$1 million grant expands climate-ready landscape plants program

Landscape plants under varying irrigation levels are evaluated at South Coast REC to determine the best irrigation level for optimal plant performance.

A research project initiated in the Department of Plant Sciences at UC Davis evaluates landscape plants in two-year trials under varying irrigation levels to determine the best irrigation level for optimal plant performance in regions requiring supplemental summer water. Creating water budgets is required by California's Model Water Efficient Landscape Ordinance (MWELO), and the results from these research trials help landscape professionals and home gardeners make informed decisions when specifying, selecting or promoting low water-use landscape plant material.

This year, the CDFA/USDA Specialty Crops Multistate Program funded a new Climate Ready Landscape Plants project, which will replicate the successful fields that are currently installed at UC Davis and UC ANR South Coast Research and Extension Center in Irvine.

Loren Oki will oversee a new Climate Ready Landscape Plants project. Photo by Ann Filmer

Loren Oki, UC Cooperative Extension specialist in the UC Davis Department of Plant Sciences, is the lead principal investigator and collaborators include researcher Jared Sisneroz;  project leader Karrie Reid, UC Cooperative Extension environmental horticulture advisor in San Joaquin County; and Darren Haver, UC Cooperative Extension water resources and water quality advisor and director of South Coast REC and UCCE in Orange County.

Under Oki's oversight, this new $999,992 grant will support the development of additional fields at several western universities:

• University of Washington, Soo-Hyung Kim
• Oregon State University, Lloyd Nackley and Ryan Contreras
• Utah State University Center, Youping Sun and Larry Rupp
• University of Arizona, Ursula Schuch

Conducting these new experiments on landscape plants at diverse sites across the western U.S. will reveal differences in recommendations since irrigation guidelines for landscapes vary depending on climate and soil type.

The initial project was initiated as Reid's master's degree thesis research in 2004, with Oki as her major professor, and has been ongoing since then.

Project descriptions, results and images can be seen at the UC Landscape Plant Irrigation Trials website at https://ucanr.edu/sites/UCLPIT.

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