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Thursday, September 24, 2015

Attention Embarq Emailers - Check Your Spam Folder for Responses from Me

Sometimes I receive emails from people using Embarg.com hosted by Century Link. I respond to these emails but I told that my email response is undeliverable. Please check your spam folder when looking for a response from me. Email address of the sender in this response was substituted with XXXXXXXX.

In the subject line of the email sent notification
Undelivered Mail Returned to Sender


Your e-mail is being returned to you because there was a problem with its delivery. The reason your mail is being returned to you is listed in the section labeled: "----- The delivery status notification errors -----".

The line beginning with "Diagnostic-Code:" describes the specific reason your e-mail could not be delivered.  The following lines contains the RFC822 header of the original email message.

Please direct further questions regarding this message to your e-mail administrator.

--AOL Postmaster

----- The delivery status notification errors -----

<XXXXXXXXX@embarqmail.com>: host mx.centurylink.net[] said: 554
    5.7.1 [P4] Message blocked due to spam content in the message. (in reply to end of DATA command)

Marble-Sized Mud Balls on Plant Leaves a Good Thing

Q. I sent you some pictures of a round object about the size of a large marble with an entry hole in it. I found it attached to the leaf of a cats claw leaf in my backyard of my Summerlin home.  I only have found one so I am not worried about lots of pests from this one vessel.
Potter wasp nest on cats claw vine leaf

A. I think this hard, mud-like ball with a hole in it, attached to a leaf, was left behind by a mason wasp. The mason wasp is also sometimes called a Potter wasp because of these round mud balls with a hole in it that resemble pottery. It has been theorized that Native Americans based some pottery designs from the mud balls left behind by Potter wasps.
            Wasps are generally divided into two categories; those that live with other wasps in a community which are called “social” wasps, and those wasp that live by themselves which are termed “solitary” wasps.

            Potter wasps are considered solitary; they live alone and build this mud nest for a single, solitary offspring. After building this pottery-like nest, the female finds a grub that will fit in it, paralyzes it by stinging and places it in the nest along with an egg. The developing youngster uses it for food.
            Potter wasps are not aggressive towards humans or other large animals unless they are provoked then they can sting multiple times without dying unlike a bee. They would be considered a beneficial insect in the garden area.

            Consider Potter wasp mud nests as one of the “good things” in gardens and landscapes. Just give the adult wasp its own space.

You can learn more about them here

Gardenia Needs Container and Extra Care in the Desert

Q. I love Veithcii Gardenia and I noticed that a local nursery has them for $10 for a 5 gallon plant. How do you keep the plant alive in the winter in Las Vegas and should it remain in a container and not in the ground? I have seen two of these plants in containers in Sun City Summerlin under a tree blooming profusely in the summer.
Gardenia In Las Vegas in filtered light

A. “Veithcii” is a popular selection or variety that has a longer bloom period than some others. Gardenias are grown by a number of home gardeners in our desert but you are right, they don't belong here so we have to put them in the right location and amend the heck out of that soil if we want them to do well.
            . It is best if they are grown in containers rather than growing them in garden soil. A good spot would be in filtered light which is what you would get growing them under some trees for protection from intense sunlight.
            Gardenias in general perform best in a bright northerly or easterly exposure. The soil should be 50% compost or at least high in organic matter. You can grow them in the ground but they will be more difficult to manage because the soil will slowly revert back to desert soil unless you continually add compost to the soil surface.

            It is also important to put a two or 3 inch layer of wood chips. I would use two drip emitters and never let the soil get overly dry. Fertilize 3 to 4 times a year and add a good iron chelate to the early spring application of fertilizer.

            The important things to remember is having a good soil, the proper exposure to light and irrigation frequency. The container should allow for drainage of water and you should see a small amount of water exit the container every time you irrigate. Good luck!

How to Rehabilitate Japanese Black Pine

Q. Are Black Pine, California Christmas Tree and Thumbergii all the same plant? I have 2 trees that are important in my landscape and have been doing well for several years. They were neglected recently so there is no place for deep watering and not fertilized in 2015. There is sap coming from the trunk. Should I try to rehabilitate them or replace them?
Japanese Black Pine

