Mount Diablo State Park

Dichelostemma capitatum

Mount Diablo is my second-favorite open space featuring fabulous flowers in the immediate Bay Area. Located an hour's drive due east of San Francisco in Contra Costa County, the state park has about 20,000 acres that form the nucleus of an impressive collection of protected lands totaling over 90,000 acres.

The mountain is 3,864 feet high and stands alone, making it one of the most recognized and recognizable geographic features in the Bay Area and adjacent portions of the Central Valley. The views from the summit are spectacular in all directions. An elfin forest grows at the summit, with trees only a little taller than your average male hiker. Ceanothus cuneatus is a dominant species starting just above the middle of the moutain and reaching the summit. It grows thickly along the mountain's southern side and can produce a mass bloom in the spring that's breathtaking in appearance and almost overpowering in fragrance. A drive to the summit is heady and fragrant when the car windows are down.

Pinus sabiniana

 
The interaction of the Pacific and North American plates along coastal California is responsible for Diablo, along with the rest of the Coast Ranges. The mountain continues to grow several millimeters per year. Tectonic forces are also responsible for a rich variety of seemingly incongruous rocks and minerals on the mountain.

Diablo lies at range border for quite a few plants, producing an unusually high species richness. Prominent plant communities include mixed oak woodland, chaparral, and grassland. There is year-round water flowing from the mountain, particularly in Mitchell Canyon.

I first encountered my absolute favorite pine tree species on Diablo, Pinus sabiniana. The glaucous blue needles are instantly recognizable. It doesn't grow in dense stands, but as scattered individuals in chaparral and oak woodlands. And the cones! They're huge! The pine nuts are edible and were a source of food for the local Native Americans.

Ceanothus cuneatus

I've hiked three trails so far on Diablo - the Globe Lily Trail in Mitchell Canyon along the northern flanks of the mountain, the North Peak Trail near the summit on the southern flank, and the short loop trail directly below the summit. Each trail was filled with rich and interesting plant communities. The road to the summit along the southern flank can produce stunning displays of Eschscholzia californica and Ceanothus cuneatus.

Calochortus pulchellus

Diablo's signature flower is Calochortus pulchellus, a species of globe lily found only on Mount Diablo, primarily along the Globe Lily Trail in Mitchell Canyon. That trail also leads through a wonderful chaparral community dominated by Salvia mellifera and an almost pure white form of Eriodictyon californicum. Ericameria linearifolia grows alongside the trails in Mitchell Canyon and I wonder why that species isn't seen more in local gardens. I think it's just as beautiful as the shrub daisy from South Africa everyone grows.

Fritillaria affinis

I really enjoyed finding Fritillaria affinis and Ribes menziesii in a small pocket of woodland along the North Peak Trail. Further along in a grassland area were several delicate patches of Castilleja exserta, a favorite in the genus for me. There were even Cardamine californica in bloom! This is one of our first spring flowers but it was still blooming at ~3500 feet! Near the start of the trail we found lots of Arabis breweri on any boulder you stopped to investigate. We even found one of the rarest flowers in the Bay Area, Streptanthus hispidus, growing in gravel next to the trail.

I'll be back next year (if I'm still living here!) to see what more interesting things I can find!

Here are some additional photos from Mount Diablo:

Orobanche fasciculata

Allium serra

Phacelia breweri

Ribes menziesii

Pinnacles National Monument

One of the best day trips so far this wildflower season has been to Pinnacles National Monument, about 2.5 hours south of San Francisco. Pinnacles is the highly eroded partial remains of a volcano that erupted directly on the San Andreas fault over 20 million years ago. In the intervening time, the volcano was split in two by the northerly motion of the Pacific Plate sliding past the North America plate and the two halves are now approx 120 miles apart!

Pinnacles is most famous for being a reintroduction site for the California Condor and as a destination for rock climbing. Less known but just as important is the wide variety of plant species found in the Monument.

Wyethia helenioides

Nhu and I entered from the less crowded West entrance, and before we even entered the monument we were stopping to photograph Wyethia helenioides, Allium crispum, Viola pedunculata, Pholistoma auritum, and Collinsia heterophylla.

Once we stopped and paid the day fee at the Ranger's Station we headed for the main loop trail. We encountered fading Castilleja exserta ssp. exserta at the start of the trail, still looking really attractive. There were brilliant white trumpets of Calystegia subacaulis ssp. subacaulis in spots along the start of the trail. Next we started seeing Clarkia modesta and various Delphinium species, including Delphinium parryi ssp. parryi. The most exciting find early in the trail for Nhu was a waning bloom of Allium fimbriatum var. fimbriatum.  There were even more Clarkias, including Clarkia epilobioides and lots of intensely deep rich purple Clarkia purpurea ssp. quadrivulnera. Other species encountered included Chorizanthe membranacea, Toxicoscordion fremontii, Leptosiphon parviflorus, Crassula connata, and Dudleya cymosa.

Allium crispum

The flat part of the trail ended and we entered the eroded portion of the volcano. We took a small detour around the first large building-sized boulder and encountered Lewisia rediviva var. rediviva growing in cracks on the rock, a spectacular sight. Next was the sclerophyllus local cherry, Prunus ilicifolia subsp. ilicifolia growing side by side with Rhamnus ilicifolia, all with the local pipe stem Clematis lasiantha scrambling here and there. Looking down at our feet there were many lovely yellow Triteleia lugens, one of the more attractive California geophytes.

Lewisia rediviva var. rediviva

Next we entered the main part of the loop trail. This took us up several hundred feet through a series of gentle switchbacks with spectacular and dramatic scenery at every turn. Here we got some amazing habitat shots of Pinus sabiniana. Drifts of Clarkia unguiculata covered the sides of the switchbacks and near the top we started seeing early blooming individuals of Calochortus venustus. A highlight for me in this section was the twining snapdragon, Antirrhinum kelloggii. Other beautiful species encountered were Cirsium occidentale, Streptanthus glandulosus ssp. glandulosus, Emmenanthe penduliflora, Mimulus fremontii, and an invasive but lovely grass, Lamarckia aurea.

Pinus sabiniana

All in all the hike was easy, the scenery among the best I've ever seen, and the plants always interesting. I hope to make a return visit at a different time of the spring bloom in the future!

Click on any of the photos to be taken to a gallery containing all the photos I took on the hike.

More photos from the day:

Drifts of Clarkia unguiculata painted the landscape in purple

Calochortus venustus

Cirsium occidentale

Clarkia purpurea ssp. quadrivulnera

A talus cave