General
Checking Tree Roots
The Basics “When woody plants decline or die, assess the root system’s health. Suspect a root injury or disorder when an entire plant declines or dies. Digging out or around newly planted woody plants makes it possible to evaluate their root systems. ...
Should I Paint Large Pruning Cuts?
According to the UC Center for Landscape and Urban Horticulture publication on Pruning: "Protecting pruning cuts with an asphalt emulsion or other coating material is of no value and could even be harmful to the tree. Coatings and coverings can trap ...
Integrated Pest Management (IPM)
UC advocates using a process called Integrated Pest Management (IPM) for dealing with all kinds of garden pests. The process provides a balanced approach between managing pests and caring for the environment and starts with identifying which pests ...
Tropical milkweed
The impact of tropical milkweed has been in the news recently. The plant has been banned from sale in Marin, Contra Costa, San Mateo, and Ventura counties after being given a "B" pest rating by the CDFA, partly due to its potential impact on monarch ...
Proper Irrigation
According to the UC Integrated Pest Management webpage on Water deficit and excess, "Inappropriate irrigation is probably the most common cause of landscape plant damage. Too little or too much soil moisture can adversely affect most any aspect of ...
Checking Soil Moisture
You don't have to have a soil moisture meter to determine if your soil is moist enough. Checking directly for both moisture and water penetration depth is a good practice for understanding how well your plants are watered. For trees or other ...
Questions from Commercial Businesses
Per the UCCE Master Gardener program administrative handbook, the "Master Gardener Program is an educational program designed to teach and effectively extend information to address home gardening and non-commercial horticulture needs in ...
Pepper Weevils
Pepper weevils have spread north from Southern California to Santa Clara County and can be quite destructive. For backyard gardeners, the best advice seems to be to clean up carefully after the pepper growing season to limit t he recurrence the ...
Water deficit and excess
According to the University of California, inappropriate irrigation is probably the most common cause of landscape plant damage. Too little or too much soil moisture can adversely affect most any aspect of the appearance, development, and growth of ...
Planting Trees
According to the UC publication on Planting Landscape Trees: "The performance of a landscape tree depends a great deal on how it is planted. Survival after initial transplanting, rate of growth and establishment, root development, and many other ...
Clay Soil
According to the UC ANR publication Get to Know Your Soil: "Clay particles are very, very small, less than .002 millimeters in size. Clay soils have small pore spaces but lots more of them and overall more pore space then in sandy soil. Clayey soils ...
Can you recommend a garden designer or contractor?
As volunteers for the UC Cooperative Extension, we are not able to recommend commercial services. The Valley Water Agency has a website focused on South Bay Green Gardens with a landscaping resources page. It includes information about landscape ...
Food Safety After Urban Wildfire
UCCE of Sonoma County has a Fire Resources website with a page dedicated to Food Safety after Urban Wildfire. One of the most applicable documents for Santa Clara homeowners is a publication titled Produce Safety After a Fire that discusses human and ...
Citrus Leafminer
Unsightly leaves at the tips of new citrus branches are often caused by citrus leafminers. They originate from a tiny moth that lays eggs only on new citrus tree growth. Its larva then tunnels around inside the leaf, eating between the top and bottom ...
Climate Zones
There are two commonly used climate zone scales: The US Department of Agriculture Plant Hardiness Zone Map (including zip code lookup) is based on the average annual minimum winter temperature, divided into 10-degree F zones. Santa Clara County ...
Recordings of online presentations
Online presentations are recorded and made available whenever possible. In most cases, videos are posted to our YouTube channel within a week of the presentation. If you missed a presentation and are still interested in seeing it, keep an eye on that ...
Pruning Apple Trees
Here are some Extension resources about pruning apple trees. Be aware that some of the advice in these non-California resources may be specific to a different climate, but the general approach for apple tree maintenance should be the same. Videos: ...
Hardening Plants
Excerpt From: California Master Gardener Handbook, Second Edition. “Hardening is the process of slowing plant growth to withstand changes in environmental conditions that occur when transplants are transferred from a greenhouse or home to the garden. ...
Pruning Hydrangeas
These links provide guidance on pruning hydrangeas. While there's redundancy in the pages, they're all listed to let you decide which works best for you. Pruning Hydrangeas, Tulare & Kings County Master Gardeners Pruning Hydrangeas for Best Bloom, ...
General Pruning Resources
There are many sources of information about pruning. This FAQ is intended as a starting point into the subject. UC ResourcesPruning Small Trees and Shrubs, Ventura County Cooperative Extension Training Young Trees for Structure and Form, California ...