A. Japanese black pine is Pinus thunbergii so Thunbergii probably refers to Japanese black pine. I do not know if it is called California Christmas tree but I doubt it because Japanese black pine has a very unusual form making it a specimen plant in the landscape. It does not have the Christmas tree shape.
          Most of the textbooks say Japanese black pine tolerates alkaline soils but I have not really found them to be very tolerant of the hot desert and our soils. Many of them have been planted in Las Vegas but very few are still around which tells me many were removed.
          If you have Japanese black pine they are characteristically slow in growth and have a very distinguished form that adds character to a landscape. If you are looking for a Christmas tree pine this is not going to be it.
          They are slow-growing. If they have been neglected and do not look good they will rehabilitate very slowly. 
          Soil applied systemic insecticides that control borers would be a good if the trees actually have them. Pines can be “sappy” so make sure it is borers before you make the application. Wounding of the trunk and limbs can also cause them to bleed sap like borer damage.
          If you choose to rehabilitate them, put tree wells around the trunk about 2 feet in diameter to hold irrigation water. Give them a deep soaking with a hose once a month along with their normal irrigations.
          Fertilize them with 16–16–16 once a year in the early spring or apply it now if they haven't been fertilized this year. Punch some holes in the soil 2 to 4 feet from the trunk to a depth of eight or 10 inches. Put a handful of fertilizer in each of the holes and water them twice to activate the fertilizer and move it into the tree.

          Expect a very slow recovery if you choose to rehabilitate them. If they look bad now, I would suggest that you consider replacing them with something that you really like and can get instant gratification.

Tuesday, September 22, 2015

Air Pruning of Roots Another Form of Root Pruning

Q. I read about air pruning the roots of potted plants using either fabric pots or drilling holes in pots and lining with landscape fabric.  Supposedly, air pruning keeps the roots in "check" so that they do not outgrow the pot.  The idea sounds logical, but with our extreme heat and hot winds, could this work in Vegas?

A. Air pruning is allowing the roots of plants are exposed to the air and die. It is normally used in greenhouse production with potted plants. It can be used for plants growing in containers as well. It is popular where other types of root pruning may not be practical.
            If plants grown in containers are allowed to rest on soil or gravel, the roots of these plants can grow out of the holes on the bottom or sides of the container and into the wet soil beneath it. Once the roots leave the container and grow into the soil, the tops of these plants typically have big growth spurts.
            In the past, if these pots or containers were given a quarter turn twist, this would sever young roots and prevent them from getting anchored in the soil beneath them. This is an older method of root pruning.
            Another older form of root pruning was using chemicals such as copper sulfate applied to the surface of the soil or gravel just under the pots or containers. The concentration of copper would kill the roots of plants growing into it but would hurt the tops of the plant.
            Air pruning is another form of root pruning where the bottoms of containers are pots are suspended in open-air. Roots exposed to the open-air will die without moisture. As roots leave the container through drainage holes, the roots die and become “root pruned” by the air.
            This would work in our climate as well. However, in our hot desert climate I worry a bit about pots or containers left in full sunlight. The soils in these containers can heat up quickly and the roots “roasted” on the side of the container facing the sun.
            If pots or containers that you are using for root pruning are in full sun make sure they are white or shiny and reflect as much sun as possible. It would be best if they were shaded. Water the plants in the containers just before the heat of the day.

Canary Island Date Palm Dying May Be Disease

Q. I had a mature canary palm in my back yard for about 10 years. This summer it became infected and died. I have a monthly service with a landscaping company and, despite their efforts, was to no avail. Do you suggest I plant another one or buy a different type of palm? It was in the center of our yard and served as a focal point to our landscaping.

A. Depending on why the palm became sick will determine if you can replant in the same hole. In California this palm is susceptible to a disease called Fusarium wilt which can contaminate the soil in the planting hole and prevent you from planting a new one in that spot. To my knowledge, this disease has not been reported on this palm in southern Nevada but your description fits.
            Older or lower leaves sometimes die before the newest leaves in the center begin to turn brown and die. In some cases leaves or fronds in the center of the canopy may die while the lower leaves appear healthy. And in even other cases, leaves on one side of the palm may brown while the other side remains green.
            Often, leaf fronds turn yellow before dying so it’s possible to confuse it with the chlorosis such as iron chlorosis or other micronutrients like manganese. The yellowing leaves may be confused with over watering symptoms. Infected palms frequently die in a couple of months or in some more rare cases die a slow death over several seasons.
            This disease can be spread on pruning tools such as chainsaws so it is important that these tools be sanitized properly between trees and between cuts if the tree is suspected of having this disease.
            Another point of entry for this disease is through the roots. If soils around this palm tree are kept excessively wet by watering daily or the soil does not drain very well, this could increase the chances of this disease.
            This disease can sit in the soil and remain active for 20 years or more so I would not recommend planting another Canary island date palm in that same hole. You would select plants that are more tolerant to this disease when planting in this area.

