July Tips & Events for Santa Clara County
“Gardening is the work of a lifetime: you never finish.”
~Oscar de la Renta
Monthly Tips
Quiz: What’s eating my fruit?
Your fruit is finally getting larger, and you can’t wait until it is ready to be picked! One day, you notice that part of the fruit has been chewed up. What ate your fruit? Was it a squirrel, a rat, a bird, or something else? How can you tell?
Photo: Damaged peach fruit, Ying Chen
Picture of a damaged peach still on the tree
Tomato Catfacing
Tomato Catfacing
Catfacing refers to misshapen puckering and scarring on the blossom end of tomatoes. It’s an environmental problem, not a disease, and can be caused by unusually high or low temperatures or cool, cloudy conditions at the time the flowers are setting fruit. Some varieties, especially large beefsteak types, are more susceptible to it. There’s little a gardener can do to avoid it, other than planting varieties that are less likely to catface. The good news is that catfaced tomatoes are generally still fine for eating once the damaged tissue is cut off, as long as no rot-causing organisms gained entry.

Photo: Catfacing on a tomato, Gerald Brust, University of Maryland
Decay in Trees
Shelf-like fungus or mushrooms growing on trees indicates advanced internal decay. Once these external fruiting structures appear, the infection is likely widespread inside the tree. To reduce the chance of infection, protect trees from injury, provide adequate water and fertilization, and prune trees correctly when young to avoid significant pruning cuts when they’re older. Regularly inspect trees and consult an arborist if you spot fungal growths or other signs of decay. The arborist can assess the extent of rot and the structural integrity and make recommendations.
Photo: Shelf fungus on tree trunk, Candace Simpson
Photo of a person looking at a large shelf fungus growing on a tree trunk
Shothole borer infestation on a Sycamore tree
Pest Update:
There’s Good News and Bad News
First, the good news: the California Department of Food & Agriculture and the USDA have declared the end of the Oriental fruit fly quarantine in Santa Clara County.

The bad news: The highly destructive shothole borer has arrived, posing an imminent threat to trees commonly found in urban landscapes and natural forests. No bigger than a sesame seed, the beetles tunnel into trees and introduce a fungus that they use as their food source. As the fungus grows, it causes a disease that kills branches or entire trees. This sobering video describes the problem and how to mitigate the threat.

Photo: This sycamore tree, a preferred host of the polyphagous shothole borer, shows signs of a severe infection, Drew Raymond, Santa Clara Department of Agriculture
Spider Mites
Spider mite webbing on a rose plant
As the days get hotter and drier, you might notice a large amount of webbing covering your plants. This is likely caused by spider mites. These tiny pests, less than 1/20 inch long, are closely related to spiders. They attack a wide variety of plants by sucking plant juices from leaves and flowers. At first, the damage shows up as stippling—light-colored dots on leaves. Eventually, leaves may turn yellow/reddish and drop. Damage is usually worse when plants are water-stressed. When managing spider mites, make sure to water the plants sufficiently and spray the leaves daily to wash off dust and mites.

Photo: Spider mite webbing on a plant, Ying Chen
Some Soil Just Wants to Stay Dry
Picture of a person watering plants using a blue plastic watering can
If you water your potted plants and see water drain quickly from the bottom, you may assume the soil is saturated. Not so fast. Many soils become hydrophobic—meaning they repel waterwhen they dry out. The water simply runs down the inside of the pot, and the root ball stays completely dry. To rehydrate small container plants, submerge the pot in a bucket of water. You’ll see air bubbles escape as water fully penetrates the soil. You can also set the pot in a shallow water container for about an hour to rewet the soil. With large containers, trickle water slowly so it has time to be absorbed.

