Conserve water in landscapes
Planting species that require little irrigation is one method of conserving water. Consider using drought-tolerant ornamentals and save the water for fruit trees and vegetable gardens. Some, but not all, California natives and plants from other areas of the world with a Mediterranean climate perform acceptably with limited irrigation once they become established.
Even when woody species requiring more water are grown in California landscapes, increasing the interval between irrigations often improves plant health and wastes less water. Group together plants with similar water requirements (use hydrozones) so that they are irrigated the same, appropriate amount and frequency.
Install an efficient, drip or low-output, sprinkler-irrigation system. Maintain and operate irrigation equipment properly and regularly inspect systems to ensure they are applying water to the desired area. Irrigate only when needed. Monitor evapotranspiration (ET), plants, or soil moisture to help you decide the appropriate amounts to apply and the proper interval between irrigations. Modify irrigation throughout the year to match plants’ changes in irrigation need.
Avoid runoff by improving soil permeability and infiltration (drainage) and modifying irrigation. For example, to avoid runoff and allow water to soak into soil, cycle irrigation systems on and off in several short periods that add up to the total run time instead of irrigating continuously for one long period.
A properly operated irrigation controller can help you avoid over- or underwatering plants. With some types, you must periodically adjust the settings manually as plants’ need for irrigation changes with the weather and seasons. Some "smart" irrigation controllers use on-site, soil-moisture sensors or weather-dependent, evapotranspiration (ET) data to automatically adjust the watering schedule.
For more information, see Estimating Irrigation Needs, Irrigation of Trees and Shrubs, Irrigation Scheduling Using Evapotranspiration (ET), Soil Properties and Water Availability to Roots, and Water Deficit and Excess. Irrigating Fruit and Shade Trees and Shrubs provides an index to more resources. Also consult the University of California, Davis Arboretum All-Stars for recommended plants that need less water and publications such as Drip Irrigation in the Home Landscape, Water Conservation Tips for the Home Lawn and Garden, and "Water Management" in the California Master Gardener Handbook.
Adapted from Pests of Landscape Trees and Shrubs: An Integrated Pest Management Guide, University of California Statewide Integrated Pest Management Program (UC IPM).
Drip system before a mulch covering.
Irrigation controller, automation can save water.