1 May 2023  •  Detail  •  By Collin Anderson

In Beverly Hills a new residential complex is enveloped in a 600 square meter living art wall. Designed by MAD Architects, it’s the largest of its kind in the United States. The project’s facade supports over 40,000 plants consisting of 30 species.

When the designers from MAD Architects first visited Los Angeles, they drove the city’s streets and were struck by the number of single-family homes largely hidden from view, only partially visible from behind tall planted hedges that lined the properties. “All you can see are the tops of the roofs in L.A.,” says MAD’s Associate Partner Flora Lee. “We thought it was intriguing in terms of the city’s characteristics. It triggers one’s curiosity, while at the same time it provides the streetscape with lots of greenery.”

The firm had been assigned a project to design a mixed-use building combining housing with commercial space, a development of 4500 square meters on Wilshire Boulevard in Beverly Hills. “We wanted to create a multifamily version of the typical ‘home behind the hedges’, to respect the existing city fabric,” says Lee.

The Gardenhouse features a two-story podium that is wrapped in the largest living green wall in the USA. The project consists of ground-level commercial spaces and studios, condominiums, townhouses and villas. It is topped by a series of white, wood-framed and gabled penthouse units that are shaped to mimic the scale of houses in the neighborhood.

The living wall is a textured surface that forms an organic and seasonal addition to the streetscape. It is lushly fitted with native, drought-tolerant succulents and vines to minimize irrigation and maintenance. To realize the living wall, MAD Architects collaborated with Los Angeles-based architecture and landscape architecture firm Gruen Associates, as well as the local green wall specialist Seasons Landscape. 

Nic Lehoux

Using living walls to connect people with nature

The living wall is a design element that also goes by a variety of other names: planted wall, green wall, vertical garden or vertical farm. Living walls, simply put, are vertical surfaces that host vegetation. Some types feature plants rooted in the wall itself; others act as trellises for climbing plants that are rooted in the ground below. Regardless of its design, a living wall can be a dynamic means to support nature within urban environments. 

When implemented indoors, living walls can bring a fresh aesthetic and the scent of nature into offices, homes and commercial spaces. And outdoors, such walls can spawn biodiversity, attracting birds, bees and other wildlife to urban areas. Living walls are often promoted to increase creativity and strengthen well-being, a popular element within the ‘biophilic’ toolkit used to yield more productive and healthy built environments.

Technical benefits and complexities

In addition to the positive psychological effects of living walls, such systems boast a range of technical properties that could benefit buildings, users and owners. Living walls have the capacity, for instance, to improve local air quality by removing pollutants from the atmosphere. They can also attenuate rainwater and act as acoustic buffers to reduce noise levels.

Whether in gardens or on buildings, plants have the power to lower temperatures when water evaporates off of their leaves during the warmest parts of the day. Plants of all shapes also absorb solar radiation, and so those used on walls or roofs can effectively act as shades to block the sun from hitting material surfaces. These characteristics allow plants to create welcome, comfortable microclimates in hot cities like Los Angeles, which suffers from urban heat island effect throughout the year. And whenever there is less demand for active cooling, a building’s long-term energy consumption and costs can be reduced.

Living walls are, however, not necessarily simple to construct. If not controlled, planted wall systems can add a level of risk to buildings that some owners do not wish to support. Roots can damage waterproofing, plumbing and structures. Shedding leaves and other debris can clog drainage systems. Moisture retention by soils can dampen surfaces and limit their ability to dry out, leading to potential rot or other deterioration issues in materials ranging from concrete to cladding and drywall. Avoiding these issues usually requires an experienced installer and advanced living wall systems. 

Vertical gardens also tend to require more maintenance than non-planted surfaces, especially for fast-growth plants that require pruning. In the case of the Gardenhouse, low-growth succulents that require only minimal care were used. And as the wall is typically two stories, all maintenance can be done from street level. An automated irrigation system supports the envelope and includes equipment such as an 8000 gallon tank in the building’s basement. Salt and pH levels are continually monitored and adjusted, while nutrients are added to the water as needed throughout the year.

Scott Hutcheon of Seasons Landscaping was engaged as the living wall specialist for the Gardenhouse development. According to Hutcheon, the biggest technical challenge this project faced was protecting the atypically large number of openings, balconies and terraces within the exterior living walls. Each opening required troughs and secure waterproofing to eliminate water infiltration and ensure proper drainage of water into collection systems.

Manolo Langis

Structural considerations and a lightweight solution 

“We have worked with a lot of landscapes,” says Lee. “But this was our first living wall project.” Determining the appropriate living wall product was therefore not a simple task. “We had to go through an extensive process to settle on the system that we ended up using,” she says. 

While living wall products are continuously being advanced, they often necessitate a double-wall buildup when used for exterior envelopes that consists of an interior wall that holds a waterproofing membrane, and an outer wall that supports the vegetation. Such a heavy buildup requires more robust and expensive building structures. 

Lee’s team ultimately landed on the AquaFelt system, a new product supplied by Seasons Landscaping that consists of two layers of synthetic felt into which plants are installed within small pockets and with a minimum amount of soil. The plant roots grow across the wall to create a vertical ecosystem, similar to those of plants that grow on cliffs. The system is hydroponic and recirculates water from a large holding tank at the bottom basement floor: water is pumped to the top of the wall through flexible tubing, and wicks down through the felt layers to reach the plants.

The wall buildup consists of an interior aluminum stud wall clad in gypsum sheathing. Aluminum tubing is fixed to the wall to support the felt layer on a poly board substrate. Aluminum troughs above windows and openings, and metal angles below, help to collect and route water.

The felt system is lightweight and reduces the amount of soil needed, thus minimizing structural requirements as well as the periodic, yet extensive, maintenance to replace soil that a typical green wall may require. “This was the happy solution to avoid stiffening our structure and increasing costs,” says Lee.

Manolo Langis

Curating the Gardenhouse living wall

Climate, sun aspect and available water sources are three major factors that affect the selection of plant species for living walls. “In L.A., drought is a critical issue,” says Lee. “So we proposed all low-water and drought tolerant plants.”

The Gardenhouse has two different microclimates due to site shape and building orientation. As a result, two sets of species that work together to achieve visual unity needed to be chosen. The wall along Stanley Drive is east-facing with a large amount of sunlight. Here succulents including jade, crassula, dwarf carpet of stars and aeonium were used. The wall along Wilshire Boulevard, on the other hand, is north-facing and predominantly shaded. Larger leaf and shade-tolerant species like fatsia, schefflera, ficus decora, and spider plant were used in this location. The species were chosen to be long-lasting and durable, and are individually replaced as needed. According to Hutcheon, in the years since the project was opened, in 2020, only a handful of plants have needed replacement. 

The plants were organized across the facade by species and color to create a natural textured mosaic that evolves seasonally. “We intentionally created this wavy organic fluid pattern so that it could soften the design, and become like a large painting made out of landscape,” says Lee. The envelope makes a statement and gives the building its one-of-a-kind identity. “We thought that the greenery would provide a beautiful artistic benefit to the public that experiences this project from outside, as well as to the people living within it,” says Lee.

To realize the pattern as it was designed on paper, Hutcheon and his team divided the expansive facade into a fine grid of 1-foot increments to determine the location of each individual plant. Like a mosaic that is created from tiles of different colors, Gardenhouse’s plants were installed individually by species, yielding geometrically smooth lines and coordinated colors. 

Darren Bradley

Nic Lehoux

Darren Bradley

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