San Luis Obispo WMA


Jon Hall, Land Conservancy of SLO:

James Moore, County of SLO Department of Agriculture/Weights & Measures:

Amy Smart, Templeton Las Tablas RCD:

Mapping contact:

John Sayers, California State Parks:

Newsletter & website contact:

CeRae M. Speidel, County of SLO Department of Agriculture/Weights & Measures:


Quarterly.  Contact WMA for more information


Noxious weeds can negatively impact both our local economy and our cherished natural resources. There are many non-native, invasive plants established within San Luis Obispo County, threatening some of our most recognizable natural landmarks. Yellow starthistle, artichoke thistle, and purple starthistle can all be found in the hills surrounding the scenic Morros. If left unchecked, these thistle infestations will likely expand, reducing rangeland productivity for county ranchers, whose cattle avoid the spiny, unpalatable plants. In addition, these weeds degrade our critical wildlands by displacing desirable native vegetation and diminishing the habitat value for local fauna.

WMA Purpose

Although the issue of noxious weeds has not raised the concern of the general public like other more high profile ecological problems, the damage caused by invasive plants is unmistakable and recognized by countless economic, political, and environmental interests. A long-standing concern for the agricultural industry, noxious weeds are now well understood to be a major environmental problem as well, as non-native plants are increasingly invading even our most pristine natural habitats.

In recognition of the enormous problems that these invasive weeds can cause, and the coordinated effort that is required to effectively control them, the San Luis Obispo County Weed Management Area (WMA) was formed. The purpose of the WMA is multi-faceted: we are working to identify and map our county’s worst weed pests, implement projects designed to prevent, eradicate, or manage these invasive plants, and educate our local residents about this issue.

Outreach Summary:

   Quarterly Newsletters


Upcoming Events:

  • 2022 CAL-IPC Symposium
    CSU East Bay (Concord), July 18
    Online, November 1-3
    Register Here

WMA Meeting Minutes:

Project Highlights:

Eradication of 5 priority species from the South Central Coast Region (SLO & SB)

    • Limonium duriusculum -European sea lavender
      • Surveyor braving the mud at the Morro Bay Estuary Limonium duriusculum site.

        Limonium duriusculum

    • Cirsium arvense -Canada thistle
    • Thinopyrum junceiforme –Russian wheatgrass
      • Russian wheatgrass on a dune.

    • Cuscuta japonica -Japanese dodder
      • Japanese dodder before treatment Lompoc, CA.

    • Linaria dalmatica –Dalmatian toadflax

Arundo in the Chorro Creek Watershed

Mapping and Control of Pioneer Infestations of Jubatagrass

Veldt Grass Control

Carrizo Plain National Monument Yellow Starthistle Project

Rancher Cost Share Project for Yellow Starthistle

County Agriculture Department’s Strategic Plan for Yellow Starthistle

Species to watch for

Petite licorice – Plecostachys serpyllifolia 

Prickly golden fleece – Urospermum picroides

Organizations on WMA’s MOU

  • Bureau of Land Management – Bakersfield Field Office
  • Cal Poly State University – San Luis Obispo
  • California Conservation Corps – Los Padres Service District
  • California Department of Food & Agriculture
  • California Native Plant Society-San Luis Obispo Chapter
  • California State Parks – Oceano Dunes District
  • California State Parks – San Luis Obispo Coast District
  • California State Parks – San Simeon District
  • Coastal San Luis Resource Conservation District
  • Land Conservancy of San Luis Obispo County
  • Morro Estuary Greenbelt Alliance
  • San Luis Obispo County Department of Agriculture
  • San Luis Obispo County Farm Bureau
  • San Luis Obispo County Parks
  • San Luis Obispo County Public Works Department
  • Sierra Club – Santa Lucia Chapter
  • Small Wilderness Area Preservation – Los Osos/Morro Bay Chapter
  • University of California Cooperative Extension
  • Upper Salinas/Las Tablas Resource Conservation District

Other Regular Participants

  • California Department of Fish & Game
  • California Department of Forestry & Fire Protection
  • California Department of Transportation – District 5
  • San Luis Obispo County Cattlemen’s Association
  • USDA Natural Resources Conservation District – Templeton Office
  • USFS – Los Padres National Forest