National Park

Blooming saguaros in Arizona’s national park are confusing

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A blooming saguaro is seen in this photo from November 2022. Saguaros typically bloom in the spring and biologists are unsure why they bloom in the fall.

National Park Service / D. Swann

Saguaros have been spotted blooming again this fall in Arizona, and biologists still don’t have an explanation.

The massive cacti typically bloom in May and June, but visitors saw some with white blooms on Saturday, November 12 on the Pink Hill Trail in the eastern part of Saguaro National Park.

Blooming cacti were also seen near the Red Hills Visitor Center on the west side of the park, officials said.

Biologists said the November saguaro bloom was odd, a park service spokesperson told McClatchy News in an email.

But “no one knows for sure” why this is happening, officials said.

The phenomenon, however, is not entirely new.

Saguaros began blooming in the Tucson area in the fall of 2018, catching the attention of biologists, the Arizona Daily Star reported.

“I’ve lived in Tucson for 30 years, and it seemed unusual to me,” Saguaro National Park biologist Don Swann told the news outlet in 2020. “It seemed unusual to almost everyone I spoke to.”

A thriving outbreak was also documented in the spring of 2021, McClatchy News reported.

Biologists are now studying off-season flowering.

Park officials have asked the public to take photos of all saguaros bearing red, ripe fruit and display its location.

Saguaros, which grow up to 80 feet tall, start producing flowers when they are around 35 years old and can live up to 150 to 175 years.

Helena Wegner is a McClatchy Live National Reporter covering Washington State and the Western Region. She holds a journalism degree from the Walter Cronkite School of Journalism and Mass Communication at Arizona State University. She is based in Phoenix.