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September Tips & Events for Santa Clara County
“Someone's sitting in the shade today because someone planted a tree a long time ago." — Warren Buffett
Asian Vegetables
You can easily grow some vegetables used in different types of Asian cuisine and found in Asian markets. They are not necessarily native to Asia but have found their way into various cuisines. One way to decide which food to grow yourself is to choose varieties that aren't readily available or are more expensive in your local markets. It’s also fun to impress your family, friends, and neighbors with something they may not have seen growing before. Possibilities include sesame seeds, bittermelon, daikon radishes, gai choy, and opo. You can start cruciferous vegetables such as bok choy and Napa cabbage from seed now.

More Information: Asian Vegetable Varieties

Photo: Sesame pods, by Barbara Williams-Sheng
Oleander by Allen Buchinski
These plants are obviously not terribly picky about conditions if they live and thrive in freeway medians. Oleander are drought tolerant once established. They rarely, if ever, need to be fertilized in our local soils or sprayed or pruned. But if you want to prune them to fit into a small yard space or to make them look like a tree rather than a bush, you can do so now. As with all pruning, first cut out any dead or dying branches. Then cut any that are deformed or growing in an undesirable direction. After that you can prune for size and shape. Cut it back to a little smaller than the size you ultimately want, keeping in mind that it will regrow. Take care not to prune off more than one third of the plant at a time. Make cuts above nodes that face out in the direction in which you want new growth to go. All parts of the plant are poisonous so do not eat it, burn it, or work on it without gloves. The good news is that this latter quality makes it deer resistant.

More Information: Oleander characteristics

Photo by Allen Buchinski
Powdery mildew on grape leaf UC image by Jack Kelly Clark
Powdery Mildew
Many plants are susceptible to powdery mildew , and different strains of the fungus attack different families of plants. It occurs on plants as varied as crape myrtle, roses, grapes, and squash. Unlike most other fungi, it does not need moisture to thrive. We tend to see a lot of it in September as we still have warm dry days, yet the nights are starting to cool off. Early symptoms include yellow chlorotic spots on the leaves. The presence of the fungus becomes obvious as it starts to produce spores that look like white powder on leaves and sometimes on fruit. Eventually the leaves will turn brown and dry. Some strategies for dealing with powdery mildew are planting resistant varieties, washing off powder in the mornings, using sulfur sprays (careful with edibles), and removing affected parts.

More Information about powdery mildew on:

Photo: powdery mildew on grape leaf, UC image by Jack Kelly Clark
Ornamental Trees and Bushes
Spring is when thoughts turn to planting, yet fall is an excellent time to plant perennials. You can plant many trees, shrubs, and other long-lasting plants now. This applies particularly well to California native plants. Putting them in now will give them a chance to start developing strong root systems with the winter rains, before they are stressed by summer heat. When choosing plants, consider our general Mediterranean climate as well as the microclimate of your yard. Sun times, water needs, wind exposure, and soil type can all impact the success of a plant. Make sure you know how large the plant will become, even if it looks innocent now in a one gallon or five gallon container.

More Information: Tree Selection Guide
Tree planting illustration from UC Master Gardeners Handbook V2
Illustration: Planting a Tree from a Container: California Master Gardener Handbook v2
Scotch boom by Allen Buchinski
Invasive Plants

Plants not native to a particular area that are either planted on purpose or hitchhike in can escape into the wild and disrupt existing habitats. They can displace native plants and therefore the native wildlife that depend on those native plants for survival. They can also do significant environmental and economic damage. You are probably already aware of the risks if you live near open space or a sensitive ecosystem. Yet closed-in backyards in an urban or suburban area can also contribute to the problem. Remember that birds and animals can carry seeds long distances. With just a little research you can avoid using plants that are unfriendly to the Bay Area. The California Invasive Plant Council (Cal-IPC) Don’t Plant a Pest! website will help you find alternatives to common invasive plants.

Photo: Scotch broom growing in Sanborn County Park, by Allen Buchinski
Giving plant advice to the public at an event
Fall Garden Market

There are many reasons to start vegetables from transplants. They will be bigger and stronger when they go into the ground and are therefore less likely to be eaten by critters. They can stay in their pots, or be potted up into larger pots, while you continue to enjoy your current harvest. And buying them at the Master Gardeners Fall Garden Market will give you access to varieties not seen in local nurseries. You will also help support the programs the Master Gardeners offer to the gardening public all year long. We hope that you will enjoy the cool season vegetables we have seeded for you, and also the Master Gardener classes and workshops, research and demonstration gardens, help desk, and various events offered throughout the county. The 2019 Fall Garden Market will take place Saturday, October 5, 10:00-3:00, at Martial Cottle Park in San Jose. 

