Home Gardening Advice from the Help Desk of the
UC Master Gardener Program of Contra Costa County
Client's Request: I have several roses in my garden that seem to bloom forever and well into late Fall/Winter. I'm confused on when to prune them compared to others that stopped blooming a month ago or so and are already going dormant. Would you provide me some guidance on when to prune these late blooming roses?
MGCC' Help Desk Response: Thank you for contacting the UC master Gardener Program Help Desk with your questions about pruning your roses that are acting like it is springtime in November!
As we discussed earlier today on the phone, in our mild climate, it is not unusual for some roses to bloom well into November and even December, so you should not prune those roses until later in winter. UC's article on rose care says that in most of California, pruning should be done in winter before buds swell, although it may be delayed where late spring frosts are common. So, as discussed, enjoy your roses until they go dormant within the next couple of months and then prune!
Here is the link to the full UC article on rose care:
http://ipm.ucanr.edu/PMG/PESTNOTES/pn7465.html
Also, Sunset magazine says that repeat-blooming roses are usually pruned just before dormancy ends in late winter or early spring. Roses that bloom only once a season are traditionally pruned just after the bloom period ends; strong new growth produced after bloom will bear flowers the following spring.
If you have additional questions, please let us know!
Help Desk of the UC Master Gardener Program of Contra Costa County (SLH)
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/).
Advice for the Home Gardener from the Help Desk of the
UC Master Gardener Program Contra Costa County
Gardener's Request: I'm a new homeowner with a garden with clay soil apparently and trees that are now dropping leaves. How do I garden with clay soil and what should I do with the dropping tree leaves – use them in the gardening and how or disposing of them in my green bin?
MGCC's Help Desk Response: Thank you for contacting the UC Master Gardeners Program's Help Desk with your questions about gardening in clay soil, and whether to remove leaves from the landscape or incorporate them into the existing soil.
First, about gardening in your clay soil:
Your clay is made up of air, water, organic materials, and minerals. The balance of these ingredients determines your soil type. Clay soils are those that are often rich with nutrients, and renowned for their water retention capabilities, but can become compacted over time, creating a less hospitable environment for plants. This link provides information from UC Davis discussing how to work with your clay soil to get the best results. http://vric.ucdavis.edu/pdf/soil_managingclay.pdf
One of the most essential components to gardening in clay soil is creating good tilth (i.e., ability to grow plants, especially from seed). This is accomplished by carefully adding organic matter such as manure, compost, and/or planting cover crops to your existing soil. This article by a Marin County master gardener discusses the many ways that you can improve the tilth of a clay soil with organic matter. http://www.marinij.com/article/NO/20160304/FEATURES/160309921
Use of fallen tree leaves in the garden:
Thank you for submitting your questions, and I wish you luck in your gardening decisions.
Help Desk of the UC Master Gardeners Program of Contra Costa (JJM)
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/).
Help for the Home Gardener from the Help Desk of the
UC Master Gardener Program of Contra Costa County
Client Request: I have several eucalyptus trees on my property. They shed a lot of leaves. I'd like to use the leaves for mulch and possibly compost, but when I research these uses, I get confusing and/or contrary guidance. My request: Can I use eucalyptus leaves/cuttings as mulch and/or compost in the home garden?
Help Desk Response: We understand your frustration with the information you're finding on the use of eucalyptus leaves as mulch. In doing the research on your question, I too, found a lot of conflicting information. The Master Gardener Program is under the umbrella of the University of California so the information that follows is all based upon scientific research.
Eucalyptus Toxicity
While it is true that eucalyptus leaves do have some toxicity, the research shows that well composted eucalyptus leaves pose no problem when used as a mulch or when mixed at appropriate quantities into a growing medium. The research also concluded that fresh eucalyptus leaves were shown to be a good weed suppressant when applied to a depth of 4 inches (10cm).
Following are two articles by James Downer & Ben Faber on the subject of eucalyptus mulch and eucalyptus compost.
http://ceventura.ucanr.edu/newsletters/Volume_23_No129817.pdf
and
http://slosson.ucdavis.edu/newsletters/Downer_199429100.pdf
Composting
The University of California research concluded that, when handled properly, eucalyptus is safe for use in compost (i.e., incorporated into the growing medium). The toxicity of the eucalyptus are rendered harmless by the composting process, especially if you are working a hot compost pile. (See http://vric.ucdavis.edu/pdf/compost_rapidcompost.pdf)
When composting eucalyptus, the leaves are considered green plant material and will constitute the nitrogen part of the composting process. To effectively use eucalyptus clippings or leaves, you will want to mix them thoroughly with carbon-based materials such as newspaper, cardboard or other dry leaves or plant material.
The University researchers suggest, if you still have concerns, that you consider composting eucalyptus in a separate hot compost pile, keeping the pile well moistened and turning it often to keep the mix hot over a longer period of time.
Once the eucalyptus is well composted you can do a germination test to test for toxicity by using the compost as a medium to start 10-12 fast growing seeds such as radishes. If a majority of the seeds germinate, the eucalyptus toxicity can be considered neutralized by the composting process.
If you want to use fresh eucalyptus leaves in your landscape, the conclusion suggests to favor using them on the woody landscape plants in the home garden setting.
I hope this gives you the information you were looking for and sets your mind at ease.
Help Desk of the UC Master Gardener Program of Contra Costa County (BHD)
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/).
Advice for the Home Gardener from the Help Desk of the
UC Master Gardener Program of Contra Costa County
Response from the UC MGCC Help Desk: Yes, the Cotoneaster lacteus is invasive. For root sprouting species, it is very difficult to find and mechanically remove all roots. Root systems generally spread beyond the width of the leaf area by 3 - 6 inches or more. So if your desirable plants are within 1 foot of the Cotoneaster, their root systems will likely overlap, making complete removal of roots difficult.
