Last Monday I joined fellow members of the California Native Plant Society (CNPS) to hike up Black Mountain, a ridge that separates the Santa Clara Valley from the San Andreas Fault. I had hiked the San Andreas Fault earlier, so this hike offered views and hiking with people who know about California native plants.
This map shows both hikes. The blue squares show the first part of the San Andreas Fault hike, from the Monte Bello trailhead to Stevens Canyon. The straight valley between those two points marks the San Andreas Fault, and the trail follows the fault.
Black Mountain is the ridge just north of the San Andreas Fault. Monday’s hike, shown with red balloons, started at the Rhus Ridge trailhead and proceeded to the Black Mountain summit. We took the Black Mountain Trail, hiking 5.1 miles each way, with a 2,400 foot elevation gain. The CNPS members knew all sorts of California native plants and happily shared their knowledge, so I learned a lot.
The initial 3.5 miles of the hike is through woodland. This ribes menziesii, canyon gooseberry, has thorns, fine hairs on the edges of its leaves, and small red flowers.
This pedicularis densiflora, indian warrior, has dark red flowers.
This trillium chloropetalum, common trillium, has a dark burgundy flower emerging from the middle of three broad leaves. A very striking combination!
This young rattlesnake, with only one rattle, was lying on a bank beside the trail. The rattlesnake kills by injecting venom from its fangs. It then swallows its prey whole.
This piperia elegans, elegant rein orchid, is growing on this dry hillside.
The last 1.5 miles in on a dirt road up a ridge line. This trail is steeper, sunny and hot. You just keep going, to get it over with.
We stopped for lunch on a limestone outcropping at the summit. Lupines grow at the summit, especially in the limestone rocks.
This view west from Black Mountain has a hazy Pacific Ocean beyond the hills. In person, we were able to see the ocean through the gap in the hills, but this photo doesn’t have enough contrast. The San Andreas Fault is in the valley below Black Mountain.
Hiking down the ridge line from the summit, we’re rewarded with views of the San Francisco Bay. The aircraft hangers at Moffett Field show up as a large, light-colored object on this side of the bay, with the cities of Los Altos and Mountain View in between. When monitoring rainfall, I use records from Moffett Field.
Black Mountain and this ridge form part of the headwaters of Permanente Creek. In the photo below, the barren mountaintop is the Lehigh Cement Plant. The limestone in these mountains contains calcium, the primary component of cement. Permanente Creek is in the canyon below this ridge. Permanente Creek flows to the right of the Lehigh plant and out to the bay.
This patch of toxicoscordion fremontii, Fremont’s star lily, grows on the south side of the road. I saw this lily last week at Rancho Canada del Oro in San Jose.
Back in the woodland we spotted this ring-necked snake on the trail, so we carefully placed it off the trail where it wouldn’t get stepped on. Notice the red belly and red ring around its neck.
The hike to Black Mountain offers bay and ocean views, California native plants, and wildlife — all at the edge of Silicon Valley. The 10-mile hike with a 2400-foot elevation gain took most of the day. Pack a lunch, and carry 2 liters of water. The parking lot at the trailhead is small, so start early. Hiking in a group is wonderful — you see and appreciate so much more because different people will spot something and point it out to the others. With the wildflowers, spring is a great time to go take a hike.