This is not meant to be a complete list, by any means, but here are a few publications and links that will be useful if you are selecting plants for a waterwise garden.
WUCOLS stands for Water Use Classification of Landscape Plants. This project, sponsored by UCDavis, California Dept of Water Resources, California Center for Urban Horticulture, lets you find out the water needs of over 3,500 landscape plants in six different regions of California. The most recent version WUCOLS IV,can be accessed at the following address:
http://ucanr.edu/sites/WUCOLS/ Click on "Plant Search" Or you can use this link: WUCOLS IV
For information on growing California Native Plants, check out the Las Pilitas web site, laspilitas.com, or use this link: Las Pilitas Nursery.
Here are links to two articles on the subject of watering trees during a drought that were recently in the San Francisco Chronicle:
Finally, here is a short list of books that you will find useful as you seek ideas and plants for a waterwise garden:
California Native Plants for the Garden, Burnstein, Fross, O'Brien, Cachuma Press, 2005.Photos, text on garden uses and care.
New Sunset Western Garden Book. I think the most recent is 2012, and it does have all color photos, which are helpful, but the text of couple of editions right before this one were a little more thorough.
Plant Life in the World's Mediterranean Climates, Peter B. Dallman, University of California Press, 1998. Maps and charts show how the 5 mediterranean regions are similar and, importantly, how they differ, then explains the habitats to which many of our favorite plants are adapted.
Plants and Landscapes for Summer-dry Climates of the San Francisco Bay Region, East Bay MUD, 2004. Inspiring photos and useful information.
The Random House Book of Indoor and Greenhouse Plants, Roger Phillips & Martyn Rix, Volumes 1 & 2, Random House,1997. Despite the name, thiese two volumes cover mostly mediterranean and other subtropical plants that we can grow outside. The photos and text about the plants in their native habitats are very useful.
Wildly Successful Plants: Northern California, Pam Peirce, Sasquatch Books, 2004.California garden history, plant origins, garden maintenance instructions, garden design, and a philosophy for a regional garden.