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From the UC Blogosphere...

EPA Proposes New Rules for Pesticide Applicators

On August 5, 2015, EPA released a proposal to revise the standards for both commercial and private pesticide applicators. In California this rule would affect anyone with a Qualified Applicator Certificate (QAC), a Qualified Applicator License (QAL), or a Private Applicator Certificate (PAC). This could affect you as a pesticide applicator, or any clientele who are commercial or private applicators.

The primary proposed changes that I think will affect California pesticide applicators the most are:

  • Category-specific Continuing Education Requirements for QACs and QALs. Commercial applicators will have to earn 6 Continuing Education Units covering Laws and Regulations (called “core”), AND 6 Continuing Education Units for each category in which you are licensed or certified. (see section XIV.B. “Recertification Requirements Unit”)
  • Category-specific Certification and Continuing Education for PACs. Private applicators performing soil fumigation or non-soil fumigation will be required to be certified in those categories; they will have to take an additional test, and there will be additional Continuing Education requirements. (see section VII. Establish Application Method-Specific Categories…..” and section XIV.B. “Recertification Requirements Unit”)

The public has the opportunity to comment on this proposal until November 23, 2015.

The proposed revisions can be found on using the Docket ID: EPA-HQ-OPP-2011-0183. The Docket is titled: Certification of Pesticide Applicators Rule Revision (40 CFR 171). There is also a link on the docket for making comments.

Posted on Thursday, August 27, 2015 at 1:30 PM

Adapting to drought by removing urban landscapes has unintended impacts

A Western scrub jay on a California lawn. (Photo: Wikimedia commons)
Removing landscaping in urban areas to adapt to the California drought carries a gamut of potential repercussions on wildlife and the environment, reported LA Weekly. Two of Gov. Brown's water conservation rules - withholding water from grassy road medians and encouraging residents to remove their lawns - are taking an unexpected toll.

The subject was raised recently by two University of California Agriculture and Natural Resources (UC ANR) experts in a position paper they published on their website, the story said. Don Hodel, UC ANR Cooperative Extension advisor in LA County, and Dennis Pittenger, UC ANR Cooperative Extension area environmental horticulturist at UC Riverside, said landscapes and turf offer tremendous benefits to residents, communities and the environment.

"Nobody thought this out," Hodel said. 

The LA Weekly article also quoted Loren Oki, the UC ANR Cooperative Extension specialist for landscape horticulture based at UC Davis. Among the obvious problems created by California's turf-removal program, Oki said, is "encouraging people to plant during the heat of the summer, which is the worst time" for new plants to survive in the ground. He predicts many of the low-water plants will not survive the late-summer heat.

Another UC Davis scientist, biochemistry professor William Horwath, raised the potential for turf removal to kill the "decomposition community" that lives in soil.

When cities and homeowners remove vegetation from land, that diminishes the diversity of the soil biology, especially the larger fauna such as worms, which feed off of the droppings of leaves and other materials from plants.

"If you are not growing anything, just gravel or mulch, you'll be losing a lot of worms, and you will at the same time be losing a lot of carbon from under the soil back into the atmosphere," Horwath said.

Oki was one of the authors of a recent post on the UC ANR California Institute for Water Resources blog, The Confluence, that provides practical, well-thought-out advice on drought-tolerant landscaping in California.

"A variety of options exist for gardeners implementing landscaping changes," the article says. "Trading in your turf for concrete, rock, or artificial turf are options. However, none of these selections promote healthy soils and other ecosystem services. In fact, all of these options can be problematic because they create a heat island effect and may have water infiltration or runoff issues."

The story details seven strategies for conserving water while maintaining a living landscape.

Posted on Thursday, August 27, 2015 at 12:07 PM

Dry Shade Gardening

Dry shade gardening under the canopy of trees or in containers in recessed corners of a patio can be a challenging venture. Often the soil, root-choked and bone-dry and the low level of light do not offer new plantings much to live on. To be successful, your understory plants and those in pots have light and moisture requirements, which must be met.

Tree canopies have a lot to do with how much light and moisture enter your garden. If your trees have broad, spreading canopies, they will cast more shade than upright trees, unless these upright trees are planted close together. If these trees are deciduous, the shade they cast will be seasonal and what you can plant beneath them may depend on when they leaf out and how dense their canopies become. 

