Southern California homeowners who have turned their yards into lush green oases filled with grass, trees and vegetable gardens may be in for a challenging summer as temperatures rise and drought-driven water restrictions take effect in parts of the region.

The instinct may be to scramble to save everything, but agricultural experts say you may have to prioritize certain plants and yard features over others. It may also be time to start looking at long-term changes to combat increasingly dry and hot conditions in the state. 

“We’re going to have to choose very, very wisely what plants stay and what plants don’t,” said Carrie-Anne Parker, owner of Rolling Hills Herbs and Annuals in Redlands. “There’s no way to sustain a lawn and a vegetable garden and an ornamental garden simultaneously.”

Parker said that rather than “trying to hold onto all things,” gardeners should give themselves permission to let their lawn go and focus their efforts on protecting the plants that are most important to them, whether that be their vegetable garden, their trees or the rose bush they planted in memory of a loved one.

Janet Hartin, an environmental horticulture advisor for the University of California Cooperative Extension who conducts research and educates communities on maintaining heat, drought and pest-tolerant trees, shared a similar sentiment. 

“The lawn can come back later,” Hartin said. “It’s much more dispensable than your trees.” 

How bad could restrictions be? The Metropolitan Water District has declared a water shortage emergency that will require member agencies to enforce water use restrictions by June 1 and parts of Los Angeles, Ventura and San Bernardino Counties could be restricted to watering only once a week. 

Examing irrigation 

Darren L. Haver, director of the University of California’s South Coast Research & Extension Center, said the first step should be to inspect irrigation systems such as sprinklers to make sure that the maximum amount of water that can remain within your yard, does. 

“It means you’re going to need to turn on your system and you’re going to need to make sure you don’t have leaks and you don’t have misdirected irrigation heads,” Haver said. 

While some gardeners like to increase the amount of time they water their lawn during hot, dry conditions, Haver said people instead need to pay attention to the time between watering. Consider the number of days the grass continues to look good between waterings and then water at that interval. The length of time during waterings should always be the same. 

Protecting established trees 

Hartin said that trees and food-producing crops are among the most important to protect. She said that trees help cool urban heat islands and play an important role in carbon capture. 

She recommends that trees that are not already connected to some form of drip irrigation get deep waterings. One way to do that, she said, is taking a hose and turning it down to a trickle and letting the water soak into the ground for between two and four hours during the early morning hours once a week to reach the tree’s deep root system. 

Homeowners may also have to think about how their trees might be affected if they decide to remove their lawns. Hartin said that some trees have very shallow root systems because they’re only supported by the same sprinkler systems that support a grass lawn, and when that grass lawn is removed and the sprinklers are turned off, those trees suffer. She said it’s important to make sure those trees are still getting regular irrigation and are then weaned off and transitioned into deep and infrequent waterings. 

Caring for the vegetable garden 

In the same way that trees benefit from deep and infrequent waterings, so do garden plants. 

Parker recommends this form of watering to encourage plants to develop deep root systems that will help them to become more resistant to drought conditions. 

How long and how frequent depends on a lot of variables including the size of a plant and the type of soil it’s in. Smaller plants with more fragile root systems need more water than bigger plants and claylike soil retains more water than sandy soil. 

Parker said there are young plants that she’s watered for as much as an hour sometimes, and in areas where she has claylike soil she can go up to four days without watering again. It’s up to gardeners to determine their own water needs based on their conditions. 

Another important tool to use is some form of mulch to help seal in moisture. Parker said she puts grass clippings around the base of her plants to help keep moisture sealed into the soil after watering. 

There are also structures that can be placed in the garden to try to deal with hot and dry conditions. In the absence of a large tree canopy, people can put up umbrellas to keep the ground cool and help keep some moisture in the soil. 

Parker said that something like a whiskey barrel planter can be placed on wheels and moved into more shaded areas to protect plants.

Planning for the future 

Though it’s not the time to plant new trees, gardeners should think about it come fall for the long-term benefits those trees can provide once they become established, Parker said. 

Hartin recommends visiting the website for the Urban Forest Ecosystems Institute at Cal Poly San Luis Obispo, which provides a feature for people to find trees that are most suited to their area of California. 

It may also be time to reevaluate the green grass lawn and start making moves toward a drought tolerant native landscape, said Muriel Fernandez, a lecturer in the Department of Landscape Architecture at Cal Poly Pomona. 

Fernandez said people might be worried that their yard will look drab if they give up their lawn, but there are plenty of plants that stay green throughout the year. Some she recommends include the Cleveland Sage, California Buckwheat and the Maritime California Lilac. 

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Fernandez said that native plant gardens also serve as “stepping stones” in an effort to help sustain local bird populations, something she said is important as native tree canopies disappear. 

She used her own garden as an example, saying that her salvia plants have fed bird species flying through her area after their stalks break and release seeds onto the ground. 

“Drought resistant can be spectacular and you’re supporting your local biodiversity,” she said.