Weighing Water Use in Gardens

An inviting vignette in the water-wise garden of Mary and Lew Reid. Photo: Saxon Holt/PhotoBotanic.com

An inviting vignette in the water-wise garden of Mary and Lew Reid. Photo: Saxon Holt/PhotoBotanic.com

Spend much time chatting with California landscape designers or working horticulturists and you’re bound to hear repeated references to WUCOLS [“woo-coals”], an acronym that stands for Water Use Classification of Landscape Species. The project, initiated by the Water Use Efficiency Office of the California Department of Water, was developed in response to the relative lack of research-based information classifying plants by irrigation need. The first edition, completed in 1992, compiled field trial results and observations contributed by regional evaluation committees made up of knowledgeable horticulturists from throughout California. Now in its fourth edition, WUCOLS IV evaluates water use needs for more than 3,500 commonly available California landscape plants. The information-rich database is freely available online and is intended to serve as a reliable resource for anyone involved with planning, designing, and managing landscapes.

Beginning with our winter 2017 issue Pacific Horticulture will run a series of four articles that we’re calling “Planting the New California Garden.” Working in collaboration with members of the California chapter of Association of Professional Landscape Designers, each story will examine a finished landscape that illustrates practical WUCOLS data within the framework of a beautifully designed garden.

Each garden in the series will focus on one of four different regions in California identified in the WUCOLS database, although many similarities exist and comparisons may be made between those regions and growing conditions found in Washington and Oregon. Our goal is to provide valuable and inspirational content for gardeners up and down the West Coast who are looking to create beautiful gardens that are in sync with, and respectful of, the local ecology and precious natural resources.


Our “Planting the New California Garden” series is supported in part by a grant from the Saratoga Horticultural Research Endowment.