California Institute for Water Resources
California Institute for Water Resources
California Institute for Water Resources
University of California
California Institute for Water Resources

Practical advice on drought tolerant landscaping in California

Photo from UC Cooperative Extension Master Gardeners of Marin County.

This is a guest post from Missy Gable, UC Cooperative Extension Master Gardener program; Dave Fujino, California Center for Urban Horticulture, UC Davis; Janet Hartin, UC Cooperative Extension; Chuck Ingels, UC Cooperative Extension; Loren Oki, UC Davis; and Karrie Reid, UC Cooperative Extension

Water scarcity is part of life in California, which has been made even clearer in this fourth year of drought. The state's long-term forecast includes less snow pack and increased demand on our diminished water resources. In response, Californians are evaluating their water use, both in the landscape and the home. An obvious sign of changing landscape practices are the ‘golden' lawns that were once green. Many water districts have restricted the installation of new residential lawns and implemented “cash-for-grass” programs.

A variety of options exist for gardeners implementing landscaping changes. Trading in your turf for concrete, rock, or artificial turf are options. However, none of these selections promote healthy soils and other ecosystem services. In fact, all of these options can be problematic because they create a heat island effect and may have water infiltration or runoff issues.

Gardeners can also change the type of turfgrass they are growing. Warm-season turfgrass such as bermudagrass and buffalograss can be substituted for traditional cool-season grasses such as tall fescue and ryegrass. Warm-season turf goes dormant in fall and winter but impressively uses about 25% less water than cool-season counterparts.

Increasing the uniformity that water is applied across a lawn, fixing broken sprinkler heads, and irrigating based on climate zone can reduce water waste by 20-50%. Consult the UC ANR Lawn Watering Guide for specific information on these topics. Switching from a fan spray irrigation system to a multi-stream rotary system that waters more evenly and more slowly over the surface of your turf can also save water and decrease water and chemical runoff.

If you intend to suspend irrigation to your lawn, be sure to provide water to trees that have relied on that water. Watch trees for water stress symptoms such as change in color, wilting, or unseasonal leaf drop and provide water if necessary. As needed, apply water using a temporary drip or sprinkler device or a garden hose. Irrigate away from tree trunks in the dripline of the tree slowly and deeply. Gradually lengthen the interval between watering.

Other planted landscapes can provide similar ecosystem services to turf. For those considering a landscape conversion from turfgrass to native or Mediterranean climate-adapted plants, there are some important practices to take into consideration. These include:

  • Delay conversion to a low water-use landscape to the mid-fall or early winter. New plants have small root systems and are not immediately water conserving when planted. In fact, they require quite a bit more water initially to become established in your landscape. Planting in cooler months allows root growth to begin with little added water and takes advantage of seasonal rains to support the healthy establishment of your new landscape. Be sure to select water-efficient plants that grow well in your climate.
  • Control weeds. A weed is a water thief in the landscape when you have limited irrigation events. Remove weeds so they do not compete with your landscape plants for water.
  • Install drip irrigation. Drip irrigation is a targeted way to ensure water is being applied directly to a plant's root zone and not ‘lost' outside the reach of those roots. Contact your local University of California Cooperative Extension (UCCE) Master Gardener Program for more information about the frequency and timing of your irrigation system. Periodically examine the soil several inches below the surface to make sure you're adding the right amount of water.
  • Maintain 3-4” of shredded bark or wood chip mulch. Mulch is an insulator. It shields the soil from sunlight so weed seeds don't sprout, reduces evaporation of moisture from the soil, and protects plant roots from harmful temperatures so they don't die. Apply up to 4” deep but be sure to keep mulch several inches away from the base of tree trunks to avoid potential rot.
  • Avoid overuse of fertilizers. Fertilizers increase plant growth, which in turn increases a plant's water need. When water is limited, do not apply fertilizer.
  • Become familiar with your irrigation controller. You are not alone if programming your irrigation controller is a daunting task. Many people do not understand how to set their irrigation controller.Helpful tipsare available as a guide to adjusting irrigation controllers and scheduling appropriate irrigation events for your landscape.
  • Consider installing a ‘laundry to landscape' graywater system. The state and most local jurisdictions have lifted or greatly lessened restrictions on graywater systems which allow irrigation of plants with water from a washing machine. Contact your local county or city public works department for specific information on local laws.

Whatever your water-saving strategy, connect with your local UCCE Master Gardener Program for information and support. Program volunteers are uniquely trained to extend University research and knowledge to California residents. They staff county phone helplines, attend local farmer's markets, and conduct public workshops. They are located in 50 counties across California and are a free and accessible service that supports Californians in creating and maintaining responsible landscapes. Many county Master Gardener web sites have extensive information about managing plants during drought.

