- Author: Joanna Solins
Front yard with water-wise landscaping. Photo Credit: Cadenasso Lab, UC Davis
California's urban water agencies have long relied on conservation measures to promote reliability and manage costs. Since landscapes are a large portion of water demand in California cities, many water agencies encourage water conservation by incentivizing the replacement of water-intensive turf lawns with water-efficient or “water-wise” landscaping.
In California's Mediterranean climate, traditional turfgrass lawns require irrigation to maintain their appearance through the hot summer months. Inefficient, poorly managed spray irrigation systems can also result in considerable water loss from runoff and evaporation. Replacing turf and overhead sprinklers with low-water-use plants, alternative ground covers like mulch and kurapia, and more efficient drip irrigation systems can potentially save hundreds of gallons of water per square meter every year.
Although the water savings from turf replacement can be substantial, generating widespread buy-in is a challenge. Landscape renovation can be expensive and intimidating, requiring residents to learn new landscape management practices or pay for professional assistance. In addition, many people appreciate their lawns as spaces for children, pets, or entertainment. Some prefer the look of turfgrass, especially where neighborhood norms promote a unified lawn aesthetic.
To help overcome cost barriers and encourage water-wise landscaping, government agencies and water suppliers commonly offer “cash for grass” programs, in which residents are offered a rebate for landscaping expenses based on the amount of turf they replace. These programs also aim to promote neighborhood adoption of water-wise landscaping by providing attractive examples. Turf replacement incentive programs are likely to expand under proposed new water use efficiency regulations, Making Conservation a California Way of Life (AB1668 - SB606).
While large-scale, regional turf replacement programs in Southern California have been evaluated in peer-reviewed studies, questions remain about the extent and impact of these programs in other parts of the state. How widely are turf replacement programs utilized, and by whom? Are these programs responsible for a substantial amount of water-wise landscaping?
Water-wise landscaping in Sacramento
With these questions in mind, we wanted to understand how both rebate recipients and houses with independently installed water-wise landscaping were distributed across an entire city in inland Northern California. The study was recently published in the Journal of Urban Ecology.
We visually surveyed the front yards of all single-family homes in 100 census tracts across the city of Sacramento—109,062 homes in total—and compared the prevalence of water-wise landscaping with the city's turf replacement rebate data. We especially wanted to understand how this landscape water conservation measure was being adopted by communities of varying socioeconomic and demographic characteristics, and which communities were benefitting from the rebate program.
Front yard with traditional turf. Photo Credit: Cadenasso Lab, UC Davis
In Sacramento, the City's Department of Utilities has offered a rebate of (typically) $1.50 per square foot of turf removed since the summer of 2014. To qualify for the rebate, replacement landscapes must meet several criteria, including efficient irrigation systems and approved plants that cover more than half of the area at maturity. The planting requirement addresses an important concern with turf replacement—the potential for an increase in urban heat. Lawns have a cooling effect through evapotranspiration, and if they are replaced primarily with non-living groundcovers, temperatures could increase. However, such program requirements can make some residents reluctant to participate.
When we conducted our visual survey of front yards in 2018, we found that approximately 10% of Sacramento's single-family-homes had water-wise yards, while 88% had conventional lawns. Only around 3% of water-wise yards were rebate recipients, though, meaning that the vast majority—97%—of water-wise yards were landscaped independently from the city's rebate program. We also found support for neighborhood adoption effects, with clustering of water-wise yards at the city block scale.
The prevalence of independent water-wise yards should be good news for water conservation, since it would not be feasible for the city to fund many thousands of turf replacement projects. However, independent turf replacement projects don't need to comply with the city's requirements for plant coverage or irrigation system efficiency, meaning that they could be contributing to increased urban temperatures or failing to save water.
