AAS trials program
All-Stars Irrigation and Climate Zone Trials
UC Davis Arboretum All-Stars that have demonstrated tolerance to heat and drought are being tested under different irrigation frequencies in a variety of climate zones by UC Davis horticulturists. Additionally, Master Gardener volunteers are growing these plants in demonstration gardens throughout the state, 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.
Plants are irrigated at four levels, ranging from 20-80% percent of normal evapotranspiration (total water lost through evaporation from plants and surrounding soil). A weather station collects data to calculate these percentages, while height and width is measured to develop a growth index for each species at a particular water level. Overall appearance, flowering time and duration, and pest or disease problems are noted to to provide a comprehensive assessment of performance.
Climate Zone Trials
The same species were distributed to demonstration gardens throughout the state, representing 12 Sunset climate zones. The project coordinator in Davis provides evaluation training to Master Gardeners, who report on 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.
These evaluations provide information on the attractiveness and usefulness of these plants in different climates from the perspective of the gardener. This information will be made available to gardeners, landscapers and nursery operators through Cooperative Extension and as part of the educational outreach programs of the Arboretum and the CCUH.
Funding provided by:
- The Elvenia J. Slosson Endowment for Ornamental Horticulture
- The Saratoga Horticultural Research Endowment
- The California Association of Nurserymen Endowment for Research and Scholarship