California’s ‘super bloom’ is underway. Here’s why it’s so epic.

By Allyson Chiu

and

Naema Ahmed

April 19 at 6:00 a.m.

(Max Whittaker for The Washington Post)

Swaths of California are awash in vibrant colors as wildflowers have erupted from the earth.

The explosion of flowers across the state is what’s known as a “super bloom.”

How long the blooms will last and when they might emerge again can be difficult to predict. Whether they pop up simultaneously like this depends on a combination of factors that don’t always happen every year.

While it isn’t a formal scientific term, a super bloom is “a wonderful natural phenomenon where many annual wildflowers all bloom simultaneously,” said Naomi Fraga, director of conservation programs at the California Botanic Garden in Claremont.

“You have a great diversity, an abundance of many different wildflower species, all flowering, creating bright patches of color on the landscape where they become the dominant feature,” Fraga said.

The blooms, she added, are an “ephemeral phenomenon.” The last time a super bloom occurred in California was in 2019.

The flowers are often dormant as seeds in the soil, waiting for “just the right conditions” to start their life cycle, she said. California’s impressive floral showing is most likely connected to the massive amounts of precipitation that drenched much of the state in recent months.

“They’re winter annuals, they respond to winter rain,” Fraga said. “So, it really is having the bulk of the rain come in the winter months that leads to this.”

Cooler temperatures are also an important ingredient for super blooms, experts say.

“When the seed bank in the soil experiences this sort of range of temperatures and precipitation across time, then that has the ability to stimulate several different species to germinate and that creates the colorful landscape,” Fraga said.

In the Lancaster area of Southern California, California poppies grow alongside other wildflowers.

Most of the plant species that make up a typical super bloom are desert annuals, which means they usually complete their entire life cycle in just a few months.

While drought can pose problems for these wildflowers, this year it might have helped create conditions for native blooms to flourish in certain areas of California, said Joan Dudney, an assistant professor at the Bren School of Environmental Science and Management at the University of California at Santa Barbara.

Before the heavy rains and snowfall that pummeled the state recently, California had experienced three of its driest years on record. The drought could have reduced the number of invasive grass seed on the landscape and helped improve the chances for native plants to capitalize on the heavy rains and thrive.

(Planet Labs PBC)

In Carrizo Plain, in San Luis Obispo County, Great Valley phacelia in bloom can be seen from space as large dark swaths of purple.

The yellow patches in this satellite image show goldfields and hillside daisies — one of the first wildflowers to bloom in Carrizo Plain.

While throngs of visitors have already started to descend on the dense wildflower patches, this year’s showy display probably pales in comparison to the amount of flowers that might have bloomed before invasive plant species were introduced.

“What we’re seeing today, I think, 300 years, 400 years ago would have seemed like a little blip, like, ‘Oh, what a cute little hillside,’ versus now it seems like this incredible event,” Dudney said. “That’s kind of a tragedy, actually, that we’ve lost so much of the diversity and such a big extent of the range in which these species used to occur.”

If people aren’t mindful when they visit these flower patches, experts say, there will probably be consequences. Walking through blooms could trample the flowers before they produce seeds. High foot traffic could also compact the soil, making it more difficult for flowers to grow in that area.

“It’s not just for our enjoyment or for the display. It’s life happening,” Fraga said. “In order for that life cycle to continue, we need to know that this flower isn’t the end goal. The end goal is the seed.”

(Planet Labs PBC)

These orange splotches in Palmdale, in Los Angeles County, are California poppies in bloom.

The large patches of yellow can contain a number of different species such as goldfields, which often grow in same areas as the poppies.

Climate change, too, poses a threat to wildflowers. Frequent dry spells could mean longer stretches of time between super blooms, Fraga said. There are also predictions that changing weather patterns could shift seasonal rains to summer rather than winter.

“But these seeds can lay dormant in the soil seed bank for decades, so I think we’d have to see some really big shifts in climate patterns before we see these species sort of start to dwindle,” she said.

Satellite imagery via Planet Labs PBC