Our study also showed that water-wise landscaping was more common in census tracts with less diverse, more highly educated, and more affluent populations, as well as fewer households with children. Rebate recipients followed the same trends, suggesting that rebates weren't overcoming barriers to adoption. The uneven distribution of resources necessary for turf replacement—money, time, and information—is likely an important driver of this pattern, along with cultural or functional preferences for lawns. Lawns may play a particularly important role for families as spaces for children to play.
Photo Credit: Cadenasso Lab, UC Davis
A Tool in the Toolbox
Turf replacement is one important tool in the water conservation toolbox, and our research suggests that many residents voluntarily install water-wise landscapes even without a rebate. However, adoption is not equal across communities. The roots of this disparity likely reflect uneven distributions of resources and preferences.
With thoughtful program design and outreach, incentive programs could help overcome some of these barriers, although funding and staffing limitations in water agencies pose a challenge for implementation. For instance, carefully crafted direct installation programs could reach lower-income residents who find it difficult to pay up-front costs associated with rebates. Tailoring efforts to the needs of lower-income and marginalized communities will be important to ensure that they do not end up with unirrigated, high-heat landscapes instead of attractive, water-wise yards.
In the Sacramento region, focus groups conducted for the Regional Water Authority revealed that some residents have a very strong preference for lawns. In these cases, water suppliers may have greater impact by promoting efficient irrigation practices, turfgrass varieties that use less water, and climate-appropriate shade trees. Partial lawn conversions are also a viable water-saving strategy, and one that Sacramento's rebate program supports.
As California's cities grapple with climate change, water reliability, cost effectiveness, and meeting new water use efficiency standards, reducing high-water-use turf lawns will continue to be an important adaptation strategy. Figuring out how to support effective and equitable landscape water conservation programs must be a focus of future research and evaluation studies to promote a California where everyone benefits from climate adaptation measures.
Joanna Solins is an Environmental Horticulture Advisor with UC Cooperative Extension, serving Sacramento, Solano, and Yolo Counties, and is an Affiliate Researcher with the California Institute for Water Resources and the UC Davis Department of Plant Sciences.
Acknowledgments: Many thanks to Erik Porse, Amy Talbot, Jasmin Green, and Mary Cadenasso for their input and assistance with this post.
Additional Reading
Green, J. C., Solins, J. P., Brissette, L. E. G., Benning, T. L., Gould, K., Bell, E. M., & Cadenasso, M. L. (2024). Patterns of water-wise residential landscaping in a drought-prone city. Journal of Urban Ecology, 10(1), juae003. https://doi.org/10.1093/jue/juae003
Alliance for Water Efficiency. (2019). Landscape transformation: Assessment of water utility programs and market readiness evaluation. https://www.allianceforwaterefficiency.org/impact/our-work/landscape-transformation-assessment-water-utility-programs-and-market-readiness
Matlock, M., Whipple, R., & Shaw, R. (2019). Just for the turf of it: Turf replacement as a water conservation tool. Journal of Soil and Water Conservation, 74(5), 449–455. https://doi.org/10.2489/jswc.74.5.449
Pincetl, S., Gillespie, T. W., Pataki, D. E., Porse, E., Jia, S., Kidera, E., Nobles, N., Rodriguez, J., & Choi, D. (2019). Evaluating the effects of turf-replacement programs in Los Angeles. Landscape and Urban Planning, 185, 210–221. https://doi.org/10.1016/j.landurbplan.2019.01.011
Simpson, S.-A., Altschuld, C., Ortiz, A., & Aravena, M. (2023). Green to gold mile: An environmental justice analysis of drought and mitigation policy impacts on home landscapes in Sacramento California. Landscape and Urban Planning, 234, 104729. https://doi.org/10.1016/j.landurbplan.2023.104729
- Author: Karey Windbiel-Rojas
- Author: Elaine Lander
The CDC health advisory states “Veterinary formulations intended for use in large animals such as horses, sheep, and cattle (e.g., “sheep drench,” injection formulations, and “pour-on” products for cattle) can be highly concentrated and result in overdoses when used by humans. Animal products may also contain inactive ingredients that have not been evaluated for use in humans. People who take inappropriately high doses of ivermectin above FDA-recommended dosing may experience toxic effects.”
