Posts Tagged: low
UC climate-ready landscape trials identify low-water yet attractive plants
Good news: roses can be a part of your water-efficient landscape. Lorence Oki, UC Cooperative Extension environmental horticulture specialist in the UC Davis Department of Plant Sciences, identified rose cultivars that remain aesthetically pleasing with little water.
Oki is the principal investigator of the Climate-Ready Landscape Plants project, which may be the largest irrigation trial in the western U.S., and the UC Plant Landscape Irrigation Trials (UCLPIT), the California component of that project. These projects evaluate landscape plants under varying irrigation levels to determine their optimal performance in regions requiring supplemental summer water.
“There are some assumptions that pretty plants use a lot of water, like roses,” Oki said. “Everyone thinks they need a lot of water, but we've found some that don't, and they still look great. A water-efficient landscape doesn't need to look like a Central Valley oak-grassland in the summer. It can look really attractive.”
In 2021, Oki's team at UC Davis identified Lomandra confertifolia ssp. pallida "Pom Pom" Shorty and Rosa "Sprogreatpink" Brick House® Pink as two of the best low-water plants in the trial.
“The useful tip or information that is shared at the end of each trial is the selection and designation of plants as Blue Ribbon winners. These are the plants that looked good with an overall rating of 4 or higher throughout and were on the low (20%) water treatment,” said Natalie Levy, associate specialist for water resources, who manages the project at the UC ANR South Coast Research and Extension Center.
How plants earn a blue ribbon
Each trial year, the selection of new plants is based on research recommendations and donated submissions from the nursery industry. The landscape plants are trialed in full sun or 50% shade cover.
Irrigation treatments are based on the rate of evaporation and plant transpiration (evapotranspiration) measured through a local California Irrigation Management Information System (CIMIS) weather station that provides a reference evapotranspiration (ETo) rate.
Three levels of irrigation are provided to the plants equal to 20%, 50%, and 80% of ETo. The volume of water applied is the same at each irrigation based on soil characteristics, but the interval between applications varies with weather and the treatment. Using this method, irrigations for the 20% treatment are less frequent than the 80% treatment.
“The 20% treatment during the 2022 trial was irrigated an average of once per month while the 80% treatment was irrigated weekly,” explained Levy.
During the deficit irrigation trial, monthly height and width measurements are taken to determine the plant growth index. Monthly qualitative aesthetic ratings on a scale of 1 to 5 are determined for foliage appearance, flowering abundance, pest tolerance, disease resistance, vigor and overall appearance.
A second round of flowering abundance and overall appearance measurements are also taken to capture more of the blooming period. For example, UCLPIT identified in the 2020 trial at South Coast REC that the "Apricot Drift" rose had a mean overall appearance score of 3.5 out of 5, deeming it “acceptable to very nice” and a low water use plant within the Water Use Classification of Landscape Species or WUCOLS guide.
Project expands options for landscape planting
“(WUCOLS) only has 3,500 plants in it. There are guesses that there are close to 10,000 cultivars in urban landscapes in California, if not more,” said Oki. “WUCOLS also didn't have numerical ratings. Instead, you'll see verbal ratings like ‘low water use' or ‘high water use.'”
The UCLPIT project has not only developed numerical recommendations for irrigation, but it has also added new landscape plants that are compliant with California's Model Water Efficient Landscape Ordinance. In fact, UCLPIT's data is one of the few sources that can be used to supplement WUCOLS.
Geographic diversity of trial sites adds to knowledge base
In addition to UC Davis and South Coast REC in Irvine, the trials have expanded beyond California as the Climate-Ready Landscape Plants project and is in progress at Oregon State University, University of Washington, University of Arizona and Utah State University thanks to a USDA/CDFA grant awarded in 2020.
Lloyd Nackley, associate professor of nursery production and greenhouse management at Oregon State University, is the principal investigator of the trial in the Portland metro area, which is entering its third year.
“People know that there are drought tolerant plants, but there are many. We're trying to highlight lesser known or newer varieties. And even though the trial is three years, most gardeners would hope that their garden lasts longer than that,” said Nackley.
One of the observations that Nackley recalls is of the Hibiscus Purple Pillar plant. Unlike the trial at South Coast, the Purple Pillar did not perform well in Oregon in the spring.
“It wasn't until August that we saw the plant bloom and begin to look like what we saw from South Coast in April,” Nackley said.
