Jake Sigg, one of California\u2019s best-known advocates for protecting native biodiversity, died on June 10, one week after his 99th birthday, in his longtime Sunset District home in San Francisco. He grew public appreciation of native plant communities and ecological restoration in California and inspired and mentored scores of professionals in the field. His legacy includes playing a vital role in forming San Francisco\u2019s network of protected natural areas and supporting the work of the California Invasive Plant Council (Cal-IPC) and the California Native Plant Society (CNPS).\u00a0<\/p>\n
Jake grew up on a ranch in rural Montana without running water or electricity for much of his childhood. Visiting San Francisco as a Navy recruit after high school in 1945, he was enchanted by its many cultural offerings, including the theater, ballet, and\u00a0 symphony. Once he finished college in Montana, he moved to San Francisco in 1950. After having tried his hand at many different jobs, Jake found his true passion in 1959, as a gardener for the City.\u00a0\u00a0<\/p>\n
![\"Jake](\"https:\/\/www.newsbeep.com\/us-ca\/wp-content\/uploads\/2026\/08\/Jake-Sigg-Portrait-by-Chris-Cambell.jpg\")
Jake Sigg kneels amid a swath of California goldfields (Lasthenia californica) during a tour of the Crystal Springs Reservoir led by the Public Utilities Commission. In the background are Montara Mountain and coastal grassland prairies. The photo was taken May 5, 2023. Christopher Campbell<\/p>\n
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Jake Sigg works to extract French broom (Genista monspessulana), a invasive species, with a weed wrench on Twin Peaks in San Francisco. The photo was taken around 1996. Greg Gaar<\/p>\n
Jake worked several park beats over his three decades with the City. His years as a lead gardener of the California Native Plant section of Strybing Arboretum (now called the San Francisco Botanical Garden) brought him satisfaction and influence. While working at Crocker Amazon Park and McLaren Park in the 1980s, Jake witnessed still extant native grasslands threatened by the spread of fennel and other invasive plants. He began to realize how special San Francisco\u2019s remaining natural areas were, and how unique their biodiversity was. This laid the foundation for his life\u2019s work: preserving and stewarding native plant and wildlife communities.\u00a0<\/p>\n
His conservation work involved many different activities. He founded and participated in regular weekly work parties to remove invasive plants. He shared his botanical knowledge with others. He spoke to decision-makers at City Hall, at the State Capitol in Sacramento, and in Washington, DC. He served in leadership roles for CNPS and helped form the organization that is now Cal-IPC.\u00a0<\/p>\n
\u201cJake\u2019s restoration legacy spans the entire city, and there is not a natural area in San Francisco that he has not helped to improve in some meaningful way,\u201d wrote Christopher Campbell, the chief natural resource specialist for the San Francisco Recreation and Parks Department, and Jake\u2019s friend, in a tribute. \u201cI imagine being with Jake is, in many ways, like being with John Muir.\u201d<\/p>\n
After Jake retired in 1990, he devoted himself to ecological conservation. With his top partner, local environmental activist Greg Gaar, he served on the City\u2019s Open Space Committee where he advocated for the City to acquire many of the natural areas that were still in private hands. Jake made plant lists for each of these native habitat remnants throughout the City, creating a foundation of knowledge for the CNPS Yerba Buena Chapter, as well as the City\u2019s Recreation and Parks Department (RPD) and other agencies. Jake ultimately convinced the RPD to create the Natural Areas Program (now called the Natural Resources Division) to lead community volunteers in stewarding the coastal scrub, grassland, wetland, and oak woodland habitats throughout the park system.<\/p>\n
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In May 2015, Jake Sigg wields a hand mattock, meant for weeding, during a weekly CNPS volunteer restoration project at O\u2019Shaunessy Hollow, an area rich with diverse native plants thanks to a natural seep. The area is just west of O\u2019Shaunessy Boulevard and immediately west of Glen Canyon in San Francisco. Christopher Campbell<\/p>\n
Though Jake was a shy person, he was able to speak knowledgeably and passionately when testifying at public meetings or describing native plants in the field. By default, he became a lead advocate and a lead organizer\u2014not his most comfortable role\u2014in the local conservation movement.\u00a0<\/p>\n
