The right-of-way located between San Bruno Avenue, 17th Street and Vermont Street sits atop ancient serpentine bedrock, composed of California’s rare state rock, serpentinite. Homes that once occupied the area were removed in the 1950s to make way for Highway 101. The largely derelict space is soon to emerge as Potrero Gateway Park, part of a chain of gardens that make up the Vermont Street Greenway.
The greenway will replace what’s now Vermont Street’s western lane. The three-lane road has been designated part of the City’s “High Injury Network;” residents hope that by reducing it to two lanes safety issues will be resolved.
“There’s a lot of exhaust and noise from the freeway, as well as camping and illegal dumping. People speed off of the highway and hit parked cars, and make the area dangerous for cyclists and pedestrians,” said Julie Christensen, executive director of the Dogpatch and NW Potrero Hill Green Benefit District (GBD). “Neighbors have pretty much been trying to minimize the problems of the freeway since it was built.”
The Potrero Gateway Park would add green to both sides of the freeway.
“The idea is to activate the space with native plants, and install some safety measures like retaining walls, bulb outs, and padded bike lanes,” said Jean Bogiages, who helped create the nearby Fallen Bridge and Benches parks. “The project started in the neighborhood about ten years ago. We had meetings in the nearby church, and worked with the City, a landscape architect, and Caltrans on how to develop the project.”
In 2020, the GBD, Yerba Buena Chapter of the California Native Plant Society, landscape architect Alexandra Harker of the Field Collective, as well as interested neighbors, set about planting native species on the Vermont Street facing grade.
“Eddie Bartley and Noreen Weeden, who live across from the slope, have been trying to plant there for twenty years,” said Christensen. “Caltrans always said no to them though. It wasn’t until the GBD pushed for the planting that Caltrans allowed it, probably because of insurance and the fact that Eddie and Noreen hadn’t been asking as part of an organized group.”
“Part of the purpose was to test the interest of the neighborhood. So far there’s been a lot. They came out to help with sheet mulching, and we had a bunch of people come out for planting days and to help with watering,” said Bogiages.
The slope’s “test patch” provides visitors with examples of how to use native plants to mitigate water use, muffle weeds, and nurture native bugs and animals.
“Right now, we’ve labeled each of the habitats and have a plastic sign on the fence explaining a little bit about the native plants and butterflies, but we hope to put up more detailed signs in the future,” said Harker.
“San Francisco was actually called Yerba Buena at one time because the plant used to carpet the ground here. Yerba Buena can be planted in your garden and will spread out for effective weed suppression like you can see here,” said Harker. “When there are enough native plants then the native bugs can come back, and when the bugs come back then native birds can come back.”
“This is not a restoration project though,” she emphasized. “We’re taking local plants and woodlands as inspiration, using lots of coastal plants, and those of the wetlands that used to be at the bottom of this hill. Sometimes people assume that native plants aren’t very attractive for their gardens, so we’re looking to come up with exciting combinations to show otherwise.”
Rare formations of serpentine bedrock and soil are created when tectonic plates scrape up what was once the ocean bottom. The soil’s unique chemical characteristics provide the sole habitat for species like the threatened Bay Checkerspot Butterfly and the endangered Mission Blue Butterfly, which co-evolved with the serpentine grasslands that used to grow here. With much of these habitats paved over, any remaining serpentinite soil, such as can be found throughout Potrero Hill, is precious to these plants and animals. Geographic isolation is a leading causes of biodiversity loss.
“Unfortunately, freeways are like giant walls for native species,” said Harker. “We’ve seen skippers and red admiral butterflies, but for the Bay Checkerspot and the Mission Blue to return, they’ll need more local plants like we have here. Some of these species can’t travel very far though, so people will need to start putting native plants in their own yards to expand critical habitats. That’s the importance of this slope; a place where neighbors can learn how to do this.”
The Vermont Street Greenway will provide additional space for native plants, while addressing traffic safety concerns.
“Vermont Street is a wide, three-lane road that people can easily speed on,” said Christensen. “Residents have successfully fought to get a stop sign put up, and have lobbied Caltrans and the City to remove the outermost lane of the street to slow down traffic from the freeway. The City proposed turning the third lane into angled parking, but the residents rejected that in favor of the greenway.”
The Department of Public Works will demolish the Vermont Street’s western lane this month, which’ll then be greened, featuring benches, a walkway, and sidewalk gardens.
“A metal picket fence is going to be put up too as a barrier to the freeway, and the 12-to-15-foot space that used to be asphalt and sidewalk will be planted. It will have the native plant palette that they’ve been testing on the slope,” said Christensen.
The GBD was awarded a $150,000 2022 Community Challenge Grant to develop the greenway, which requires a 35 percent match that’ll be met from the NW Potrero capital budget, donations of items, volunteer labor, and in-kind professional services. The GBD also received a $10,000 grant from SPEAR Capital, for a total budget of approximately $210,000. Greenway completion is expected by the end of next year.