- Author: Chantal Guillemin
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.
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.
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.
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: http://ccmg.ucanr.edu/?mapd=&calnum=267082
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.)
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: http://afghanag.ucdavis.edu/a_horticulture/fruits-trees/grapes/presentations-powerpoint/PPT_Grape_Pruning_Systems.ppt. 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: http://iv.ucdavis.edu/files/24366.pdf 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.
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: http://ir.library.oregonstate.edu/xmlui/bitstream/handle/1957/21285/ec1639.pdf The OSU publication focuses on table grapes, but the pruning principles would apply equally well for wine grapes.
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: ccmg@ucanr.edu, or on the web at http://ccmg.ucanr.edu/Ask_Us/
/span>/span>Client's Request: Can you give me some help on locating bee-friendly plants that are extremely drought tolerant (we have typical clay soil with a thin cover of mulch)—Thanks
There are a variety of bee-friendly plants that are drought-tolerant.
To get started, the University of California's Urban Bee Lab has a list of best bee plants for California: http://www.helpabee.org/best-bee-plants-for-california.html. Most of the plants listed are drought-tolerant. In general, they note if additional water is required.
Further information is available from the California Native Plant Society (CNPS). It has a good article on establishing a bee-friendly garden: http://grownatives.cnps.org/2013/03/25/to-bee-or-not-to-bee/. The article provides a starter list of plants plus advice on the characteristics of a good bee-friendly garden with emphasis on growing a variety of plants in terms of size, shape, and colors and differing blooming periods. Advantages of native plants is that they are typically drought-tolerant and many are adapted to clay soils.
You can also use the Sunset Western Garden book sfor descriptions of many of the plants on both lists. CNPS also has a database of natives that you can use for reference: http://calscape.cnps.org/.
Keep in mind that drought-tolerant plants are best planted in the fall so that they can take advantage of the fall and winter rains. So, now is a good time to plan your garden. I usually start looking and buying native plants now while the selection is often greater and then care for them in their containers awaiting fall planting. Also, keep in mind that even drought-tolerant plants will require water for the first several years to get established.
Good luck with your bee-friendly drought-tolerant garden. Please feel free to get back to us if you have further questions.
Note: Both pictures above aref from the Bringing Back the Natives 2015 Tour in the Bay Area. there are many pictures of bee garden on their web site that should give you plenty of ideas about planning and planting a bee garden.
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: ccmg@ucanr.edu, or on the web at http://ccmg.ucanr.edu/Ask_Us/
/span>/span>- Author: Stephen I Morse
The editor of the PHGSC's in-house newsletter, Eileen Housfeld, has produced a one-page summary of the major points of Steve's hour-long presentation. It is a good start to remind you about the importance of what you should be doing to manage your garden soil during the drought. It also includes links for even more information. You can find the one-page summary at http://phgsc.com/Galleries/Aug15mtg/FPAndrewsTalk.pdf
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Advice From the Help Desk of the Master Gardeners of Contra Costa County
MGCC Help Desk Response: I'm responding to your request to the MGCC Help Desk and provide some information about how you might try to eliminate or at least manage and reduce further spread of the mistletoe that has invaded your Japanese Maple.
As you know, mistletoe is a parasitic plant that lives on trees. Mistletoe is the common name given to several parasitic plants that grow on trees. It absorbs both water and nutrients from the tree. While an otherwise healthy tree can tolerate a couple of mistletoe infestations, trees that are stressed become even more stressed from the presence of mistletoe. Also, about 3 or 4 years after mistletoe starts growing on a tree, if the plant is a female, it can start producing sticky seeds which can fall and infect other branches or can be carried by birds to new locations. For these reasons, the University of California recommends that the problem be managed (http://www.ipm.ucdavis.edu/PMG/PESTNOTES/pn7437.html).
If it is possible to remove the branches or a portion of the branches where mistletoe is attached, that approach is the most likely to rid the tree of the infestation. If you use this approach, you will want to make your pruning cuts at least a foot below the location where the mistletoe is attached. The reason to make the cuts well below the attachment point is because the mistletoe creates rootlike structures in the water conducting tissue of the tree. These structures extend both up and down the branch. Removing the branch at least a foot below the point of attachment makes it more likely that you will remove the rootlike structures. If you fail to remove them, the mistletoe can regrow from the root structures. Before undertaking your pruning, you might also want to look at this University of California website which has a diagram depicting how the root like structures develop in the tree's tissue above and below the point of attachment of the mistletoe.http://www.ipm.ucdavis.edu/PMG/WEEDS/ID/mistletoechar.html
Also, as mistletoe can easily spread from tree to tree, you might want to encourage any neighbors with infected trees to take steps to eliminate infestations in their trees.
Finally, if you see that the tree is being stressed from the drought, giving the tree some additional water should help reduce the tree's stress. In addition to a deep watering approach, if you don't already have mulch around the base of the tree, you might want to add some. The mulch layer can help the soils retain water. Mulch 3-4 inches deep under the canopy of the tree. Avoid placing mulch immediately next to the trunk as it could harbor insect pests and diseases that may harm the tree.
We hope that this information is useful in your efforts to help your tree become and remain healthy. You're welcome to contact us again, either at a Farmers Market or through our Help Desk, if you have further 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: ccmg@ucanr.edu, or on the web at http://ccmg.ucanr.edu/Ask_Us/
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