- Author: Cynthia Nations
- Editor: Maggie Mah
Last winter's storms were unprecedented. The volume and intensity of rainfall turned creeks and streams into rushing torrents that overflowed their banks and flooded nearby areas. Gutters and drains couldn't handle the flow and turned streets into virtual canals. We now know that, with climate change, weather patterns are becoming more extreme and we can expect more of this in the future. How can we prepare for and mitigate these episodes of torrential rainfall? Can it be done sustainably and in ways that are beneficial? The answer is “yes,” and the basic idea is thousands of years old. UC SMSF Master Gardeners teamed up with the Half Moon Bay Public Works staff recently to work on one type of solution. Located in front of the Half Moon Bay Library is something called a “green stormwater infrastructure” (GSI). What is a GSI, what is its history, and how do these techniques help in today's urban settings?
Throughout our history, humans have devised a variety of ways to deal with the problem of too much surface water. In Mesopotamia and ancient Egypt, irrigation canals were built with areas of vegetation incorporated into the design. This slowed the water's velocity, allowed it to percolate and prevented the precious, fertile topsoil from being swept away. As time went on, the Romans built aqueducts to direct water flow and constructed roads with permeable surfaces that allowed rainfall to be absorbed.
In the 19th and 20th centuries, the rapid growth of urban areas created more paved surfaces and consequently, fewer permeable areas. Yet another consequence of pavement is that there is less vegetative growth, thereby decreasing evapotranspiration, a process in which plants absorb water through their roots and release it back into the atmosphere. The solution to the problem was to construct vast centralized drainage systems, “gray infrastructure,” to collect both wastewater (sewage) and stormwater to funnel it away from homes, businesses and roadways. Unfortunately, urban stormwater runoff is polluted with trash, bacteria, heavy metals, pesticides and more. In some areas, the water is channeled to treatment plants but in others, it flows directly into rivers, lakes, bays, and oceans. In addition to being a major source of water pollution, these systems are aging and are less able to handle large volumes of water.
In the latter part of the 20th century, due to increased environmental awareness, cities began to explore alternative ways to manage stormwater that included the installation of “green infrastructure systems” as part of the concept of Low Impact Development (LID). Simply put, “green infrastructure systems” utilize plants, soil systems and permeable surfaces to filter and absorb stormwater on site instead of channeling it, along with whatever it picks up along the way, to unknown destinations. LID practices led to improved water quality, the creation of more green spaces in urban settings, and reduction of stormwater flooding.
The San Mateo County-wide Water Pollution Prevention Program was formed in 1990 to reduce the pollution carried by stormwater into local creeks, the San Francisco Bay, and the Pacific Ocean. Flows to Bay is the public outreach arm of this program and endeavors to protect our waterways, the Bay, and the ocean, and to create safer communities and minimize the impacts of heavy storms and climate change. In urban development, GSI is used to balance existing infrastructure and minimize the detrimental effects on the natural system. Impervious surfaces, like roads and parking lots, provide opportunities for managing rainwater.
--Bioswales: strategically located channels or ditches planted with hardy, low maintenance vegetation.
Bioswales are designed to capture stormwater runoff and slow it down. As the water percolates and is taken
up by the plants, sediment and pollutants are filtered out.
--Permeable pavements: firm surfaces that allow water to percolate down instead of sheeting off. Materials
include pervious concrete, porous asphalt and interlocking permeable pavers
--Rain gardens: shallow depressions planted with native vegetation that are designed to collect and absorb
stormwater runoff and act as natural filtration systems that remove pollutants.
--Green roofs: living vegetation on building rooftops that retain rainwater and reduce stormwater runoff. The
insulation improves energy efficiency and promotes biodiversity in urban areas.
--Rainwater harvesting: collecting and storing run-off from rooftops and other impervious surfaces to use for
non-potable applications such as landscape irrigation.
--Tree planting: landscape trees in urban areas help by intercepting rainfall and reducing runoff as well as
filtering pollutants and providing many environmental and social benefits.
--Constructed Wetland Systems: areas designed to mimic natural wetlands for the removal of pollutants and
to improve water quality through biological and physical processes. These areas also provide habitat for
-Parks and green spaces: integrating these areas into urban landscapes allows for increased infiltration of
stormwater provides recreational areas for the community and reduces the impact of urban heat islands.
Green stormwater infrastructures are located throughout San Mateo, and there is a comprehensive Green Infrastructure plan to guide the siting, implementation, tracking, and reporting of GI projects over the next several decades. Currently, a trained cohort of UC Master Gardeners collect data at two GSI (Bioswales) coastside locations. One is in front of the Half Moon Bay library located at 620 Correas Street, HMB, CA 94019 and one is located in Pacifica in front of Cabrillo Middle School at 601 Crespi Drive, Pacifica, CA 94044. UC Master Gardeners record and measure plant vigor and growth, soil conditions, and specific functional elements in these two bioswales while the HMB Public Works staff maintains the bioswales. More information on GSI is found in the resources below.
--Bioswale Education and Stewardship Training (BEaST): https://smsf-mastergardeners.ucanr.edu/projects/bioswale-education-stewardship-training/
--City of San Mateo Green Infrastructure Plan: https://www.cityofsanmateo.org/4134/Green-Infrastructure
--Flows to Bay Studies and Research Link: https://www.flowstobay.org/data-resources/reports/studies-research/
Cynthia Nations is a UC Master Gardener interested in all aspects of Green Stormwater Infrastructures. The article was edited by UC Master Gardener Maggie Mah.
For more news and information about UC SM-SF Master Gardeners visit our website: https://ucanr.edu/sites/MGsSMSF/
- Author: Barbara Williams-Sheng
- Editor: Cynthia Nations
- Editor: Maggie Mah
“I think that I shall never see/ A poem as lovely as a tree,” wrote the poet, Joyce Kilmer. The mere sight of a strong, graceful tree inspires poetry, offers peace for the soul, and provides welcome sanctuary. And now, in the face of rapid environmental change due to global warming, trees are more important than ever. In fact, planting trees is something we can do to help mitigate the degradation caused by climate change.
Through the process of photosynthesis, trees take in carbon dioxide from the atmosphere, sequestering excess carbon in the soil and returning oxygen back into the air for all living beings to breathe. Unfortunately, one of the things commonly done in the planting of “urban” or landscape trees is also what often ruins them. What is it? Improper staking and here's why it's important to be done right and in some cases, not done at all.
Not all young trees need support but, for those that do, staking must be done in such a way that the tree is allowed to move. This is because trunk girth and root systems grow as the tree experiences movement. As the tree moves, it signals the development of a strong central trunk that can support the canopy of the tree in an upright position and a root system that is capable of anchoring the tree into the ground.
How Stakes Damage Trees
The outer bark of young trees is very thin and easily damaged. Nutrients and water flow up and down the tree just beneath the bark. When nursery stakes are left strapped tightly around the trunk this flow becomes restricted, much like a tight rubber band around your wrist cuts off the flow of blood and lymphatic fluids to your hand. Stakes that extend beyond the trunk and into the canopy of the tree are abrasive and cause damage to the bark. This exposes the tree to disease pathogens and can break branches as they hit the stakes.
Becoming an Urban Tree Steward
You can play an essential role in the health and longevity of trees. If you think about how similar the needs of urban trees are to us humans (good food, clean water and air, sunshine, and exercise) it's easy to see them as friends. Urban trees live in a non-native human-impacted landscape their whole lives, they depend on us to provide healthy soil, sufficient water, judicious trimming, and the exercise they need to grow big and strong. If you have prepared the soil prior to planting, followed the planting guidelines referenced above, provided adequate water for the first 2-3 years, and, only if needed, staked the tree properly, consider yourself an excellent tree steward!
Here are some resources that will teach you how to select, plant, and care for a tree.
• UC Center for Urban Landscape and Horticulture Tree Planting--
• Oregon State University Selecting, Planting, and Caring for New Trees--
• University of Minnesota Staking and Guying Trees--
This article was written by SM-SF Master Gardener Barbara Williams-Sheng who is a tree steward living in El Granada and edited by SM/SF Master Gardeners Maggie Mah and Cynthia Nations. Photos by Barbara Williams-Sheng
UC Master Gardeners of San Mateo-San Francisco County are volunteers who are trained under the auspices of the University of California to provide science-based information on plants, horticulture, soil, and pest management at no charge to the public. For more information and to find out about classes and events in your area, visit our website where you can also sign up for our newsletter and contact our Helpline: http://smsf-mastergardeners.ucanr.edu/
- Author: Maggie Mah
- Editor: Cynthia Nations
Many parts of California sizzle in the summer heat, but living on the coast means spending most days under a thick marine layer blanket and being buffeted by chilly breezes. Cool temperatures and proximity to a large body of water can lull us into thinking that wildfires happen somewhere else, but climate change is turning a lot of things upside down and we now know that's not the case. How we think about landscaping is part of this “New Abnormal” of bigger, more destructive fires. We are learning that the kinds of plants we choose and where we put them can help to protect our homes in the event of a wildfire. This concept is known as “firescaping” and if the term conjures up an image of a barren moonscape reminiscent of a scene from Star Wars, that's not it. However, cling as we might to the traditional, cozy look of trees and shrubs encircling our homes, adopting a new proactive garden aesthetic could mean the difference between survival and devastation.
