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March 6, 2023

UArizona experts available to discuss spring wildflower season

TUCSON, Ariz. — Can Arizona expect a spring wildflower "superbloom" event in 2023?

March and April are peak months for showy annual wildflowers across lower elevations of the state. Periodically, the show is intense – colorful enough to be seen from space.

University of Arizona experts track multiple factors – primarily temperatures and precipitation over the previous winter, fall and even summer monsoon – that influence bloom events. They build databases and track historical records with the help of citizen observers to determine if conditions are right for a multicolored carpet on the desert floor.

But in the end, it's the plants that decide what kind of show they'll put on.

"We received good rainfall in October and then again in December, January and February, which are key ingredients to a good bloom event," said Theresa Crimmins, a professor in the UArizona School of Natural Resources and the Environment whose research focuses on phenology – the timing of seasonal events in plants and animals. "However, a few factors could impede a major flowering event, namely that November was dry, winter temperatures have been cool, and we had a wet summer last year, which can lead to heavy growth in summer annuals that can impede the germination of winter annuals. I think the fall and winter rains have set us up to have at least good pockets of flowering."

Scientists don't yet have the mechanism to accurately predict superbloom seasons, but the public can help, Crimmins said.

Crimmins is director of the USA National Phenology Network, which collects and shares information on when plants and animals undergo seasonal events like flowering and migration. These observations contribute to a massive resource used by scientists, government agencies, and many others to better understand events like spring superblooms and when they may occur. Citizen scientists are encouraged to use the network's Nature's Notebook to record observations of plants and animals.

"Observations of when different species of plants are in flower, as well as when they are not in flower, help us to unravel the mystery of why superbloom events happen in some years and not in others," Crimmins said.

UArizona experts are available to speak about the factors that contribute to spring wildflower season and how observers can contribute to the database of information on the annual bloom.

  • Theresa Crimmins, professor in the School of Natural Resources and the Environment and director of the USA National Phenology Network, coordinates the efforts of thousands of professional and citizen scientists from across the country to document the timing of seasonal events in plants and animals such as flowering, leaf-out, migration and egg hatch. Her research has contributed to a greater understanding of how the timing of such events – phenology – is shifting under rapidly changing climate conditions. 
  • Mike Crimmins, professor in the Department of Environmental Science and an Arizona Cooperative Extension climate science specialist, works with ranchers, farmers and natural resource managers across Arizona to integrate climate information in their planning and decision making, and assists them in developing strategies to adapt to a changing climate. He has expertise in numerous aspects of the climate of the Southwest, including drought conditions, weather and climate mechanisms, and climate extremes and impacts.

The University of Arizona Cooperative Extension Pima County Master Gardeners program is offering a free online class titled "Perennial Wildflowers to Plant in Spring for Summer Bloom" at 4 p.m. on Monday, March 13. The session is scheduled for 15 to 30 minutes and is for gardeners of all experience levels. For more information and to register, visit the Cooperative Extension website.

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Media contact:
Joel Badzinski
College of Agriculture and Life Sciences

The University of Arizona, a land-grant university with two independently accredited medical schools, is one of the nation's top 50 public universities, according to U.S. News & World Report. Established in 1885, the university is widely recognized as a student-centric university and has been designated as a Hispanic Serving Institution by the U.S. Department of Education. The university ranked in the top 20 in 2021 in research expenditures among all public universities, according to the National Science Foundation, and is a leading Research 1 institution with $770 million in annual research expenditures. The university advances the frontiers of interdisciplinary scholarship and entrepreneurial partnerships as a member of the Association of American Universities, the 66 leading public and private research universities in the U.S. It benefits the state with an estimated economic impact of $4.1 billion annually. For the latest on the University of Arizona response to the novel coronavirus, visit the university's COVID-19 webpage.

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