Apr 21, 2017
BY:
THEME: Sustainability

When in Drought: A Front Lawn Experiment

In our landscape architecture studio, we live by several imperatives. One of them is “find your own projects.” And where better to start than the front yard? On my first day of work at Perkins+Will in 2015, Managing Director, Peter Busby, and I were walking by the office’s lawn, composed of bright green, water-hogging sod. He turned to me and said, “Jen, we gotta do something about this.” And he was right; as a firm known for sustainable design, advertising a lawn in the middle of California’s historic drought was not exactly living our values.

After clearing the change with our landlord, we decided to start small, with a pilot project—called “When in Drought,” naturally—looking at which grasses would hold up best amid the punishing dry spell. The land in front of our building, located on the Embarcadero, is owned by the Port of San Francisco. So, in conversation with Dan Hodapp, the Senior Waterfront Planner with the Port of San Francisco, and the Port’s Central Waterfront Advisory Group, we proposed removing the lawn’s eastern half and replacing it with large strips of drought-tolerant alternatives.

 

A bit about each contender:

Carex divulsa (Berkeley Sedge): Evergreen grass that forms arching clumps. Does well in full sun to shade and tolerates both wet and dry soils.

Festuca rubra (Red Fescue): Native grass that prefers sun, has an attractive mounding quality and looks rather windblown.

Fescue Mix (Native Mow FreeTM by Delta Bluegrass): A combination of native (Fescue idahoensis and rubra) and naturalized (Festuca occidentalis) shade-tolerant fescues available in sod.

Festuca glauca (Blue Fescue): An evergreen, clumping silvery-blue grass that prefers full sun on the coast and some protection inland. Trim in the winter for a neater appearance.

Dymondia margaretae (Silver carpet): Low-growing, silver-leaved evergreen spreading groundcover with yellow flowers. Prefers full sun and well-drained soil. It can be a slow grower in drought conditions but will eventually fill in to provide a low-maintenance yet expansive look.

Nassella pulcha (Purple Needlegrass): Summer dormant California native and state grass, blooms in late winter to early spring. Showy seed heads go from purple to tan, with roots that can go as deep as 20 feet, making it highly drought tolerant.

Once we had decided on the grasses to use, our spring intern from University of California, Berkeley, Chris He, developed the design and plant-spacing using the sod width as a module. Then our summer intern from Harvard’s Graduate School of Design, Lanisha Blount, picked up the torch. Using a time lapse camera, she studied the current use of the site, which included mostly dog walking and significant traffic from pedestrians en route to San Francisco Giants games. This study set a baseline for the analysis of future interventions. Lanisha also designed and fabricated, in-house, small signs indicating each plant species and larger signs explaining the project.

The irrigation was initially kept at the same level as before, but we swapped in better irrigation heads that use a finer spray for a longer duration. Once the plants are established, the irrigation was periodically be turned down until it is fifty percent less than the baseline usage. We will continue to monitor the installation for approximately one year. The true test will come next summer, after all of the plants are well established, to see how they compete against the remaining control group of the lawn’s western half.

In our presentation to the Central Waterfront Advisory Group, the board was enthusiastic about the project and even inquired about a possible expansion that would redesign the whole plaza into a gateway to the Rincon Hill neighborhood. In the meantime, stay tuned to learn who is the king of drought-tolerant grasses!

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