The UC Davis guidance mentions 2 herbicides that are effective for chemical control of Cotoneaster and available in California.
Glyphosate concentrate (e.g., Roundup™ for stumps) used as a cut stump treatment is a good option for management of woody weedy invaders. To use, you would leave some of the stems protruding above ground and carefully apply the product to the cut surfaces immediately after making the cuts. A small paint brush is often used for this typr of treatment. Fall is the best time for this type of treatment since the product will be carried down into the roots. If it is not 100% effective the first time, you can re-treat the few sprouts that might come up. Glyphosate degrades quickly, does not spread to other plants in the soil, and has low toxicity to humans and other animals. Glyphosate is usually available in smaller sized containers (eg. 8 ounces). There would not be concerns about replanting if you use this method.
The triclopyr herbicide, sold as Garlon 4 ultra™, has some serious downsides, but is another option. I found a 1 quart size through a Google search of "Garlon 4 ultra" under the "shopping" tab. This herbicide is also best applied as a cut stump treatment and fall is the best time of year to do this. The serious downsides to this chemical are that it can easily spread into water sources via runoff, has a 30 day half-life (i.e. is persistent), and is very toxic to fish and other aquatic species. This product is also volatile and should only be used during cool weather when there is no wind.
If you choose to use chemical control, we recommend that you try the glyphosate concentrate first, and only resort to triclopyr if the glyphosate is not effective after 2 or more applications.
Precautions should always be taken when using pesticides, as detailed here: http://ipm.ucanr.edu/PMG/PESTNOTES/warning.html.
I hope that this information is helpful. Please do not hesitate to contact us again if you need further assistance.
Note: The 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/).
Advice from the Help Desk of the
UC Master Gardener Program of Contra Costa County
MGCC Help Desk Request:I am located in Central County. I am having issues with my lemon tree. I have attached some photos. I was hoping you could give me some advice.
I have never sprayed pesticides. I am hoping for a more organic solution to the issues. I know it might not be possible.
I have not fertilized it this year. It is on our sprinkler system so it gets water daily. Some of the leafs have spiderweb looking substance under the leafs. Some leafs are yellow. I have also noticed the spikes are very large. Thank you so much for your help.
MGCC Help Desk Response: Thank you for contacting UC Master Gardener Program with your lemon tree questions and for sending the photos. The symptoms you are seeing could be the result of various minor problems that occur on citrus. The curled leaves show signs of citrus leaf miner. Citrus leaf miners are moth larvae that create shallow tunnels in young leaves. They can distort the leaves but are generally not harmful to the tree. You are probably seeing the end result of leaf miner damage that was done previously. For more information on citrus leaf miners, see: http://ipm.ucanr.edu/PMG/PESTNOTES/pn74137.html.
We are not sure about the spiderweb type substance. It could be from an insect, e.g., whiteflies, but if so you should also find sticky areas on the leaves. Also, any pictures of the insect would be helpful. It is also possible that there are spiders on your tree. If that is the case, I would not worry. If you want the spider identified, see if you can get a photo and we will try to identify it.
The fruits look like they may have been damaged by the thorns which you indicated are very large. That would happen if the fruits were rubbing against the thorns. Is that possible? If not, another possibility would be herbicide damage. Is it possible that herbicides were used anywhere near the citrus tree? Even your neighbors? Make sure you remove the damaged fruits from the tree before we have any more rain. The damaged areas provide an opening for fungi and other diseases to get into the tree. Also, large thorns might indicate that the branch is a juvenile branch or is coming from below the graft, the "bump" near the bottom of the trunk. If from below the graft, you should consider removing that branch as it probably will not produce edible fruit.
The spots on the leaves may be from a fungus. The fungus may be the result of the watering, especially if the sprinkler system is putting water on the leaves. Make sure that the sprinkler is set low and also make sure that the sprinklers are not dampening the tree trunk. Wet tree trunks can lead to root or crown rot from fungus growing around the roots and crown (where the roots and trunk meet). Root and crown rots are serious diseases that are difficult to treat and can ultimately kill the tree.
The daily sprinkling may also be causing other problems for the overall health of your tree. Daily watering might not be supplying the citrus with enough water. Citrus, like most trees, do best with less frequent, and deep watering to promote stronger roots. To give you an example of how infrequent the watering should be, watering in the heat of summer should be done about every seven to ten days. This would be for citrus planted in the ground and with several inches of mulch under the tree out to drip line. In a pot you would need more frequent watering as they dry out faster. If other plants on your irrigation system need frequent watering, you should consider setting up a separate irrigation system on a different timer for the lemon. For more information on watering citrus, see: http://ipm.ucanr.edu/PMG/GARDEN/FRUIT/CULTURAL/citruswatering.html.
You mentioned that you had not fertilized the tree this year. Yellow leaves are a common sign of a lack of nitrogen. Citrus trees require regular fertilization, especially with nitrogen. The fertilizer should be applied in January or February (prior to bloom) with a second application in May and perhaps a third in June. This link has more information on fertilizing citrus: http://ipm.ucanr.edu/PMG/GARDEN/FRUIT/CULTURAL/citfertilization.html.
Finally, I thought that you might be interested in this general write-up on growing citrus in Contra Costa County: http://ucanr.edu/blogs/slomggarden/blogfiles/4260.pdf
Please let us know if you have any remaining questions. You are also welcome to bring plant samples into our office if you want more information. We are open Monday to Thursday, 9am to 12 noon.
Good luck with your lemon tree..
Help Desk of the UC Master Gardener Program of Contra Costa County (ECS)
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/).