Advice for the Home Gardener from the Help Desk of the
UC Master Gardener Program of Contra Costa County
pix: CalPhoto
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.
pix: MGSonoma
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/).
Advice From the Help Desk of the
UC Master Gardener Program of Contra Costa County
MGCC Help Desk Client: I've attached photos of our Patriot blueberry bush. Why are the leaves turning brown and curling? The problem began about a month ago. We tried to treat with acidifying powdered fertilizer, applied to the soil and cultivated in prior to watering. We water every other day or as needed (we check soil moisture with a short stick). The plant is now sending out new growth which looks relatively healthy.
Blueberriy showing sun burn/scald and/or water stress...
MGCC Help Desk Response: Thank you for contacting the UC Master Gardener Program Help Desk with your blueberry question. You wrote that the leaves were turning brown and curling.
Your photographs were helpful. We think the plant has been experiencing sun scald and/or water stress. Several different factors may be contributing to this.
1. Blueberries have a shallow root system. During times of high moisture demand the roots may not be able to keep the leaves hydrated. This is especially true for container plants in full sun where during significant heat spells they will likely need water every day. To help the roots function, we recommend that you put an inch or two of mulch such as wood chips, or well-decomposed compost on the top of the soil (but keep it at least an inch away from the stems). This will help the soil to remain cool and reduce water loss.
2. Shallow rooted plants are susceptible to damage from cultivation. When you apply fertilizer or acidifier, just water it in without cultivating. Plants with damaged roots will have a much more difficult time absorbing sufficient water.
3. Shallow rooted plants need room to expand sideways in order to have an adequate root volume. We recommend that you re-pot your blueberry plant into a wider container in the fall once the weather cools down (e.g. November). Wait at least 4 weeks after re-potting before applying any fertilizer.
Additional information on growing blueberries can be found at this University of California website http://ucanr.edu/sites/gardenweb/files/29062.pdf.
I hope that this information is helpful.
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 Gardeners Program of Contra Costa
Scab spots showing on leaves
UCMGCC Help Desk Response: Thank you for sending in the photo of your Toyon. It was very helpful.
Based on the picture, it looks like your Toyon has a mild form of scab. Scab is caused by various types of fungus. Scab appears first as pale or yellow dots on leaves. Affected leaves can twist or pucker. At more advanced stages, which you do not seem to have, you would see dark, olive-colored spots on the leaves. You could also find soft, velvety spots on the undersides of the leaves.
Scab is spread through the air, and more importantly by splashing water. Hot dry weather usually slows the development of scab. The disease is most active during spring rains.
To limit the spread of the disease, remove and dispose in your garbage waste bin of any fallen leaves from the plant. Avoid any overhead watering. You may also want to prune the plant to open up the canopy to allow more air on the leaves.
For more information on scab, see http://ipm.ucanr.edu/PMG/GARDEN/PLANTS/DISEASES/scab.html
For information on pruning, see http://extension.oregonstate.edu/linn/sites/default/files/pruning_pub_handout2012.pdf
Note that there are two basic types of pruning cuts: thinning (which remove entire branches) and heading (which shorten branches). You want to focus on thinning cuts which reduce plant density. See page 2 of the document for the complete descriptions of the differences.
Please let us know if you have further questions.
Good luck with your Toyon.
Help Desk of the UC Master Gardener Program of Contra Costa (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/).
UC Master Gardener Program of Contra Costa
Client's Request: My coworker brought me some red onion seeds from Mexico. I have a small garden bed in my backyard and wanted to get some general info. on planting them. Some of the questions I had were: -How deep should I plant the seeds? -how far apart? how often should I water them? and what nutrients do they need to thrive?
UCMGCC Help Desk Response: Thank you for contacting the UC Master Gardener Help Desk with your question about onion seed from Mexico.
Please help protect California agriculture by not importing foreign pests or diseases!!
If the seeds did go through inspection at the border and were Ok'd for entry, then it would be Ok to use them.
Onion seed should be planted 1/4 inch deep. Plants should be 4 - 5 inches apart - you can plant the seed more closely and then thin to the proper distance once you see which seedlings are the strongest. You may also be able to eat the “thinnings”.
If you live in west county, plant between January and September. If you live in a warmer part of the county, plant between February and October.
Keep the soil moist until the plants have emerged and look sturdy. Onion is a high water needs plant. Additional information on watering and harvesting can be found here http://ipm.ucanr.edu/PMG/GARDEN/VEGES/CULTURAL/onionwatering.html
Fertilizer needs depend upon the quality of your soil. You should test your soil for the 3 main nutrients: nitrogen, potassium and phosphorus. You should also do a pH test, since if pH is high, micronutrients may not be available to the plants. Relatively inexpensive soil test kits can be purchased at garden centers. Or, if you prefer, you can send a soil sample to be analyzed by a commercial laboratory. A suggested list of laboratories can be found at http://ccmg.ucanr.edu/files/51308.pdf. You'll want to visit their websites to learn how to take and submit samples, and what the service will cost. Once you know the condition of your soil, you can determine what nutrients would need to be added, if any. If you needed further advice about fertilizing once you have your soil test results, feel free to contact us again. Additional information on fertilizing can be found here: http://ipm.ucanr.edu/PMG/GARDEN/VEGES/CULTURAL/vegefertilizing.html.
More information about growing onions can also be found at this University of California website: http://ipm.ucanr.edu/PMG/GARDEN/VEGES/onions.html.
I hope that this information is helpful and you get some great onions.
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/).
