Advice for the Home Gardener from the Help Desk of the
UC Master Gardener Program of Contra Costa County
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Help Desk Response: Thank you for contacting the UC Master Gardener Program of Contra Costa County. We are unable to locate any specific research which directly addresses your question about fountain height as a raccoon deterrence but have some general recommendations. We also know that raccoons are quite agile, strong, and industrious in the garden, especially where water features are present.
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It is appropriate for you to deter raccoons from using your fountain as the Center for Disease Control and Prevention (CDC) states that raccoons like to defecate in shallow water (and elsewhere as well) and their feces can contain eggs of the worm Baylisascaris Procyonis, which can infect humans and cause a neurological illness. The CDC recommends placing spikes at the bottom of the pool (e.g., nails in boards would work). Other possible deterrents are to install a fountain that has steep rather than sloping sides, dropping to a foot or more, and/or to cover the fountain with a heavy screen at night.
The University of California Integrated Pest Management Program (IPM) recommends a number of steps for managing raccoon pests which include how to detect their presence, habitat modification, and exclusion. The overall recommendation is to ensure that you and your neighbors are not attracting them by providing them food or nesting dens. If the suggestions above don't work, excluding them from pools (or fountains) can also be accomplished by installing commercially available devices with one or two low-lying electric wires, 6 and 12 inches from the ground, around the pond or fountain, and activated only at night via a timer.
For additional information on raccoons in the garden, please see the UC Pest Note below:.
http://ipm.ucanr.edu/PMG/PESTNOTES/pn74116.html
Thank you again for contacting us and please let us know if you have any additional questions.
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Help Desk of the UC Master Gardener Program of Contra Costa County (NP)
Note: The UC Master Gardeners Program of Contra Costa's Help Desk is available year-round to answer your gardening questions. Except for a few holidays, we're open every week, Monday through Thursday for walk-ins from 9:00 am to Noon at 75 Santa Barbara Road, 2d Floor, Pleasant Hill, CA 94523. We can also be reached via telephone: (925)646-6586, email: ccmg@ucanr.edu, or on the web at http://ccmg.ucanr.edu/Ask_Us/ MGCC Blogs can be found at http://ccmg.ucanr.edu/HortCoCo/ You can also subscribe to the Blog (http://ucanr.edu/blogs/CCMGBlog/).
/span>Advice for the Home Gardener from the Help Desk of the
UC Master Gardener Program of Contra Costa County
Client's Request: I recently found out about your program at Todos Santos Square Farmer's Market in Concord. I spoke to one of your representatives about creating some privacy in our backyard, and he told me to consider privet because it can grow up to 40 feet high. I went to Home Depot, but they only have privet that grows to 7-8 feet. Could you please give me the name of privet that can grow up to 40 feet? Thank you!
The Glossy Privet, Ligustrum lucida, is the tallest privet; other privets grow up to 15 feet. Whilst the Glossy Privet is attractive and can grow quickly to 20-40', it also comes with significant maintenance problems. It naturalizes very easily and seedlings from the “fruit” (i.e., berries) will sprout virtually everywhere (even in groundcover). In fact, it is on the watch list of the California Invasive Plant Council (as are two other privets). Fruit drop can cause a mess unless trimmed early, and trimming will eventually prove difficult and expensive as your hedge grows taller. These issues are probably the reason that it is hard to find in stores.
Fortunately, there are several good alternatives to privets. For attractive taller hedges, you might consider:
Hop Bush, Dodonea viscosa 12-18 tall, 6-8' wide
Pacific Wax Myrtle, Myrica californica 15-30' tall and wide
Strawberry Tree, Arbutus Uneda 15-30' tall and wide
Sweet Viburnam, Viburnum awabuki 12' tall 8' wide
Pittisporum - several species
Photinia - several species
I have included suggestions above 10' tall as this height usually provides good privacy and is more manageable in terms of trimming than a 40' hedge!
When making your selection, please check these plants for temperature, soil and water needs for your location, as well as other criteria that are important to you.
If you would like to explore other options, we recommend the Sunset Western Garden Book and Plants and EBMUD's Landscapes for Summer-Dry Climates in the San Francisco Bay Area. These books have lists of plants suitable for hedges and screens, as well as plant descriptions and great photographs. Both are normally available through the Contra Costa Public Library, online, or local book stores.
Please do not hesitate to contact the Help Desk if you have further questions.
Help Desk of the UC Master Gardener Program of Contra Costa County (GHG)
Note: The UC Master Gardeners Program of Contra Costa's Help Desk is available year-round to answer your gardening questions. Except for a few holidays, we're open every week, Monday through Thursday for walk-ins from 9:00 am to Noon at 75 Santa Barbara Road, 2d Floor, Pleasant Hill, CA 94523. We can also be reached via telephone: (925)646-6586, email: ccmg@ucanr.edu, or on the web at http://ccmg.ucanr.edu/Ask_Us/ MGCC Blogs can be found at http://ccmg.ucanr.edu/HortCoCo/ You can also subscribe to the Blog (http://ucanr.edu/blogs/CCMGBlog/).
