Softening Concrete and Metal with Native Plants

By Kathy Morrison

Going green takes on new meaning as designers of urban spaces include living walls featuring native plants as integral parts of their projects. Plants growing on the sides of buildings soften the landscape, providing contrast to the harsh edges and hard surfaces. Appropriate for the climate and the space, the greenery contributes to urban biodiversity, cooling, and carbon sequestration. Plus, they’re beautiful to see.

Here are two examples of dramatic living walls using native plants in urban California spaces.

San Francisco Museum of Modern Art (SFMOMA) Living Wall

Address: Third and Howard streets, San Francisco
Designer: David Brenner, Habitat Horticulture, San Francisco
Architect: Snøhetta, Oslo, Norway
Opened: May 2016
Wall size: 4,400 square feet
Plants: 19,442 plants, 38 species, including 21 California natives

Installation method: A geotextile created from recycled plastic bottles and other sustainable materials holds the plants in pockets. It is irrigated mostly with stormwater and excess water from the building’s HVAC system. Runoff water is captured and recirculated.

Why it’s significant: The 29-foot-tall, 150-foot-wide living wall is visible in part from the six floors of SFMOMA’s addition. At the third-floor open-air terrace, it forms a backdrop to several large sculptures. In his artist statement, Brenner says, “In conceiving the wall, it was important for it to be perceived as an extension of the natural world, to not be overly designed. I also felt that the wall needed to be rooted somehow in the California landscape, its wider home. Drawing practical inspiration from the fairly shaded exposure of the site, I worked to capture the essence of an under-story plant community in a California woodland.”

Natives in Brenner’s palette range from 1,450 California huckleberry (Vaccinium ovatum) and 1,255 redwood sorrel (Oxalis oregana) plants to a few dozen Solomon’s plumes (Maianthemum racemosum).

Drew School, Sam Cuddeback III Assembly Wing

Address: California and Broderick streets, San Francisco Designer: Patrick Blanc
Architect: ROMA Design Group, San Francisco
Opened: 2011
Wall size: 1,720 square feet over three stories
Plants: 4,579 originally planted, 105 species, all California natives

Installation method: A frame of metal, PVC, and nonbio-degradable felt holds the plants. The irrigation system sends water from top to bottom. An alarm system was created to alert the school if any part of the irrigation system failed.

Why it’s significant: Blanc is a renowned French botanist and artist who has created hundred of vertical gardens on six continents. Bonnie Fisher of ROMA says the Drew School living wall was a real collaboration with Blanc. “We encouraged him to go native” on the project and found the seeds, nurseries, botanists, and landscape specialists to carry out his plan. His unique, flowing designs are copyrighted.

Blanc’s longtime experience with species that grow on cliffs and rocks has taught him to trust plants in unex-pected places, defying skeptics, Fisher says. But there are no vines used; all the plants are graded in terms of light and aspect. She says that at first she wanted to use all succulents, but he pointed out that those grow leggy over time, not leafy. The palette as planted included Munz’s sage (Salvia munzii), Catalina currant (Ribes viburnifolium), several varieties of monkeyflower and, naturally, the plant after which San Francisco and its chapter were both named: yerba buena (Clinopodium douglasii).

The Drew School is LEED (Leadership in Energy and Environmental Design) Gold certified for sustainability and efficiency. The wall brings green to the neigh-borhood and provides educational material for six academic subjects at the school. In the time since the wall’s completion, the plants have evolved, with a little help from nature. “Birds are attracted to it, and later there’s a tomato plant in the middle of it,” Fisher notes. “I’m a true believer” in this kind of project now, she says. These aren’t short-lived projects, either. Blanc’s home in Paris includes indoor walls with plants that have been there 25 years, she noted. “Amazing.”