The most challenging shade trees to plant under are those whose foliage emerges early and whose canopy is dense. The best shade trees give plants beneath them good early season light and cast lighter shade during summer. While retaining the overall shape of trees, thin them in late winter when the branch structure is completely visible. For the impenetrable canopies of some evergreens, remove limbs within 8 feet of the ground to allow direct sunlight to penetrate the area at the base of the tree. 

More critical to reducing shade is increasing moisture levels beneath trees. Tree roots extract every drop of moisture from the ground and leave nothing for other plants. A recommended approach to increasing moisture content in the soil is to build a well-draining raised bed and fill it with humus-rich, water retentive soil. Do not place your raised bed against or close to a tree trunk as this would interfere with oxygen availability to tree roots. Install an automatic irrigation system using soaker hoses or drip irrigation rather than a sprinkler system. The use of mulch materials such as bark, wood chips, straw, shredded leaves, even rocks, will help prevent water in the soil from evaporating too quickly.

Many trees are sensitive to root disturbances. California oaks, for example, have grown with dry summers and cool, wet winters. Poor drainage or summer watering can put these trees at risk of root disease. For that reason, native California plants, which have evolved alongside our oaks and require minimal water, are best suited under these trees.

To keep soil disturbances to a minimum, start with small understory plants. Begin planting at least 12 inches away from the trunk and plant in an outwardly direction. Spacing plants too closely reduces air circulation and encourages fungal diseases like powdery mildew. Avoid nicking tree roots, as you prepare the planting holes. Water the plantings thoroughly. Annually, apply 2 to 3 inches of topdressing such as compost, shredded leaves or well-rotted manure. This organic material replicates nature without damaging tree roots and provides many benefits. 

There are hundreds of varieties of groundcovers, bulbs, perennials, ferns, vines and shrubs available to dry shade gardeners. While these plants tend to store water in roots, rhizomes, tubers and stems, they lose less water through their leaves than most plants and can cope with low light levels. Many can be grown in containers.




Resources to help with Dry Shading Gardening:
For standard pruning guidelines, see:
A plant list for landscaping under native oaks can be found at:
For a list of part to full shade plants, visit:


Posted on Tuesday, August 25, 2015 at 7:20 PM

How Are You Caring For Your Grapes?

Zinfandel Grape Cluster
Help for the Home Gardener From the Help Desk
of the Master Gardeners of Contra Costa County

Client's Request:  (via earlier phone call) I have Zinfandel grapes in my backyard garden. Looking at them now it appears that they aren't providing me with a good harvest. I'm concerned about pruning them this winter to get the best harvest. Would you please provide me with the appropriate information about pruning Zinfandel grape vines.

MGCC's Help Desk Response:  Thank you for contacting Master Gardeners with your Zinfandel grape pruning question. I understand that when you phoned our offices, the Master Gardener with whom you spoke mentioned that we occasionally have presentations on growing and caring for grapes. Right now, we have only one such presentation on the calendar. It will occur at “Our Garden” on Saturday, October 3, beginning at 10 a.m (click for more info). Our Garden is a demonstration garden that is maintained by our Master Gardener program. It is located at the corner of Wiget Lane and Shadelands Drive in Walnut Creek. This link will take you to a map where you can download driving directions:

I believe that the presenter at Our Garden will demonstrate grape pruning on table grapes that grow in the garden. However, he is quite knowledgeable about grapes and will probably reserve some time to answer questions that attendees may have after seeing the demonstration.

Now for some general information about pruning Zinfandel grapes. As you may know, there are two primary systems of pruning for grapes. The system you use is based on the variety of grapes you are growing. Zinfadel grapes are typically spur pruned. (The other pruning system is called cane pruning.)

grape buds (2)
The information that I have from your conversation with another of our Master Gardeners does not indicate the age of your grape vines. If the grapes were planted just this year, you may want to wait until they are two years old before you start pruning and training them. Allowing them to grow unpruned in the first year can help them develop a strong root system.

Pruning of grape vines typically occurs in the dormant season (any time after the leaves have fallen from the plants and before new growth begins the following spring… usually mid to late winter.)

