San Francisco Weed Management Area

Table of  Contents

I.   Introduction  

Mission Statement  

The Problem

The Solution
II.   Program Description

General Overview

III.  Program Elements

Education, Awareness and Outreach

Prevention, Exclusion and Early Detection

Survey, Inventory and Mapping

Weed Management, Restoration and Project Monitoring 

Administration and Funding Opportunities

A.    List of Priority Weeds For Management Action In San Francisco County


This Strategic Plan outlines the framework in which the San Francisco Weed Management Area (SFWMA) will accomplish its goals.  The Plan articulates the problem of invasive weeds and the mission of the SFWMA.  It describes the various program elements the SFWMA will pursue in order to manage invasive weeds.  The accompanying Memorandum of Understanding (MOU) establishes the SFWMA and defines the terms and conditions under which participating agencies and individuals will cooperate and coordinate their activities.


The mission of the SFWMA is to promote and coordinate activities necessary to prevent the introduction, spread and establishment of invasive weeds in the City and County of San Francisco.  In addition, the SFWMA hopes to educate the general public and others about the problem of weedy plants and help make this knowledge more integral to the way urban dwellers interact with the land.  Thus, the two principal arenas of action will be 1) employing an integrated strategy for exclusion, detection, eradication and suppression of designated invasive weeds and 2) developing a multi-media education program targeted to local decision-makers, landowners and the general public about invasive weeds, including their identification, impacts and management methods.  


The San Francisco Peninsula is a globally-significant hotspot for nature and biodiversity.  The region harbors the Golden Gate Biosphere Reserve, which includes many of the natural lands in San Francisco County.  Invasive weeds are a serious threat to San Francisco's natural resources.  Weeds threaten our precious remnants of the original landscape including habitat for rare plants and wildlife.  Weeds can have the following additional negative effects on the land and people:

•    Create fire danger
•    Promote soil erosion
•    Impair unique geologic resources
•    Threaten local food productivity
•    Dominate open space areas turning them into uninviting, impenetrable, and potentially unsafe wastelands
•    Reduce water quality, including sedimentation and pollution in San Francisco Bay
•    Increase costs for private landowners and land management programs

San Francisco has many areas where the proximity of intense urban development to wildlands can lead to invasive weeds escaping from developed and landscaped areas into natural areas.  Of the thousands of plants in the nursery trade, only a handful are considered to be invasive weeds. These plant species are capable of spreading rapidly and displacing native plants because they are adapted to similar climatic conditions, lack predators or pests and/or have other characteristics that make them thrive.  San Francisco is also host to a number of endangered plant and animal species.  If invasive weeds are allowed to spread and take over important native habitat, the survival of these species, and the natural heritage they contain, is at risk.


San Francisco includes lands that fall under multiple political jurisdictions.  In addition, several non-governmental organizations exist which are active in issues related to weed management and conservation.  Several agencies and organizations are currently running successful conservation programs that address the problem of invasive weeds.  However, because invasive species are easily spread and do not abide by political or jurisdictional boundaries, there is a need to coordinate weed management activities across political and organizational boundaries.  The formation of the SFWMA will serve the overall shared vision of creating a City and County liberated from the scourge of invasive weeds.

The goals of the SFWMA that provide the framework for this Strategic Plan include:

1.    Protect and enhance the biodiversity of San Francisco’s natural ecosystems
2.    Make San Francisco’s rich natural heritage accessible to people
3.    Ensure that invasive weeds are not the primary cause of degradation or demise of rare and/or endangered plant and animal species or geologic features within our unique native habitats
4.    Increase the effectiveness of invasive weed management
5.    Eradicate or contain key weeds from the priority weed list
6.    Reduce fire hazard
7.    Ensure invasive weeds are not significantly contributing to reduced water quality
8.    Educate the public about invasive weeds and what they can do to help
9.    Make invasive weed management a priority for all of San Francisco’s land management agencies
10.    Cooperate in an adaptive management program which dynamically responds to monitoring data

The following sections outline the weed management program, emphasizing the application of Integrated Weed Management practices.  The plan will be revised annually to reflect program successes and new challenges.



The invasive weed management program in San Francisco is a cooperative effort among federal, state and local agencies and other interested organizations and individuals. SFWMA cooperators will join resources, priorities and strategies into unified action. These organizations and agencies will cooperate in procuring grants and other financial aid and may supply money, personnel (volunteers and/or staff) and/or equipment (see also the attached MOU).

Integrated Weed Management is a system used to plan and recommend selected methods to prevent, contain or manage the spread of undesirable plant species or groups of species.  Strategic use of all available tools and techniques is economically and environmentally more effective than depending on any single option.  The elements of integrated management include:

1.    Education and outreach, to encourage public awareness and participation
2.    Prevention and early detection of incipient infestations
3.    Mapping and inventory of existing populations
4.    Management (physical/mechanical, biological, chemical, cultural) of existing infestations
5.    Monitoring and evaluation of completed weed management projects (See Program Elements below)

Since many invasive weeds are found in San Francisco, an integrated strategy to manage these populations could minimize their negative effects and prevent future infestations of undesirable plant species.


