Sign Hill in South San Francisco

The north slope of Sign Hill as seen from San Bruno MountainOn the north slope of Sign Hill, behind the famous “South San Francisco, The Industrial City” sign, you can find something that is all too rare these days in South San Francisco – 46 acres of healthy and relatively untouched native habitat. This land is privately owned and during the last housing boom it was slated for development.

While the south side of Sign Hill is publicly owned and protected as a South San Francisco city park, three privately owned parcels totaling 46 acres located on the eastern slope and the north-facing slopes, are zoned residential, with a planned density of one home per acre. The parcel on the eastern slope is the most immediately vulnerable to development, and is the focus of Mountain Watch’s current attention.

Sign Hill is a treasured San Mateo County landmark and nationally registered historic site. Less known is its stunning biodiversity and the rare value of its native Franciscan grassland habitat. As habitat for two rare and endangered species, the Callippe silverspot and Mission blue butterflies, the hill is a vital part of “… the largest, intact, healthy grouping of grassland habitat in the Bay Area...” according to Bay Area local Jake Sigg, California Native Plant Society guru. More than a landmark, this area contains the valuable natural resources and open space so needed in our over-crowded world.

Field of Hummingbird Sage (Salvia spathacea)The north side of the hill is a rich, diverse grassland habitat, never grazed by cattle. The eastern slopes are home to the federally endangered Mission Blue butterfly, that was recently adopted as the official butterfly of South San Francisco (download SSF Resolution to declare the Mission Blue as the city's official butterfly; link to South San Francisco Patch article, May 2012). Farther west is a stunning colony of Hummingbird Sage. The eastern parcel, with its Mission Blue butterfly habitat, is currently being considered for development. In an effort of cooperation, the developer has shared preliminary plans to put 20 houses on the site, including several going up the eastern ridge of the hill toward the famous sign.

The benefits of adequate, accessible open space on the northern Peninsula cannot be overstated. Mounting scientific evidence verifies what we all know: Being in nature helps clear our minds and raise our spirits. It is good for both our health and our future.

San Bruno Mountain Watch is talking with planners, council members and possible funders with the goal of purchasing this parcel, as well as the two others, in order to save them. We are teaming up with Friends of Sign Hill to build active local support for safeguarding these valuable parcels from development.