On a warm, cloudy morning this past September 16, nine members of the Simi Trail Blazers met at the Pentachaeta Trailhead in Westlake Village. They climbed the Westlake Vista Trail to a flat plateau above the reservoir. From a higher lookout they watched ring-shaped ripples spread across the water where fish were feeding on insects. Then they dropped back to the Pentachaeta Trail and followed it east to Triunfo Creek, where the path ran into thick woodland. Their total for the morning was 4.37 miles and 716 feet of climbing. The group's trip report called the trail "somewhat rocky in places."
That trailhead sits on Triunfo Canyon Road, east of where Lindero Canyon Road ends, across from Oak Forest Mobile Home. It has only a few off-pavement parking spots. Plenty of Westlake Village drivers pass it every week without stopping. The land behind it is open for two reasons. A water district needed to protect the reservoir that supplied local taps. A conservation agency was willing to split the bill for a small yellow flower that blooms for a few weeks each spring. Neither one set out to build a park.
The hillside a failed Dallas thrift left behind
The chain of ownership reads like a footnote to the savings and loan crisis. In December 1993, the Los Angeles Times reported that the Las Virgenes Municipal Water District had bought a 491-acre parcel near the reservoir from the Federal Deposit Insurance Corp. for $6.3 million. The Baldwin Co. had planned 300 luxury homes on Westlake Vista there. The FDIC had held the property since 1989, when it took it over from Vernon Savings & Loan, a failed thrift in Dallas.
The district's reason was the water. The 9,800 acre-foot reservoir supplied tap water to homes in Calabasas, Agoura Hills and Westlake Village. Building on the slopes above it could have contaminated that supply. District spokeswoman Bobbe Wymer told the Times:
"This is the only source of water for those areas. We would have ended up having to expand our filtration plant, which would have made water much more costly for our customers."
Her quote describes the water system in 1993. It is a record of why the land was bought, and it says nothing about where today's tap water comes from.
Here is how the pieces lined up:
- 1989. The FDIC takes over the property from Vernon Savings & Loan.
- 1990. California lists Lyon's pentachaeta as endangered.
- September 1993. Los Angeles County supervisors release Proposition A park funds. The list includes "Westlake Vista: 492 acres, including watershed of the Las Virgenes Reservoir near Westlake Village," as the Times reported at the time.
- December 1993. Escrow closes on the water district's purchase. The Santa Monica Mountains Conservancy agrees to pay half the price early the next year. In exchange it gets 235 acres of the new purchase plus 237 acres the district already owned. A lawsuit from the planned developer is still pending against the sale.
- January 29, 1997. The U.S. Fish and Wildlife Service lists Lyon's pentachaeta as federally endangered.
The Conservancy now owns and manages Triunfo Creek Park, 600 acres of oak woodland and native grassland. The trailhead also leads onto the separate Westlake Vista parcel, which the Conservancy owns as well. That parcel name is the one that appeared on the plans for 300 houses.
Half the price went to a yellow aster
The water district came for its reservoir. According to the 1993 Times account, the Conservancy saw the land as crucial to protecting two rare plants: Lyon's pentachaeta, a yellow-flowered aster, and the Santa Monica Mountains dudleya, a rare succulent that federal officials were then considering for threatened status.
The federal recovery plan for the pentachaeta, published in 1999, shows why this hillside mattered. It recorded more than 5,000 plants at a site called "Baldwin Westlake" in 1992. The water district was listed as owner and the Conservancy as manager. Compare that with other Conejo-area sites in the same table:
| Site in the 1999 recovery plan | Plants counted | Survey year | Listed owner or manager |
|---|---|---|---|
| Baldwin Westlake | more than 5,000 | 1992 | Las Virgenes MWD owner, SMMC manager |
| Lake Eleanor Hills | 7,500 | 1992 | Private |
| Newbury Park Academy | 1,000 | 1993 | Private |
| Lynnmere | 500 | 1991 | COSCA |
The name "Baldwin Westlake," the owner and the manager all match the 1993 purchase. Still, the plan never draws a line on a map, and no source confirms that the counted plants sit inside today's Triunfo Creek Park. The match is consistent, not proven. The trail name is easier to pin down. The Mountains Recreation and Conservation Authority says the Pentachaeta Trail is named for the endangered pentachaeta found in the park.
In October, the trail's namesake has nothing to show
Walk the Pentachaeta Trail this month and you won't see a single pentachaeta in bloom. The plant is an annual, between 2.4 and 18.9 inches tall, with reddish branches near the top and yellow flower heads. It blooms from April to June. Early in the day, the petals on its ray flowers are often still curled.
Its habitat explains why the trail and the flower are so closely tied. The Fish and Wildlife Service describes it growing in small grassland pockets at the edge of shrubland: openings in chaparral and coastal sage scrub, and "along edges of roads and trails." In undisturbed spots, the ground has sparse plant cover and exposed soil held together by a microbiotic crust. Local rodents and harvester ants help keep competing plants thin. On a trail named for this flower, the bare shoulder beside your boots in October is the kind of ground where it comes up in spring.
The service still tracks the species. Its listing page shows a five-year review dated July 19, 2024. At the trailhead, an information kiosk explains the pentachaeta along with two other unusual wildflowers on the site, the chocolate lily and the white globe lily. In fall, that kiosk is the only place you'll see any of the three.
Walking it this fall
From the trailhead, the route splits two ways. Here is what each direction offers, drawn from MRCA, the Conejo Valley Guide's write-up and the Trail Blazers' September report:
- West, on the Westlake Vista Trail. It climbs to the fence around the reservoir. From there, a path follows the fence uphill to views down to Westlake Lake and south to the Santa Monica Mountains. This is the stretch where the September group stood on the plateau watching fish rise. The Guide also photographed an abandoned, wrecked car beside this trail.
- East, on the Pentachaeta Trail. MRCA's map shows a 1.5-mile corridor, with spot elevations of 840 and 920 feet. It ends at Triunfo Creek and a stand of thick woodland. The Trail Blazers took it out and back. The other end of the trail is at the west end of Triunfo Canyon Road, about 1.5 miles west of Kanan Road.
- Who can use it. MRCA's listing includes hiking, dogs on leash and equestrian use. The page doesn't list hours or parking rules, and the few pullout spots at the main trailhead fill fast.
- A map quirk. The Conservancy's own trail map misspells the park as "Truinfo" seven times, and the Conejo Valley Guide pointed it out with obvious amusement. If a printout looks off, that's why.
Combining the two directions, as the September group did, comes to a little over four miles. That's a full morning on land that was set to become a subdivision 33 years ago.
Work on the trails next door
North of the freeway, the Conejo Open Space Conservation Agency maintains a separate network, and it has been busy this season. A September 17, 2026 notice closed the Los Robles Trail for repairs near the Ventu Park Fire Road from September 21 to October 5. During the closure, hikers and riders couldn't get through between the Spring Canyon and Rosewood trails. Those dates have passed, but the agency hasn't yet posted that the work is done, so check COSCA's homepage before planning a through-hike.
The same page announces a new monthly trail-work program. It adds to the existing fall and spring workdays and sends crews of about 20 volunteers to smaller projects across the system. Sign-ups go through the Conejo Recreation and Park District at crpd.org: search "COSCA" under Registration. Neither agency's pages list a fall 2026 event at Triunfo Creek Park itself.
At Valerie Punwar Associates, we think knowing why a hillside stayed open is part of knowing Westlake Village. That goes for every stretch of open space bordering a street you might one day live on. If you'd like to talk through the open land and history around a specific address, from Triunfo Canyon Road to the lake, Valerie is glad to start that conversation.
