Mineral Treasures and Natural Beauty at Alum Rock Park

Date: February 26 and May 11, 2019
Place: Alum Rock Park, San Jose, California
Coordinates: 37.396132, -121.801633
Length: About 3.5 miles
Level: moderate

Considering how old is this park (the oldest municipal park in California) it is surprising how long it took me to find it. I knew it was there because I saw the signs every time I drove down I-680 past that area, but I never took the time to check it out before. Not until last winter when I was looking for new trails for our 4-H Hiking Project. And from the first few steps on the park's trails I was completely taken by it.
It was May already when I finally got to lead our 4H Hiking Project on the trail I checked last February. The masonry still looked the same, but everything else changed with the season. Most of the photos here were taken during the May hike (some by Pappa Quail and the elder chika) but a few are from the February hike.

Alum Rock Park has a rich history of human indulgence. Once discovered, the Pentensia Creek mineral springs became a hot sensation among spa seekers, attracting visitors from all around.

Penitensia Creek, the mineral springs area. May 11, 2019

The creek was tamed between stone walls and stone grottos were built at the springs, channeling the water to sitting pools.

Mineral spring grotto, May 11

The Penitensia springs are rich in salts and minerals but none more evident than the sulfur, which I could smell in the air. The mineral water is also a splendid substrate for bacteria: white filaments of bacterial growth mark the water flow from the springs to the creek.

Mineral spring grotto, February 26

It was high spring when I lead the 4H group along that trail and the birds were active all around us. Pappa Quail had joined our hike and captured many of them, including this pretty grosbeak female.

Black-headed Grosbeak, May 11

He had seen only female grosbeaks on that hike. The elder chika, however, had seen the male.

Black-headed Grosbeak, male, May 11

The elder chika was also quick to see a garter snake slithering through the vegetation. By the time I came over it was already gone.

Garter Snake, May 11

At its prime, Alum Rock Park had a Natatorium with an indoor pool, a zoo, a carousel, and many other attractions. A railroad connected the park to downtown San Jose and thousands of people visited it every year. Much of the masonry from those days is still present, rendering the area a look of a reconstructed archeological site.
Across the bridge there is a narrow trail following the north bank of the creek back to the road and the parking lot area. We crossed and continued west along that trail.

Foot bridge across Penitensia Creek, February 26. 

The mineral springs aren't hot springs, so the water in the sitting pools was heated. While most of these pools are now broken and drained, some still hold water.

Mineral spring pool, February 26, 2019

The pool's water was green with algae growth, as expected of standing water. Ten weeks later it was full of a different kind if growth, foretelling a very itchy future for the nearby neighborhoods.

Mosquito larvae at the sitting pool, May 11.

Other, more benign and much prettier insects were flying all around us, enjoying the lovely spring. I had a hard time photographing them because they were constantly on the move.

Checkerspot, May 11

My chika however, got a nice shot of swallowtails when they posed a little to drink some mineral water.

Pale Swallowtail, May 11

Butterflies and birds, birds and butterflies. I love spring in the Bay Area. Everyone is so busy with love! Colors and love songs fill the air.

Mourning Dove, May 11

Pappa Quail was busy photographing the birds but when I caught sight of some orange poppies down by the creek way beyond the range of my wide lens zoom, I grabbed him to get a close up for me.

Wind Poppy, Papaver, heterophyllum, May 11

Back at the road we turned onto the North rim Trail that leads up high above the creek. Back in February I walked through lush green open oak savannah.

February 26

The firs wave of wildflowers had just begun and I was excited to see any a bloom. 

February 26

The surrounding hills looked like an image taken from The Sound of Music. All that was missing was Julie Andrews dancing on the ridge.

February 26

Needless to say, two and a half months later the scenery looked very different.

May 11 

Although the hills were already turning yellow, there were many more wildflowers and they were painting much of the slopes in lively colors.

Morning Glory, Calistegia sp. May 11 

Although much of the wildflowers-painted slopes was because of invasive plants it was still very pretty.

May 11

The plants that were blooming February were now bearing fruit. Pretty fruit.