/span>Advice for the Home Gardener from the Help Desk of the
UC Master Gardener Program of Contra Costa County
Help Desk Response (via email after phone conversation followup to original email request) Thank you for contacting the UC Master Gardener Help Desk. It was nice to speak with you about your unidentified plant with “black stuff” on the leaves. As we discussed, your plants have sooty mold covering the tops of the leaves. It's growing on the honeydew that was excreted by insects living under the leaves above. From your description, those insects are most likely scales of some kind.
The sooty mold is really no problem for the plant, except in extreme cases where it blocks the sun and stops photosynthesis. It won't spread to other plants that don't have honeydew on them. Here's a link to more information about it: http://ipm.ucanr.edu/PMG/PESTNOTES/pn74108.html.
Many species are well controlled by natural enemies, but ants can protect the scales against the predators, so take measures to control the ants. Spraying horticultural oil during the dormant season or early summer when crawlers are moving may be all the treatment you need.
Information about scales and their control: http://ipm.ucanr.edu/PMG/PESTNOTES/pn7408.html and
Information about ants and their control: http://ipm.ucanr.edu/PMG/PESTNOTES/pn7411.html
Please let us know if you have more questions.
Help Desk of the UC Master Gardener Program of Contra Costa County (SEH)
Note: The UC Master Gardeners Program of Contra Costa's Help Desk is available year-round to answer your gardening questions. Except for a few holidays, we're open every week, Monday through Thursday for walk-ins from 9:00 am to Noon at 75 Santa Barbara Road, 2d Floor, Pleasant Hill, CA 94523. We can also be reached via telephone: (925)646-6586, email: ccmg@ucanr.edu, or on the web at http://ccmg.ucanr.edu/Ask_Us/ MGCC Blogs can be found at http://ccmg.ucanr.edu/HortCoCo/ You can also subscribe to the Blog (http://ucanr.edu/blogs/CCMGBlog/).
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Help for the Home Gardener from the Help Desk of the
UC Master Gardener Program of Contra Costa County
Help Desk Response: Thank you for contacting the UC Master Gardener Program Help Desk with your question about managing poison oak (Toxicodendron diversilobum) on your back yard hillside that has yet to be landscaped. Poison oak thrives in uncultivated areas so it is not surprising that you would have a healthy population of it on your hillside.
Poison oak eradication and control can be a formidable task, especially for a home gardener.
University of California guidance is: “The primary ways of managing poison oak are mechanical removal by hand pulling, which is not recommended for individuals who are sensitive to this plant, and treatment with herbicides. Maintaining a healthy cover of desirable vegetation will reduce potential invasion. This is easiest where you have available irrigation and regularly cultivated soil.”
You mentioned that herbicide had been applied several years ago but that the poison oak has grown back. Unfortunately, one application of herbicide is not expected to control poison oak. It will resprout, and the new growth should be treated again. The timing of herbicide treatment is also important for effectiveness, and different herbicides have different optimal application timing related to the plant growth stage.
Spraying the leaves with herbicide is most effective after leaves are fully developed and when the plant is actively growing. This period is normally from April into June or July, when soil moisture is still adequate.
Glyphosate is one of the most effective herbicides for controlling poison oak. However, effective control depends upon the proper timing of the application. Apply glyphosate late in the growth cycle, after the fruit has formed but before leaves have lost their green color. Be sure to check the product label before you buy: you should apply glyphosate as a 2% solution in water. Products or spray mixtures containing less than 2% glyphosate may not effectively control poison oak.
Auxinic herbicides such as triclopyr, 2,4-D, dicamba, and combinations of these herbicides also control poison oak. You can apply these herbicides earlier than glyphosate when plants are growing rapidly from spring to midsummer.
If you want to begin controlling the poison oak right away, we recommend that you use triclopyr, 2,4-D, dicamba, or combinations of these herbicides, as described above. If you want to wait until later, or if you treat now and then there is resprouting later in the season, a 2% solution of glyphosate would be your best choice.
Be sure to follow all label directions when using a herbicide, and take precautions to avoid endangering yourself, other persons, pets, wildlife, and sensitive plants that you do not wish to kill. A discussion of precautions can be found at this University of California website: http://ipm.ucanr.edu/PMG/PESTNOTES/warning.html.
Additional information about poison oak can also be found here http://ipm.ucanr.edu/PMG/PESTNOTES/pn7431.html.
I hope that this information is helpful.
