How Often Should You Water Mature Trees in California?

If you recently transplanted a young tree in California, you’ll want to give it extra care and attention during its early years to help it grow big and strong. This involves watering the tree two to three times a week for the first year after planting, once a week in the second year, and every other week in the third year.

But what about once the tree matures? Is it necessary to continue watering once a tree is well established? Yes, most mature trees should be watered once a month when the weather is dry. In California, this means during the summer.

Trees need deep, slow watering to encourage a healthy root system. You can’t rely on sprinklers to do the job because they don’t saturate the ground deep enough to reach the roots. Instead, follow these tips to water mature trees in California:

• Measure the soil dampness: Ideally, you should use a meter designed for this task, though you can also break up a small patch of soil with a screwdriver. If the meter reads “dry” or the soil is crumbly, you can assume your tree is thirsty.
• Set up your watering method: Plants and grasses with shallow roots may do just fine when watered with a regular sprinkler system, but trees require a different method. You may use a soaker hose, drip tubing or emitters, or a portable sprinkler set on low. These water-wise methods are exempt from most California watering schedules and restrictions. You can also water the tree by hand.
• Water along the drip line: Don’t water too close to the trunk. Instead, focus your efforts on the circular area under the farthest reaches of the tree’s canopy. This is where thirsty roots are most concentrated. If the root zone extends under a paved surface or behind a fence, soak the area accessible to you as thoroughly as possible.
• Soak deeply: You want the water to reach at least 6 inches below the surface. Check the soil with a meter or screwdriver every 10 to 20 minutes of slow soaking. Stop once the water reaches the desired depth.
• Add mulch: To reduce runoff, both while watering and during natural rainfall, surround your tree with mulch. Expand the mulched area over the years as the canopy grows. Avoid using rocks, decomposed granite, wood-blocking fabric, and artificial turf that could increase runoff and trap heat within the root zone.

You may not need to water your mature trees as often, or ever, if you plant native, water-wise trees on your property. For help watering your plants responsibly based on your situation, please reach out to Moon Valley Nurseries. We can offer tree care tips and suggest drought-resistant desert trees for your California home. With over 25 years of tree-growing experience, you can trust our team to provide the best tips and tricks! To learn more, contact us online or visit one of our California locations today.