- Author: Nadia Zane
When we think about saving water in the garden, the first things that usually come to mind are irrigation systems and
Hydrozoning calls for you to step outside and make observations about your landscape. Even if you have lived in your home for many years, solidifying any vague conjectures about the various microclimates on your property will make planning more effective. There are three basic factors to consider when creating hydrozones:
1. How much sun is there?
Different plants have different metabolic processes; Each has an optimum light requirement to meet its needs for photosynthesis, the process by which plants use sunlight to convert carbon dioxide and water into food.
You can track available sunlight by watching when and how long the sun shines directly on various areas of your garden. Also note if there are extended periods when the sun disappears behind a tree or building before returning, and how the amount and intensity of light changes with the seasons as the sun is higher or lower in the sky.
2. How much water will your plants need?
Plants take up and lose water at different rates, as we all know, but other factors come into play as well. Moisture, temperature, and oxygen levels affect soil biology, a major component of plant health. Plants have various preferences, and while many species are quite tolerant of a wide range of environments, it's a safe bet that mixing high and low water plants will result in someone being under- or over-watered.
Once you have divided your landscape into zones by sun exposure, you can decide whether these areas will be low, medium, or high water use. Watering issues account for a large proportion of plant problems, so designate water requirements before heading to the nursery.
3. What plants do you want to keep?
This is really important if you have an established landscape and are looking to improve your water efficiency. First, look up at the established trees and shrubs that will form the foundation of your garden; these “keepers” will guide you when choosing other plant species to share that hydrozone.
You may have to make some difficult choices about what to keep, but in the long run, water-related problems will probably decrease once you organize your hydrozones. Plants that get their sun and water requirements met are more likely to reward you for your efforts.
Doing your research is essential to understanding what plants want. A great resource for determining the water needs of various plants is the Water Classification of Landscape Species tool (WUCOLS), a searchable database of plants that have been classified by water requirements according to the different climates of California:
To search for plants by function with a basic description of cultural requirements (and photographs), visit Water Wise Gardening in the Gold Country Region.
You can also create a plant list for your various hydrozones using this chart: