- (Focus Area) Yard & Garden
We have endured multiple years of drought, and are probably in store for more. For many of us, it makes sense to replace all or part of our lawn area with less water-intensive plantings.
Step One: observe and plan. What existing trees and plants do you want to keep or remove? What are the sun and shade patterns within your yard? What types of grass grow in your lawn? Do you want any additional amenities, such as paving or a shade structure? How will you irrigate your new plants?
Step Two: kill your lawn. Homeowners can use two eco-friendly methods to kill their lawns: Solarizing or Sheet Mulching. For detailed instructions on solarizing, see UC IPM Pestnote on solarization. For instructions on sheet mulching, see our Real Dirt blog post on Sheet Composting.
Sheet mulching kills weeds by starving them of light. It takes 6 to 10 months and can be started any time of the year as long as at least three months of growing season are included. Sheet mulching works in sun or shade, and is effective on all grasses, including Bermuda grass, and many annual and perennial weeds. It is left in place permanently; over time, the dead lawn, sheeting, and mulch will break down into soil-enriching compost. Sheet mulching should be placed before new plants are installed if being used alone to kill lawn or weeds. It can be placed after plants are installed if solarizing has been completed first. New hardscape and irrigation should be installed before commencing solarizing or sheet mulching.
Step Three: replant. Whichever method you choose to kill your lawn, time it so that you are ready to replant in the fall, winter, or early spring. The cool temperatures and moist soils of our wet season allow drought tolerant plants to develop the healthy roots they need to thrive with little water during the heat of summer. Taking time to thoroughly kill the grass and waiting until the climate conditions are suitable for new plants will ensure the long-term success of a lawn replacement project.
UC Master Gardeners of Butte County are part of the University of California Cooperative Extension (UCCE) system. To learn more about us and our upcoming events, and for help with gardening in our area visit our website. If you have a gardening question or problem, email the Hotline at mgbutte@ucanr.edu or leave a phone message on our Hotline at 530-552-5812. To speak to a Master Gardener about a gardening issue, or to drop by the MG office during Hotline hours, see the most current information on our Ask Us section of our website.
- Author: Kathy Keatley Garvey
And it's double delightful with twins!
Such was the case at the Vacaville Museum Guild's recent Children's Party when two-year-old twins Ford and Wyatt Devine were thumbing through "The Story of the Dogface Butterfly," a children's book written by UC Davis doctoral alumna Fran Keller, a Folsom Lake College professor and a Bohart Museum of Entomology research scientist.
The twins, along with big brother, Buck, 7, were among the youngsters fascinated by the book, which features macro images by Bohart associate Greg Kareofelas and illustrations by Laine Bauer, then a UC Davis student.
It was just one of the many attractions at the annual Children's Party, held Aug. 8 in the museum courtyard.
Not many know that the butterfly's most prevalent habitat is the 40-acre Shutamul Bear River Preserve near Auburn, on a Placer Land Trust conservation site; Kareofelas serves as a docent on the Placer Land Trust tours. (See virtual tour on YouTube). The butterfly is there because its larval host plant, false indigo (Amorpha californica), is there.
Are there dogface butterflies in Vacaville? Yes. The butterfly's breeding grounds include Gates Canyon. (See UC Davis emeritus professor Art Shapiro's website.)
Director of the insect museum is Professor Jason Bond, the Evert and Marion Schlinger Endowed Chair, UC Davis Department of Entomology and Nematology, and associate dean, Agricultural Sciences, UC Davis College of Agricultural and Environmental Sciences.
Meanwhile, Bohart scientists are gearing up for their next open house, set for 1 to 4 p.m., Saturday, Sept. 28. The theme is "Museum ABC's: Arthropods, Bohart and Collecting." All open houses are free and family friendly. Parking is also free. For more information, contact bmuseum@ucdavis.edu or access the website at https://bohart.ucdavis.edu.
- Author: Judy Quan
The excessive heat days we have experienced in Northern California in 2024 may have caused us to look at our landscape trees and shrubs and notice that some are not looking so good. What does that mean? What can be done to help them survive and thrive? The answer often lies in the quality of water management for our trees and shrubs. Since water is such an important aspect, we begin this series on landscape trees and shrubs with a discussion on water management. The main focus will be on the watering of trees; however, that information can be applied to most shrubs and other woody plants.
Water Management - Critical to the Health and Survival of Trees and Shrubs
Symptoms of stress and disease Wilting or yellowing leaves, early leaf loss, twig and branch die-back, and a thinning canopy are symptoms that a tree is under stress.
When, Where, How Much Water – Direct and Critical Impact on Tree Health Reasons for the decline in the health of a woody plant are many, but water management is the most critical aspect to investigate when a plant seems to be under stress and declining. The amount of water has a direct impact on the health of the plant. Inappropriate soil moisture has an important secondary impact in that it can promote pest and disease problems. Poor water management can predispose plants to infection, leaf and fruit diseases. It can also lead to root and crown rot as well as an active infection of oak root fungus.
Water management takes on many aspects. Proper water management promotes healthy plant growth and development.
Factors affecting how much and when to water
Unfortunately, there is no simple answer to the amount of water to give your trees and shrubs.
How much, how fast and how often to water varies widely, depending on soil type, soil drainage, and moisture demand according to the plant species. The water needs of trees and shrubs are affected by the season and weather such as extended and prolonged drought, more extreme heat, and intense, wet winter storms (atmospheric rivers). Newly planted trees and shrubs, young trees, and mature trees have different water needs, but nearly all, including mature trees, need some summer water.
Useful resources for learning more about factors that impact watering practices include those that address:
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Type of trees - related environment and water needs https://selectree.calpoly.edu/
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Look up the watering needs of specific trees https://canopy.org/tree-info/caring-for-trees/trees-and-water/watering-guidelines/
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Look up watering needs of trees, shrubs and other plants by city or region using the UC Davis California Center for Urban Horticulture “enhanced” WUCOLS (Water Use Classification of Landscape Species) Plant Searchable Database
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Add compost to increase the amount of moisture your soil can hold https://mg.ucanr.edu/Gardening/Vegetable/Preparing/SoilImprovement/
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Mulch https://cealameda.ucanr.edu/?blogpost=50517&blogasset=118849
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Learn about Irrigation 101 for Landscape Trees https://ucanr.edu/blogs/blogcore/postdetail.cfm?postnum=41260
Good watering practices
Knowledge of the water needs of your plants and monitoring the moisture level of your soil will guide you in determining the amount of water needed and how to water.
8 tips on watering trees
Excerpted with minor modifications from Tips on Watering Trees
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Keep tree trunks dry. Trunks should not come into contact with water from sprinklers or hoses.
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Apply the right amount of water at the right time.
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Water newly planted trees regularly for a full season Many newly transplanted landscape trees die from the soil drying out too much between waterings because their root systems are small and need to be kept moist for a full growing season. Water newly planted trees regularly.
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Water newly planted trees, including drought-tolerant species too. This schedule of regularly watering newly planted trees holds true for drought-tolerant species as well as those that require more water. Once plants become well rooted they should be watered less often but for longer periods of time. Established drought-tolerant trees will be able to go longer between waterings than those trees with moderate- or high-water needs
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Water halfway to the dripline and beyond. Since tree roots spread outward as well as downward, water should be applied from mid-dropline and beyond the dripline of the tree.
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Most established trees need water too. Most trees in California need supplemental irrigation above and beyond the naturally occurring rains, especially in times of drought. Water established trees less often but more deeply to encourage deep rooting and structural balance above and below ground. Be very careful if watering established native oaks since summer water can be detrimental to native oaks.
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Trees need to be watered slowly and deeply. If you use a garden hose, apply the smallest trickle of water slowly, moving the hose every few hours to water the entire area around the tree. The deep watering encourages roots to grow downward and helps prevent sidewalk damage.
