Green Thumb: Threat of frost looms as days grow shorter
by Linda Edwards / Submitted to the Tracy Press
Nov 08, 2012 | 2753 views | 0 0 comments | 8 8 recommendations | email to a friend | print
November is upon us, and this is a perfect time to start preparing for our first expected frost.

Protection for frost-tender perennial and tropical plants — such as citrus, hibiscus, some palms, bananas and bougainvillea — is a must for them to weather the Big Chill.

Take time now to organize what you will do and have on hand for those frosty nights.

Keep these ideas in mind:

Think about a spot indoors that receives bright light where you can move small potted patio plants. They can go back out as temperatures rise.

Pick up some protective plant wraps, something made with a material that breathes easily but keeps out cold air. Simply drape the wrap over your plant for night protection. Remove it when the sun shines.

Pre-split pipe insulation made of foam tubing works wonders to protect the trunks of small trees. Often, the trunk of a young or newly planted tree can split due to sharp temperature changes between day and night that freeze the water within the trunk. This symptom is called frost crack. Protection will help your young trees survive this.

Spraying leaves of frost-tender plants such as citrus, bougainvillea, tropical hibiscus and philodendron with a product called Cloud Cover monthly will coat the leaves and stems, providing 2 to 8 degrees of protection.

Even before the holidays, you can decorate cold-sensitive plants with outdoor Christmas tree lights. The heat they radiate moderates the cold air temperatures. You can maximize this heat source by draping or tenting your plants with a translucent plant-blanket material to create a greenhouse effect. The plant blanket alone will give you 2 to 3 degrees of protection.

Simply remembering to keep your outdoor plants well watered between rainstorms is also a plus.

The holidays also provide a great time to schedule your fruit trees for dormant spraying. Most people are not sure when this should take place. A good rule of thumb is Thanksgiving, New Year’s and Valentine’s Day.

Even before trees are leafless in winter, they benefit from applications of disease- and insect-controlling products. The first spraying should be just before or at leaf fall — about mid-November. A second spraying one week later helps ensure complete coverage.

Bark contracts with the onset of cold weather, sealing in organisms that can cause disease, such as shot hole fungus or peach leaf curl. Therefore, it is essential to spray with a copper-based fungicide before freezing weather sets in. Do not spray if rains are expected within 24 hours.

Happy gardening, as always.

The Green Thumb is a column by Tracy’s master gardeners. University of California-certified master gardeners are available to answer gardening questions from 9 a.m. to noon Tuesdays, Wednesdays and Thursdays at 953-6112 or

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