Hypericum Eradication


Project Overview:

RCD is working with The Mushroom Farm, San Mateo County Department of Agriculture, CAL FIRE, and other stakeholders to eradicate Hypericum canariense (Hypericum) from San Mateo County. This class B noxious weed forms dense woody monocultures displacing coastal scrub and grasslands, making it a threat to native species, natural resources, and agriculture. The core infestation exists along Hwy 1, south of Gazos Creek Road. The project incorporates CAL FIRE’s fuel reduction elements of prescribed fire as part of the treatment methods. The project will restore 500 acres of grassland, shrubland, and habitat for California red-legged frog and San Francisco garter snake.  The project will also protect cultural resources and restore the land so that it is once again viable for agriculture.


Project Goal:

Eradication of Hypericum canariense and restoring the land to rangeland and cropland for agricultural purposes and to prevent spread to neighboring properties and beyond. In addition to restoring agricultural lands, the project will reduce fire fuels and increase fire resiliency, enhance habitat for endangered California red-legged frog and San Francisco garter snake, and protect the remaining coastal chaparral and grassland from invasion. In collaboration with adjoining landowners and agencies, the larger regional eradication surrounding the property will follow.


This eradication project combines CAL FIRE’s fuel reduction and prescribed fire plans while also protecting sensitive species and cultural resources. The first phase is to reduce the Hypericum biomass. Treatment methods include mastication, prescribed fire, disking (in cropland areas), burn piles, hand cutting, and chemical treatment. Follow-up treatments will be applied until the seedbank has been eliminated and the area will be restored to grassland and shrubland and can support agricultural activities, provide enhanced habitat for endangered species, and increase fire resiliency.


CEQA completion is scheduled for early 2022. We hope to secure funding and begin implementation in 2022. Implementation will be completed in three phases: biomass removal, selective control, and restoration. Crews will be visiting the site for up to 10 years after biomass removal (until there is no more seed bank).


  • The Mushroom Farm
  • Peninsula Open Space Trust (POST)
  • Coastal Conservancy


  • San Mateo County Department of Agriculture Weights/Measures
  • Peninsula Open Space Trust (POST)
  • Coastal Conservancy

RCD Contact: Erica Harris


An image of a landscape overlooking a small pond surrounded by shrubs.