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Do NOT water trees on the same irrigation/drip system as those used for lawns and groundcovers. The light, frequent watering every few days that is appropriate for lawns/groundcovers discourages the deep growth of tree roots.
Other tips for watering fruit trees and California natives
Watering fruit trees including citrus and avocados
Watering correctly is essential to the production of fruit and allows trees to keep a natural resistance to fungal diseases. This link https://ipm.ucanr.edu/homegarden/irrigating/ has more specific watering information on different trees including citrus, avocados and other fruit trees.
Watering of California natives
The vast majority of California's native plants are well-adapted to California's wet winter and summer dry climate, but even well-established native plants may need an occasional deep watering during hot, dry periods, perhaps one or two deep waterings over the summer. https://calscape.org/watering-native-plants
Tip: Don't water your ceanothus during the summer. Once established, summer watering may kill the plant. There are varieties of salvia that also don't like summer watering. Review watering guidelines by variety.
Watering established native California oak trees
“Even though oaks are known to be drought tolerant, summer irrigation may be beneficial to oak trees, especially during periods of prolonged drought, if water is kept at least 3 m (10 ft.) away from tree root crowns, or applied in the outer two-thirds of the root zone.” https://oaks.cnr.berkeley.edu/summer-irrigation-of-established-oak-trees/
Make sure California Oaks have a chance to dry out between waterings.
Common problems with water management
UC IPM, the statewide integrated pest management program has a very useful and detailed site on environmental disorders that focuses on the water management and pest problems. The information from that site formed the backbone of this section. Too little or too much water, the timing of water irrigation, and the downside of dripping, ponding, spraying water are all covered.
Water deficit
Symptoms: Leaves may droop, yellow, wilt, or drop prematurely. Severe, prolonged water deficit leads to shoot and branch dieback and, in some cases, bark cracking and trunk bleeding may occur. Mild but prolonged moisture deficit results in fewer flowers, fruit, slower growth, smaller leaves and increased sensitivity to pests. Plants stressed by drought are more susceptible to damage from mites, certain leaf-sucking insects, and most wood-boring insects
Management: Deep water your trees and shrubs by trickle watering, watering slowly for perhaps two hours. Water tree away from trunk, midway between trunk and dripline where the leaves end and rain drips off the tree, getting the water down to the roots that are often 12-18 inches or more below the surface.
Even trees that did fine without summer water in past years may need an occasional deep watering every month or two during extended hot weather.
Excess soil moisture
Symptoms: Over-irrigation has symptoms similar to those of underwatering. (See above.) Prolonged exposure to excess moisture results in roots dying, and plants become unable to take up water, resulting in symptoms similar to those of underwatering. Root decay pathogens such as Dematophora and Phytophthora spp. are present in many soils, yet usually become damaging only when excessively wet soil conditions favor them.
Management: Determine the cause of excess water. Soil that holds water too long can be improved by the addition of compost and other organics. The grade that causes water to pool or hold water for a long period can be altered. Change the irrigation schedule to adjust for changing seasons. If flooding of an area happens due to extended rains, drain the area when possible.
Water placement
Water dripping, ponding or spraying near the base of the trunk of a tree or shrub are primary causes of root and crown diseases. Soggy soil around the root collar, where the root and trunk join, promotes. Splashing water spreads fungal spores and splashing wets foliage, promoting leaf and fruit diseases such as anthracnose, brown rot, leaf spots and rust.
Seasonal timing
The seasonal timing of irrigation is important in disease development. Some California native trees may need summer water in drought years, but are sensitive to overwatering. For example, oak root fungus, Armillaria mellea, is present in dead or living roots in many soils, and it becomes active when soils are warm and moist. When people water native oaks frequently during the summer, moist roots and warm soils work together to predispose oaks and many other species to infection and death by oak root fungus.
Resources:
- Center for Landscape and Urban Horticulture
- Canopy - Healthy Trees, Healthy Communities
- Irrigation of trees and shrubs
- Irrigating fruit and shade trees and shrubs
- Landscape Tree Irrigation 101
- Oak Root Fungus
- Online Tools from UC IPM for Plant Problem Identification
- Root and Crown Rot
- Summer Irrigation of Established Oak Trees by UC Oaks
- Tips on Watering Trees
- University of California Integrated Pest Management (UC IPM)
- Water Management and Pest Problems from UC IPM
- Water Use Classification of Landscape Species ( UC Davis WUCOLS)
- UC Oaks - summer-irrigation-of-established-oak-trees/
- Watering Native Plants by Calscape
Have a gardening question? We'll help. You can reach us by:
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Emailing acmg@ucanr.edu. Please include a photo of the problem, if you can, plus your name, phone number, city and a description of the problem.
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Using our online form.
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By phone, during our office hours, 10 am to noon Wednesday and 11 am to 1 pm Thursday: 510-670-5645. At other times, please leave a message and we'll return your call during our office hours.
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In person at our Hayward office, during our office hours, only by appointment.
- Author: Ryan Daugherty
Pallets are an attractive option for raised bed construction due to their affordability and availability. Often found discarded behind stores, at the dump, or sold cheaply, pallets provide a sustainable alternative to buying new lumber. Additionally, re-purposing pallets aligns with the principles of recycling and reducing waste which is never a bad idea to consider. Constructing raised beds from pallets can also add a rustic, charming aesthetic to your garden.
However, before you rush to build your raised beds from pallets, it's essential to understand the risks, especially when it comes to the treatment of the wood.
Pallets are designed for transporting goods, and as such, they are often treated to prevent the spread of pests and diseases across borders. The type of treatment a pallet has undergone is typically indicated by a series of markings found on the pallet's side. These markings provide crucial information that determines whether the pallet is safe for use in a garden, where the wood will come into contact with soil and plants. Keep in mind that a pallet may have one or a combination of these markings.
Pallets at the end of their lives, usually when gardeners acquire them, are often unmarked or in poor enough condition that markings or evidence of treatment are not obvious.
Here's a breakdown of the most common markings you may encounter:
The IPPC Logo. The IPPC (International Plant Protection Convention) logo is the most common marking found on pallets. It resembles a small tree symbol with an outline and is a part of the global standardization for wood packaging materials. This logo indicates that the pallet meets international shipping standards and has undergone treatment to prevent the spread of pests.
HT Pallets marked with an “HT” have been heat-treated. This process is popular in Canada and the United States. It involves heating the wood to a specific temperature for a set period, which kills any pests like fungi, or insects that might be present in the wood. Soft wood pallets are heated to a core temperature of 132°f, and 140°f for hard wood if you're interested. Importantly, no chemicals are used in this process, making HT pallets generally safe for garden use.
DB The “DB” marking indicates that the pallet wood has been debarked, meaning the bark was scraped off of the wood before it was milled. Debarking is not a treatment method but rather a process that makes the wood easier to work with and less susceptible to pests. Debarking has no effect on the chemical properties of the wood and as such is generally safe to use for lumber.
KD “KD” stands for kiln-dried, which is a process where the wood is dried in a kiln to reduce moisture content down to at least 19% or below. Kiln-drying helps prevent warping and splitting but does not indicate whether the wood has been treated with chemicals. Kiln-drying temperatures don't necessarily reach up to the level of heat treatments and so it isn't really considered a treatment for pest control. It's not uncommon to see code “KD-HT” indicating kiln-drying and heat treatment with both processes accomplishing something different. KD pallets are safe to use in gardening.
MB This is one that you want to watch out for! If you see the letters “MB” on a pallet, it indicates that the wood was treated with methyl bromide, a toxic chemical fumigant used to kill pests. Methyl bromide is a highly effective pesticide, but it's also toxic to both plants and animals. Pallets treated with this chemical should never be used in gardening, as the chemical residues can leach into the soil and be absorbed by plants, posing serious health risks to humans and animals. You will often see “MB” paired with other treatments like “DB-MB” meaning debarked and treated with methyl bromide, or “KD-MB” for kiln-dried and treated with methyl bromide for example.
Using chemically treated wood in your garden can lead to the contamination of your soil, which in turn can affect the health of your plants and pose risks to anyone consuming the produce. The leaching of toxic substances like methyl bromide can have long-term effects on soil quality, potentially rendering it unusable for safe food production.
While the IPPC logo and the accompanying treatment codes are the most common markings on pallets, you may also encounter regional markings or codes that provide additional information. For example, some pallets might include a country code (e.g., “US” for the United States) or a manufacturer's identification code. These additional markings can help trace the origin of the pallet, but they don't usually impact its safety for garden use.
It's important to note that some pallets, especially those used for domestic purposes or in certain industries, may not have any markings at all. There are still unmarked CCA-treated pallets circulating about, and you don't want to use them in your garden. In these cases, it may be best to err on the side of caution and avoid using the pallet for gardening unless you can confirm the pallet's provenance and treatments, if any. (That's unlikely.)
Markings or not, it's wise to check any pallet you intend to use for any signs of spills, stains, or unusual odors that might indicate contamination from the materials it previously carried. And some contaminants are colorless and odorless.
Using pallets as lumber for raised bed gardening is a sustainable and economical option, but it requires careful consideration of the wood treatment. Understanding pallet markings is essential to ensure the safety of your garden and the health of your plants. Always prioritize heat-treated (HT) pallets, avoid those marked with methyl bromide (MB), and thoroughly inspect any pallets before use.
If you are at all in doubt about your pallets' source or past, it's safest to use them for applications that do not involve edible crops. They can also be recycled! Inyo County Residents can take them to the Bishop or Big Pine drop offs. Mono County residents should contact their Solid Waste Department.
Keep in mind wood from pallets that are not chemically treated may not be long-lasting in the garden due to the moisture. Be prepared to maintain them as the boards wear out.
With the right precautions, pallet wood could be a valuable resource for your garden, contributing to a productive and environmentally growing space.
A new season of Master Gardener Workshops is about to start! The series begins September 9th with a session on Neighborhood Habitat Certification, and concludes on December 3rd with a timely workshop on Perennial Vegetable Gardening. In all, this Fall Series totals 14 workshops, including three new topics. There is something here for every type of gardener and every size of home garden, whether you maintain a balcony of plants in containers or produce fruit and vegetables on a large plot for your family, friends and neighbors. For full descriptions of all the workshops and to register, visit our website,
In the months to come, the foundational skills of creating soil-enriching compost; propagating plants through cuttings and divisions; and preparing the garden for winter will be covered. If you are interested in learning fundamental principles of landscape design you can employ in your own garden, our new two-part series on that topic may be just what you've been waiting for.
A new workshop on cultivating perennial vegetables offers a wealth of possibilities for planting vegetables that come back every year, saving labor and introducing new varieties to consider for extra interest in the vegetable garden.
If you are planning to convert all or some of your lawn area to a low-water landscape alive with native plants and humming with beneficial pollinators, our workshop on How to Remove Your Lawn will provide the valuable information you need for this process, from methods of lawn removal through the eventual planting of low water and native plants.
Critters commonly found in our local gardens feature prominently in this Fall Workshop Series, from beneficial visitors (Native Bees, Bats) to unwelcome intruders (Gophers, Moles, and Voles). Learn how to support pollinators and other native wildlife by making your own yard count in the effort to conserve water resources and rebuild local wildlife corridors in our workshop led by the coordinator of Altacal Audubon's Certified Neighborhood Habitat Program.
For the other side of the coin (those unwelcome intruders) our workshop on the basics of Integrated Pest Management focuses on solving pest problems while minimizing risks to people and the environment.
Most of the workshops will be held in the outdoor classroom located in the Master Gardener Demonstration Garden or inside Pat's Barn; both are located at the Patrick Ranch (10381 Midway, between Chico and Durham). The workshops on neighborhood habitat certification and native bees will be will be held in Paradise, at the Terry Ash Center on Skyway; and the Garden Guide workshop will be held at the Plant Barn Nursery on Entler Avenue in Chico. All of the workshops will take place in the morning or early afternoon.
