University of California Cooperative Extension Drought Resources To Keep Your Plants Alive

"Trees Come First Under Drought and Water Restrictions"

Keeping Plants Alive Under Drought and Water Restrictions (English) https://anrcatalog.ucanr.edu/pdf/8553.pdf

Keeping Plants Alive Under Drought and Water Restrictions (Spanish) https://anrcatalog.ucanr.edu/pdf/8628.pdf

Prioritizing Trees During Drought and Water Restrictions (5 minute Youtube) 

https://www.youtube.com/watch?v=CTKLlJgdLVk

Tips to Keep Your Landscape Trees Alive Under Drought https://ucanr.edu/b/~IjC

Landscape Tree Irrigation to Maximize Tree Health, Benefits, and Beauty https://ucanr.edu/b/~YjA

Landscape Tree Irrigation 101 https://ucanr.edu/b/~UjA

Top 10 Ways to Conserve Water in Your Landscape and Garden https://ucanr.edu/b/~tTD

Asphalt and Synthetic Turf are Superheating our Cities (in Desert Sun newspaper) https://www.desertsun.com/story/opinion/contributors/valley-voice/2022/04/09/coachella-valleys-asphalt-synthetic-lawn-heat-islands-reach-170/9515857002/

Use of Graywater in Urban Landscapes in California https://anrcatalog.ucanr.edu/pdf/8536.pdf

Need More Help?  Speak to a UC Cooperative Extension Master Gardener in Your County of Residence. 

Find email and phone helplines here: Find a UC Master Gardener Program - UC Master Gardener Program (ucanr.edu)

o you ever wonder if plants “communicate” with each other? If so, you're not alone. The research on this important and fascinating topic has increased dramatically in the last decade. My interest in it dates back decades to my graduate school thesis that involved how phenolic acids exuded by the roots of garden pea (Pisum sativum) accessions from around the world warded off weeds that would otherwise have crowded them out. This was an early form of biological weed control for sure! The seeds we studied were 20-30 years old and had been carefully stored and preserved in USDA facilities for research such as this.

 

They were all non-hybrids that had unadulterated natural genetic qualities. While I am in no way suggesting that plant breeding isn't overall a positive advancement, there are instances where something is lost when something is gained, and genes are certainly no exception! Sometimes breeding for an improvement in one facet (production per acre, nutrition, etc.) results in the loss of another genetically controlled factors that may be negative or positive.

At about the same time I was pursuing my research described above at University of Minnesota, University of Washington zoologist David Rhoades demonstrated how some plants defend themselves against insect attacks by changing the nutritional and/or taste of their foliage. In turn, insects that otherwise would chow down on the tasty leaves look elsewhere for their lunch. Since then, research identifying the multiple paths that plants use to exchange information with neighboring plants (largely within their own species) and ward off herbivores (organisms feeding mostly on plants), diseases, and weeds has nearly tripled. While a lot of this chemical information exchange relates to the release of volatile organic compounds in the root zone and through the air, electrical signaling among plants also occurs.

Below are a few recent examples:

-Lima beans attacked by insects signaled nearby lima bean plants who built up defenses to avoid damage

-Lodgepole pines attacked by a beetle signaled neighboring trees who had time to prepare for attack. 

While, traditionally, research identified these chemical warnings occurring only in neighboring plants of the same species, Cornell researchers discovered that  sagebrush (Artemisia tridentata)with insect damage can release chemical signals recognized by wild tobacco (Nicotiana attenuata). In turn, the tobacco plants pump up their arsenal of chemical defenses to avoid damage. (Interestingly, the tobacco plants don't waste precious nitrogen and carbon on defense mechanisms until they are actually attacked since these elements need to be conserved as much as possible for future seed production.)

Ted Farmer's team at University of Lausanne, attached leaves of thale cress (Arabidopsis thaliana) with microelectrodes prior to infesting them with Egyptian cotton leafworms. Almost immediately, voltage changes radiated outward from the damaged leaf tissue in the damaged plant and other neighboring plants resulting in accumulation of jasmonic acid which reduced further damage. Genes responsible for transmitting the electrical signal create membrane channels inside cell walls that provide a conduit for charged ions. The genes in some ways parallel receptors that animals rely on to relay sensory signals through their bodies.

