This year’s theme was “San Francisco Icons,” with dahlia arrangements evoking the Golden Gate Bridge, Lombard Street, the Painted Ladies, Coit Tower and other city landmarks.

Aug 17, 2026

Updated 11:44 am PT

Selina Yep admires a dahlia at the annual Dahlia Show & Competition at the Hall of Flowers in Golden Gate Park on Aug. 15, 2026. This year marks the 100th anniversary of the dahlia being named San Francisco’s official flower. (Gina Castro for KQED)

Hundreds of dahlias turned a corner of Golden Gate Park in San Francisco into a showcase of color, shape and genetic diversity this past weekend.

The Dahlia Society of California’s annual show returned to the park, this time to mark the 100th anniversary of San Francisco naming the dahlia its official flower.

This year was themed “San Francisco Icons,” with dahlia arrangements evoking the Golden Gate Bridge, Lombard Street, the Painted Ladies, Coit Tower and other city landmarks.

Single-bloom dahlias are displayed at the annual Dahlia Show & Competition at the Hall of Flowers in Golden Gate Park on Aug. 15, 2026.

Marzieh Yaghini admires a dahlia at the annual Dahlia Show & Competition at the Hall of Flowers in Golden Gate Park on Aug. 15, 2026.

A Golden Gate Bridge dahlia arrangement is displayed at the annual Dahlia Show & Competition at the Hall of Flowers in Golden Gate Park on Aug. 15, 2026.

Visitors wandered among rows of carefully cultivated blooms, many of them competing for ribbons and recognition from judges and, for attendees, simply offering a chance to slow down and look closely at a flower that can be surprisingly complex.

“One of the reasons we love San Francisco is because there’s so many different kinds of people here. And Dahlias are kind of the San Francisco of floral society,” said Deborah Dietz, corresponding secretary for the Dahlia Society and longtime volunteer in Golden Gate Park.

“There’s 21 forms of dahlias, there’s 15 official colors and there’s five different sizes,” she added. “And that’s just categories.”

Judges examine dahlias at the annual Dahlia Show & Competition at the Hall of Flowers in Golden Gate Park on Aug. 15, 2026.

Members of the public enjoy the annual Dahlia Show & Competition at the Hall of Flowers in Golden Gate Park on Aug. 15, 2026.

A Raeann’s Tiger Eye dahlia is displayed at the annual Dahlia Show & Competition at the Hall of Flowers in Golden Gate Park on Aug. 15, 2026.

An Ask With Minnie dahlia is displayed at the annual Dahlia Show & Competition at the Hall of Flowers in Golden Gate Park on Aug. 15, 2026.

Dahlias can resemble water lilies, daisies, golf balls or spiky cacti. Some have multiple colors within a single petal. And because of their unusual genetics, new variations can arise through cloning and sexual reproduction.

Dahlia tubers can be divided into genetically identical plants, said Erik Gaensler, president of the Dahlia Society of California. But growing from seed produces something entirely new.

“If you plant 100 dahlia seeds, most won’t be that great,” Gaensler said. “So we have some people in our society who will grow hundreds of seedlings, and they only save the best.”

Jenna Kaiser, a dahlia ambassador with the Dahlia Society of California, poses for a photo at the annual Dahlia Show & Competition at the Hall of Flowers in Golden Gate Park on Aug. 15, 2026.

Ivy Lou, 70, takes a photo with dahlias at the annual Dahlia Show & Competition at the Hall of Flowers in Golden Gate Park on Aug. 15, 2026.

Addie Lee, 2, takes photos of dahlias at the annual Dahlia Show & Competition at the Hall of Flowers in Golden Gate Park on Aug. 15, 2026.

Those seedlings can be cultivated for years before eventually being named and entered into competitions. Many dahlias grown in San Francisco originated locally, Gaensler said, making them particularly well suited to the city’s climate.

The flower’s history in San Francisco dates back more than a century. When the Sunset and Richmond districts were undeveloped and still largely dunes, dahlias could thrive in the sandy soil. By the 1920s, several commercial dahlia growers operated in the area, and the Palace Hotel hosted annual shows. In 1926, the city officially adopted the dahlia as its flower.

For Dietz, that history is part of what makes the flower special, but so is the scientific curiosity surrounding it. Dahlias have eight sets of chromosomes and genetic elements that can shift around within their DNA, occasionally producing new traits.

Sir Richard Dahlias are displayed at the annual Dahlia Show & Competition at the Hall of Flowers in Golden Gate Park on Aug. 15, 2026.

Nathan Gomez makes petal art at the annual Dahlia Show & Competition at the Hall of Flowers in Golden Gate Park on Aug. 15, 2026.

Natalie Samuels, left, and Abby Klinkenberg, right, admire dahlias at the annual Dahlia Show & Competition at the Hall of Flowers in Golden Gate Park on Aug. 15, 2026.

The Dahlia Society of America has funded work to map the dahlia genome, Dietz said, which could help researchers better understand which genetic sequences determine traits such as shape and color.

That diversity was also what drew first-time visitors Natalie Samuels and Abby Klinkenberg to the weekend’s show.

“It’s a chance to reorient ourselves and connect to the things around us,” Klinkenberg said.

Samuels said the flowers encouraged her to slow down and observe each individually, a welcome contrast to the pace of modern San Francisco.

You can see the winning blooms on the Dahlia Society’s Instagram page.