This article, written by Katie F. Hetrick, UC Davis Arboretum and Public Garden director of marketing and communications, appeared on the front page The Davis Enterprise on October 24, 2014.
According to a California Department of Water Resources study, about 53 percent of our household water use goes toward irrigating our landscapes.
So, when it comes to saving water, cutting back in our outdoor spaces is an obvious first step toward conservation. But just how much water can we cut back without turning our yards into a Western movie set complete with tumbleweeds?
That’s the same question asked by University of California Agriculture and Natural Resources Cooperative Extension researchers Loren Oki and Karrie Reid.
Since 2004, they have been testing a variety of plants at the UC Davis Plant Science field research station on south campus. Behind a locked gate, a short gravel driveway away from Old Davis Road, lies an acre exposed to full sun as well as a half-acre exposed to 50 percent shade, where they test plants’ ability to thrive with different levels of water.
“We study these plants for two years at a time,” explains Reid, UC Cooperative Extension adviser for California’s Central Valley region. “The first year, we water them about once a week to get them established. A healthy root system is the key component of long-term drought-tolerance. Just because you buy a low-water plant, doesn’t mean it doesn’t need water when it’s young.
“The second year it’s trial by fire,” Reid says. “This time we study how multiples of the same plant respond to a variety of water deficit scenarios.”
From May to November — a normal growing season for this area — they supplied the subject plants with varying levels of water: high (once every 13 to 18 days); medium (once every 16 to 23 days); low (once every 26 to 34 days); and very low (once approximately every 58 days, or twice during the growing season).
“We want to be able to provide consumers with a source of beautiful landscape materials that will flourish in a wide variety of California climate zones with little input of water or chemicals,” says Loren Oki, UC Cooperative Extension specialist in landscape horticulture with the UCD department of plant sciences.
“A corollary goal is to provide the nursery industry with a source of new and interesting, economically advantageous and environmentally sound plant revenue.”
Like most businesses that rely on consumer demand, the horticulture industry thrives on a constant influx of new and beautiful plants to tantalize its customers year to year, and, despite growing demand for low-input plants — meaning plants that are drought-tolerant, have few pest problems and do not require fertilizers to keep them looking their best — they have been slow in coming to the mainstream nursery market.
That’s where studies from researchers Oki and Reid help to fill in the blanks.
Their research project started in 2004 with UCD’s Arboretum All-Stars, plants that thrive in their Central Valley location under a low-water watering regimen (generally twice a month), looking good at least three seasons a year, resisting pests and diseases, and attracting beneficial wildlife such as bees, insects and birds.
“We loved the list, but because we wanted to also be able to recommend these plants to the nursery industry for propagation,,” Oki says. “We not only wanted scientific data to back up our low-water claims, we also wanted to be able to provide growers with standard protocols for what it takes to propagate these types of plants successfully.”
Adds Reid, “Our research is not just about our particular planting zone either. When we find a plant that performs, we test it out in up to nine different climate zones throughout the state. That’s where our incredible Master Gardener program comes into play.
“They will take our star performing plants and conduct further assessments in demonstration gardens throughout California, and then we incorporate their feedback and scores into our final reports.”
UCD recently completed a study on kurapia, a newly developed, highly versatile groundcover that was developed and now is widely used in Japan. It is available for the first time to the public at the Arboretum and Public Garden plant sale on Saturday.
“Kurapia is a great option where you need a groundcover that won’t get irrigated. I think it will be great in what they call ‘hell strips,’ ” Reid says. “That’s the area between the sidewalk and the street where it’s notoriously difficult to grow anything. Kurapia will do just fine there! Homeowners may want to consider using it as a lawn replacement, too. We’ve found that it looks good year-round.
“Really the public wants it all,” she continues. “Whether you are a homeowner or a large-scale landscaper, we want beautiful and low-water. So we don’t solely look at water use. We want to also know how irrigation and its frequency correlate to attractiveness, seasonal interest and blooms. We report on that, too.”
The researchers’ full reports can be found on the California Center for Urban Horticulture’s website, ccuh.ucdavis.edu.
GARBAGE NEEDED! On Sunday, November 16 from 1-3 p.m. the UC Davis Arboretum and Public Garden is hosting our first ever Go Green Drop-In Day at the trellis in the Arboretum GATEway Garden behind the Davis Commons Shopping Center.
A portion of the event will include all-ages, hands-on crafts demonstrating creative re-use projects for everyday garbage and recyclables, but we need your help gathering supplies! Please bring your used wine corks, paperboard egg cartons, toilet paper and paper towel tubes, soup/bean cans, aluminum punch tabs from soda cans, glass pasta sauce jars/mason jars, and bottle caps to the Arboretum Headquarters this week and next! There will be a bin outside our front door where you can drop them off. They will be put to good reuse!
On September 18, 2014 we hosted a 1-day “Convert Your Water-Hungry Lawn to a Drought-tolerant Landscape” workshop sponsored by the California Native Grassland Association. Participants received in-depth information for converting high-water-use conventional lawns into beautiful low-water-use, attractive, native, and climate-appropriate landscapes.
A portion of the day included a walking tour of a few campus and Arboretum locations where lots of California native grasses and other plants have been incorporated in the landscapes.
DOWNLOAD the TOUR. It includes a selection of the drought-tolerant plants located in each of the areas.
Construction has begun on the first part of a multi-year plan to improve access and create campus- and visitor-friendly features at the west end of the Arboretum. The area is part of an exciting initiative zone that contains several large, campus-funded projects. Our team has been working with campus project managers and departments to coordinate and leverage these projects to enhance the visitor experience in the Arboretum.
Crews have already broken ground on the first project, which is to reroute Garrod Drive further to the north and expand the Putah Creek Lodge parking lot to the west to meet the new road, improving access to the Teaching Nursery. The road realignment will make space for a new Veterinary Medicine Students Services and Administration Center and events lawn, which will be built within a few years. In addition, we are thrilled that the plans call for a dining pavilion that will be accessible to our visitors. We are working closely with School of Veterinary Medicine faculty and staff to develop ideas for the new landscape exhibits that will be developed.
There are many sustainability features being built into the new landscapes and projects. The parking lot will feature trees specifically chosen for their ability to tolerate tough, urban conditions, a bioswale will filter water that runs off from the parking lot, and a California native plant meadow will collect excess water from the entire site while creating wildlife habitat.
On Saturday, October 18, 2014 the UC Davis Arboretum Ambassadors, Bohart Museum of Entomology interns, UC Davis Entomology Club students, students from UC Davis Wild Campus, and Department of Entomology Professor Robbin Thorpe joined forces to facilitate our first annual Nature Discovery Day–an outstanding public program for all ages!
About 50 visitors learned how to capture and identify insects, discovered the hidden world of plant galls, held live walking sticks and Madagascan cockroaches from the Bohart Museum, and indulged in a variety of different arts and crafts including creating pine cone bird feeders and seed bombs!