Incorrect use of any pesticide can lead to injury, negative health impacts, or severe illness. Be sure to always read and understand the label when using pesticides and only use them where specified on the label. As a reminder, disinfectants are pesticides too, and should be used properly to minimize health risks.
Visit our website for more information on pesticides in homes and landscapes. If you suspect that you or someone you know is experiencing serious illness due to pesticide exposure, contact the Poison Control hotline at 800-222-1222.
- Author: Janet Hartin
Landscape trees provide shade, cool urban heat islands, reduce interior energy use and related costs, provide habitat for pollinators and wildlife, and beautify our communities. They also help clean our environment by absorbing carbon dioxide emitted by vehicles and other producers of fossil fuels.
Taking care of our urban trees is an important way to maximize these benefits. Unfortunately, their average lifespan in our cities is less than 1/4 of their potential due to poor selection and care. You can help enact change and increase the health, longevity and canopy coverage of our urban forests by encouraging your city leaders, local non-profit organizations interested in ‘green cities' arborists, landscape architects, nursery growers, HOAs, and concerned citizens to register for our free ‘Trees for Tomorrow Start Today' workshop (via Zoom) on Tuesday, March 9, 2021 (8:15am – 3pm).
Please reach out to your city leaders and local ‘green industry' professionals to encourage their attendance and participation. While the workshop is free, registration is required through this secure link: http://ucanr.edu/u.cfm?id=264
A bevy of speakers including certified arborists, horticulturists, planners, water district personnel and other non-profit and green industry representatives will discuss the benefits of urban trees; recommended practices for their selection and care; how to avoid hazardous trees that damage property and structures; and share success stories resulting from partnerships through cities, non-profit organizations, the green industry, HOAs, and street tree committees.
A highlight of the workshop will be the opportunity for attendees to participate in breakout sessions that cut across professions and interest groups (city planners, community service directors, arborists, landscape architects, landscapers, water district managers, HOA managers, golf course superintendents, nursery growers, UC master gardeners, concerned citizens, etc.) to enact positive change regarding tree selection and care.
Thank you for sharing this opportunity to help ensure a healthy future for our children's children with your city leaders and decision-makers.
In the meantime, here are some tree care tips to ‘start the conversation' between now and the workshop:
• Select trees that perform well in your climate. The Sunset Western Climate Zone maps are more precise than USDA zones for our warmer climates. Trees should also be selected based on their adaptation to the ‘micro-climate' in each particular landscape, as well (shade, proximity to buildings, space needs below as well as above ground, soil type, water source, etc.)
• Plant trees the same depth they were in their container in holes at least 2-1/2 times wider. Do not add compost or organic matter to the hole. This practice can result in circled roots that never grow laterally out of the confines of the dug hole.
• Remove any tree ties that are cutting into the trunk or branches of your trees. If trees must be staked due to windy conditions, make sure that the ties are loose enough to allow trees to gently flex in the wind. This helps trees develop the necessary lower trunk strength and stability to support the tree as it matures. Over time, you may be able to completely remove the ties and stakes once the lower trunk becomes stronger and self-supporting.
• Keep all plants and mulch several inches away from tree trunks.
• Keep tree trunks dry. They should not come into contact with water from sprinklers or hoses.
• Regularly water newly planted trees but water mature trees infrequently and deeply. Watering too often reduces the level of oxygen in the rootzone and can lead to waterlogged soils prone to crown and root rots. During fall, trees require only about 15% of the water they require in the summer.
• Prune trees only as needed and avoid topping them. Invest in the services of a credentialed and knowledgeable professional to correctly care for your valued trees. Find a list of International Society of Arboriculture Certified Arborists in your area here: https://www.treesaregood.org/findanarborist.