Ursula Schuch, horticulture professor and principal investigator of the trial taking place at the University of Arizona, was also surprised at the range of performance among different plant types and the effects of irrigation, heat and temperature.
“This research will reassure green industry professionals that they can stretch their water budget to successfully cultivate more plants, watering them according to their needs instead of irrigating every plant according to the highest water-using plants,” said Schuch.
Although research is only conducted in the West, the hope is that there will be trials in other regions of U.S.
Doing so would yield comprehensive information about the plants and their performance in different climates. As extreme weather events persist in the U.S., disease pressure and risks do too. Trials throughout the country would provide location-specific data regarding disease susceptibility.
To learn more about the UCLPIT research project, visit https://ucanr.edu/sites/UCLPIT//h3>/h3>/h3>/h3>
Bees and other pollinators may have a tough time during the fourth year of California's severe drought, as they search for nectar and pollen. Expect...
A honey bee foraging on anemone. (Photo by Kathy Keatley Garvey)
A cuckoo bee foraging on a gum plant. This insect is Triepeolus (maybe Epeolus), says native pollinator specialist Robbin Thorp, distingished emeritus professor of entomology at UC Davis. The little bug on the right appears to be a lygaeid bug nymph, according to Lynn Kimsey, director of the Bohart Museum of Entomology and professor of entomology at UC Davis. (Photo by Kathy Keatley Garvey)
The Mexican sunflower (Tithonia) is a drought-tolerant annual. (Photo by Kathy Keatley Garvey)
An inner-city Los Angeles school has a small vegetable garden that is overseen by a University of California Cooperative Extension Master Gardener, according to a story published yesterday in the Daily Breeze.
"This may be the only place they can have access to nature," the story quoted Master Gardener Kris Lauritson. "It's an outdoor classroom."
The school serves primarily Latino students; about 80 percent qualify for free and reduced lunches.
The program teaches students about healthy diets and gives them a chance to taste fresh foods they may not normally have at home. Students eat what they grow - turnips and broccoli, lettuce and spinach, soybeans, potatoes and cabbage.
Alice Acevedo, a school office worker observing the students as they worked in the garden, told reporter Douglas Morino the kids won't touch fresh fruits and vegetables put out in the cafeteria at lunch.
"But once they grow it themselves, they can't get enough. They're taking pride in what they're doing," Acevedo was quoted.
Los Angeles County's 181 Master Gardeners volunteered 9,272 hours in 2008, serving 87,376 low-income gardeners at 28 community gardens, 46 school gardens, 15 shelter gardens, 5 senior gardens and 13 fairs and farmers markets. For more information on the program and its services, see the LA Common Ground Web site.
It's worth clicking through to the Daily Breeze to see the photographs that accompany the school garden story. The off-axis, vivid and creative images are uncommon in photojournalism. I asked ANR Communications Services media services manager Mike Poe about the trendy garden art.
He said a lot of hip, cool, current video is shot that way.
"The photos are emulating that style to appeal to a young audience or indicate the subject is young," Poe said. "It's a technique I'd use very judiciously."
The school garden story and photos also appeared in the Pasadena Star-News.
LA's 2008 Master Gardener graduates.
The prime reason: low-income areas aren't served by large supermarkets, forcing people with limited transportation to purchase staples like bread and milk at corner markets and convenience stores.
The first expert cited in the lengthy piece was UC Cooperative Extension nutrition, family and consumer sciences advisor Connie Schneider.
She said poor people know they are paying exorbitant prices for food at small stores, but the next opportunity to shop at a supermarket could be weeks away.
"When you're hungry, you're looking at something to fill a stomach," Schneider was quoted.
Fresno Bee writers Barbara Anderson and Bethany Clough delineated the fallout from inadequate access to healthy food:
- The risk of obesity and chronic illnesses, such as diabetes and high blood pressure, increases, straining health-care resources
- Children without proper nutrition become sicker, stay sick longer and miss more days of school
- Lower academic performance leads to higher dropout rates and to more adults without the skills necessary to secure well-paying jobs
The story seems to have struck a cord with area readers. As of Monday morning, 25 comments had been posted, many of them expressing frustration at being faced with a problem that has no easy solution.
Wrote one: "Maybe the two writers of this article could open a grocery store in a poor neighborhood. They could then sell healthy food for a loss instead of implying that the major chains are somehow at fault for not doing so. Contrary to what the writers seem to think, grocery stores are not charities. The stores actually have to show a profit to stay in business."