In the first year the grapes are pruned, start by cutting each plant back to a single two bud spur. Page 11 of the PowerPoint presentation slides at this link shows a photograph of a two bud spur: Keep in mind that the photo was taken after the buds had begun growing. When you do your pruning, the buds will not yet have begun growing.

When the plants start growing, you'll need to decide whether you are going to train them as bilateral cordons attached to a trellis or “head train” them which uses stakes to support the plants but does not require a trellis system.

This publication on growing Zinfadel from the University of California indicates that either cordon training or head training can be used for Zinfandel grapes: As you'll see in the article, the author indicates that many Zinfandel growers prefer to use head training. The reason is that Zinfandel tends to overcrop easily, and if the fruit is not thinned, it will ripen with difficulty or not at all. Because head training produces fewer fruiting spurs than cordon training, using head training will reduce the chance that you will accidentally allow too many grape clusters to remain on the plant.

bilateral cordon training
with spur pruning
If your vines are more mature and have already been previously pruned and trained to grow as bilateral cordons, it may be best to stay with that training system. Just be sure to thin the grape clusters when they start to develop.

Here is a UC diagram that illustrates how a bilatereal cordon trained spur pruned grapevine will look:

The best illustration I located of what head pruned grapevines look like appears on page 16 of this Oregon State University publication: The OSU publication focuses on table grapes, but the pruning principles would apply equally well for wine grapes.

head pruning
The OSU publication has good directions on how to do both head training and cordon training. Assuming that you opt for head training your vines, you'll find more information about how to do the head training in this UC publication:  As you'll see, it includes a photograph of what mature head-trained Zinfandel vines will look like.

Finally, keep in mind that once your vines are mature and fully trained, you'll need to do annual pruning to prompt development of new grapes and to keep them producing well. The OSU publication as well as the UC article on head-pruning also contain good information about pruning of mature, fully trained vines.

I hope that this information is helpful and that you have an opportunity to attend the presentation at Our Garden on October 3. You are welcome to contact us again if you have additional questions.

Help Desk of the Master Gardeners of Contra Costa County

Note: The  Master Gardeners 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:, or on the web at

Posted on Monday, August 24, 2015 at 12:11 AM

Tomato Extravaganza!


 Tomato Extravaganza!

By Tami Reece   UCCE Master Gardener


The 9th Annual Tomato Extravaganza will feature informative workshops, a plant sale, the very popular tomato and basil tasting, and much more! The Master Gardeners will gather 15 to 20 heirloom and hybrid tomato varieties from local farmers and have grown 10 different varieties of basil for this year's tomato and basil tasting. 


Heirloom tomatoes will be available for purchase, but if you want to grow your own, there are over 7,500 varieties of tomatoes on the market and they do love sunny California. However, several varieties are well-adapted to less sunny conditions. Black krim grows very well along the coastal areas of San Luis Obispo County. North County has the opposite problem - too much sun. The optimal temperature range is between 55 and 85 degrees Fahrenheit depending on the variety. Heirloom tomatoes come in shades of red, green, orange, pink, white, blue, yellow, and purple. They can be a solid rich color, striped or mottled.  They can be larger than the palm of your hand or as small as a cherry or grape which is also the name of two varieties.


There are between 50 to 150 different varieties of basil available on the market. The colors and flavors of basil continue to expand as growers cross different varieties to create new basil plants each year. 

If you have only known the common red tomato and green Italian Basil, join us to experience the many flavors and colors that are available.  The Tomato Extravaganza is on Saturday August 29, 10:00 to 2:00 p.m.  We are located at 2156 Sierra Way, San Luis Obispo. The presentations will begin at 10:00 am with Water Catchment, Gopher and Ground Squirrels at 11:00, and Edible Landscaping at 12:00. The plant sale will feature Mediterranean plants, herbs, and basil, and the California Rare Fruit Growers will be on hand selling trees. Children's activities and displays will be available and a locally owned food truck will be on site from 11:00 to 1:00.  Spend the day with us or stop by to see our beautiful demonstration garden. Either way you will not be disappointed!! For more information, visit or call (805)781-5939.


Posted on Sunday, August 23, 2015 at 9:04 PM

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