The following is a list of workshop topics and dates. All workshops are free, but they do require advance registration. For full workshop descriptions and to register, visit our website.
Neighborhood Habitat Certification (Monday 9/9). Learn how to make your own yard part of a larger movement to conserve valuable water resources and rebuild much-needed wildlife corridors.
Propagation (Saturday 9/21). Come to learn when and how to propagate woody perennials and divide plants; leave this workshop with plant cuttings from our Demonstration Garden to start at home.
Irrigation (Tuesday 9/24). Drip irrigation is arguably the most efficient method of providing water to trees, crops, gardens, and landscapes. This workshop provides an overview of different options available for drip irrigation systems and covers how to install, inspect, troubleshoot, and repair them.
How to Remove Your Lawn (Thursday 9/26). Learn the steps of killing lawn through sheet mulching or soil solarization, and the process of replanting an area with low water and native plants. A walk through our Demonstration Garden will provide plenty of inspiration.
Gophers, Moles, and Voles (Wednesday 10/9). Learn how to deal with these little monsters that plague our yards; this workshop will include a demonstration on how to set a gopher trap.
Integrated Pest Management (Tuesday 10/15). In this interactive class learn the basics of Integrated Pest Management (IPM) so you can solve your pest problems while minimizing risks to people and the environment.
It's a Wrap! Autumn Garden Cleanup, Winter Prep and Preservation (Saturday 10/19). This workshop/discussion delves into some essential steps to ensure that next year's garden is even more successful.
Composting (Friday 10/25). Learn to make wonderful soil-enriching compost from leaves, garden waste, and kitchen scraps. This workshop covers the different ways to create compost, using techniques that range from simple to complex. Knowing the choices can help you decide which style best fits your own resources and needs.
How to Use Our Garden Guide (Saturday 10/26). Join us to explore how to us our Butte County Garden Guide and Three-Year Journal to find the best times to perform seasonal and weekly garden tasks, as well as useful information on plants, climate, and soil for our region. An integral part of this workshop is using the Garden Guide to record lessons learned and keep track of useful plant and weather information for your garden over the years.
Landscape Design (Thursday 11/7 and Thursday 11/14). Learn the steps that professionals use to develop beautiful, cohesive, lower maintenance planting designs.
Bats (Saturday 11/16). Join our local bat expert, Butte College's Dr. Shahroukh Mistry, to learn everything you've always wanted to know about these fascinating creatures.
Native Bees (Monday 11/18). Did you know that 1600 species of native bees can be found in California? This workshop focuses on a few of them: bumblebees, leaf cutting bees, mason bees, and carpenter bees. Understanding the bees' lifespans and their plant and habitat needs will help you support these valuable pollinators.
DECEMBER
Perennial Vegetable Gardening (Tuesday 12/3). Learn the differences between perennial and annual vegetables, then delve into how to cultivate perennial vegetables. Thirty-five of the best perennial vegetables for our local gardens will be introduced. Why not explore new plants and reduce your gardening labor?
Our Butte County Garden Guide and Three-Year Journal is available in two versions: bound as a book and unbound, ready to add to a loose-leaf binder. It can be found at the Plant Barn Nursery (406 Entler Avenue, Chico), Magnolia Gift and Garden (1367 East Avenue, Chico), and Pat's Barn at the Patrick Ranch Museum (10381 Midway, Durham). They can be ordered online via our website.
UC Master Gardeners of Butte County are part of the University of California Cooperative Extension (UCCE) system. To learn more about us and our upcoming events, and for help with gardening in our area visit our website. If you have a gardening question or problem, email the Hotline at mgbutte@ucanr.edu or leave a phone message on our Hotline at 530-552-5812. To speak to a Master Gardener about a gardening issue, or to drop by the MG office during Hotline hours, see the most current information on our Ask Us section of our website.