August Tips & Events for Santa Clara County
Even with insects—some can sing, some can't " Kobayashi Issa
Mole damage in lawn by Laura Monczynski
You and the moles will probably never see each other: they won’t see you due to very poor vision and you won’t see them because they live underground. But you will see the damage they do. Unlike gophers which eat plant roots, moles eat insects and worms. Yet they can do collateral damage to plant roots as they tunnel through in search of their preferred food. Plants can also suffer if the tunnels redirect water away from the roots when you try to irrigate. Moles create what look like mountain ridges as they tunnel through near the surface, and they leave behind round mounds of soil when they dive deep. The most effective way to manage them is to use traps specifically designed for moles.

Photo: mole damage in lawn, by Laura Monczynski
Rose by Kathy Keatley Garvey
Healthy Roses
Roses are notoriously susceptible to many diseases, including rust, black spot, and powdery mildew. For this reason, they are often planted at the edges of vineyards as a sentinel species to give an early warning to protect grape vines before a disease can affect the vines. Yet not everything that negatively impacts roses is a disease or pest, so don’t automatically reach for the chemicals. Abiotic disorders are caused by nonliving factors and can be addressed with cultural changes. Blackened areas on canes can be from sunburn. Brown-edged leaves may signal a high concentration of salt in the soil. Yellow leaves may be due to nutrient deficiencies. Deformed growth may be due to exposure to glyphosate, the active ingredient in Roundup. Some practices to keep your roses healthy are to choose hardy varieties, enrich the soil with compost, fertilize regularly but not too much, and irrigate directly to the root zone.

Photo: rose photo by Kathy Keatley Garvey
Pruning for small fruit trees by Allen Buchinski
Fruit Trees in Small Spaces
There are several ways to squeeze multiple fruits into a small yard. You can graft related fruits onto the same tree, so that one tree might have apricots and plums and peaches or another might have four varieties of apples. You can choose dwarf trees or trees on dwarfing rootstock. You can plant them in larger containers like half wine barrels. You can plant them close together and keep them pruned small. And you can do summer pruning after harvest in addition to dormant pruning in the winter on most trees. Just make sure to do your annual pruning of apricot and cherry trees now so that they have time to heal before it rains again.

Photo: photo by Allen Buchinski
Boxwood blight by Joan Allen U Conn
Boxwood Blight
Boxwood is an evergreen shrub typically grown as a short border hedge. It is often pruned in a straight, formal style. It has been falling out of favor as native, drought-resistant plantings are increasing in popularity. Another reason for reconsidering its use is the fairly recent arrival of a fungal disease called Boxwood Blight. It was first detected in the U.S. in Connecticut in 2011 and reported in Santa Clara County in 2017. It is spread by contact through pruning tools, gardeners’ clothing, and irrigation. This blight can show symptoms in as little as a week. Look for brown leaf spots with dark edges, white spores on the undersides of leaves, black lesions on stems, and severe dieback. Humidity and overhead watering contribute to the disease being able to take hold. Pruning infected branches, with sterilization of tools between each cut, may help. Fungicides cannot control the disease once it starts. More likely the plant will have to be removed, bagged, and thrown in the garbage.

Boxwood Blight , Purdue Botany and Plant Pathology

Photo: by Joan Allen, University of Connecticut
Asian citrus psyllid feeding on brandy from UC ANR Repository by E.M. Rogers
Protecting California
Our Agricultural Commissioner, County Biologists, UC Master Gardeners, Cal Fire, and other interested parties are always on the lookout for new pests and diseases that can threaten our agricultural economy, our gardens, and our safety. As observant gardeners and residents we can also do several things to help. Do not transport plant material from other areas unless it has been inspected, approved, or otherwise deemed safe. This includes firewood, unpackaged seeds, fruits and vegetables, and green waste. Nursery stock is inspected and is considered generally safe. Obey any quarantines in effect. Report any suspicious pests to the Master Gardener Help Desk . Do not transport a sample to the office unless instructed to do so. Master Gardeners will help identify the pest and connect you with any appropriate agencies.

Photo: Asian citrus psyllid feeding on citrus, UC by E. M. Rogers
Green Gardeners
Would you like your gardener or your neighbor’s gardener to use more environmentally friendly methods? Or would you like to learn more yourself and to become certified as a Green Gardener? The Green Gardener Program is a ten-week course sponsored by several local agencies. The course teaches a variety of topics including soil, irrigation, pruning, fertilizing, composting, plant selection, and pest management. It will be taught on Wednesdays in English and on Thursdays in Spanish beginning August 28 and continuing through the end of October. Classes meet 4:00-6:00 p.m. in Cupertino. The cost is $60 for industry professionals and $120 for others. Anyone who successfully completes the class will earn a certificate and can be listed on the website where people can find and hire them. Please share the program flyer with anyone you think might be interested. 

