General
Plum Bud Gall Mites
As noted in the Plum Bud Gall Mite Fact Sheet, this is a fairly new pest in California, and there aren't tested treatment options available. However, a CDFA pest rating proposal for the plum bud gall mite says, “The galls appear to have little or no ...
Lawn Alternative Demonstration
We have a Lawn and Lawn Alternatives area in our Palo Alto Demonstration Garden waterwise area. It demos choices for lower water, lower maintenance, and less fertilizer-using plants for home landscapes in three categories: Lawns, four types, with ...
Insect Identification
The Master Gardeners are happy to help with insect identification. In order for us to do so, please provide information about where the insect(s) were found, specifics about the size, and close-up photos, showing front/back/top/bottom views. However, ...
Replacing Your Lawn
Whether you want to plant a different kind of lawn or some alternative, the first step is removing the lawn you currently have. The UC Integrated Pest Management Program has advice for Killing Your Lawn which describes both non-chemical and chemical ...
Is That Pesticide Safe?
Questions related to the use of pesticides can be complicated. For example, wondering if a termite treatment might affect plants in a nearby garden. While we often aren't able to provide definite answers, there are several resources that have ...
Soil Testing
A note about soil testing: if your plants are growing well, you may not have to worry about it. However, from the Master Gardener Handbook 2nd Ed.: "because most nutritional disorders of plants are difficult to diagnose from visual symptoms alone, ...
Why Does My Fruit Tree Have No Fruit?
The following articles provide information about why fruit trees aren't bearing fruit: Why Fruit Trees Fail to Bear, UC ANR Publication 31-S68 (Web Archive link) Why is There No Fruit on My Tree?, PennState Extension, the UC article above is the best ...
How Much to Water Fruit Trees
When watering fruit trees, it's crucial to focus on the right amount of water per week rather than how long or often to water. A general guideline is to provide one gallon of water per square foot of tree per week during hot summer months, with ...
Tomato Leaf Curl
The North Carolina Cooperative Extension has an article titled Curling Tomato Leaves? Here’s What to Know! that covers common causes of tomato leaf curl. It includes a discussion of curl-related factors including: environmental, variety, insect ...
Growing Cotton
We have received inquiries about the legality of growing cotton in Santa Clara County. To address these concerns, we reached out to the California Department of Food and Agriculture (CDFA) in April 2023 and obtained the following information: We ...
Spring Planting (when it is cold and wet)
When starting seeds or planting seedlings the soil temperature should be considered. Here is a good guideline for soil temperature for seed germination from the University of California. The soil moisture content is an important factor in plant ...
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. It 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 ...
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 ...
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, ...
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. ...
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. UC ...
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 ...
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