East Contra Costa County Residents, this is your day! This Saturday, April 16, from 10:00 am to 3:00 pm at the Mangini Agricultural Museum at the Contra Costa County Fairgrounds in Antioch the Contra Costa County Master Gardeners will be hosting an East County edition of the 5th Annual Great Tomato Plant Sale. This is the first year we have brought our plants to Antioch, and we are happy to have an opportunity to meet and serve more East County residents.

For more information on the sale, please go here. For a shopping guide of tomato varieties that will be available in Antioch, please go here.

We hope the Antioch sale is a huge success, and we can't wait to see you there!

Garden Advice from the Help Desk of the
UC Master Gardener Program of Contra Costa County

Client's Request:  I have several citrus trees. I would like advice on why my citrus aren't producing. What's wrong? What can I do?

UC MGCC Program's Help Desk Response:  Thank you for contacting Master Gardeners' with your citrus question. We would need to have more information about your citrus trees in order to pinpoint the reason that they are not producing. We can suggest a few possible causes for the lack of production that may give you sufficient guidance. If you don't think any of the causes that I've listed applies to your trees, you can provide us with more information about your trees (see the list of questions at the end of the blog) to help us focus more closely on what is causing your problems.

One possible cause of the non-fruiting could be the age of the tree. Many varieties of citrus do not produce fruit until their third year. I have a satsuma mandarin tree growing in a large container that took four years after planting to start producing. Some other citrus varieties (including, for example, Meyer lemons) may start producing at a younger age, but the fruit that is produced in the early years is often smaller than the tree will produce as it matures, and in the early years the fruit can also appear very rough and misshapen.

Another possible cause of non-fruiting could be a lack of sun or inadequate irrigation. Citrus performs best when it receives the sun for most of the day. Proper irrigation is also important. An under-watered citrus tree will produce few if any fruits. But it is also important not to overwater citrus which can also cause problems. This link from the UC Master Gardener Program of Orange County has some very good guidance on how to water citrus:  http://mgorange.ucanr.edu/Edible_Plants/?uid=58&ds=530

Lack of soil fertility could also cause problems. Citrus does need to be fertilized. The Orange County MG site referenced above also has good information on how and when to fertilize citrus with guidance on how much fertilizer to use (which depends on the age and size of the trees).

Another possible cause for nonproducing citrus trees is a lack of pollination. While many citrus varieties are capable of producing fruit without bees or other pollinizers visiting the flowers, a few varieties do require cross-pollination.  For example, some clementines and mandarin hybrids require cross pollination by another tree to produce fruit. (Other mandarin varieties can produce without pollinizers and commercial growers sometimes try to keep pollinizers away from the trees so that the fruit will not contain seeds.)

Finally, some citrus trees will produce well only every other year, producing a good number of fruits one year and only a few fruits (or none at all) the next year. So, if you've observed the trees for less than two full years, you may have seen them in their non-productive year.

Hopefully, with this information you can determine and correct the cause of the problem. If not, here's the type of information we would need to help focus on your particular trees. 

• In what City or part of the County are the trees located?
• What varieties do you have?
• When were the trees planted?  What was the size of the tree when initially planted?  What is the current size?
• How many hours of sun per day do the trees receive in spring and summer months?
• How are the trees irrigated?  How much water is provided and how often do you irrigate?
• Are the trees planted in the ground or in containers?
• If the trees are in the ground, what type of soil do you have (for example, is it heavy clay or are you one of the lucky souls who have more loamy soil?  If the trees are in containers, what type of soil mixture was used to fill the container?
• Is the area under the canopy of the trees mulched (which helps the soil retain moisture)?
• How have you been fertilizing the trees?  (frequency, amount and type of fertilizer used)
• Does the foliage on the tree look healthy?  Are the leaves green or are they yellowing?  If the tree does not look healthy or you have yellowing leaves, it would help to have some photos of the trees. Take some close-up shots of the leaves but also, send us some photos taken further from the trees so that we can get a better sense of the environment and the overall look of the trees. In fact, even if the trees look healthy to you, it would be helpful for us to have photos.
• Any signs of insect damage?  (for example, holes in the leaves, curled leaves, sticky substances on the leaves which could be honeydew from insects, ants crawling in the tree)
• Do the trees have flowers in the spring time?  (A few varieties of citrus are just starting to show signs that blossoms will appear soon; other varieties won't bloom for a few more weeks. Some varieties may bloom at other seasonal times…. Editor's note: This response was originally written in late February)
• If the trees have bloomed in past years, have you observed any bees or other pollinizers visiting the blossoms?  Are there many bees or just a few?

In addition to answering these questions, feel free to add any additional observations about the tree that you think could be relevant.

We hope that this information is helpful in getting your trees in shape to produce. If not, we encourage you to provide the additional information described above so that we can focus more precisely on your particular problems.

Help Desk of the UC Master Gardener Program of Contra Costa County (tkl)

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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/).

Due to the overwhelming success of the Great Tomato Plant Sale this past Saturday at Our Garden in Walnut Creek, our stock is wiped out and the second sale scheduled for this coming Saturday the 9th is Canceled! We are so excited to have served so many people and sold so many plants, but disappointed that we don't get to see you all again this coming Saturday.

But fear not, the Richmond sale is still on! The Contra Costa Master Gardeners are also hosting a sale in Richmond on Saturday April 9 from 10:00 am to 3:00 pm at the Richmond Public Library. This is the only sale date in Richmond, so don't miss it!

For all the details on the sale, please go here. For a descriptive list of the tomatoes that will be available at the Richmond sale, please go here.

Don't forget your bags, boxes (or wagon, yes, wagon!) and your sun hat, and we will see you on Saturday in Richmond!

From the Help Desk of the
UC Master Gardener Program of Contra Costa County 

Client's Request:  I'm removing some large ash and elm trees to the ground and will be grinding the trunk below ground surface as well. We won't be removing any of the remaining tree roots although they both appear to have extensive root systems. My question: “Will the remaining unremoved ash or elm trees' roots continue to grow once the trees have been cut to the ground?

UC MGCC's Help Desk Response: Thank you for contacting the UC Master Gardener Program of Contra Costa County regarding the remaining roots after removal of your large trees. 

Based upon our research about invasive tree-root problems, there seems to be no real difference between ash or elm trees in the strength of their roots. Many other types of trees' roots are much more aggressive.

Regardless, these trees do have extensive roots that will try to live on reserve sugars for awhile. The roots will send up shoots as long as they are able, about a year or so, and if the leafy shoots find sun, they will try to grow. However, without sun, water and an unimpeded growing space, the weakened roots will eventually fail. To eliminate the trees from your garden, do not allow the shoots to succeed as that will create new sugars via photosynthesis from sunlight exposure.

You will have to be vigilant for a year or two, cutting back the shoots and sprouts as they pop up. Those severed roots under the foundation & walkways cannot live after their food reserve is gone.

Below is a a link to the University of California's Pest Note about woody weeds - which includes tree roots. It explains various methods to keep those tree shoots down and out.
http://www.ipm.ucdavis.edu/PMG/PESTNOTES/pn74142.html

Please do not hesitate to contact us again for garden assistance.

Help Desk of the UC Master Gardener Program of Contra Costa County (MKW)
Don't miss our 2016 Great Tomato Plant Sale:
http://ccmg.ucanr.edu/EdibleGardening/GreatTomatoPlantSale/

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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/).