Because so many invasive weeds thrive in San Francisco County, it is impossible to manage everything at once.  Prioritization is therefore essential.  The SFWMA’s prioritization of weed species for management action reflects the experience and expertise of its members, as well as federal and state laws and regulations.  Whether a certain weed is eradicated, suppressed or otherwise managed may be determined by 1) state rating, 2) pest potential in San Francisco, 3) size of infestation in the county, 4) whether control methods are available and/or 5) whether there is interest from participating agencies, organizations or other landowners.  We focus our limited resources on the highest priority weed species.  Please see attached list of Priority Weeds For Management Action In San Francisco County.  Weed management activities are not limited to species on this list, which may be modified as needed.



Education is one of the best tools for preventing the further spread of invasive species, locating previously unknown and remote weed populations, and in rallying support for managing and eradicating infested sites.  A major goal of the SFWMA is to raise awareness about the threat invasive weeds pose to local native plants and wildlife, fragile riparian corridors and endangered species, public and private landscapes, and other treasured elements of San Francisco’s ecosystems and aesthetic.  This effort requires a well-planned, well-coordinated, well-funded, and long-term program targeted at agency staff and the public.


1.    The SFWMA is in the process of producing a brochure, which is targeted to the general public and describes priority weeds in the City and County of San Francisco, their impacts and key contacts for information.  Once complete, a targeted distribution list for the brochure will be developed to ensure priority audiences receive copies.

2.    The SFWMA is currently distributing copies of the California Invasive Plant Council’s (Cal-IPC) “Don’t Plant a Pest” brochures to public agency landscape maintenance personnel, commercial plant nurseries, local environmental organizations, libraries, and other public and private entities.  

3.    SFWMA members participate in on-going educational and outreach activities aimed at invasive weed awareness and management.  For example, SFWMA members participate in Cal-IPC’s outreach booth at the annual San Francisco Landscape Garden Show, as well as the Strybing Arboretum’s Summer Garden Fair, San Francisco Integrated Pest Management Technical Advisory Committee, San Francisco’s Annual Restoration Conference, and other local professional and volunteer organizations.  The SFWMA plans to participate in “World Environment Day” activities in June 2005 hosted by the City and County of San Francisco.

4.    The SFWMA plans to maintain a website through the statewide California Department of Food and Agriculture (CDFA) Weed Management Area website. Efforts to add invasive weed education and resource links to websites maintained by the San Francisco Department of the Environment, San Francisco Department of Recreation and Parks, San Francisco Public Utilities Commission, and other local websites will also be undertaken.


Preventing a weed pest from becoming established in an area avoids future costs for managing that pest.  Prevention covers all aspects of keeping an invasive species from becoming established in a new territory.  The components of prevention commonly include exclusion, detection and eradication of small or isolated infestations. Public outreach is a key component in all aspects of prevention.

Exclusion includes activities to prevent an invasive species from crossing the border of a region.  At the national or state level, this often includes border inspections. At the county and city level, it often depends heavily on appeals to the public to use caution in activities that can intentionally or unintentionally move species.  It also includes county regulatory activities such as plant quarantine inspections, nursery inspections, and other weed exclusion activities.

Detection and eradication of early small infestations involves locating and removing weeds that have eluded the exclusion system. Because new weeds are constantly being introduced into the region, a good detection system is critical to reducing the cost of eradication and increasing the chances of a successful eradication.     

Quarantine, nursery inspection and other regulatory activities related to the prevention of the spread of weeds is typically the responsibility of the agricultural commissioner. As of Sept. 1, 2004, the City Department of Consumer Assurance has been dismantled and now the nurseries inspection unit of the San Francisco Department of Environmental Health regularly inspects nurseries and performs plant quarantine inspections of incoming plant product shipments for listed regulated weeds.


1.    The SFWMA plans to develop an Invasive Weed Prevention Resource List.  This document will list such resources such as:
•    locations where organizations and individuals can take weeds for identification and where to report locations of suspected invasive weeds in the City,
•    key literature, websites, and organizations that address invasive weed prevention and management,
•    “weed pulling” volunteer days at local parks, open spaces and natural areas,
•    educational activities on invasive weed prevention and management targeted at youth and schools, and
•    contact information on speakers available to discuss invasive weed issues and activities.

2.    On-going monitoring activities by SFWMA members groups of A-rated, B-rated and Q-rated weeds will help detect early stage invasive weed infestations.

3.    Through education and outreach (see previous section), the SFWMA will encourage public and private entities to use preventative techniques to keep invasive weeds from becoming established in new areas.


A strategic and long-term approach to invasive weed management is based on a solid knowledge of the countywide distribution of the weeds.  This includes low-resolution mapping where weeds are common and higher resolution mapping in areas where weeds are rare.  Knowing the location of the priority weed species through mapping and weed inventory will allow for the appropriate implementation of management strategies.  Mapping where weeds are not found is as important as recording where they are found.  It is important to classify non-surveyed lands as "non-surveyed" rather than "uninfested."