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Library presentation by Tuan Hoang
Upcoming Events
We offer free or low-cost gardening talks, workshops, and courses all over the county, as well as hosting information tables at many community events. Please join us and bring your questions!

Palo Alto Demo Garden Open Saturdays from 10 a.m.–noon (May–Oct)
Come see what we're growing at our  edible and water wise gardens   and get answers to your gardening questions. Feel free to bring plant pests or disease samples for identification. We're located at Eleanor Pardee Community Gardens, on Center Road near Martin Street,  Palo Alto   (v iew map ).

Sat, Aug 03, 10:00 a.m.–12:00 p.m.,  Open House - Palo Alto Demonstration Garden , Palo Alto Demonstration Garden, 851 Center Dr,  Palo Alto

Sat, Aug 03, 10:00 a.m.–11:00 a.m.,  Less Work-More Food: The Joy of a Productive Fall Vegetable Garden , Palo Alto Demonstration Garden, 851 Center Dr,  Palo Alto

Sat, Aug 10, 9:00 a.m.–11:00 a.m.,  Flower Cutting and Arranging Workshop , Martial Cottle Park, 5283 Snell Ave,  San Jose

Sat, Aug 10, 10:00 a.m.–12:00 p.m.,  Open House - Palo Alto Demonstration Garden , Palo Alto Demonstration Garden, 851 Center Dr,  Palo Alto

Sat, Aug 10, 11:30 a.m.–1:00 p.m.,  Protecting Your Home and Garden from Critters , Mountain View Library, 585 Franklin Street,  Mountain View

Tue, Aug 13, 7:00 p.m.–8:00 p.m.,  Crash Course on Succulents , Campbell Library, 77 Harrison Ave,  Campbell

Thu, Aug 15, 7:00 p.m.–8:30 p.m.,  Cool Season Vegetable Gardening , Palo Alto Rinconada Library, 1213 Newell Rd,  Palo Alto

Sat, Aug 17, 9:00 a.m.–12:00 p.m.,  Succulent Sale - Martial Cottle Park , Martial Cottle Park, 351 Chenowyth,  San Jose

Sat, Aug 17, 10:00 a.m.–12:00 p.m.,  Open House - Palo Alto Demonstration Garden , Palo Alto Demonstration Garden, 851 Center Dr,  Palo Alto

Sat, Aug 17, 10:00 a.m.–11:30 a.m.,  Learn the Basics of Food Preservation by Canning , St. Louise Hospital, 9400 No Name Uno Way,  Gilroy

Sat, Aug 17, 10:30 a.m.–12:00 p.m.,  Cover Crops for Home Gardens , Martial Cottle Park at the UC Master Gardener Parcel in the Pavilion, 5283 Snell Ave,  San Jose

Sat, Aug 17, 1:00 p.m.–3:00 p.m.,  Sustainable Pest Management , Sunnyvale Teaching and Demonstration Garden, Charles Street Gardens, 433 Charles St.,  Sunnyvale

Mon, Aug 19, 7:00 p.m.–8:30 p.m.,  Planning Your Fall and Winter Vegetable , Morgan Hill Library, 60 West Main Ave,  Morgan Hill

Wed, Aug 21, 6:30 p.m.–8:00 p.m.,  Growing Onions & Garlic , Calabazas Branch Library, 1230 S Blaney Ave,  San Jose

Sat, Aug 24, 10:00 a.m.–12:00 p.m.,  Open House - Palo Alto Demonstration Garden , Palo Alto Demonstration Garden, 851 Center Dr,  Palo Alto

Wed, Aug 28, 7:00 p.m.–8:30 p.m.,  Saving Vegetable Seeds , Los Altos Library, Orchard Room, 13 S. San Antonio Road,  Los Altos

Sat, Aug 31, 10:00 a.m.–12:00 p.m.,  Open House - Palo Alto Demonstration Garden , Palo Alto Demonstration Garden, 851 Center Dr,  Palo Alto

Wed, Sep 04, 7:00 p.m.–8:30 p.m.,  Landscaping for Wildfire Protection , Cupertino Community Hall, 10350 Torre Ave,  Cupertino
Visit the UC Master Gardener Program website  for additional information including an up-to-date list of events and classes .

Have a gardening question? Contact our Help Desk (for Santa Clara County residents). Start by reviewing our plant  problem diagnosis tips .
  • Mon-Fri 9:30 a.m.–12:30 p.m., 408-282-3105
  • Fri ONLY 1:00 p.m.–4:00 p.m., 650-329-1356 (Closed Dec. & Jan.)
  • Or send us your question online

The University of California Cooperative Extension (UCCE) Santa Clara County Master Gardener Program volunteers are trained under the auspices of the UCCE. Our mission is to promote sustainable gardening practices by providing up-to-date, research-based horticultural information to home gardeners.

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