Riverside County, CA Invasive Plant Rules: Prohibited Species (2026)

Riverside County Ordinance No. 859, adopted in 2006, governs landscaping for new and rehabilitated projects with landscape areas of 2,500 square feet or more. The ordinance references Table 4-113: Prohibited Invasive Ornamental Plants, which bans specific species from new landscaping projects. Key prohibited species include: giant reed (Arundo donax), pampas grass (Cortaderia selloana and C. jubata), fountain grass (Pennisetum setaceum), Mexican fan palm seedlings in natural areas, and several species of ice plant (Carpobrotus edulis). At the state level, the California Department of Food and Agriculture (CDFA) maintains a noxious weed list under the Food and Agricultural Code §5004, with species rated A, B, or C based on eradication priority. The Cal-IPC Inventory categorizes over 200 non-native plants as High, Moderate, or Limited invasive threats in California. The California Department of Fish and Wildlife also publishes a 'Don't Plant Me' list of common nursery plants with invasive potential. In Riverside County's desert communities, tamarisk (salt cedar) is a particularly destructive invasive that consumes 200–300 gallons of water per day and is targeted for removal along waterways.