1.    The SFWMA will collect and synthesize existing invasive weed inventories and vegetation maps from the various public agencies and organizations in San Francisco with vegetation management responsibilities.  The objective is to develop a baseline inventory of existing invasive weeds within the county.  Funding will be sought to create a countywide Geographic Information System (GIS) that will compile data on target invasive weeds.  This database will collect all existing geographic data and form the repository for ongoing data acquisition.  If possible, one of the agency members of the SFWMA will be funded to expand its existing GIS invasive weed database to include new data from other agencies/organizations in the county.  This expanded file would be shared by all participants in order to facilitate coordination.

2.    The SFWMA will coordinate a working group consisting of representatives of major land-managing organizations in the county.  The working group will develop consistent standards and protocols to ensure compatibility of data gathered by each organization.

3.    The SFWMA will facilitate increased use of Global Positioning System units by organization staff as well as the general public in mapping infestations. Other mapping methods will be explored as appropriate.

4.    The SFWMA will generate GIS layers for each high priority weed in the county.


The fundamental means by which the biodiversity of San Francisco’s natural ecosystems and heritage can be preserved and restored is through aggressive weed management in natural areas.  Integrated Weed Management (IWM) is a systems approach to management of undesirable plants.  IWM is defined in the Federal Noxious Weed Act as a "system for the planning and implementation of a program, using an interdisciplinary approach, to select a method for controlling undesirable plant species or group of species using all available methods, including education, prevention, physical or mechanical methods, biological control agents, herbicide methods, cultural methods, and general land management practices."   IWM, combined with revegetation and re-introduction efforts, will help ensure that invasive weeds are not the primary cause of degradation or demise of rare and/or endangered plant and animal species or geologic features within our unique native habitats.  

Adaptive management is a flexible learning-based approach to natural ecosystem management.  This approach recognizes that some uncertainty exists about natural systems and the processes that define them.  Adaptive management is a continuous cycle of planning, implementation, monitoring and assessment used to evaluate successes and failures of management techniques.

Several Integrated Pest Management (IPM) laws and regulations apply to weed management in San Francisco.  IPM  is a science- based, decision-making process that coordinates knowledge of pest biology, the  environment, and available technology to prevent  unacceptable levels of pest damage, by cost-effective means, while posing the least possible risk to  people, resources and the environment.

The City and County of San Francisco’s IPM Ordinance is the legal framework for decision-making on pest management practices occurring on City-owned property.  The IPM Ordinance requires department IPM plans, places restrictions on pesticide use, requires posting of intent to apply pesticides prior to applications, and requires regular reporting of pesticide use.  Only pesticides included on the City’s “Reduced-Risk Pesticide List” (AKA “Approved Pesticide List”) are allowed.  The IPM Ordinance and the Reduced-Risk Pesticide List can be viewed at  

On National Park Service (NPS) lands, the NPS “implements a nationwide Integrated Pest Management Program to reduce risks to the public, park resources, and the environment from pests and pest-related management strategies (”.  The California Department of Pesticide Regulation monitors pesticide use throughout the state.

Several SFWMA member groups have active weed management and habitat restoration programs.  Some local, state and federal land management agencies have dedicated staff that manage weeds and restore natural areas.  In addition, the Presidio Site Stewards, the San Francisco Recreation and Park Department Natural Areas Program and the California Native Plant Society, among others, have on-going community-based habitat restoration programs throughout San Francisco that involve thousands of volunteers each year.  The activities and on-going participation of these land stewards are critical to the long-term survival of natural areas in San Francisco.


1.    The SFWMA will work with CDFA to locate sites for eradication of A-rated weeds, share information and work together to eradicate B-rated weeds, and share information with each other and CDFA about locations and impacts of newly discovered Q-rated weeds.

2.    SFWMA members will share experience with weed management, project monitoring, and revegetation strategies through presentations by group members at open meetings.

3.    The SFWMA will develop an annual Integrated Weed Management Plan, which will set forth additional priority activities for the coming year(s).  

4.    Using the GIS database described above (see Survey, Inventory and Mapping above), the SFWMA will coordinate countywide invasive weed management activities among partner agencies and organizations.  Collaborative efforts will include prioritizing target species, coordinating management activities, and where possible pooling labor, equipment, outreach and other resources.

5.    Document the effectiveness of weed management techniques for priority weed species for dissemination to land managers and other interested parties.


Funding for all phases of invasive weed management is chronically inadequate.  Managing the current rate of spread of major weeds and the introduction of new species is challenging and requires additional funding and resources beyond current levels.


1.    The SFWMA is seeking a sponsoring agency to act as fiscal agent and point of contact.

2.    SFWMA is also seeking funding for:
•    a paid Coordinator
•    GIS database
•    educational materials
•    specific weed management projects
•    documenting the effectiveness of weed management techniques

3.    Member groups of the SFWMA are obtaining grants from various foundations and agencies. Partnering with other SFWMA groups enhances the likelihood for success in obtaining grants.

4.    Member groups will provide in-kind support for the Weed Management Area and Projects.


A.    List of Priority Weeds For Management Action In San Francisco County (PDF file) - This is a dynamic priority list, so if you have corrections or additions, please send an email message to the SFWMA Chair at: