries, sometimes attached to buildings but often structures
in themselves. Looking at the wall of Les Halles in Avignon, with its
substantial size and artistic swirls of plant material, prompted me to
investigate the engineering that makes these modern structures possible.
Les Halles Avignon, Flickr/TracyElaine
As usual when I get to sleuthing, I uncovered much more
interesting material than I'd expected. This week's blog post will provide some
additional history of living walls, plusses and minuses, and an introduction to
Patrick Blanc, a French botanist who has designed and installed many walls in
the past 15 years, including the one in Avignon. Future posts will cover some of the really
interesting technology behind (literally) living walls, and the story behind a
local, just-completed living roof.
A living wall vs. a green façade
The main distinction between a living wall - also known as a
vertical garden or biowall - and a green façade is that with a living wall, the wall supports the growing medium, so the plants root in the medium and not in the ground at the base
of the wall. Living walls can be installed inside and outside.
Some History
Sod roofs and arbors aside, Stanley Hart White, an American
landscape architect, patented his idea for a vertical garden in 1938. White was
granted a patent "for the Vegetation-Bearing Architectonic Structure and System"
describing a method "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." As far as we know, however, White
never constructed his vegetation-bearing structure.
The Arts and Crafts movement of the early 20th
century, followed by Art Nouveau, favored plants that climbed up the sides of
buildings and thus bridged the junction of lawn and built environment. Their
favored plant? Parthenocissus tricuspidata, also known as Boston ivy (not to be
confused with Hedera helix, English
ivy). Whether the ivy is Boston, English, or some other species, ivy-covered
walls are ubiquitous. They're not living walls, though, despite ivy's
propensity for covering up nearly everything in its path. Like kudzu.
Why bother?
Construction of a living wall isn't inexpensive. Why go to
the expense and trouble, other than the aesthetics of the finished design?
These walls have several advantages, some obvious, others more subtle.
Reduced costs for air
conditioning and heating: External living walls absorb sunlight, preventing
sunlight from striking and warming the building. The cushion of air between the
building and the plant support frame provides insulation. Plants also provide
shade and evaporative cooling.
Reduced air and noise
pollution: Both interior and exterior living walls reduce air pollution, by
using carbon dioxide in photosynthesis and absorbing other compounds, such as
nitrogen dioxide and particulates. Plants help absorb sounds, providing an
acoustical advantage.
Improved aesthetics:
Living walls are often planted in patterns. Small green "pictures" can be
incorporated indoors or outside.
Improved quality of
life and job satisfaction: Some studies have shown that seeing nature in
the work environment can increase job satisfaction.
Depending on choice of plant material used and living-wall
accessibility, some vegetables and herbs can be grown on living walls.
Types of Living Wall Systems
Living walls have two basic construction styles:
- Pots or pouches assembled on a framework and
filled with growing medium, with irrigation provided
- Panel systems that combine irrigation and a growing medium, mounted on a support framework
Both types of garden systems can be used indoors and outdoors. My next blog will dig into some of the
interesting materials used for these systems.
Image credit: Vertipak
Patrick Blanc: Father of Modern Living Walls
The Avignon living wall that so entranced me is the work of Frenchman Patrick
Blanc, the inventor of the modern vertical plant wall. Blanc started his botanical
career as a specialist in tropical forests, writing his Ph.D. thesis on
understory plants in tropical forests. In
1982, he signed on as a resident scientist at the prestigious Centre National
de la Recherche Scientifique (CNRF), making field trips to Southeast Asia in
search of new plant species. He
discovered Begonia blancii , one new
species, in the Philippines. Working for CNRF is still Blanc's day job.
Blanc's claim to international fame, however, is his championing of
living walls. In 1986, he installed his first living wall, at the Cite des
Sciences et de l'Industrie de la Villette in Paris. In 1988, Blanc patented his
vertical garden system, described as follows:
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. [https://en.wikipedia.org/wiki/Patrick_Blanc]
Since 1988, Blanc has designed and installed dozens of these "vertical
tapestries," as Kristin Hohenadel of the New York Times describes them.
Blanc's designs often incorporate plants that create not only an
aesthetic but an educational experience. For example, the installation at the Musee de Quai Branly in Paris, completed in 2006, incorporates 15,000 plants of
150 different varieties, representing countries whose artifacts are included in
the museum's collections.
Could vertical gardens also grow food? Sure. Several years ago, a group of high-school students in the Bronx successfully grew many pounds of fresh
vegetables for their school cafeteria. The Bronx group partnered with Green Living
Technologies, which claims to be the inventor of "edible green walls" and a
mobile edible wall system. Other commercial enterprises offer living wall
systems that could adapt to growing lettuce as well as ferns and pachysandra.
Resources
https://en.wikipedia.org/wiki/Stanley_Hart_White
http://www.ambius.com/blog/ultimate-guide-to-living-green-walls/
http://landarchs.com/vertical/
https://en.wikipedia.org/wiki/Patrick_Blanc
http://www.verticalgardenpatrickblanc.com/
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Re: Living Walls, Living Roofs: Old Ideas and New Technologies