Citrus Sprouting Rootstock
Nursery-grown citrus plants generally consist of a desirable variety grafted onto a rootstock cultivar. "The rootstock cultivar makes up the lower few inches of the trunk and the tree’s roots. The scion cultivar makes up the rest of the trunk and ...
Chill Hours
Many fruits and nuts require a certain number of chill hours in order to produce. The UC Home Orchard website describes chilling as "the number of hours below 45°F, is an important climatic factor that influences bud break, fruit set, and fruit ...
Best time of the year to plant strawberries
The University of California recommends that mid to late August is generally the best time to plant strawberries in all locations. Day-neutral cultivars can be planted in the fall, February and March. Short day varieties can be planted in November. ...
Plant Identification
If you're interested in trying to identify a plant yourself, our favorite tools are: iNaturalist: it's available on the web and in an app. It's a joint initiative of the California Academy of Sciences and the National Geographic Society. The tool ...
Oxalis
There are two types of Oxalis weeds found in Santa Clara County: Creeping Woodsorrel (Oxalis corniculata) Bermuda Buttercup (Oxalis pes-caprae) also known as Buttercup Oxalis Information about how to control both of these weeds can be found in the UC ...
Citrus Grafting
If you're interested in cloning citrus, you should know about the Citrus Clonal Protection Program (CCPP). The CCPP "provides a safe mechanism for the introduction into California of citrus varieties from any citrus-growing area of the world" and ...
Fruit Tree Pruning Resources
Our website has a selection of links covering Fruit Tree Pruning.
Spanish Gardening Resources
En español — Spanish gardening resources in California: CA IPM website: Manejo de plagas en el hogar y en jardines . Resolver todo tipo de problemas de plagas en cualquier lugar y reducir al minimo los riesgos para las personas y el medio ambiente. ...
Bed Bugs
Here are some bed bug facts: Contrary to popular belief, bed bugs are not microscopic. While small, you can see all life stages with the naked eye. Both nymphs (immatures) and adults only feed on blood and must have a blood meal in order to develop ...
Asian Citrus Psyllid
The most recent quarantine information related to the Asian Citrus Psyllid can be found on our website. The County is actively monitoring for this pest and coordinating treatment as needed.
Choosing a Tree
There are a number of good resources to help you select a tree: Selectree from Cal Poly, lets you choose plants by characteristics. Arboretum All-stars from UC Davis, with an emphasis on water wise trees. Our City Forest , a San Jose based non profit ...
Wood Preservatives
Wood preservatives have changed over the years and newer wood treatments are less toxic than those used before 2003. Iowa State University has published a helpful article on toxicity concerns about raised beds. In addition, the National Pesticide ...
When to apply fertilizer?
The practice of automatically adding fertilizer in the spring is no longer considered a best practice. Excess fertilizing can cause excessive growth resulting in higher water needs, and might well contribute to softer growth which can make plants ...
Is Disease in Wood Chips a Problem?
Linda Chalker-Scott, an Extension Horticulturist and Associate Professor at Washington State University has a nice publication on her website discussing The Myth of Pathogenic Wood Chips. Her bottom line? It's not generally a problem as long as you ...
Composting
The UCCE Composting Education Program is a partnership with the cities and county of Santa Clara to educate the community about composting. Their website has a lot of information about composting including: A summary of composting basics A schedule ...
Event Participation Request
Would you like UC Master Gardeners at your next event? If you are having an event that would attract people interested in gardening, we may be able to provide an information table and/or a children's activities table staffed by UC Master Gardeners. ...
Request a Speaker
Does your organization need a speaker for an upcoming meeting? We provide knowledgeable speakers on many gardening topics. Just complete the speaker request form on our website and someone from our Speakers Bureau will get back to you.
School Garden Advice
Need help with a school garden? Be sure to check out all of the useful school garden advice we have gathered for you. If you need additional assistance, we can work with you to advise, mentor and answer gardening questions. Please complete and submit ...
Arborists and Tree Services
We recommend consulting with a certified arborist for many tree issues. While we are not able to recommend commercial services, the website for the International Society of Arboriculture has a search feature to help locate arborists who work in your ...
Peach Tree Pruning
Peaches and nectarines are usually pruned during the winter dormant season. It's important to know that fruiting takes place on one year old wood. The UC Integrated Pest Management website has a brief summary of peach and nectarine tree ...
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