Pillars of the Idea: “Firescaping” is defined as designing your landscape in a strategic way to reduce the impact that a fire could have on your property. There are two key elements. The first is to minimize the amount of flammable vegetation that could “feed” a fire and the second is to interrupt the “path” of an approaching fire to slow its progress and ultimately prevent it from reaching a house or other structure.
Defending Your Space: According to studies by the National Fire Protection Association and others, most homes are not destroyed by a wall of flame but by wind-blown embers which ignite flammable materials on or near the structure. Many of the homes that survive in fire-devastated areas are those that are surrounded by 30 feet of defensible space. The good news: it's easy to see how keeping the area surrounding your home as fire resistant as possible can make an enormous difference.
Getting Into the Zones: Picture your house in the center of a circle with a series of concentric rings radiating outward. These represents the “zones” that will guide the type, placement/location and amount of maintenance and irrigation needed for creating an effective “firescape.”
Think of the first 5 feet around a house or other structure as a kind of “thin red line” when it comes to fire because preventing fire from reaching this area is crucial. It should be kept free of anything combustible, including plants. Unfortunately: “foundation plantings,” those familiar shrubs and planter boxes immediately next to the house, are highly problematic in a fire situation and need to go. (If you must have a plant right next to your house, make it a succulent in a ceramic pot that can be easily moved.) In addition to being flammable, tools, furniture, toys and pretty much “stuff” of any kind creates nooks and crannies for dry leaves to collect. In short: neatness really does count!
Next is the area between 5 and 30 feet away from your house or other structure. The terms often used to describe this area are “lean, clean and green.” In choosing plants for this area, limit the number of plants overall and make fire-resistant varieties the top priority. If properly maintained, these types of plants can trap and help to extinguish flying embers. When it comes to design, think in terms of clusters or groupings of plants with space in between. This type of arrangement makes it harder for flames to spread and climb. These areas should also be kept free of dry, dead debris. When you plant, incorporate plenty of organic soil amendments to increase the water-holding capacity of the soil and use inflammable rock mulches to hold in moisture. If flammable mulches such as “arbor” chippings are used, keep them on the perimeter and away from low lying branches and remove any large twigs or pieces of bark. Even fire-resistant plants can become problematic if not properly maintained so it is important to ensure that plants in this area get plenty of care and adequate irrigation.
30 Feet and Counting: If the perimeter of your property extends beyond 30 feet from your home, you have additional “zones.” Slope and overall terrain are complicating factors that must be considered but reducing the amount of flammable material that would allow fire to move inward toward your home and upward into taller trees is essential. This means removing all dead and dying trees, dead branches, and dried vegetation. Healthy trees should be trimmed so that lowest branches are both 10 feet from the ground and 10 feet away from other trees. Trees and shrubs that are spaced appropriately and with adequate separation from combustible materials will lower the chances of flames being able to make their way to your house.
Bottom Line: Whether or not you decide to make changes to your existing landscape, proper maintenance of the vegetation surrounding your home is a given. Anything dry, dead, or brittle should be considered kindling that even the tiniest spark could set ablaze. Also, good to know: the traditional method of shearing shrubs and hedges from the outside creates dense, flammable interiors. Diving inside on a regular basis to prune out shaggy bits, dry twigs and branches will make them less flammable. Removing any overhanging tree branches at least 10 feet away from your roof is also a must. This might require having a heart-to-heart with the folks next door and if this seems awkward, remember that minimizing the threat of fire takes a neighborhood. Ultimately, they will thank you.For more on choosing fire-resistant plants go to:
The article was written by Maggie Mah who is currently the Marketing Chair for SM/SF UC Master Gardeners. The article was edited by Cynthia Nations.
