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Saturday, January 17, 2015

Fruit Tree Pruning Workshop Saturday AM January 24

Location: South Jones and Patrick Lane area. Exact location will be sent to participants after they register for this class on Eventbrite. There is no fee for this workshop.

Eventbrite - Fruit Tree Pruning Workshop
Older and fruitful Gravenstein apple
 Limited to 25 people only due to the size of the yard. I will be demonstrating how to prepare your equipment, make correct pruning cuts and how to prune apple (20+ years old and one young one), apricot (5 to 7 yrs old), peach (3 to 5 year old), dwarf peach (container), fig (3 to 5 yr old) and pomegranate.(3 to 5 yr old). Location is a residential property in the Southwest of the Las Vegas Valley near South Jones and Patrick Ln. (north of CC 215, southern part of the loop).
Older and fruitful apricot


Tuesday, January 13, 2015

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Monday, January 12, 2015

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I Am Looking for Fruit Trees to Prune

I want to try something different this year.

In previous years I conducted fruit tree pruning workshops at a university facility. This year I would like to try something different. If there are homeowners who would like to cooperate in a community fruit tree pruning workshop in their home landscape, I would be interested in pursuing it during the month of January. We can talk about large fruit trees but I am not prepared to climb them for demonstration purposes.

Interested parties can contact me at Extremehort@aol.com and we can exchange phone numbers.

Requirements.
  • Fruit trees should be between newly planted up to 5 or maybe even 7 years old.
  • Home landscapes should be open to the invited public.
  • Permission to prune fruit trees and use them for demonstration purposes.

How Do You Sterilize Pruning Equipment?

Q. You often discuss the need to "sterilize" your garden tools to prevent transfer of disease. How do you "sterilize" these items?

A. A. What I mean by “sterilize” is exactly what is meant to a medical doctor and for some of the same reasons. Not sterilizing pruning equipment before its use is a terrible oversight. People overlook cleaning and sanitizing equipment because people don't understand why it is needed.
99% of the time unsterilized equipment is not a problem. It’s that 1% of the time when it becomes a problem. These are the times I receive questions about the dieback in olive, mulberry, silk tree and perhaps even ash trees.

Diseases are transmitted. Several important diseases are transmitted on pruning equipment. These include sooty canker (fungal disease of mostly ornamental plants), fire blight (bacterial disease of
Mimosa or silk tree die back due to Verticillium wilt.
many ornamental plants and fruit trees), crown gall (bacterial disease of many woody plants), slime flux (bacterial disease of many plants), Exocortis (viroid disease of citrus and tomatoes), bacterial spot (Xanthamonas, a bacterial disease), sudden oak death (fungal disease), figure mosaic virus, rose mosaic virus, tobacco mosaic virus, Fusicoccum viticolum on grape (fungal disease), Pierce's disease of grapes (5% transmission rate, bacterial disease) and others. I did not include tropical plant diseases like papaya ring spot virus and banana wilt.

Sooty canker on ash.
Cut flower growers and florists also realize the importance of sanitizing knives and pruners to prevent infections from entering the cut flower and promoting its longevity.

Whenever we enter fresh plant tissue with a pruning shears or saw the equipment needs to be sharpened, cleaned and sanitized. Adjusted and sharpened pruning equipment provides a narrow point of entry which minimizes plant damage around the cut. The concept that gardening tools should be kept clean, adjusted and sharpened is less controversial since this makes sense to people.
Equipment should be adjusted, sharpened and sterilized at the beginning of a pruning day. Equipment used for pruning should be sterilized for the same reasons we sterilize hypodermic needles and scalpels. Several important diseases are transmitted on pruning equipment. You can read more extensively about this topic this week on my blog.
Sanitize and sterilize pruning equipment. Here I am using an alcohol wipe after cleaning, sharpening and adjusting the blades.
Unlike a medical procedure which usually enters the body in one location, pruning involves entering the plant multiple times at different locations. So when pruning we must be concerned about transmitting a disease from plant to plant and the possibility of spreading a disease on the same plant to multiple locations.
If trees are healthy, then there is no reason to sterilize or sanitize pruning equipment between cuts or between trees. If the disease is present or you suspect a disease, sanitize between every cut to prevent the disease from spreading within the tree.

Sterilizing methods have been researched and there is some disagreement about what works best. Sterilizing solutions recommended include household bleach, Pine-Sol, rubbing alcohol, trisodium phosphate (TSP), and household disinfectants. 

Household bleach (ex: Clorox): 25% solution (1 part bleach + 3 parts water)
Pine oil cleaner (ex. Pine-Sol): 25% solution (1 part cleaner + 3 parts water)
Rubbing alcohol (70% isopropyl): 50% solution (1 part alcohol + 1 part water)
Denatured ethanol (95%): 50% solution (1 part alcohol + 1 part water)
Trisodium phosphate (Na3PO4): 10% solution (1 part Na3PO4 + 9 parts water)
Quaternary ammonium salts: use as directed on product label
Household Disinfectants (Lysol, etc): full strength

Personally, I have used alcohol and even a cigarette lighter when nothing else was available.
By the way, bleach can be very corrosive to steel. When using bleach, oil your equipment at the end of the pruning day.