Help Desk of the UC Master Gardener Program of Contra Costa County (JL)
Note: The UC Master Gardeners Program of Contra Costa's Help Desk is available year-round to answer your gardening questions. Except for a few holidays, we're open every week, Monday through Thursday for walk-ins from 9:00 am to Noon at 75 Santa Barbara Road, 2d Floor, Pleasant Hill, CA 94523. We can also be reached via telephone: (925) 646-6586, email: ccmg@ucanr.edu, or on the web at http://ccmg.ucanr.edu/Ask_Us/ MGCC Blogs can be found at http://ccmg.ucanr.edu/HortCoCo/ You can also subscribe to the Blog (http://ucanr.edu/blogs/CCMGBlog/).
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Advice from the Help Desk of the
UC Master Gardener Program of Contra Costa County
Response from the Help Desk: Thank you for contacting the UC Master Gardener Program Help Desk, and for resending the photos of your plum tree.
It looks like your tree is heavily infested with Kuno scale (Eulecanium kunoense), which is a common pest in plum trees in the Bay Area. Kuno scale females are almost spherical, resembling beads on stems. They are dark brown and shiny most of the year, turning yellow/orangish during egg production in spring. The nymphs (young scale) are yellow or brown and flattened. They feed on leaves during summer, then go to the branches to overwinter. There is one generation per year. This link will take you information from the University of California on Kuno scale: http://ipm.ucanr.edu/PMG/GARDEN/PLANTS/INVERT/kuno.html. And for more information on scale management in general: http://ipm.ucanr.edu/PMG/PESTNOTES/pn7408.html.
Scales secrete honeydew, a sticky sweet substance that attracts ants. Ants in turn protect the scales from their natural enemies that could help control their population. So, the first thing to do is to control the ants. If the tree's branches touch other plants or structures, prune those branches back so the ants don't have that access route. Use a sticky substance on the trunk to prevent ants' access that way. Wrap the trunk with a collar of heavy paper, duct tape, or fabric tree wrap and coat it with a sticky material such as Tanglefoot. Check the coating every week or so, and stir it to expose new sticky material. If left too long, ants, other insects, and debris will collect on it and obscure the sticky material, allowing access once again. You should also be aware and check to assure that birds occasionally get stuck in this substance trying to eat the trapped ants, etc.
You can also use bait stations to reduce the ant population. Borate-based products seem to be the most effective, as the bait is sugar based and should attract the honeydew-eating ants. Place the station near the base of the tree. Ant baits take a while to work, so it may be a while before you see any results. This link will take you to information on ant management: http://ipm.ucanr.edu/PMG/GARDEN/CONTROLS/antmanagement.html. For more information about ants: http://ipm.ucanr.edu/PMG/PESTNOTES/pn7411.html.
You mus also make sure you are giving good cultural care to your tree, especially with adequate irrigation, to make it more resistant to scale damage. To immediately reduce the scale population, you can prune off the most heavily infested twigs or branches, if that's appropriate for the tree's form. Your pictures look like it is a mature plum that might benefit from a little summer pruning anyway. By opening up the tree, it may increase scale mortality from exposure to heat and predators.
Chemical controls can be used for especially bad infestations. Horticultural oils (narrow-range, superior or supreme), insecticidal soaps, neem oil, or other botanical oils have low toxicity to people and pets, and appropriately applied should have little impact on pollinators and natural enemies. Make sure you follow all instructions on the products' labels, looking especially for which plants not to use the product on. For your plum, spraying with an oil during the dormant season may be the easiest. Foliage spray can be effective to get the nymphs in their crawling stage, but it can be difficult to make sure the product covers all leaf surfaces on a large tree.
To recap: Ant control is the first thing to do. Good cultural care is next. To encourage natural enemies, grow a variety of flowering plants to help attract and support them. Adults of predatory bugs, lacewings, lady beetles, and parasitic wasps live longer, lay more eggs, and kill more scales when they have plant nectar or pollen and insect honeydew to feed on.
It will take several months of efforts (such as controlling ants) or until the next season or longer before scale populations are reduced by biological control. If the level of scales is still intolerable, then consider spraying insecticidal oils to reduce scale populations while conserving natural enemies.
Please let us know if you have further questions.
Good luck with your plum tree!
Help Desk of the UC Master Gardener Program of Contra Costa County (SEH)
Note: The UC Master Gardeners Program of Contra Costa's Help Desk is available year-round to answer your gardening questions. Except for a few holidays, we're open every week, Monday through Thursday for walk-ins from 9:00 am to Noon at 75 Santa Barbara Road, 2d Floor, Pleasant Hill, CA 94523. We can also be reached via telephone: (925) 646-6586, email: ccmg@ucanr.edu, or on the web at http://ccmg.ucanr.edu/Ask_Us/ MGCC Blogs can be found at http://ccmg.ucanr.edu/HortCoCo/ You can also subscribe to the Blog (http://ucanr.edu/blogs/CCMGBlog/).
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