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

Subject: Grapefruit Tree vs Woodpecker

Cllient's Request: How can we keep a woodpecker(s) from making holes in the tree bark?  We don't have any insects/ants on the tree bark and we're concerned that the damage will make the tree susceptible to disease.  Thank you.

MGCC Help Desk Response: Thank you for contacting the UC Master Gardener Program Help Desk with a question about woodpeckers on your grapefruit tree. From our phone conversation this morning, I identified the culprits as sapsuckers. These drill a series of holes, usually in straight horizontal lines, in live trees so plant sap oozes out of the holes. Sapsuckers feed on the sap, as well as on any insects that become trapped in the sap. Most of the time, sapsucker holes do not cause problems for the tree. When there is continuous sapsucker activity that increases the lines of holes to a significant percentage of the tree's trunk area, it can weaken the tree and potentially kill it. 

Physical exclusion is the best way to prevent any kind of woodpecker damage. There are several methods you might see mentioned to prevent such as frightening devices or repellents, but these are not typically successful as birds quickly become accustomed to the deterrent. Covering the trunk with something that will prevent access to the tree bark is the best way to get sapsuckers to move on. Sections of lightweight sheet metal or roof flashing are fairly easy to shape around the trunk. You can get rolls of aluminum flashing at home improvement stores. Heavyweight plastic material can also be used. Use duct tape to hold it in place. You can also use wire mesh such as chicken wire, especially if it's bunched up somewhat. You will probably need to cover a great deal of the tree's bark to prevent the birds from just moving to an uncovered area. Whatever you use to cover the bark, make sure it is not too tight--you want to leave room for the tree to grow--and remove it when the birds have moved on. Depending on the size of the tree, you could also cover the entire tree with bird netting that you securely attach around the low base of the trunk to prevent all access to the tree.

Woodpeckers drill holes in trees for a variety of reasons. The largest holes are drilled for nest construction, usually in dead trees. Acorn woodpeckers drill 1/2 inch holes in which they store acorns. Smaller random holes are those made while looking for food. Woodpeckers' sharply pointed beaks and long tongues are used for extracting larvae and other insects from wood crevices. This can actually alert you to burrowing insects damaging a tree.  

This link is to more information from the University of California about managing woodpeckers: http://ipm.ucanr.edu/PMG/PESTNOTES/pn74124.html.

I hope this information is helpful. Please don't hesitate to contact us again if you have more questions.

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

Notes: Contra Costa MG's Help Desk is available almost year-round to answer your gardening questions. Except for a few holidays (e.g., last 2 weeks December), we're open every week, Monday through Thursday for walk-ins from 9:00 am to Noon at 2380 Bisso Lane, Concord, CA 94520. We can also be reached via telephone:  (925) 608-6683, email: ccmg@ucanr.edu, or on the web at  http://ccmg.ucanr.edu/Ask_Us/. MGCC Blogs can be found at http://ccmg.edu/HortCoCo/ You can also subscribe to the Biog.

Advice for the Home Gardener
from the UC Master Gardener Program
of Contra Costa County

Client's Request:  Hello. We would like to plant a shade tree in our backyard in mid-County. We have a fairly shallow well… and am assuming a high water table although we don't have any wet, boggy areas. We have two semi-dwarf orange trees s that we never water and they are productive and sweet. Can you recommend links for some shade trees in these conditions .... such as Crape Myrtle, deciduous Magnolia, and Japanese Maples? Thank You.

MGCC Help Desk Response:  Thank you for contacting the UC Master Gardener Program Help Desk with a question about tree selection. You didn't say how deep your well is, but the water table is probably deep enough that it won't impact trees in your landscape. Tree roots are generally found in the top 1 to 3 feet of soil, with only some sinker roots possibly venturing deeper. Trees don't usually have tap roots past the seedling stage, but rather grow roots that extend well past the dripline (outer edge of the tree's canopy). 

If you have good drainage in your soil, any tree suited for your climate should be fine. To test your drainage, dig a hole about a foot deep. Fill it with water and allow it to drain completely. Immediately refill the hole and measure the depth of the water with a ruler. Fifteen minutes later, measure the drop in water in inches, and multiply by 4 to calculate how much water drains in an hour. Ideally, you should have 1 to 6 inches drainage per hour.

The trees you specifically asked about were Crape Myrtle, deciduous Magnolia and Japanese maple. Crape Myrtles (Lagerstroemia spp.) do well in mid-county. They need full sun and seem to appreciate our hot summers. There are many varieties to choose from. This link is to an article from the Sonoma County Master Gardeners about growing Crape Myrtles: http://sonomamg.ucanr.edu/Plant_of_the_Month/Lagerstroemia_spp_Crepe_Myrtle/.

Deciduous Magnolia may not be a good choice. According to Sunset Western Garden Book, deciduous magnolias with saucer flowers do poorly in hot and dry areas. Deciduous magnolias with star flowers seem to do better, but are very slow-growing, and the variety called Star Magnolia (Magnolia stellata) stays quite small and is usually grown as a shrub.