More Information: Fall Garden Market Vegetables
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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 ).

Wed, Sep 04, 7:00 p.m.–8:30 p.m.,  Landscaping for Wildfire Protection , Cupertino Community Hall, 10350 Torre Ave,  Cupertino

Wed, Sep 04, 7:00 p.m.–8:30 p.m., Planning Your Fall and Winter Vegetable Garden , Gilroy Library, 350 W. 6th St, Gilroy

Sat, Sep 07, 10:00 a.m.–12:00 p.m., Open House - Palo Alto Demonstration Garden , 851 Center Dr, Palo Alto

Sat, Sep 07, 10:00 a.m.–11:00 a.m., Compost! , Palo Alto Demonstration Garden, 851 Center Dr, Palo Alto

Sun, Sep 08, 2:00 p.m.–3:00 p.m., Saving Seeds , Eddie Souza Community Garden, Monroe and San Thomas Expressway, Santa Clara

Tue, Sep 10, 7:00 p.m.–8:30 p.m., Growing Garlic , Campbell Library, 77 Harrison Ave, Campbell

Sat, Sep 14, 10:00 a.m.–11:30 a.m., Selecting California Natives , The Board Room in St. Louise Hospital, 9400 No Name Uno Way, Gilroy

Sat, Sep 14, 10:00 a.m.–12:00 p.m., Open House - Palo Alto Demonstration Garden , 851 Center Dr, Palo Alto

Mon, Sep 16, 7:00 p.m.–9:00 p.m., Beautiful Waterwise Landscaping ($55), 10123 N. Wolfe Road, Suite 2085, Cupertino

Thu, Sep 19, 7:00 p.m.–8:30 p.m., An Early Start For Your Winter Garden: Growing From Seed , Santa Clara Central Park Public Library, 2635 Homestead Rd, Santa Clara

Sat, Sep 21, 10:00 a.m.–12:00 p.m., Open House - Palo Alto Demonstration Garden , 851 Center Dr, Palo Alto

Sat, Sep 21, 10:30 a.m.–12:00 p.m., Wonderful Winter Vegetables , Martial Cottle Park, 5283 Snell Ave, San Jose

Sat, Sep 21, 11:00 a.m.–12:30 p.m., Saving Vegetable Seeds , Berryessa Library Community Room, 3355 Noble Ave, San Jose

Sat, Sep 21, 1:00 p.m.–3:00 p.m., A Plant for All Reasons - Succulents in Pots & in Ground; Indoors & Out! , Sunnyvale Teaching and Demonstration Garden, Charles Street Gardens, 433 Charles St, Sunnyvale

Mon, Sep 23, 7:00 p.m.–8:30 p.m., Trees and Shrubs to Plant in Fall , Morgan Hill Library, 60 West Main Ave, Morgan Hill

Wed, Sep 25, 6:30 p.m.–8:00 p.m., Success with Cool Season Vegetables , West Valley Branch Library, 1243 San Tomas Aquino Rd, San Jose

Wed, Sep 25, 7:00 p.m.–8:30 p.m., Spice it Up : Growing Garlic & Ginger & Chives , Los Altos Library, 13 S. San Antonio Rd, Orchard Room, Los Altos

Sat, Sep 28, 10:00 a.m.–11:00 a.m., Plant Your California Natives Now! , Martial Cottle Park, 5283 Snell Ave, San Jose

Sat, Sep 28, 10:00 a.m.–12:00 p.m., Fall Vegetable Garden Market , Palo Alto Demonstration Garden, 851 Center St, Palo Alto

Sat, Sep 28, 10:00 a.m.–12:00 p.m., Open House - Palo Alto Demonstration Garden , 851 Center Dr, Palo Alto

Sat, Sep 28, 11:00 a.m.–12:00 p.m., How I Succeeded With Native Annual Wildflowers , Martial Cottle Park, 5283 Snell Ave, San Jose

Sat, Oct 05, 10:00 a.m.–3:00 p.m., Fall Garden Market - Martial Cottle Park , Martial Cottle Park, 5283 Snell Ave, San Jose

Sat, Oct 05, 10:00 a.m.–12:00 p.m., Open House - Palo Alto Demonstration Garden , 851 Center Dr, Palo Alto
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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