Edgar McGregor

The post-fire landscape at Eaton Canyon has brought about a period of change as dramatic as the fire itself. Following the February 2025 flood, the canyon became prime habitat for invasive plant species not native to North America to take over. Although castor bean, short-pod mustard, and tree tobacco often top the list of what comes to mind, County staff and volunteers have also been watching for several other highly invasive species that pose significant long-term ecological threats.

Throughout California, invasive plant species such as Arundo cane, Spanish broom, tamarisk, and Russian thistle have become major ecological problems. At San Gabriel River Park, another Los Angeles County Natural Area acquired and opened to the public in 2024, park staff inherited a well-established infestation of Russian thistle that has proven difficult to control. A quick drive along Highway 126 between Ventura and Santa Clarita reveals the heartbreaking encroachment of Arundo cane in the Santa Clarita Riverbed. 

Fortunately, these species have never become firmly established in Eaton Canyon. The exact reason remains unclear, but it may be the result of several factors, including decades without heavy construction equipment capable of spreading seeds, the constant presence of watchdog volunteer naturalists and other regular visitors who quickly dispatch new infestations, and simply the amount of time required for invasive species to gain a foothold.

The fire and flood, however, fundamentally changed those conditions. With the disruption of soil by these natural disasters, these invasive plants have been given the opportunity to establish themselves.

 

However, the window for those plants to establish themselves has already long ended. Since January 2026, park staff and volunteers have been rigorously dispatching these plants on a weekly, sometimes daily basis. Staff have removed more than 80 individual Arundo cane plants. One plant, which was located below the Pinecrest Gate, required more than 10 hours of labor and the removal of approximately 3 tons of rock and sand (done by shovel) to fully eradicate. Arundo has a rhizome root that must be removed, or else the plant has a 100% chance of regrowing.

In addition, crews have removed 38 newly established tamarisk tree saplings and 12 Russian thistle plants, all before they were able to produce seed. While those numbers may seem small, an unchecked infestation of any one of these species can quickly grow into thousands of plants, making early intervention far less costly than large-scale eradication. No heavy machinery has been required for any of the invasive weed removal.

 

Although community volunteer events remain within the confines of the County Natural Area portion, staff are doing what they can to get ahead of these species throughout the entire wash ecosystem, and all the way up to the waterfall.

Although castor bean, Maltese star-thistle, tree tobacco, and other invasive grasses remain major ecological challenges in Eaton Canyon, Arundo cane, spanish broom, tamarisk, and Russian thistle are on track to remain absent from that list thanks to the vigilance and early intervention of park staff and volunteers.

Much like trash, keeping the graffiti at bay in Eaton Canyon was a constant battle for Angeles National Forest volunteers. Nearly every week, park patrons with little understanding of nature’s beauty would enter Eaton Canyon intending to deface public property. While most of the blame went towards hoodlum teenagers, the culprits have been found in all demographics, including one mother (with three children under 10 alongside her) who was caught defacing a rock below the Pinecrest Gate in July 2023 and subsequently chewed out by other park visitors.

While Eaton Canyon enjoys its longest break from human activity in recorded history, a small group of certified Angeles National Forest volunteers has been coordinating with Eaton Canyon Natural Area Park staff to access limited areas of the canyon and get ahead of the graffiti battle before the eventual grand reopening. In previous years, volunteers were often so occupied with removing tagging from highly visible locations that they had little time to address more remote sites.

During a recent outing, USFS volunteer Pat Bylard mentioned that he was finally able to reach an area he had been monitoring for years but had never been able to prioritize because it was, in his words, “out of sight, out of mind.”

On Wednesday, March 25, 2026, the County of Los Angeles Department of Parks and Recreation hosted a community meeting to share its conceptual understanding and plans for the rebuild of Eaton Canyon. Included in the discussion were four panelists: Megan Horn of Studio MLA, Kim Bosell with the County of Los Angeles, Marcus Gonçalves with SWCA Environmental Consultants, and Tim Becker of the Theodore Payne Foundation.

During the discussion, the panelists shared their understanding of how Eaton Canyon served the broader Los Angeles Community before the Eaton Fire, how a future nature center can better meet the needs the canyon serves, what lessons they’ve learned from past wildfires that will help inform their decision-making, and how the County plans to reconstruct the park.

Of particular note was the County’s emphasis that they understand Eaton Canyon is not like its regular grass-and-playground urban parks; it is a native landscape where natural processes are left to shape the park on their own. Dead trees are left to rot (so long as they aren’t next to public amenities), debris flows are free to reshape the canyon, and native plants complete their lifecycle without any intervention from humans. Here were the key pointers:

A recurring theme across disciplines—ecology, engineering, and landscape architecture—is that Eaton Canyon must be treated as a system. According to Studio MLA Principal Megan Horn and her understanding of her team’s role, this system must:

– Accommodate wildfire and post-fire flooding
– Create a defensible structure that protects both the building and the surrounding neighborhoods
– Stabilize slopes and manage sediment transport
– Support native plant regeneration
– Integrate recreation without compromising recovery

This approach extends to infrastructure. Any new facility, including the proposed Landscape Recovery Center (LRC), must be defensible by design and capable of withstanding fire exposure while minimizing risk to both people and the surrounding environment. Importantly, Megan noted, this is “not a blank slate.” The site carries constraints, history, and ecological memory. Designing within that context is essential.

Although the County is directing resources towards understanding its future presence in the canyon, it is also allocating resources to aid the park’s natural recovery. This is where Marcus Gonçalves, with SWCA Environmental Consultants, and Tim Becker of the Theodore Payne Foundation, come in. Here, the panelists shared that they understand that both their organizations and the County of Los Angeles have a responsibility in aiding Eaton Canyon in its natural recovery. Tim Becker, in particular, noted that “although nature can recover on its own, the timescales we are discussing here are a human lifetime. In fact, they may even be longer as we keep negatively impacting the park.” Through climate change and user impacts, the full natural recovery of Eaton Canyon depends on our ability to support it. How does one do that? First and foremost, remove the invasive plant species.

Every Friday since August 2025, the County of Los Angeles has supported group volunteer efforts in the canyon to remove invasive plants. Members of the general public have been targeting these plants that do not belong in Southern California, including Short-pod Mustard, Castor Bean, Tree Tobacco, and other annual invasive grasses.

Ultimately, the County wanted to share that moving forward, recovery at Eaton Canyon will be deliberate—act where needed, but do not rush decisions that will affect the site for decades.

This is not a simple rebuild. The canyon sits in a high-risk urban–wildland area, and the old way of managing it is no longer sufficient.