Updated: Nov 16
By Stephanie Rosenblatt
According to Jorge Ochoa, the biggest mistake people make when creating a low-water landscape is turning off the water to kill the grass and forgetting to water the trees. Ochoa is a Professor of Horticulture at Long Beach City College where he has worked for over 17 years.
People also remove mature and established trees and replace them with drought-resistant saplings, not realizing they will need more water than the old trees.
While mature trees can be watered just three or four times a month, new trees need damp soil until they are established which could take two years or more. A new tree will be established when it has doubled in size, so a three-foot sapling would need to grow to six feet.
Many people also water in the wrong place. Trees need to be watered at their drip lines, not near their trunks. It’s easy to find a tree’s drip line when the sun is directly overhead by mapping the edges of its canopy using the tree’s shadow.
There is often some confusion about how much to water. Ochoa says to water until the water stops being absorbed by the soil and you can see it visibly runoff.
It’s also okay to water a tree slowly over the course of a week without causing it any problems. Make sure to water a new area on the drip line each day so the area previously watered has time to dry out.
If you’re putting in a new sprinkler system, Ochoa recommends getting one with multiple zones so your trees can be on a different schedule than the rest of the yard. He suggests investing in a smart irrigation clock that uses satellite information to determine when to turn on the sprinklers. The Water Department provides rebates for these devices.
For those watering by hand, make sure the nozzle is on the shower setting and aim at the tree’s drip line. Stay in one place until the water begins to run off, then slowly move around the tree. When you’re back where you started, check the soil. If the water has been absorbed, water that spot again and repeat until the water begins to run off.