And last but certainly not least, Kudos to UC Davis ecologist/entomologist Richard “Rick” Karban, who was named a fellow of the Ecological Society of America (ESA) for “his innovative contributions to community and evolutionary ecology, especially through providing conceptual advances and rigorous experimental work on plant-insect interactions." Want to learn a log more about this topic."  Still "hungry" for more information on this topic?   You're in luck! Dr. Karban wrote a 240-page book entitled: Plant Sensing and Communication (University of Chicago Press).

 

 

It's only right that our University of California Cooperative Extension (UCCE) San Bernardino County Master Gardener ‘Trees for Tomorrow' team of volunteers are our featured ‘Spotlight' Master Gardeners for September, 2021. They provided vital education to Redlands residents receiving gratis trees through a multi-partnership grant obtained by Inland Empire Resource Conservation District Manager Mandy Parkes. 

It's an honor and privilege to recognize UCCE San Bernardino County Master Gardener Project Leader Debbie LeDoux and her dedicated team of 'Trees for Tomorrow' volunteers: Zhibo (Sandy) Anderson; Consuelo (Connie) Davis (pictured); Pam O'Connell; Gail Sefl; and Husam Yousef. These dedicated Master Gardeners were tasked with helping residents select, plant and care for drought, heat, and pest tolerant trees. (Species including Chilopsis linearis 'Bubba', and Pistacia x 'Red Push' were selected due to their excellent performance in our University of California/United States Forest Service research project as 'climate-ready' trees able to withstand harsh conditions related to our changing climate.) Working with a team of California Climate Action Corps volunteers, civic leaders, Common Vision Coalition, and other groups, nearly 100 trees were planted in yards and parks lacking the preferred 25% tree canopy cover.

Trees can cool urban heat islands by 50 degrees Fahrenheit or more during spring and summer, creating welcome oases in hot inland communities. With spring 2021 temperatures so high they broke previous records on multiple dates, the project is especially timely and necessary.

In addition to proper tree selection, trees require the right long-term care. Master Gardeners will continue to provide advice on irrigation, pruning, fertilizing and pest control to residents receiving trees long after the trees are planted. This is critical since an average urban tree lives less than 20% of its potential lifespan due largely to poor care. The long-term engagement of Master Gardeners with residents is as important as is selecting the right species.

UCCE Master Gardeners are all volunteers, giving of their time and talents to enhance the quality of life for individuals and families who call San Bernardino County their home. Each Master Gardener is required to complete a rigorous 18-week training class complete with exams, class projects, and lots of participation! Due to COVID-19, volunteers had to master key horticultural concepts during the first ever all on-line training class. Only recently have they been able to meet fellow Master Gardener graduates and, in some cases, the Redlands residents they mentored through the tree canopy enhancement project. They truly exemplify community spirit and all it takes to successfully work together under adverse conditions. Kudos to each and every one of you from Master Gardener Coordinator Maggie O'Neil and myself! You are creating a cooler, greener and healthier environment for our children's children.  

 

I asked the honored Master Gardeners their thoughts on the project. Here's what they had to say:

“The Redlands tree canopy project was the best volunteer project ever. In the midst of Covid-19, horrific politics and way too many good byes, it was a truly joyous experience. The legacy of being a part of the group that promoted healthy sustainable trees, knowledge of how to plant and care for them, tips on maintaining their health and beauty was the absolute best. For me as a Master Gardener, it was so much fun. I loved the site walks and getting to help our participants select the perfect sustainable trees for their properties. What started as a one-on-one visit often expanded to an enlarged group of neighbors and extended family. I got to give out many handouts and publications and promote our excellent Master Gardener program. I got to share our helpline email and phone numbers. I love the fact that I have been asked to revisit sites to see how great they are doing (once to make sure the tree did not look funny!). I receive emails every now and then asking me questions and showing me pictures of "Our Trees.” So much fun, Janet. Thank you. By far the coolest project ever! Pam O'Connell

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There are a few things that really made an impact on me.