Japanese maples (Acer palmatum) do best in cool climates and will need partial shade and protection from hot, dry wind in the hotter areas of the County. Morning sun and afternoon shade is best. The varieties with green leaves do better with more sun exposure than the varieties with red leaves or those with lacier leaves.

You might also consider Chinese pistache (Pistacia chinesis). It is well suited for our climate and makes a good shade tree. This link is to another article from the Sonoma Master gardeners:  http://sonomamg.ucanr.edu/Plant_of_the_Month/Chinese_Pistache/.

For other ideas, this link is to a searchable database where you can select aspects you want such as shade tree, deciduous, maximum height, etc. https://selectree.calpoly.edu/about. They have good descriptions of the trees, along with photographs.

If after you perform a drainage test you find you have poor drainage (less than 1 inch per hour), contact us again and we will research those trees more suitable for a boggier area. Don't hesitate to contact us if you have any questions.

I hope this information is helpful and you find a good shade tree for your yard!

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

Notes: Contra Costa MG's Help Desk is available almost year-round to answer your gardening questions. Except for a few holidays (e.g., last 2 weeks December), we're open every week, Monday through Thursday for walk-ins from 9:00 am to Noon at 2380 Bisso Lane, Concord, CA 94520. We can also be reached via telephone:  (925) 608-6683, email: ccmg@ucanr.edu, or on the web at  http://ccmg.ucanr.edu/Ask_Us/. MGCC Blogs can be found at http://ccmg.edu/HortCoCo/ You can also subscribe to the Biog.

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

Camellia flower

The leaning bush has been propped up and the soil tamped down, but I'm concerned about the long term health of these bushes.  Can you offer any advice for the eaten roots and over-all care of these bushes?  I prefer organic methods, where possible.

Thank you in advance for any assistance you may have available.

Help Desk Response:  Thank you for contacting the UC Master Gardener Program Help Desk about the damage to your camellia bush.

Camellias are beautiful evergreen broad-leaved shrubs with fibrous shallow root systems that lie close to the surface of the soil, so immediately identifying and excluding any burrowing pest is critical!  Unfortunately, I can't locate any specific information on vertebrate pests that prefer camellias, so you'll need to investigate the potential of a few of our common burrowing and root damaging vertebrate pests.  The common pests in our area are ground squirrels, moles, pocket gophers or voles.

• The best way to determine what type of pest you have is by the damage you see:

Ground Squirrels: The key identifier for these rodents is an exposed tunnel entrance with discarded dirt surrounding the entrance of the tunnel. You can see right into a ground squirrel burrow, unlike that of moles or pocket gophers.
Moles: If you have a mole, you will see mounds of dirt and/or surface tunnels. Dirt mounds (look like piles or "puffs" of dirt shaped like a volcano) and surface tunnels (look like the veins on the back of your hand). Not all moles will have both surface tunnels and dirt mounds. If you see one or the other (or both), you have a mole.
Pocket Gophers:  Damage done by pocket gophers is similar to moles, but there is a major difference. Dirt mounds are crescent-shaped (like a "C") with a "dirt plug" on one side of the mound.
Voles: Voles typically “piggy back” on the damage done by moles and tend to travel in mole tunnels and often are the cause of damage to roots, bulbs, and tubers within.

Here is a link that includes a good photo of the various types of soil disruption from these pests:  https://ucanr.edu/blogs/blogcore/postdetail.cfm?postnum=21028

UC IPM Pest Notes provide specific guidance on identification of these garden pests as well as suggested management strategies to control pests.  Here are links to the Pest Notes for the pests listed above that will help you identify the damage they cause and how best to control them:

Ground Squirrels:  http://www.ipm.ucdavis.edu/PMG/PESTNOTES/pn7438.html

Moles: http://www.ipm.ucdavis.edu/PMG/PESTNOTES/pn74115.html

Pocket Gophers: http://www.ipm.ucdavis.edu/PMG/PESTNOTES/pn7433.html  
 
Voles: http://www.ipm.ucdavis.edu/PMG/PESTNOTES/pn7439.html

Once the pest is identified and controlled, we suggest that you may want to replant the leaning shrub that has suffered the most root damage.  This is a good time to do it as camellias are generally planted in the late fall through the early spring.  There is no guarantee that the plant will survive as it will depend on how serious the damage is.  If a small portion of the root system is damaged, there is a greater likelihood the plant will survive.

Here are recommended steps to replant camellias from the American Camellia Society:
Dig a hole that is 1 to 2 inches shorter than the length of the root ball, but make the hole 2 feet wider than the width of the camellia bush. This allows adequate space for the roots to branch out but keeps the top of the root ball above the rim of the hole. Gently loosen the soil at the bottom of the hole with a garden claw or hoe.

Place the camellia bush on top of the soil in the hole; the top of the root ball should protrude out of the hole slightly. Backfill with the enriched soil until the root ball is completely covered. Mound the soil over the top of the root ball and press down gently but firmly to stabilize the plant.

