Tilden Botanic Garden Cultivates Rare Alpine Plants to Combat Climate Change

At the summit of Mount Whitney, towering at 14,505 feet, a rare plant called Sky Pilot thrives in isolation, known for its striking purple-blue flowers and musky aroma. This unique species, found nowhere else on Earth, requires a challenging trek through the wilderness of California to be seen. Efforts to cultivate this alpine treasure are being spearheaded by Michael Uhler, a gardener at the Tilden Regional Park Botanic Garden, who considers it the “holy grail” of alpine plants. Uhler’s ambition to grow Sky Pilot is not merely a personal goal; he views it as a vital step in preserving plants at risk of extinction.

In recent years, Uhler received permission from the National Parks to collect Sky Pilot seeds, beginning a challenging journey to cultivate them at Tilden Park. He emphasizes the urgency of his work, stating, “Climate change is the game-changer for alpine plants. We don’t have a lot of time to learn as much as we can.”

In 2022, Tilden Park introduced a crevice garden designed to support the growth of alpine plants that would struggle at lower elevations. This innovative feature, constructed from 7-foot-tall slabs of slate and schist sourced from Mariposa Slate Quarry, creates a microclimate conducive to the survival of these unique species. The plants benefit from the natural drainage provided by the rock formations while their roots penetrate deep into the ground, enhancing their drought resistance and ability to withstand extreme weather.

Bart O’Brien, director of the botanic garden, notes the global evolution of crevice gardens, which gained popularity in the 1990s. The first in the United States was established at the Denver Botanic Gardens in 2012. Inspired by this development, O’Brien sent Uhler to observe its design and functionality, aiding the Tilden garden’s mission to replicate high-altitude growing conditions without the challenges of snow cover.

Uhler’s passion for alpine plants has led him to explore remote, high-altitude locations in the Sierra. His relationship with the National Parks has allowed him to cultivate rare species, transforming the crevice garden into a vibrant display of California’s alpine flora. “The crevice garden becomes a natural display case. It’s beautiful,” Uhler said. “Before this, we were not able to grow a lot of these plants.”

The success of the crevice garden is evident. “We’ve been able to grow more species from the Sierra than anyone else anywhere has ever been able to grow,” O’Brien stated. Visitors to the garden can find various high-altitude plants, including Alpine Buckwheat, Frosted Buckwheat, and Lobb’s Buckwheat, all currently in bloom. Uhler encourages guests to visit soon, as these flowers have a short blooming cycle.

Uhler also highlights the beauty of the Sierra Columbine, a striking flower that captures the essence of the mountains. “Everyone likes the alpine plants,” O’Brien remarked. “They’re tiny but usually have big flowers and they remind people of the mountains.”

Many visitors encounter the crevice garden serendipitously while exploring Tilden Park. Uhler describes its allure as having “a certain gravitational pull.”

Although Uhler briefly displayed Sky Pilot in the garden, it did not survive the seasonal changes. “It’s stressful,” Uhler admitted. “You spend a lot of time growing these plants, then they’re gone.” He is now attempting to cultivate Sky Pilot through nursery culture, acknowledging the challenges of replicating its natural habitat.

The Tilden Regional Park Botanic Garden, which marks its 85th anniversary this year, features approximately 3,600 species of plants, representing nearly half of California’s native flora. Among these, more than 700 species are classified as rare, threatened, or endangered. O’Brien noted, “Some of our iconic collections are aging out,” but the garden continues to cultivate new plants to preserve California’s botanical heritage.

Uhler remains committed to the garden’s mission, stating, “Our goal is to grow the greatest diversity of California natives as possible. It’s a challenge. And it’s a lifestyle, for sure.” He plans to embark on a ten-day backpacking trip to the high Sierra, where he hopes to see Sky Pilot and other alpine plants in their natural setting. “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.”

Visitors can explore the Tilden Regional Park Botanic Garden daily from 8:30 a.m. to 5:30 p.m. at 1550 Wildcat Canyon Road, Berkeley. Entry is free, offering a unique opportunity to witness the efforts to preserve California’s rare and beautiful native plants.