The California Institute for Water Resources also has many links to drought tips, videos, and other useful resources.

Posted on Thursday, August 20, 2015 at 9:57 AM

Comments:

1.
109%: Another Perspective on the California Drought and Landscape Water Use  
By Vincent Lazaneo, Urban Horticulture Advisor Emeritus  
 
 
I understand the desire to defend urban landscapes and justify the amount of water we use to maintain them. But I think the focus of the article 9%: Perspective on the California drought and landscape water use by Dennis Pittinger and Don Hodel is short-sighted. The discussion of issues raised in the article would, I believe, benefit from a broader perspective. It should take into account both the historic record of drought in the region and the profound changes caused by global warming that have begun and are predicted to accelerate as the century progresses.  
 
The historic record of our region’s climate over the past 2,000 years has been scientifically reconstructed using proxy data. Researchers have studied the growth rings of long-lived trees and ancient stumps at the bottom of Mono Lake, geological records that reveal the previous levels of Mono Lake and analysis of deposits deep under San Francisco Bay which collects sediment from a large water shed. The research and its implications are presented in a 20-minute long PowerPoint talk “Climate Change and Paleoclimatology: 2013/2014 in Perspective” by Lynn Ingram, professor of Earth and Planetary Sciences at UC Berkeley. It is available on-line at: http://ucanr.edu/insights. I recommend viewing this presentation.  
 
We have experienced some of the warmest years on record since the turn of the century. According to Ingram, the paleoclimate record shows that past periods of warming were associated with drier conditions in California. We have difficulty coping with recent droughts that last less than a decade but during the medieval warm period there were two dry periods with century-long droughts that had 60-70% of average precipitation. The proxy data shows that our climate is influenced by cyclical patterns and Ingram states that “we see wet/dry cycles over the past 2,000 years with periods of 30, 65, 90 and 200 years”. She also states that “the past 150 years have been unusually wet when viewed over the past 2,000 year period. The 20th century was a wetter century and this is when all our water development population growth and agricultural industry were established.”  
 
Ingram concludes “it’s possible the climate may now be shifting to a drier regime. We have already seen the impact of warming that’s been occurring since 1960. We are seeing a reduced snowpack that will continue into the future, and a drier climate with increased evaporation rates, so we’ll have drier soils, more frequent wild fires and increased dust levels.” It is also predicted that we will have a more extreme climate…that will produce larger floods and deeper droughts in the future.  
 
Considering the data and its implications, it’s difficult to justify maintaining the status quo with respect to the use of water for landscape irrigation. Our water pie is not as large as we thought it was and it will need to serve more people in the future as our population continues to increase. We will pay more for water and have less to use although this may be alleviated somewhat by desalinization and reclaiming water from the waste stream. (The city of San Diego plans to raise water rates by 41% over the next five years. It also has a large desalinization plant under construction and is considering claiming potable water from sewage water. The latter is already being done in Orange County.)  
 
The amount of water we can obtain from precipitation is limited and the use of water for any purpose reduces the amount available for other purposes. A large amount of the water from precipitation (about 50% I have heard) is devoted to environmental purposes such as maintaining lake levels, river flows, wetlands, etc. The percentage of total water used for this purpose could increase during a drought since there’s a minimum threshold for the amount of water needed. Providing enough water for environmental needs would leave less water for other sectors including agriculture, industry and urban.  
 
Potable water has been plentiful and cheap for several decades and we don’t consider it a valuable resource. This attitude has begun to change during the drought. This is good because future conditions will require us to use water more efficiently and curtail wasteful practices. I believe it would be beneficial for the urban landscape sector to be proactive in this effort. We should lead by example and do what is needed to create sustainable water-wise landscapes that are less dependent on supplemental irrigation with potable water.  
 
Using as much water as you desire and can afford and applying more potable water on a landscape than a sight normally would receive from annual precipitation is not a sustainable practice. Realistic limits should be set on the amount of potable water used for landscape irrigation. We should encourage the creation of landscapes that require little or no supplemental irrigation. The current drought has provided an opportunity to reevaluate our landscapes and the lessons we are learning on how to have functional landscapes with less water should not be forgotten if an El Nino temporarily refills reservoirs. About 19% of the state’s total energy is currently used to transport and process water. Reducing the amount of water used on landscapes would reduce the need to generate electricity from fossil fuels and help decrease carbon emissions into the atmosphere.

Posted by Vincent F. Lazaneo on October 26, 2015 at 11:55 AM

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