Landscape trees
Even stringent drought restrictions allow for watering of trees on residential and commercial property. Courtesy Helix Water District

Sixteenth in a series republished with permission from the San Diego County Water Authority‘s website.

As the unprecedented drought continues to affect California and the San Diego region, homeowners can still balance the need to conserve water as efficiently as possible while preserving valuable landscaping, including trees.

Trees can be maintained while following California’s water guidelines. Trees are among the most valuable investments in San Diego County’s landscape — including your own home landscaping.

No other landscape plant offers more significant benefits to your landscape and the environment. Trees provide much-needed shade and cooling to increasingly hot neighborhoods and cities and are among the most efficient natural ways to remove harmful carbon dioxide fueling global warming.

When mature trees die due to lack of irrigation, they become a dangerous fire hazard. They are expensive to remove. Young replacement trees take many years to provide the benefits of mature trees.

So taking care of your trees during drought ensures a tremendous return on this investment.

Deep Soaking Maximizes Tree Irrigation

Even when not in an acute drought, trees planted in a Mediterranean climate often need some additional water. Mimic the way Mother Nature provides water for the most effective irrigation.

Healthy tree roots reach three to four feet deep at the outer edge of a tree’s branches, where rainfall would naturally run off leaves. This area at the edge of the tree canopy is called the drip line.

When it does rain, Mother Nature’s rainfall is primarily steady, slow, and spread out. Follow this method to deliver a prolonged, slow soaking. Trees prefer infrequent deep watering.

During drought, slow watering every two or three weeks for more established trees is sufficient. Avoid runoff with multiple cycles to allow water to soak deeply. Irrigate early in the morning to minimize evaporation.

Keep in mind turf competes with your trees for water. Even if you want to retain some lawn, it’s smart to remove the lawn immediately around your trees and replace it with water-saving landscaping.

Protecting Trees from Climate Change

Drought is a reality in the San Diego region as average temperatures increase. As summer months become hotter, soils dry out. Trees must be deep watered to supply their roots and preserve their health.

San Diego forestry and landscaping professionals are working with the San Diego County Water Authority and its 24 member agencies to help protect our region’s trees while also conserving water. Find more resources and learn more at

The San Diego County Water Authority offers programs, resources, and incentives to improve water-use efficiency for residential, commercial, and agricultural users. For more water-use efficiency resources, go to