- Author: Maggie Mah
- Editor: Cynthia Nations
This article was originally published in Coastside Magazine on
Since 2016, Coastside Magazine has featured monthly articles written and edited by members of the San Mateo-San Francisco chapter of UC Master Gardeners. But what, exactly, is a “Master Gardener?” Presumably, “Master Gardeners” are really good at gardening, but what does the title really mean and where does it come from? The short answer is this: Master Gardeners are volunteers from your community who have been trained under the direction of the University of California Cooperative Extension to assist home gardens with science-based information. But there's more to it than that, so what follows is a bit of history, personal reflections from veteran UC Master Gardeners, and information about how you, too, can become a UC Master Gardener.
Roots of the Program
In 1862, Abraham Lincoln signed the Morrill Act, which granted federally owned lands to each state to use for the creation of public colleges and universities and led to the founding of the University of California in 1868. A revolutionary idea at the time, these “land grant” schools were centered around a practical curriculum of agriculture, science and engineering and made higher education widely available to people of modest means. Subsequent legislation led to the establishment of Cooperative Extension programs under the auspices of each land grant institution for the purpose of connecting farmers and growers directly with university research.
Making of a UC Master Gardener: What does it take?Anyone 18 years and older who is a resident of San Mateo or San Francisco Counties may apply to become a SM-SF Master Gardener. Once accepted, applicants must complete an intensive course of training on everything related to plants including Abiotic Disorders, Botany, Bugs, Composting, Pruning, Plant Taxonomy, Water Management, Weeds, Invasive Plants and more. Trainees are also required to hone their presentation and public speaking skills. Master Gardeners are volunteers from your community who have been trained under the direction of the University of California Cooperative Extension to assist home gardeners with science-based information.
After training, First Year Master Gardeners must complete a minimum of 50 hours of volunteer service with additional requirements for continuing education in subsequent years. Many Master Gardeners amass hundreds and even thousands of hours while working on projects in their communities.
Q: What is the most valuable thing you have learned about gardening that you would like to pass along to Coastside readers?
BW-S: We are a part of nature. To be healthy ourselves, we must take care of the soil beneath our feet and the air we breathe and the water we drink. What is good for us will probably be good for the earth so eliminate plastics (landscape cloth/artificial turf), pesticides, and herbicides; rejoice at bugs, birds, and butterflies in your garden. Feed them native plants so they are plentiful and will pollinate the foods that keep us healthy.”
CO'D: I've had time to form deep friendships with like-minded Master Gardeners, especially cherished during Covid when we could garden together.
CO'D: I have to confess—TOMATO. They're nutritious, and delicious. But my fascination lies in the variety of different, beautiful, tomato varieties. In 2007, I lead a Master Gardener Tomato Trial on Kelly Avenue in Half Moon Bay to see which of 27 different varieties grew well on the coast. You guessed it—Cherry and Plum tomatoes.
The article was written by Maggie Mah who is currently the marketing chair for SM/SF UC Master Gardeners. The article was edited by Cynthia Nations
- Author: Jamie M. Chan
- Editor: Maggie Mah
- Editor: Cynthia Nations
While it may not be top of mind when you sip a Margarita, nearly all of the beverages we consume come from plants. Apart from plain water and traditional dairy milk, virtually everything else--coffee, tea, cocoa, wine, beer, fruit and vegetable juices, cola, vodka, bourbon—the list goes on!—starts in a garden. In addition to the basic beverages we consume every day, the flavor, aroma, and visual excitement of unique plant ingredients has also become an essential part of the carefully crafted cocktails and other drinks we enjoy. You might be surprised to learn that some of the most interesting and flavorful edible plant ingredients are actually easy to grow and make attractive additions to an existing landscape. Down the road, you might even be inspired to go all out and create a unique, drink-themed section of your garden. For now, here is a list of unfussy, coast-friendly plants that will take your mixology skills to a new level.
Now, about that Margarita garden...
For more information and answers to questions about the plants in your garden, contact the UC SM-SF Master Gardener Helpline by sending an email to email@example.com or calling (650) 276-7430.
Jamie Chan is a UC Master Gardener from the San Mateo-San Francisco Chapter. A San Francisco native, she is Director of Programs and Partnerships at The Gardens of Golden Gate Park and an adjunct professor at SF State University. The article was edited by SM-SF Master Gardeners Maggie Mah, and Cynthia Nations.