Yes, San Francisco has an official flower and it's blooming at Golden Gate Park

SAN FRANCISCO (KGO) -- Deborah Dietz has been tending to the dahlia garden in San Francisco's Golden Gate Park for more than 30 years.

Despite all these years, she still sparkles when talking about the flower.

"Dahlias are just not like any other flowers, some of them are rambunctious like flamenco dancers and other ones are mathematical precision instruments," said Dietz as she trimmed back buds from the plants.

She's not alone in her obsession.

"You get addicted. You want to have the biggest, the best, the most colorful, the smallest, the craziest. I love it," said Jenna Kaiser, of the Dahlia Society of California.

The Dahlia Dell is unique among the gardens in Golden Gate Park. It's not maintained by San Francisco Recreation and Parks Department staff.

Plantings and maintenance is all done by volunteers like Dietz, who grows about 220 dahlia plants at the dell. There are about 700 in the garden.

The Dahlia Dell has been around since the 1880s, when Golden Gate Park was created, but it wasn't until the 1920s that the flower's popularity exploded in San Francisco.

"It turned into a bit of a rage. People were paying a lot of money for them, as much as $15 for a prized tuber in the 1920s," said Eric Gensler, president of the Dahlia Society of California.

$15 in 1920 is about $250 in today's money.

The dahlia mania started in Victorian times, after tubers were taken from its native Mexico to Europe, but the obsession in San Francisco was by the newly developed Sunset and Richmond neighborhoods, which were built on sand dunes.

"It was hard to grow much of anything in these gardens, but it turns out dahlias love the sandy soil," said Gensler.

Neighbors banded together to grow them and enter the best ones at a competition held at the Palace Hotel.

By 1926, the dahlia craze was so big that it was declared the official flower of San Francisco.

After World War II, the Dahlia Dell was cared for by Roy Takeuchi after he returned from a concentration camp, where Japanese-American citizens were incarcerated.

Takeuchi sold and planted dahlias for 40 years. When he became ill, Gensler and Dietz took over and decided to fill the garden with pedigree varieties.

"Dahlias have attitude. They don't look up at the sky, they don't look down at the ground, they look right at the judges," said Dietz.

Antoinette Nascimento joined the Dahlia Society of California just a few months ago and now shares her enthusiasm by giving free tours of the dell every Saturday at noon.

"I'm a diploid, you're a diploid. These are octoploids, which means instead of having two sets of chromosomes, they have eight. That's wild," said Nascimento..

Those eight sets of chromosomes allow for a large variety of flowers.

"There's 21 forms recognized by the Dahlia Society and different sizes within those forms."

Some are as big as a dinnerplate, others the size of a quarter.

Dietz said the rainbow of colors is yet another connection to San Francisco.

"Dahlias just have such infinite variety. We San Franciscans have infinite variety"

The best dahlias from the dell and gardens in Northern California will be on display Saturday and Sunday at the annual dahlia show.

The free event will be held at San Francisco County Fair Building in Golden Gate Park on August 15 and 16.