\u201cHis voice mattered especially in places like the Presidio, where, even during the Army period and through the transition to National Park stewardship, he helped insist that the remnant dunes, grasslands, coastal scrub, and rare plant habitats were not vacant or ornamental landscapes, but irreplaceable fragments of San Francisco\u2019s original ecological inheritance,\u201d wrote Lewis Stringer, associate director of natural resources at Presidio Trust, in an email tribute.\u00a0<\/p>\n
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Being a leader put Jake in the line of fire when conservation of native plants ran into competing issues, like the desire of some dog owners and professional dog walkers to use natural areas in San Francisco to exercise pets.\u00a0<\/p>\n
Around the time the \u201cdog wars\u201d exploded, Jake started his popular email newsletter, Nature News. Over the next twenty years, it became a valued source of information on ecologically relevant topics (as well as a smorgasbord of poetry, politics, history, and astronomy) with alerts about issues that needed attention from conservationists. Jake enjoyed writing and the discussions that ensued when readers would write responses to his views in the newsletter.<\/p>\n
In 1998, CNPS published a special issue of their journal Fremontia (now called Artemisia) on the topic of invasive plants. In it was an article by Jake titled, \u201cThe Role of Herbicides in Protecting Biodiversity,\u201d expressing his view, based on years of experience, that herbicides are sometimes essential for controlling invasive plants and protecting native plants. Given that environmentalists often fight against pesticide use, the idea of incorporating them into the land steward\u2019s integrated pest management (IPM) toolbox runs counter to common assumptions held by some of the general public about how to protect the environment. CNPS\u2019s recently updated herbicide policy aligns well with the viewpoint Jake so cogently presented.<\/p>\n
Though Jake never served on the board of directors for Cal-IPC, he was a key player in the organization\u2019s formation in the early 1990s, and he attended board meetings for a decade. Together with Don Mayall of Palo Alto and Bob Case of Concord, he led the CNPS Invasive Exotics Committee. As CNPS local chapters initiated stewardship work parties to address invasive plants, these three represented CNPS in advocacy efforts to strengthen stewardship policy at the state and federal levels. They attended Cal-IPC\u2019s annual Day at the Capitol events in Sacramento to educate legislators about the impacts of invasive plants and to gain their support for funding of the state\u2019s local Weed Management Areas (WMAs).\u00a0\u00a0<\/p>\n
![\"Jake](\"https:\/\/www.newsbeep.com\/us-ca\/wp-content\/uploads\/2026\/08\/Jake-Sigg-Mt-D-Greg-Garr.jpg\")
Jake Sigg leads a native plant tour on the north side of Mount Davidson in San Francisco in 2005. Greg Gaar<\/p>\n
Jake had a special interest in biological control agents as an effective landscape-level management strategy for widespread weed species. He was a regular advocate at the USDA Agricultural Research Service lab in Albany, California, encouraging development of biocontrol agents for various high-priority plants. (Agencies even flew Jake to Washington, DC, to testify on the need for biological control agents that protect native habitats.)\u00a0He led fundraising efforts that supported USDA\u2019s work in South Africa, finding potential biocontrol agents for Cape-ivy, a scourge of coastal watersheds in northern California that has spread rapidly over the last five decades. After years of host specificity research and regulatory permitting, one agent\u2014the Cape-ivy shoot tip-galling fly\u2014has been successfully released and become established in California, while a second potential agent, a leaf- and stem-mining moth, is still being researched.\u00a0<\/p>\n
Jake\u2019s knowledge, passion, and eloquence made him a beloved conservation leader, though he had no aspiration to be revered. He had a talent for combining thoughtful, well-grounded arguments with passionate exhortations. He encouraged us not to be \u201cindifferent to the rending of nature\u2019s fabric\u2026\u201d but to dedicate ourselves to protecting \u201cthe miraculous diversity of life we have inherited.\u201d The work of stewarding California\u2019s native biodiversity will be carried on by the many people Jake has inspired, building on the foundation he and others have built.<\/p>\n