1. Create a circular ridge or berm of dirt two to three feet away from the bush; press down firmly so the dirt will not easily wash away. This ridge will help contain water.
2. Water the soil thoroughly but do not leave the camellia bush standing in water. Keep it watered regularly until the roots are established and the plant shows signs of growth, then soak the plant once a week to encourage deeper root growth, as camellias roots stay toward the surface.
3. Mulch around the camellia bush to retain moisture and even out the soil temperature. Mulch also suppresses weeds.

Here are several additional links for information on camellias pests and culture:
http://ipm.ucanr.edu/PMG/GARDEN/PLANTS/camellia.html
https://ucanr.edu/sites/urbanhort/files/80153.pdf

I hope you've found this information helpful. Good luck with your camellias and please let us know if you have further questions.

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

Notes: Contra Costa MG's Help Desk is available almost year-round to answer your gardening questions. Except for a few holidays (e.g., last 2 weeks December), we're open every week, Monday through Thursday for walk-ins from 9:00 am to Noon at 2380 Bisso Lane, Concord, CA 94520. We can also be reached via telephone:  (925) 608-6683, email: ccmg@ucanr.edu, or on the web at  http://ccmg.ucanr.edu/Ask_Us/. MGCC Blogs can be found at http://ccmg.edu/HortCoCo/ You can also subscribe to the Biog.

Subject: Control of Anthracnose on Sycamore Trees

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

MGCC Help Desk Response to Sprays for Control of  Anthracnose on Sycamores:  Thank you for contacting the UC Master Gardener Program Help Desk with your question about treating anthracnose on Sycamore trees.  You have done a lot of research on this problem, so I am not sure we can tell you anything you do not already know. Sycamore, full-grown in suburbia is a large tree, and were a common tree planted usually several decades ago, but smaller lots and today's suburbia limit their planting these days. While they are often prized for their majesty (and heigh 60-100') they can e a problem from dropping branches, debris from leaves and branches, and anthracnose, especially if planted to close to a house and other trees. 

As you know, anthracnose is a fungal disease which can cause unsightly changes to Sycamore trees.  The effects on the tree can be brown spots on infected leaves to distortion of branches, cankers and dieback.  Unless signs consistently occur every year, trees are usually not seriously harmed; they just may not be aesthetically pleasing.  The fungi survive over winter on infected leaves and twigs or dead leaf litter under the trees.  Rain in the spring splashes the fungus onto new growth and starts the infection cycle again.  Infections are worse in years with heavy spring rain than those with dry springs.  The best management mechanism is to remove infected twigs, branches, nd leafs during the fall or winter to decrease the re-infection of the trees in the spring.  If there is a wet spring, spraying new growth with fungicides can be protective: however, University of California does not recommend fungicide applications for trees other than ash.  I believe you have already reviewed this document but the UC web link to the Integrative Pest Management (IPM) on anthracnose is below. http://ipm.ucanr.edu/PMG/PESTNOTES/pn7420.html

I reviewed the pesticide labels of the two products we discussed - Agri-Fos and Reliant.  If there is a difference in the products, it was not apparent to me.  It does appear that Agri-Fos is not labeled for use on sycamores for anthracnose and Reliant is allowed to be used as a foliar spray and as an injection into the tree trunk in sycamores for anthracnose.  Why these products, with the same active ingredient in the same concentration, are labeled differently is not apparent to me.  So, we forwarded this part of your question onto our local Urban IPM advisor to see if he can provide clarification on this…. And we heard back from our Urban IPM Coordinator. Here is his response:

 “Product registrants can seek wide or narrow spectrum labels, depending on targeted markets, costs, and efficacy information. In this case, the manufacturers of Reliant have included sycamore anthracnose while the manufacturers of Agri-Fos have not. It seems that Reliant is an older product that is registered for use against a very wide range of agricultural pathogens, so maybe it was cost-effective to include anthracnose. It's also likely that the inert ingredients of these two products are different. Agri-Fos, for instance, is usually injected or otherwise introduced internally, while Reliant is sprayed.

The more important consideration here is that phosphonates (active ingredients in both these products) are not considered effective sprays as per the UC IPM 'Anthracnose' 
Pest Note: http://ipm.ucanr.edu/PMG/PESTNOTES/pn7420.html

I think the last paragraph is the most important for this discussion, that phosphonates are not considered effective sprays against anthracnose."

Finally, as we discussed on the phone, you may try consulting another certified arborist to see what their recommendations for management would be.  We cannot recommend a specific company, but would recommend you find a certified arborist through the following website. https://www.treesaregood.org/findanarborist 

Best of luck and we will let you know if we find out more Please do not hesitate to contact the Help Desk again if you have more questions. 

Help Desk of the UC Master Gardener Program of Contra Costa County (SEH/SES)

Notes: Contra Costa MG's Help Desk is available almost year-round to answer your gardening questions. Except for a few holidays (e.g., last 2 weeks December), we're open every week, Monday through Thursday for walk-ins from 9:00 am to Noon at 2380 Bisso Lane, Concord, CA 94520. We can also be reached via telephone:  (925) 608-6683, email: ccmg@ucanr.edu, or on the web at  http://ccmg.ucanr.edu/Ask_Us/. MGCC Blogs can be found at http://ccmg.edu/HortCoCo/ You can also subscribe to the Blog.