 

1) It was rewarding to attend the Zoom presentation you developed that provided education to various professionals on the importance of planting sustainable trees. I found it to be open and inclusive allowing for good interchange of ideas and concerns. 

2) There are many beautiful trees that are sustainable.

3) Reaching out to the community to offer beautiful, sustainable trees was a worthwhile way to show how various organizations can work together to benefit the community while trying to improve our environment.

4) When dealing with homeowners that belong to an HOA, additional time and communication may be needed to assist them in obtaining approval for trees from their HOA's. Connie Davis

 

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"I see tree planting efforts similar to what a trend of the future is to combat climate change and increase awareness of the importance of trees and tree canopies in our neighborhoods. Not only that but I see this project expanded to other cities in the county of San Bernardino. The continuity of this project is so valuable so that we can see the positive impact on the environment and the well-being of San Bernardino residents in the coming decades. I see this important work being organized and well-coordinated by involving the appropriate stakeholders at all stages of the planning project. It is about time to give back what we have taken for tens of years!" Husam Yousef 

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It was rewarding to see local homeowners excited about planting trees and grateful for the program providing them. Gail Sefl

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THANK YOU ALL!   Janet Hartin and Maggie O'Neill

an plants help cool our urban heat islands and mitigate impacts of climate change in our inland cities? I've been interested in measuring the temperatures of living and non-living surfaces for some time. Preliminary results are in! Use of dark asphalt, synthetic turf,

and dark colored mulches are superheating our inland and desert cities. The hottest material of the three is synthetic turf which reached over 165 degrees F in Palm Springs and 159 degrees F in Redlands on days when the  air temperatures were, respectively, 113 and 108 degrees F this summer. On five separate days in July, seconds after I took a quick photo above the artificial turf, my I-phone shut down, leaving me with the ominous heat warning message shown here (lower right).

What can you do?

Take care of your trees, shrubs, groundcovers, and lawns to maximize their ability to cool the surrounding environment. In the same experiment described above, the coolest temperatures occurred in lawns growing in the shade of a mature tree. This is due to living plants cooling the environment during the process of transpiration. Non-living surfaces don't provide this natural air-conditioning. While many people believe lawns waste water, it's important to fully consider the alternative of replacing a water-efficient warm-season lawn like Bermuda or Buffalograss with either dark mulch or no living plants at all.  The lawns are much cooler! Our previous UC studies determined that it's often not the lawns (and other sprinkler-irrigated plants like groundcovers) that waste the water, it's the uneven coverage (low distribution uniformity) of most sprinkler systems, coupled with not applying the right amount of water seasonally. 

However, If you're tired of your high maintenance lawn and want to ditch your lawnmower, fertilizers, and pesticides, consider a low-maintenance drought-resistant groundcover that has similar cooling effects without the need for chemical inputs.

Plant drought-tolerant groundcovers

Here are just a few examples: 

Peruvian Verbena (Verbena peruviana). This groundcover grows to only 1" tall  and sports dark green leaves and white to pinkish (several hybrids available) blossoms that bloom from spring through fall. It spreads quickly and requires little water once established.

Dwarf Rosemary (Rosmarinus prostratus) This particular rosemary species is a low-growing groundcover.  It is a great choice for rock gardens, reaching only 6 inches tall. It produces purple flowers in the summer and attracts pollinators and can be used for culinary purposes (bottom). 

Gold Dalea (Dalea capitata). This semi-deciduous evergreen grows between 8" to 1' tall and has small yellow flowers that bloom in spring and fall and a pleasant scent. It is very heat tolerant and great for urban heat islands (parking lots, etc.) as well as planters and paths (lower right).

For more information on trees, groundcovers, shrubs, and vines suitable for your own home, contact a UC Cooperative Extension Master Gardener volunteer in your county using this link: https://mg.ucanr.edu/FindUs/