As the weather heats up in spring, sprays of bright yellow flowers pop up amidst the green shrubbery along roadsides, disturbed areas, and preserves throughout much of California. These striking yellow flowers are not California native wildflowers, but rather an invasive species known as French broom.

Spring landscapes are covered in beautiful blooms, but not every wildflower belongs here. Mediterranean lineseed (Bellardia trixago) is one invasive species that has been spreading across California’s grassland ecosystems. 

Yellow star-thistle is an annual invasive plant that has spread across more than 15 million acres of land in California, and costs millions of dollars each year, especially in water loss. With the help of interns and dedicated volunteers, we’re managing this thorny invader and bringing back biodiversity.

Every spring, Grassroots Ecology staff head off-trail at Pearson-Arastradero Preserve to monitor, map, and remove an invasive annual grass called medusahead (Taeniatherum caput-medusae or Elymus caput-medusae). Grassroots Ecology has been actively managing medusahead here since 2010. Learn why and how we’re managing this invasive species.

Growing up, I was obsessed with two things: horses and nature (to be fair, I am still pretty interested in both). As luck would have it, I lived quite close to Westwind Barn and its neighbor, Byrne Preserve. I began taking riding lessons at the barn when I was about six or seven, and soon I was looking for any possible excuse to return.

Given the right conditions, non-native plants can outcompete and displace many of the California native plants that local insects and other animals depend on. Stinkwort is one of those weeds we’ve been successful in removing, thanks to Grassroots Ecology volunteers.

One way to support California native habitat is to remove weeds that overcrowd our open spaces. Teasel is one of those weeds we've been successful in managing, thanks to Grassroots Ecology volunteers.

By Claire Elliott, Senior Ecologist

You may know that Grassroots Ecology’s team has worked for many years to restore habitat in our local parks and preserves. But, did you know we also have projects designed to support nature in our cities? Invasive ornamentals and edibles are a big problem. Three that I am on constant vigil for are Mexican feather grass, Algerian ivy and glossy privet.