Serpentine Loop Trail

Overview: 5.5-mile hike with great views of spring wildflowers. And it’s dog-friendly!

Distance: 5.5 miles round trip

Elevation gain: 1,300 feet

Difficulty: Moderate

Hiking time: 3 hours

Season: All year, but spring is best for wildflower viewing.

Parking lot directions: Click here

Managing agency: Santa Clara County Parks

Trail map: View online

Calero County Park - POST
It was still early for wildflowers when I visited in late March, but California poppy (pictured here) were already on display. Photo: S. Suresh
Calero County Park - POST
Serpentine soil, pictured here, is home to a range of native flora and fauna. It is also the soil type with the greatest display of spring flowers. Photo: S. Suresh
Calero County Park - POST
Aside from the terrific wildflowers, Calero County Park is a great dog-friendly preserve with fantastic views of the South Bay area. Photo: S. Suresh

Hike Description:
This is one of my favorite hikes to see wildflowers in the spring. Not only is it dog-friendly, but it takes you through some of the best terrain for viewing native wildflowers. I visited a little too early this year (late March) as the peak of the bloom typically falls in mid-April. I guess I’ll have to go back.

From the main parking area, follow the short access trail to the Los Cerritos Trail. You’ll experience a short climb on the Los Cerritos Trail before reaching a pond that shares the name with the trail. When I visited, a lone duck was waddling in the pond enjoying the solitude of a fine spring morning. At the next intersection, I turned left at Peña Trail, making my way to the Serpentine Loop Trail.

The crisp spring morning offered excellent visibility and a picturesque background. The trails were wet in several locations and sported a lush green grass cover in other spots as the first 1.5 mile of the trek brought me to where the loop trail starts.

The Serpentine Loop Trail is named so for the serpentine soil found along this route. This soil offers the perfect habitat for native wildflowers and is the best place to look for them in the spring. I took the loop in a counterclockwise direction, this time not missing the Calero Bat Inn that I had overlooked during my previous hike.

The Serpentine Loop Trail descends all the way to the Cottle Trail junction, but stay left to stay on the loop trail. From this part of the trail there are several spots offering excellent views of the Calero reservoir and the Santa Cruz Mountains.

The high point, of course, was the wildflowers dotting both sides of the trails. Sure, it wasn’t a lush carpet of flowers when I visited, but the variety and colorfulness of what existed was impressive. I was able to identify California gilia, shooting star and California buttercup flowers in this stretch.

From near the Cottle Trail junction, the Serpentine Trail starts looping back and gradually gaining the elevation lost in the previous leg. You will be able to see fiddleneck and goldfields in this section as you approach a distinct spot of serpentine rocks around which you will see plenty of our state flower, California poppy.

At the Fish Camp there is a picnic bench along with an informational board explaining the self-contained ecosystem the pond provides to insects, birds and amphibians. California poppy should be visible in abundance, as are other varieties as the trail completes the 2.5 mile loop back at the intersection of Pena and Figueroa Trails.

From here, I retraced the 1.5 mile stretch along Pena, Los Cerritos and the access trails to the main parking lot. I hope people get out to experience the wildflowers first hand!

The featured hike originally appeared in the author’s blog, Dog Friendly Hikes in Bay Area


In 2009, POST purchased the 966-acre Rancho San Vicente from private developers, who had originally intended to build a luxury housing development. The ranch property is an important piece in completing a 15-mile greenbelt from Los Gatos to near Highway 101 in Morgan Hill. POST has since transferred the property to the Santa Clara County Parks and Recreation Department who incorporated it into Calero County Park in 2018.

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About Post

Peninsula Open Space Trust (POST) protects open space on the Peninsula and in the South Bay for the benefit of all. Since its founding in 1977, POST has been responsible for saving more than 87,000 acres as permanently protected land in San Mateo, Santa Clara and Santa Cruz counties. Learn more

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