- Author: Cheryl A. Wilen
Nurseries and garden centers often sell a wide range of plants for use in gardens and landscapes. As a consumer, you may manage a complex array of different landscape plantings, including woody trees and shrubs, woody ground cover beds, annual flower beds, herbaceous perennial beds, and mixed plantings. This complexity often makes weed management difficult. An integrated approach is the most economical and efficient way to control weeds, so knowing strategies for managing weeds in a variety of landscapes can help.
Woody Trees and Shrub Beds
Control perennial weeds before planting, although weed control can also be done after planting. Densely planted areas will reduce weeds. Geotextile (landscape) fabrics rather than black plastic used with a shallow layer of mulch will keep weeds from emerging. If you mulch without a geotextile base, the mulch layer must be thicker to prevent weed emergence.
If needed, you can use a preemergence herbicide to control annual weeds and supplement with hand weeding and spot applications of postemergence herbicides for weeds that are not well-controlled by hand weeding, such as perennial grasses.
Woody Ground Cover Beds
Mature, woody ground cover beds should exclude most weeds; however, when ground cover is just establishing, weed growth is likely. Perennial weeds must be controlled before planting, although perennial grasses may be selectively controlled after planting with a grass-selective herbicide like sethoxydim (Grass-Getter). Annual weeds may be controlled with mulch plus a preemergence herbicide but rooting of stolons in new plantings may be affected. You will need to supplement with some hand weeding.
Annual Flower Beds
A dense planting in annual flower beds will help shade out and compete with many weeds. Flower species should be carefully selected for weed management compatibility. Periodic cultivation at 3- to 4-week intervals and between flower beds plant rotations will also suppress weeds. Perennial weeds must be controlled before planting. Annual weeds can be controlled with mulches, preemergence herbicides, frequent cultivation, and/or hand weeding. Control perennial grasses with grass-selective herbicides like clethodim, sethoxydim, or fluazifop. Avoid nonselective herbicides in annual flower beds after planting.
Herbaceous Perennial Beds
Weed management options in herbaceous perennial beds are similar to those for annual flowers, except that it is more important to eradicate perennial weeds as there will be no opportunity to cultivate or renovate the bed for several years; and fewer species are included on herbicide labels. Geotextiles may be used in these types of plantings. Manage weeds with mulches and supplement with hand weeding. If needed, use preemergence herbicides after hand weeding.
Mixed Plantings of Woody and Herbaceous Plants
Weed management in mixed plantings is complex because of the diversity of species. Different areas of the bed could receive different weed treatments. Site preparation is critical because post-plant herbicide choices are few. Plant the woody species first and control perennial weeds in the first two growing seasons, then introduce the herbaceous species. Plant close together to shade the soil. Group plants within the bed that will receive similar weed management programs.
In most landscape situations, herbicides should not normally be needed by home gardeners. Mulching, removal by hand, and proper irrigation (pattern and amount of water) are sufficient in most cases. Find more information in the UC IPM Pest Notes: Weed Management in Landscapes.
[Originally published as "Managing Weeds in Landscapes" published in the Fall 2018 issue of the Retail Nursery and Garden Center IPM News.]
/h2>/h2>/h2>/h2>/h2>In mid-March, many people use clover-themed decorations in preparation for St. Patrick's Day. Many gardens and landscaped areas are “decorated” with clovers too, especially with recent rains and mild temperatures in much of California. For some people, clovers are considered weeds, but others enjoy the green color they bring!
Clovers begin to germinate in the fall and continue throughout winter and early spring. Their bright green leaves can blemish the look of lawns and may be unsightly when found in ornamental plantings.
Clovers growing in lawns or landscapes are often a sign of low soil nitrogen, so changing fertilization can help prevent their growth. Read the UC IPM publication Pest Notes: Clovers for much more information about identifying clovers and how to manage them.