At the summit of Mount Whitney, 14,505 feet, there’s a big sphere of purple-blue flowers with an intense, musky smell. It’s found nowhere else on earth. Nobody can drive to see it. It requires time and effort, trekking through the wilderness at the highest peak of the contiguous United States just to catch a glimpse.
“It’s called Sky Pilot,” said Michael Uhler, gardener at the Tilden Regional Park Botanic Garden. “It’s the holy grail of alpine plants in California. If I ever bloom that, I’m retiring.”
A few years ago, Uhler obtained permission to collect Sky Pilot seeds from the National Parks. He’s been trying to grow it at Tilden Park ever since.
This isn’t just a garden vanity project. To him, this is about preserving plants before they disappear.
“Climate change is the game-changer for alpine plants,” he said. “We don’t have a lot of time to learn as much as we can.”
To help Uhler have a chance at growing the rare purple-blue plant, among other unique California natives, Tilden Park started its newest feature, the crevice garden, in 2022. Today, it grows new flowers and alpine plants that would otherwise have no chance to at this low an elevation.
The garden, made with 7-foot-tall, 2-to-4-inch thick slabs of slate and schist collected from Mariposa Slate Quarry, uses the rocks as protection for the plants, which are grown in the space between the slabs. The plants’ roots can then grow deep into the ground, becoming drought-resistant while able to withstand extreme weather conditions.
Plants grow among the rocks in the crevice garden at the Tilden Regional Park Botanic Garden in Berkeley, Calif., on Tuesday, July 22, 2025. (Jane Tyska/Bay Area News Group)
“Crevice gardens are unique,” said Bart O’Brien, director of the botanic garden. “They started becoming globally known in the 1990s. They came out of Czechoslovakia.”
When the Denver Botanic Gardens started the United States’ first crevice garden in 2012, other botanic gardens took notice. And a few years ago, O’Brien sent Uhler to Denver to get a sense of what might be possible.
“These crevice gardens provide superb drainage, which most alpine plants require,” O’Brien said. “And what most people don’t realize is, because the Sierra is a Mediterranean climate on one side and desert on the other side, it doesn’t ever freeze deeply. So typically the soils will only be frozen an inch or two.”
And with a lot of soil still unfrozen, a lot of the plants have roots that survive the entire year.
But trying to replicate those growing conditions in a normal garden isn’t possible.
“At low elevation, there’s too much heat in the summer or too much rain in the winter,” O’Brien said. “So with the crevice garden, we can mimic the conditions of the high altitude, but without snow on top of it.”
Uhler has gotten to know the alpine plants quite well over the years. When he’s not working full-time at the botanical garden, he’s usually hiking off-trail in super remote, high locations in the Sierra.
He’s also developed a good relationship with the National Parks, who gave him permission to collect seeds of rare plants and attempt to grow them in Tilden Park.
“You need a special environment to grow these plants,” Uhler said. “The crevice garden becomes a natural display case. It’s beautiful. Before this we were not able to grow a lot of these plants. And there are many species here, true alpines, that have never successfully grown to a bloom cycle.”
Has the crevice garden worked?
“We’ve been able to grow more species from the Sierra than anyone else anywhere has ever been able to grow,” O’Brien said.
Walk around the crevice garden and you’ll find labels of several of the high-altitude plants Uhler has been able to successfully grow down here in the East Bay.
The Alpine Buckwheat, Frosted Buckwheat and Lobb’s Buckwheat are among his favorites currently in bloom, though he recommends going to see them as soon as possible; they won’t be in bloom long.
He also recommends checking out the Sierra Columbine plant, a radiant flower that looks alive with its pointy legs and insect-like features.
“Everyone likes the alpine plants,” O’Brien said. “They’re tiny but usually have big flowers and they remind people of the mountains.”
Most people walking through the botanic garden in Tilden Park stumble into the crevice garden by accident, Uhler said.
“It’s got a certain gravitational pull,” he said.
Visitors wander through the Tilden Regional Park Botanic Garden on their way to the crevice garden in Berkeley, Calif., on Tuesday, July 22, 2025. (Jane Tyska/Bay Area News Group)
Briefly, the Sky Pilot was on display. But it didn’t survive the change in seasons.
“It’s stressful,” Uhler said. “You spend a lot of time growing these plants, then they’re gone.”
Now he’s trying again, this time in the nursery culture.
“It’s the holy grail and it may be unachievable,” he said. “I grew it in the crevice garden, but in the winter, the plants go dormant and should be under snow. We may not be able to grow this exposed to the outdoors.”
Related Articles
Former residents remember Russell City after historic passage of reparation fund
Horoscopes Aug. 3, 2025: Michael Ealy, strive for brilliance
Word Game: Aug. 3, 2025
Asking Eric: My cheating husband failed the polygraph, but still he says I’m making things up
Dear Abby: I want to dance and hike. He wants to get drunk in the garage.
Elsewhere in the 10-acre botanic garden, celebrating its 85th anniversary this year, there are 3,600 species of plants, representing roughly half of California’s native flora. More than 700 of them are rare, threatened or endangered species.
Many of them won’t be here this time next year.
“Some of our iconic collections are aging out,” O’Brien said.
But the garden is constantly growing new plants to replace the old, creating a time capsule to celebrate some of the most beautiful plants in California.
“Our mission is to grow the greatest diversity of California natives as possible,” Uhler said. “It’s a challenge. And it’s a lifestyle, for sure.
“I’m leaving tomorrow, 10 days backpacking above the level the trees grow. I’ll see Sky Pilot. I’ll see Alpine Gold. If I don’t ever grow them, I’m OK with that too. It’s so nice to visit and see them. I really appreciate their beauty. Especially when I realize you can’t just put this in a pot and grow it.”
Details: Tilden Regional Parks Botanic Garden is free to enter and open daily, 8:30 a.m. to 5:30 p.m., at 1550 Wildcat Canyon Road, Berkeley; https://www.ebparks.org/parks/tilden/botanic-garden.
Red-spotted Clarkia grow among the rocks in the crevice garden at the Tilden Regional Park Botanic Garden in Berkeley, Calif., on Tuesday, July 22, 2025. (Jane Tyska/Bay Area News Group)