Conservation Update 2019 Mar | Laguna Hills – Aliso Creek Herbicide


The City of Laguna Hills is doing a one-year test, at two city parks, of the efficacy of organic-based herbicides. The testing is in response to lobbying by a community group to discontinue the use of synthetic herbicides on all city-maintained properties (OC Register, 1/28/2019). See video of the 1/27/2019 City Council meeting:, Staff Report item 6.3.1.

Laguna Hills is fully developed and has several maintained city parks. A few small areas of natural vegetation remain in the city; the largest and most important is a 1/2-mile reach of Aliso Creek that crosses the city from I-5 to Paseo de Valencia. This reach still runs in a natural channel—the only almost-unmodified stretch of channel between Portola Parkway (north of I-5) and Alicia Parkway/Aliso-Woods Canyons Wilderness Park (south of I-405). In other words, this still-natural 1/2 mile is just about in the middle of about 10 miles of creek bed that has been modified to at least some degree.

The reach’s riparian vegetation is the usual mix: invasive non-natives such as palms, arundo, pampas grass, etc, and native willows, mule fat, cattails and such. The Aliso Creek Bikeway/Trail runs along the west side, the Avila Trail along the east side; houses line the upland edges.

A multi-agency/NGO collaborative team has a long-term project underway to remove all arundo from the entire 19-mile length of Aliso Creek. It is one of the largest restoration projects in Orange County history. See

The agency or jurisdiction in charge of managing this 1/2-mile remnant of natural creek is not readily discernable. If the city is in charge, and the use of synthetic herbicides is deemed not allowable, restoration of this reach—hence the rest of the creek—will be that much harder.

ACTION NOW:  If you live in or near Laguna Hills, contact the City to find out what entity has jurisdiction over this 1/2-mile of Aliso Creek, and what management/restoration plans there may be. Plan to speak at a City Council meeting (see how-to at website, above), to encourage the continued use of synthetic herbicides as a necessary tool for invasive-plant management in areas of natural vegetation, such as this 1/2-mile of Aliso Creek. It would be useful to cite CNPS’ Policies on Herbicides and on Integrated Weed Management (, and OCCNPS’ position on herbicide use—which is more specific to OC conditions. Ask Celia Kutcher for details regarding our position. And thank you!

Celia Kutcher, Conservation Chair