December Tips & Events for Santa Clara County
“The garden suggests there might be a place where we can meet nature halfway” — Michael Pollen
Asian citrus psyllid UC ANR Repository
Serious Citrus Pest
Citrus is a hugely popular backyard and commercial crop for California and it is being threatened by a tiny pest. The Asian citrus psyllid spreads the pathogen for Huanglongbing from plant to plant. Unlike other citrus pests and diseases which can affect fruit, leaves, and branches, this problem, also known as Citrus Greening Disease, is lethal and untreatable. To protect your trees, inspect them for signs of the Asian citrus psyllid , particularly on the newer growth. The County of Santa Clara Department of Agriculture has established a local quarantine zone for the entire county. It is okay to transport fruit and plants within the quarantine zone. Only clean fruit—with no stems, leaves, or other plant material attached—can be moved out of the quarantine zone. Visit our website for more information.

Photos: Top, Asian citrus psyllid adult and nymphs. Middle, adult psyllid on finger at actual size. Bottom, nymphs tucked down in new leaves.
Holiday cactus Allen Buchinski
Christmas Cactus
Zygocactus has bright blooms, most commonly pink, that provide vivid color around the holidays. It can be easily propagated from stem cuttings and shared with your willing friends. While it is typically used as a houseplant, in our area it can be grown outdoors in a container if it is protected from frost and strong sun. In spite of the cactus in the name, it originated in the forests of Brazil, growing on tree branches. To mimic its native conditions and help it thrive, give it well-drained soil, regular water, and frequent fertilizer. To help it bloom every year, also give it cool temperatures and 12-16 hours of darkness per day in December. Yet it does fairly well without a lot of fuss.

Care and re-blooming info: UC Publication 8114 Holiday Cacti
Photo by Allen Buchinski
Pruning shears by Allen Buchinski
Tool Maintenance
If the wet and cold are making you avoid working in the garden, you can use this time to get your garden tools in good shape. It’s good to clean them after each use and keep them sharpened. But if you’ve been neglecting these tasks, you can catch up now. You can clean dirty tools with a foaming bathroom cleaner. Remove buildup and rust with a wire brush, flat headed screw driver, and a steel wood pad. Many sharpening tools are available on the market, including carbide, diamond, or a simple sharpening stone. Start with the coarse side of the sharpener. Sharpen in small circular motions at the same angle as the blade (or with carbide, slide it along the full blade). Then finish off with the fine grit. Applying a little household oil to the moving parts keeps the tools operating smoothly. Well-maintained tools help keep both the garden and the gardener healthy.

Photo by Allen Buchinski
Living Christmas Tree - by Our City Forest
Living Christmas Trees
You might consider an eco-friendly living Christmas tree this year. This is a live tree, in soil and in a container, that can continue to live after the holidays. You can plant it in your yard or keep it in the container outside to use again next year. Our City Forest is a local nonprofit that rents out living trees that are later returned to them and then planted out into the community ( rent-a-tree website ). It is important to keep the trees as cool and moist as possible as they can easily dry out indoors. That might mean that they are indoors and decorated for a shorter period of time. The tree might be a little smaller, but so is the carbon footprint.

Photo by Our CityForest
Yellow onions - MorgueFile Free Photo
Onions can be grown from seeds, sets, or transplants. Transplants are the best choice for this time of year and generally result in larger bulbs and better long-term storage. They need loose soil and plenty of fertilizer. Amending soil with compost will help with drainage and fertility. Plant the tiny green onions 4-5 inches apart to give room for the bulbs to expand. Water them in the absence of rain, and cut back on fertilizer when the bulbs start to emerge above the soil. The onions will be fully mature when the tops die back and fall over next summer, but they can be harvested and eaten any time as green onions or small bulb onions.  

Photo: yellow garden onions, Morguefile Free Photo
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Upcoming Events
We offer lots of 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!

Sat, Dec 15, 9:00 a.m.–12:00 p.m.,  Succulents Plant Sale , Martial Cottle Park-Master Gardener Area, : 5283 Snell Ave,  San Jose

Sat, Jan 12, 3:00 p.m.–4:00 p.m.,  Marvelous Succulents: How to Grow and Create Attractive Containers , Willow Glen Public Library, 1157 Minnesota Ave,  San Jose

Sat, Jan 26, 2:00 p.m.–4:00 p.m.,  Fruit Tree Selection and Care , Program Room, Sunnyvale Public Library, 665 W Olive Ave Sunnyvale 94086,  Sunnyvale

Wed, Jan 30, 7:00 p.m.–8:30 p.m.,  Back Yard Fruit Tree Basics , Library, Orchard Room, 13 S. San Antonio Road,  Los Altos
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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