            You should also amend the soil for better drainage and make sure the planting hole drains properly before putting another plant in the same or near the same hole.

Here is a picture of what this disease may look like in Canary Island Date Palm

Here is some information from the University of California regarding this disease in Canary Island Date Palms


The fungus Fusarium oxysporum f. sp. canariensis causes Fusarium wilt, a lethal, vascular disease of Canary Island date palms (Phoenix canariensis). There are different forms of this fungus, and they typically are host-species specific. The form referred to as forma specialis canariensis causes disease only on Canary Island date palms. Other forms of this fungus cause wilts on other species in other parts of the world.
Identification and Damage
Symptoms usually appear in older or lower leaves before moving toward the center or newest leaves, although occasionally this fungus will affect mid-canopy leaves first. Leaves turn yellow then brown but remain hanging on the palm. Initially symptoms might affect the leaflets or pinnae on only one side of the leaf. Pinnae on the other side remain green, although they eventually also will turn brown and die. This pattern was once thought to be diagnostic for Fusarium wilt, but other diseases such as pink rot also can cause one-sided death of leaves. Pinnae death typically occurs first at the base then moves progressively toward the leaf tip, although this pattern sometimes is reversed.

Extensive discoloration along the petiole, the stalk connecting the leaf base to the leaf blade, is another common symptom of Fusarium wilt. External streaking is brown to black while internal, or vascular, discoloration is reddish brown to pinkish. Although incompletely understood, this pinkish discoloration might be a good diagnostic symptom of the disease.

Infected palms can die within a few months after symptoms appear, or they can linger for several years. Because wilt diseases decrease the ability of the host to take up water, palms with Fusarium wilt in cooler, more humid environments, such as near the coast, might show reduced disease severity and survive for many years. Infected palms in hotter, drier interior climates might show severe symptoms and die rapidly.
Because Fusarium wilt stresses palms, the opportunistic and mostly secondary disease pink rot frequently is present and can obscure or mask symptoms and hasten death. In fact, pink rot might kill a palm before Fusarium wilt runs its course.

In the landscape Fusarium wilt spreads frequently on pruning tools, especially chain saws. The pathogen enters cut petioles and, in extreme cases, the cut and exposed vascular tissue of severely pruned or skinned trunks. The pathogen can spread indirectly during pruning, because contaminated sawdust can drift as far as 100 feet.

The pathogen also can spread by entering the palm through its roots. Canary Island date palms tend to form a dense, extensive network of above-ground roots called pneumatophores, especially under excessively damp or wet conditions, which may facilitate pathogen entry.
Fusarium wilt can spread if people dispose of diseased palms or their seeds using a municipal yard-waste program that recycles debris into mulch. The pathogen can survive in the soil for at least 25 years.
Because no cure exists for Fusarium wilt and it is nearly 100 percent fatal, prevention and exclusion are critical to disease management. Obtain palms from a reliable source and avoid poorly drained soils and excessive irrigation that can increase the formation of above-ground roots. Keep the area around the base of the trunk free of plants, because they can damage above-ground roots, and avoid using municipal-yard waste as mulch on Canary Island date palms.

Also avoid or minimize pruning if possible. Frequently pruned palms are more likely to suffer from Fusarium wilt than those in an unmaintained setting. If you must prune, thoroughly clean all tools by vigorously brushing them to remove sawdust and other particles. Disinfect the equipment for 10 minutes in a 1:3 pine oil to water solution, or heat saw blades for at least 10 seconds per side with a handheld butane torch. Use manual pruning saws rather than chain saws whenever possible, because the latter are difficult if not impossible to clean and disinfect adequately. If you have extremely valuable palms, consider using a new saw for each tree, which you either could discard after one use or dedicate for future use on that one palm only. Avoid pruning palms in windy weather to minimize the spread of infected sawdust.

Because a Canary Island date palm with Fusarium wilt eventually will die, it is prudent to remove it as soon as feasible. To avoid spreading the pathogen, excavate the root ball and use a crane to remove the palm with its crown of leaves, trunk, and root ball still attached. Use plastic or wooden barriers to contain any cutting, grinding, digging, or other operations that can spread diseased plant parts. After bagging all debris, prepare removed palms for incineration or removal to a landfill; do not use a waste recycling program.

