Bull thistle (Cirsium vulgare) invades Tioga Pass in Yosemite National Park Photo courtesy Bob Case

Bull thistle (Cirsium vulgare) invades Tioga Pass in Yosemite National Park. Photo courtesy Bob Case

When plants that evolved in one region of the globe are moved by humans to another region, a few of them flourish, crowding out native vegetation and the wildlife that feeds on it. These invasive plants have a competitive advantage because they are no longer controlled by their natural predators, and can quickly spread out of control. Invasives can degrade our food and water supply and increase the risk of damage from wildfire and flooding, all of which can cause major economic damage to our state.

In California, approximately 3% of the plant species growing in the wild are considered invasive, but they inhabit a much greater proportion of the landscape. Cal-IPC focuses on plant species that impact natural areas, sometimes called “wildland weeds.”

The Cal-IPC Inventory

The California Invasive Plant Inventory categorizes non-native invasive plants that threaten the state’s wildlands. The inventory was created in collaboration with land managers and experts, and is updated regularly to reflect the best available knowledge.

Plants A-Z

Peruse a photo gallery of invasive plants with full plant profiles. Listed in alpha order by scientific name, each entry also includes common names and additional resources.

Impact of Invasive Plants

Why should you care about invasive plants? Their presence impacts everyone in California. Left unchecked, these plants can destroy wildlands, farm land, encroach on urban or suburban areas, and destroy infrastructure, including drinking reservoirs. Read more about their impact on the state.