Creek Clematis, Clematis ligusticifolia, May 11

The North Rim Trail rises up high above Penitensia Creek. The way up was about half a mile of moderate grade slope. We walked slowly and steadily, but then Pappa Quail stopped walking altogether: he saw a male lazuli bunting! Ever since my first hike up Mission Peak where I had seen a lazuli bunting, Pappa Quail had a burning desire to see one too. We did see them since - in Joshua Tree National Park. Now however, it was sitting in a perfect pose, perched fairly close. A very beautiful bird.

Lazuli Bunting, May 11

He didn't settle for the bunting - even the very commonly seen red-tailed hawk  was given appropriate attention.

Red-tailed Hawk, May 11

High up above the creek the view was fantastic. It would have been spectacular if not for the cloud of smog hanging over the Santa Clara Valley.

May 11

By May the buckeye trees were in full bloom. One of the nicest trees of the bay Area, the buckeye changes its appearance throughout the year and renders its own seasonal tag to the local landscape.

Buckeye, Aesculus californica, May 11

 I think this year I saw a record high of the yellow flowering coastal bush lupine. They were literally everywhere in the East Bay, and of course in Alum Rock Park.

Coastal Bush Lupine, Lupinus arboreus, May 11

We ad a nice break in the shade of a knoll of large oak trees. The day was getting hotter and we were grateful for any patch of shade we passed under.

May 11

The North Rim Trail, however, is exposed to the sun almost all its length. But after the initial ascent the slope grade mellowed and we were making a good pace on our hike. Even the adults.

May 11

From a distance the slope seemed to be covered will only tall, dry grasses and some low chaparral. When looking into the grass however, I could see smaller wildflowers making themselves known to the bees and other insects that were buzzing about.

Blue-eyed Grass, Sisyrinchium bellum, May 11

The name of Alum Rock comes from a large, prominent and colorful rock that filled early prospectors to believe it might contain alum ore. They were wrong, but the name stuck. And the rock is still present and looking very lovely.

'Alum' Rock, May 11

There are other trails that split off the North Rim Trail and extend higher uphill into Sierra Vista Open Space Preserve. I looked wistfully at the trails leading to the high ridge. I had no time to extend my hike there in February, and it wasn't an option during the 4H hike. I therefore added the Sierra Vista OSP to my wish list for the near future.

May 11

After nearly a mile of a pleasant walk westward on the North Rim Trail we took the turn south to go back down to Penitensia Creek. The trail drops sharply right to the access road and crosses the creek on the old railroad bridge.
At its prime, thousands of people would visit Alum Rock Park each year. In time the facilities could not be upkept anymore and the city scaled back on maintenance. One by one the recreation facilities closed and dismantled and the park was put on the long and continuous path of nature restoration.
After crossing the creek we turned left and followed Penitensia Creek on the nicely shaded South Rim Trail close to the running water.
On my February solo hike there were only a few wildflowers blooming along that trail. Of those in bloom the most common was the milkmaids.

Milk maids, Cardamon californica, February 26

On our May hike the south rim trail side was a celebration of colorful wildflowers. Every sunny patch was filled with the common gumplant and many invasive thistles.

Common Gumplant,  Grindelia camporum, May 11

Pink onion inflorescences towered over lower weeds and poison oak. These didn't grow in patches but as separate individuals here and there.

Onion, Allium sp. May 11

Carpets of Chinese houses flowers covered the ground between trees and poison oak bushes and their colors were as intense as I've ever seen.

Chinese Houses, Collinsia heterophylla, May 11

I was starting to fall behind the group, trying to get good shots of all of the wildflowers when the chikas call me excitedly - they had found fairylantern flowers!

Fairylantern, Calochortus albus, May 11

Pappa Quail was also happy - he caught on camera a tree swallow in a rare perching pose.

Tree Swallow, May 11

He had also captured a small house wren that was singing out for its mate.

House Wren, May 11

I left the bird photographing to Pappa Quail and the elder chika and trained my camera on other, less conspicuous beings. 

Cobweb covered in willow seeds, May 11

Most of the group had already arrived back at the visitor center when I caught up with them. We finished our hike with a nice picnic - it was the last hike of this 4H year, and this trail was a perfect one to conclude this year with.

February 26