It is unwise to replant another Canary Island date palm at the same location where a diseased palm once grew, because remnants of infected roots can remain in the soil and transfer the pathogen to the newly planted palm. Removing the soil might not prevent the spread of disease either, because just one small piece of infected root is all that is necessary to infect a newly planted palm. Avoid replanting with any palm species, because host range susceptibility to this disease has not been fully established.

If you must plant a replacement palm, some species to consider include Mexican blue palm, San Jose hesper palm, Guadalupe palm, pindo palm (Butia capitata), queen palm (Syagrus romanzoffiana), and Mexican fan palm. If you want the Phoenix or date palm “look,” consider staminate (male) plants of the date palm (Phoenix dactylifera), because they are more robust than the pistillate (female) fruit-bearing plants and more closely imitate the larger, robust habit of Canary Island date palms.

What Is an Amended Soil?

Q. You recommended that to grow a persimmon tree in our area, the soil needs to be amended. What is amended soil? Do you a technique you recommend to amend the Las Vegas soil?

A. Soil is amended by mixing it with something that improves the existing soil in some way. There are a number of amendments available but I prefer compost for most garden soils and fruit trees.
            Compost improves the desert soil chemistry, soil structure and its biological activity. Compost opens the soil improving drainage and aeration as well. Our desert soils have very tiny pore spaces between soil minerals. Larger pore spaces are important for roots to stay healthy. Roots need about an equal mixture of water and air between soil particles.
Desert soils have very small amounts of organic amendments in them making them very poor at growing vegetables

            Compost improves soil chemistry by reducing the alkalinity of desert soils and helps chemicals required by the plant to become more available to them.
Compost added to a vegetable growing area. The compost will be mixed with the desert soil and raised beds will be shaped from this amended soil
            I recommend that existing desert soil be removed from a future planting hole and this soil mixed about half and half with compost. Once the large rocks are removed, this amended soil is used to fill the spaces around plant roots when planting.

            Organic soil amendments like compost disappear in the soil over time so they must be replenished. Replenish soil amendments by adding a 1 inch layer of compost to the top of the soil every year. Compost slowly “dissolves” back into the soil, keeping the soil amended.

Woody Warts on Oleander Is Gall

Q. I live 8 miles northeast of Mesquite NV in Littlefield Arizona. I'm sending two pictures of some scaly growth like woody galls on the tips of my Oleander branches. There is also galling taking place on the branches and leaves. My oleanders are the only ones infected. How do I correct this problem? Will it kill the plants? Every plant is infected, about 300.
Oleander gall from the reader
A. This is called oleander gall in Arizona, oleander knot in California and Texas calls it bacterial gall. I wouldn't use any chemicals. Prune it out and sterilize pruners after cutting because it will spread on pruning instruments. If you use bleach as a disinfectant make sure you oil any steel that it comes in contact with.

This particular disease is spread from plant to plant on pruning tools. It can also be spread during wet, windy weather just after pruning. Avoid irrigating oleander with overhead sprinklers. Drip irrigation or bubblers would be a better choice.
            Even though it’s a bacterial disease, you can use chemicals such as copper fungicides to help reduce the infection but they are not necessary. Most of this can be handled with proper pruning.
            Make sure all pruning equipment is sanitized. In this particular case, you should sanitize pruning tools between cuts and between plants to keep from spreading this disease on pruning tools.
            I would use a 10% bleach solution applied to pruning blades or pruning saw with a spray bottle. Make sure you oil all pruning tools and blades when finished or the bleach will rust them.
            Plants that have a few of these galls present can be pruned and the galls removed. Prune 6 to 10 inches below the galls and sanitize your pruning equipment before each new cut.
            If a plant is severely infested with oleander gall, I would cut it to the ground this winter and let it regrow from the base.

            Fertilize the plants with a high nitrogen and high phosphorus fertilizer in January and give them a large volume of water each time you irrigate.

Oleander Galls in the Low Desert

Rough, fissured growths on twigs, branches, leaves, flowers, and seedpods, often appearing in chains. Galls start out as small bumps and grow into wart-like growths generally between 1/2 to 1 inch in diameter. Large galls may actually be several small galls that have grown together.

These galls are the result of growth of the bacteria Pseudomonas syringae inside the plant. The bacteria can enter the plant through wounds caused by pruning, frost damage or other injury or through natural openings in the leaf, blossom and stem. Water can carry the bacteria from diseased plants to healthy ones in the splash from rain or sprinklers. The bacteria is also moved from infected plants to healthy ones by unsuspecting gardeners on their pruning tools.

Prevention: Inspect oleanders carefully prior to purchase, do not buy plants that have galls.