Photo credit: Unsplash
Quiz Answer
To figure out what’s eating your fruit, start by narrowing down the list of possible pests in your area. Observe whether the damage is likely caused by insects, birds, or rodents. Birds tend to peck at ripe fruits, and rodents take bites. Also observe what time of day the damage happens. Squirrels are active during the daytime, and rats are mainly active at night. Look for other signs, such as placement of the damaged fruits, tracks, and possibly droppings, and compare that to the habits of the pest you suspect. When you are sure what the pest is, you can take appropriate action to protect your fruits.
Rat damage on tomato
Photo: Rat damage on tomato, B. Messenger-Sikes
Photo: Aphid images, by Jack Kelly Clark, UC
In the June issue of Tips and Events, we stated that neem or canola oil wouldn’t harm natural enemies. While horticultural oils leave no toxic residue and won’t kill insects that arrive after the oil is applied, natural enemies can still be killed if they are directly sprayed. Use Integrated Pest Management practices, including applying pesticides only when needed, to minimize risks to people and the environment.
Upcoming Events
Our monthly Plant Clinic Online is an opportunity to chat with a Master Gardener via Zoom to diagnose a plant problem. You can also listen and learn while other people ask questions. It takes place on the second Tuesday of the month (July 9), from 7–8:30 pm. Priority will be given to questions that are emailed in advance; instructions are in the Zoom registration confirmation. Registration required.

PADG Open Garden Saturdays, Saturday, July 6, 10 am–noon, Palo Alto Demonstration Garden, 851 Center Drive, Palo Alto

How Does Your Veggie Garden Grow?, Saturday, July 6, 10–11 am, Palo Alto Demonstration Garden, 851 Center Drive, Palo Alto

Container Gardening, Tuesday, July 9, 6:30–7:30 pm, First Floor, Mountain View Public Library, 585 Franklin Street, Mountain View

Plant Clinic Online, Tuesday, July 9, 7–8:30 pm, Online

PADG Open Garden Saturdays, Saturday, July 13, 10 am–noon, Palo Alto Demonstration Garden, 851 Center Drive, Palo Alto

STDG Ask a Master Gardener, Saturday, July 13, 10 am–noon, Sunnyvale Teaching and Demonstration Garden, Charles Street Gardens, 433 Charles Street, Sunnyvale

MCP Open Garden Sundays, Sunday, July 14, 1–3 pm, Martial Cottle Park, 5283 Snell Avenue, San Jose

Top Ten Habits of Happy and Successful Gardeners, Sunday, July 14, 1:30–2:30 pm, Rinconada Library, 1213 Newell Road, Palo Alto

Container Gardening!, Wednesday, July 17, 7–8:30 pm, Los Altos Library, 13 S. San Antonio Road, Los Altos

Common Wood Decay Fungi in Landscape Trees of California, Thursday, July 18, noon–1 pm, Online

MCP Succulent Open House & Sale, Saturday, July 20, 9 am–noon, Martial Cottle Park, 5283 Snell Avenue, San Jose

PADG Open Garden Saturdays, Saturday, July 20, 10 am–noon, Palo Alto Demonstration Garden, 851 Center Drive, Palo Alto

Special Kids Event: What’s All the Buzz about Pollinators?, Saturday, July 20, 10:30–11:30 am, Willow Glen Public Library, 1157 Minnesota Avenue, San Jose

STDG Garden Structures, Saturday, July 20, 1–3 pm, Sunnyvale Teaching and Demonstration Garden, Charles Street Gardens, 433 Charles Street, Sunnyvale

MCP Flower Cutting and Arranging Workshop, Sunday, July 21, 10 am–noon, Martial Cottle Park, 5283 Snell Avenue, San Jose

PADG Open Garden Saturdays, Saturday, July 27, 10 am–noon, Palo Alto Demonstration Garden, 851 Center Drive, Palo Alto

Gardening Is for the Birds—Reasons to Plant CA Natives!, Saturday, July 27, 11 am–12:30 pm, Berryessa Public Library, 3355 Noble Avenue, San Jose
Check our calendar for the latest schedule of events. Videos of many past presentations are also available.
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