AAS trials program

All-Stars Irrigation and Climate Zone Trials

FIELD TRIALS for WATER-CONSERVING plants for California gardens

Plant species from the UC Davis Arboretum that have demonstrated tolerance to summer heat and drought are being tested under different irrigation frequencies AND in a variety of climate zones by UC Davis horticulturists.  Testing is taking place at a campus field site where irrigation can be controlled to reflect varying intensities from practically no water to regular irrigation.

A second layer of research is being done through Master Gardener volunteers.  Demonstration gardens throughout the state are testing these plants, documenting their appearance and performance in the different climate zones.  The results of these trials will provide growers and retailers the information they need to successfully distribute and market these plants to the public.

IRRIGATION TRIALS

Ten species were tested in 2005-2007, and an additional 10 species in 2007-2009. The field testing involves irrigation frequencies at four different levels ranging between 20 percent and 80 percent of normal plant evapotranspiration (the total water lost from plants and their surrounding soil).  A field weather station collects and logs weather data used to calculate the various percentages. Height and width measurements are taken monthly to determine a growth index for each species at each water level. General appearance, flowering time and duration, and any pest or disease problems are noted to determine how a plant performs at different levels of irrigation.

To view results from the first trials, CLICK HERE.

CLIMATE ZONE TRIALS

The same plant species in the field trials in Davis are distributed to established demonstration gardens in Redding, Grass Valley, Plymouth, Livermore, Palo Alto, Stockton, Mariposa, Fresno, Sun Valley, Riverside, Irvine, Point Loma, and El Cajon, representing 12Sunset climate zones.  The project coordinator in Davis provides training to Master Gardeners who carry out monthly evaluations.  Master Gardeners report on plant features such as general appearance, pest or disease problems, flowering, and other ornamental features, such  as durability, size, form, and leaf qualities.  The monthly evaluations are compiled by the project coordinator for analysis and publication.

Evaluations by Master Gardeners in a wide range of areas in the state provide information on the attractiveness and usefulness of these plants from the perspective of the gardener. This information will be made available to other gardeners, landscapers and nursery operators through Cooperative Extension and as part of the educational outreach programs of the UC Davis Arboretum and the California Center for Urban Horticulture.

To see a map of the garden locations, CLICK HERE.

MEETING THE NEEDS OF CALIFORNIA'S GARDENERS

Population increases and growth in California will strain the quality of life for communities with limited water supplies that continue to landscape with plants requiring frequent irrigation. A greater availability of plants tested for drought and heat tolerance, coupled with information about their cultural needs, will encourage expanded use of these plants in low water-use landscapes and help conserve this precious resource.

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