Management: Remove the galls by pruning several inches below. Treat each cut with 10% bleach solution. Dip pruning tools in a 10% bleach solution between EACH cut to reduce the possibility of spreading the bacteria. Bag and discard cuttings. Do not compost diseased plant material.

Prune during the dry seasons to avoid infection of wounds. Avoid sprinkler irrigation while pruning wounds are fresh.

Severe infection of large shrubs is difficult to control by selective pruning. Even if you cut down the entire shrub, the new succulent growth will still be extremely susceptible to infection. In certain situations, removal of the diseased plant and replanting may be the best method of control.

Oleander knot—Pseudomonas savastanoi pv. nerii
Pseudomonas savastanoi pv. nerii causes galls or knots on oleander stems, bark, and leaves. Twigs and branches can die back, but the overall plant health is usually not seriously threatened. Gall bacteria reproduce in fissured or galled bark and are spread by contaminated water, implements, or hands. Healthy tissue is infected through fresh wounds during wet weather. Susceptible wounds include frost cracks and any leaf scars on branches.

Avoid overhead watering. Prune out and dispose of infected tissue during the dry season. To prevent spreading pathogens on infected tools, clean tools of debris after each use and thoroughly spray them with disinfectant or soak them in disinfectant for one or more minutes. Tools can be sterilized using a commercial disinfectant as directed on the product label. Homeowners on their private property can use household bleach or disinfectant cleaners diluted 1 part disinfectant to 10 parts water.

Bacterial gall
Disease Pathogen Name: Pseudomonas syringae pv. savastanoi
Pathogen Type: Bacterium
Period of Primary Occurrence: after spring rains & cool weather
• The bacterium must have a wound site to enter the plant, and cold weather injury in early
spring after a rain is a common circumstance under which infection takes place
• Most common after a cool wet spring
Description / Symptoms
• The bacterium is systemic in the plant, and causes galls to form on flowers and stems
• Leaves also become galled
• Twigs and branches can die back, but overall plant health is usually not seriously
• Gall bacteria reproduce in fissured or galled bark and are spread by contaminated water,
implements, or hands
• Healthy tissue is infected through fresh wounds during wet weather
Best Management Practices (BMP)

• Bacterial gall normally will not kill the plant
• Infected plant parts can be pruned, but care should be taken not to disseminate the
bacterium on pruning tools
• Prune infected tissue well below the infection site, at least a foot if possible, and disinfect
pruners between cuts by dipping them in a 10% bleach solution (common household
bleach at 1:10 dilution) for a few seconds
• Be sure to rinse the bleach off tools when you are finished and apply an oil lubricant to
avoid corrosion of the metal

• Severe infections can be controlled by applying Bordeaux mixture or a copper fungicide
beginning in the fall and periodically spraying through the spring as new growth
• Bordeaux mixture (originated in France) as a 4-4-50 ratio. For a small amount of mixture,
the ingredients are:
- 3 1/3 tablespoons of copper sulfate and 3 tablespoons of hydrated lime, mixed in
one gallon of water
- The mixture will turn the tree blue; however, the color will eventually disappear.
Caution must be taken NOT to store a mixture of Bordeaux

- The ingredients must be kept separate and custom-mixed as a fresh spray

Fall Planting Guide and Constructing Raised Beds

Q. My husband and I appreciate your input in guiding us to our next planting season. I know it might be a little too late but I am open for ideas to continue our gardening on a raised bed. This summer we had a great time growing Kale, red and green chard and jalapeno peppers and basil.
 Any suggestions will be greatly appreciated.

A. I will give you my version of raised beds, the kind we built at the University Orchard for growing vegetable crops. I wrote some instructions for building these types of raised beds for Viragrow, Inc. as a consultant. I attached to these instructions so that you could follow them.
Raised bed made without sidewalls

The first part tells you what to plant in the fall and winter months and whether you can start them from seed (s) or transplants (T). The second part tells you how to construct raised beds without building sidewalls but just using the natural slope of the soil to retain their raised shape. 

Raised bed made from wood
Some people like to build sidewalls from wood, brick or cement block to surround these raised beds. This is entirely up to you. But once you have constructed raised beds you should not be walking in them unless you are preparing the soil. 

Raised beds should be wide enough so that you can access the entire bad by using either side. Walkways are 18 to 24 inches wide between them and this is where traffic should be kept. Walking on these beds transfers weed seeds, diseases and compacts the soil making the soil more difficult to grow vegetables. I hope this helps.