- Author: Anne E Schellman
Over the past few months, gardeners have asked the UCCE Master Gardeners for help with their grapes. They want to know:
- What's this white powdery substance on my grape plants?
- Why are my grapes so small?
- What's causing my grapes to split?
- What can I do to “save” my grape plants?
Powdery mildew on grapes. (Jack Kelly Clark, UC IPM)
The culprit is a common grape disease called powdery mildew. This fungus leaves a telltale white powdery coating on plants. It also deforms leaves, shoots, and grapes. Young grapes can be stunted or scarred, and sometimes split open.
We've told gardeners that unfortunately, powdery mildew can't be eradicated. For now, gently hosing down plants weekly with water will help to wash off and kill the spores.
In winter, prune grapes and remove and destroy infected materials. During spring, use fungicides to protect grapevines. Timing is important. Read about how and when to prevent and control this disease in the publication Pest Notes: Powdery Mildew.
Small Grapes
Small grapes are a result of too many clusters of grapes on a vine. The clusters will need to be thinned. Sometimes gardeners have trouble doing this. It may feel like you are throwing away perfectly good fruit! However, thinning out grape clusters is a necessary task that should be done in early spring during the first three to four weeks after fruit has set.
Study up on grapes now! Then you'll know what you need to do next year. For information on pruning, thinning, and growing grapes, visit The California Garden Web page Growing Grapes in Your Backyard.
- Author: Anne E Schellman
University of California Cooperative Extension (UCCE) Stanislaus County started a brand-new Master Gardener Program in January of 2019. Our first class of twenty-three volunteers just graduated and are out in the community making a difference.
If you enjoy gardening, live in Stanislaus County, and are willing to volunteer your time and talent, keep reading! We are now taking applications for our 2020 class that will start in early January. To learn more and apply:
- Visit our Become a UCCE Master Gardener website
- Click on the bright yellow button to fill out our application form before September 8, 2019
- Attend a mandatory orientation meeting in October
- Interview in November
- Acceptance letters mailed in early December
- Author: Anne E Schellman
Summer is here, and so is the Stanislaus County Fair! Our brand-new University of California Cooperative Extension (UCCE) Master Gardener Program is excited to have a presence at the fair this year, with volunteers who have just graduated this past June.
Come see us in front of the Floriculture building located just inside the fairgrounds near the arch gate off 900 North Broadway. Our table that will showcase a colorful poster all about our program. Come find out who we are and what we do and ask your gardening or pest questions.
Pick up free copies of Quick Tips cards on pests like ants, powdery mildew, cockroaches, and more! We'll also be giving away carrot and California poppy seeds (while supplies last).
Want to be a UCCE Master Gardener in Stanislaus County? We have flyers with all the information you need and will be taking applications next week!
For more information about the fair, visit the Stanislaus County Fair website.
- Author: Ed Perry
Although many coast redwoods (Sequoia sempervirons) appear to grow well in some parts of the San Joaquin Valley, the UCCE Master Gardeners are often contacted for help diagnosing redwoods with dead branches that seem to be dying.
It's important to remember that coast redwoods are native to the coasts of Central and Northern California. In this environment, the trees are shaded by each other and experience significant cooling from fog. They also receive moisture from fog drip and high rainfall. In their native forests, redwoods grow with large amounts of forest litter over their roots.
While coast redwood trees are susceptible to some serious diseases, they are most often injured or killed by abiotic (non living) problems. High soil salinity caused by excess sodium (alkaline soil), and toxicity caused by high concentrations of specific ions such as boron and chlorides will stunt their growth and cause their leaves to turn yellow and “burn.” They grow poorly in heavy soils that are too wet, or in dry, compacted soils with poor drainage. Coast redwoods are also susceptible to iron deficiency, especially in high pH soils. They may be injured by freezing temperatures, especially in dry soil. Because they are adapted to a cool, moist environment, they will develop brown and scorched leaves during our hot and dry summers, especially if they're not adequately watered. Drought stressed trees may then be attacked by bark beetles.
In dry or compacted soils the trees grow slowly and their trunks develop a distinct taper. Under ideal soil and moisture conditions, such as along portions of the California Coast, the trunks will be nearly the same diameter from the base of the tree to several feet high. Some brown foliage in the interior of the tree is normal. In fact, it is normal for the oldest leaves to turn yellow, then brown, and finally drop from the tree in late summer and early fall. It is also normal for short twigs to turn brown and fall. New growth at the ends of branches indicates that the branches are alive and healthy, despite some dieback of twigs and leaves.
As mentioned, coast redwoods are susceptible to some diseases. In Stanislaus County, redwoods infected by Botryosphaeria canker (Botryosphaeria dothidea), crown rot (Phytophthora sp.) and Armellaria root rot (Armillaria mellea) have been identified. However, these diseases are relatively uncommon on redwoods here. If you're trying to diagnose a redwood problem, be sure to consider soil and water-related problems first.
Redwoods are forest trees. We have cultivated them for use in non-forest landscapes as street and park trees, and as specimen trees. These conditions are not always favorable to their growth or long term establishment. They grow best with shade, cool root systems, abundant mulch, and continual moisture that is relatively salt free. If you can create some of these conditions in the landscape, redwood culture and disease management will be much less problematic.
Ed Perry is the emeritus Environmental Horticultural Advisor for University of California Cooperative Extension (UCCE) in Stanislaus County where he worked for over 30 years.
- Author: Anne E Schellman
On June 5, the University of California Cooperative Extension (UCCE) Stanislaus County Master Gardener Program hosted an online giving event called #BigDigDay. This was an opportunity for community members to invest in our new local program.
Together, we raised a total of $630! These funds will go towards helping us purchase needed items like a pop-up-tent, tables, chairs, brochure holders, and other materials needed for outdoor events, workshops, and classes.
Our twenty-three brand new UCCE Master Gardener volunteers will soon (July) be out in the community! Please stop by and say “hello” if you see them at the Stanislaus County Fair, a local farmers market, local nursery, or local library.
If you are interested in becoming a UCCE Master Gardener, visit our website and fill out our online interest survey. We will be recruiting for our next class soon!
If you missed out on #BigDigDay, you don't have to wait until next year to give to our program. Visit the UC Cooperative Extension website for Stanislaus County at https://donate.ucanr.edu/pages/uccestanislaus and choose “UCCE Stanislaus County - Master Gardener Fund” from the designation heading.
