San Francisco's official flower celebrates 100th birthday

If you’ve ever wondered what hundreds of the most ornamental flowers with striking geometric forms would look like under one roof, there’s a free event in Golden Gate Park this weekend that can give you a pretty good idea.

The Dahlia Society of California’s annual Dahlia Show and Competition returns this Saturday and Sunday at the County Fair Building near Ninth Avenue and Lincoln Way. The show is free and open to the public. More than a hundred growers are expected to enter blooms for judging, with ribbons and cash prizes awarded in categories including Best in Show, photography and floral arrangements.

“Thousands of people pour through these doors over the weekends, and there’s something for everyone,” said Jenna Kaiser, a dahlia ambassador with the society. “There’s a photo booth, and the orchid people will have a table there as well. The arrangement category is a big hit with the general public because there’s a theme to it.” This year’s arrangement theme is San Francisco icons, Kaiser said.

And there’s an extra reason to celebrate. 2026 marks 100 years since the dahlia became San Francisco’s official flower. The city’s Board of Supervisors designated the dahlia the official flower on Oct. 4, 1926. The flower had already been growing in Golden Gate Park since the 1880s, and its ability to thrive in San Francisco’s cool summers and moist air helped make it a natural fit for the city.