Sterilizing and sanitizing solutions have a life span. Dispose of these solutions at the end of the day and reformulate them again when needed. If there is a lot of pruning and equipment is particularly dirty, then sterilizing solutions will need to be reformulated more frequently. 

One excellent method that reduces disease transmission from a piece of equipment is air drying it.  Unfortunately, when you are pruning the cuts are made fairly rapidly and the blades never really have a chance to dry between cuts which increases disease transmission potential, particularly bacterial, viral and viral-like diseases.

How often should you sterilize equipment? Equipment should be adjusted, sharpened and sterilized at the beginning of a pruning day. If trees are healthy then there is no reason to sterilize her sanitize pruning equipment between cuts or between trees.

When you encounter a tree that is diseased or you are not sure if it does have the disease, I would recommend sanitizing between every cut to reduce the potential from spreading it within the tree.

Workers who are moving between properties must sterilize equipment between properties at a minimum. They should be taught that if a tree or shrub looks unhealthy, they need to sterilize between cuts. This is when a rag for wiping off debris and cigarette lighter that can fit into your pocket becomes handy. Any attempt is better than no attempt.

Root pruning. Sometimes I recommend pruning roots of plants. When cuts are made on roots of plants it is important to keep the pruning cut exposed to the open air for 24 to 48 hours before allowing it to come in contact with the soil again. This helps prevent disease transmission from the soil to the plant of soilborne diseases which are numerous.

Encouraging Monarch Butterfly in the Mojave Desert?

Q. I've been thinking about growing milkweed plants to help in the Monarch fight. Two varieties look worth pursuing Asclepias EROSA and SUBULATA. Any thoughts?

A. I grew up in the Midwest and in the path of Monarch butterflies migration routes to Mexico. In fact, as a boy I volunteered to monitor Monarch butterflies for a research study done in Canada back in the 1960's.

After moving to southern Nevada I have not seen any Monarch butterflies in the 30 years I've been here in the Las Vegas Valley. My understanding is there are two migration routes; one from the eastern population of Monarch butterflies and one from the Western population.

Map of Monarch butterfly routes

The eastern population misses us completely in the Western population is pretty much restricted from us by the Sierra Nevada Mountains.

Encourage and sustain local populations. I agree with you wholeheartedly on encouraging our local populations of butterflies and moths. They had a lot of beauty and grace to our landscape and provide some pollination and a food supply. Instead of focusing just on milkweeds I think a diversity of plant material for attracting these insects might be important.

Be careful of pesticide use. Also, reducing or eliminating pesticide use in the butterfly garden area would be wise. There are a number of pesticides that are harmful including two that I recommend frequently to organic gardeners: Bt and Spinosad. When considering pollinators both of these insecticides can be lethal, in particular Spinosad to bees.

Always apply pesticides, if they must be applied, at times when these creatures are not active. This means the very early morning hours. Many of our moths fly at night so I would avoid applying pesticides at dusk if a major concern are night flying moths.

Further reading. I put together some links on general information on Monarch butterflies, moths and butterflies of southern Nevada and how to make a butterfly garden. I wish you much success.

Wikipedia on Monarch butterflies
Donate to Wikipedia

Threats to Monarch butterflies

Butterflies of southern Nevada.

How to make a butterfly garden in the southwestern desert of the US

Time of the Year for Holes to Appear in Trees

Q. I noticed that the woodpeckers have attacked our Palo verde tree. There are probably 60 holes around the truck and main limbs. The sap is running even though the holes are just under the surface - not deep. Any advice how to prevent further damage and do you think this can eventually kill the tree.

A. The only thing is exclusion and putting up some wire mesh to keep them from the trunk. They will still get into the lower limbs since it is hard to put wire mesh there.

Sapsucker damage to apple (above) and eucalyptus, aka gum (below).
I have seen our fruit trees attacked, the same ones, year after year and the trees still seem to be doing well. I know it causes damage but it seems to be not life threatening so I would let it go.

You could try some hot pepper sprays just before they begin damaging plants. Mark the event on your calendar. They are migratory so putting on some sprays might discourage them and force them on to your neighbor’s trees.

Imidacloprid and Bee Decline Linkage

Q. I don't like what I'm reading about Imidacloprid and wanted to know if there is a better insecticide that won't harms bees.

A. Trade names for this chemical name include Gaucho, Admire, Merit, Advantage, Confidor, Provado and Winner.This particular pesticide has a lot of problems and will probably be eliminated in the not-too-distant future because of these problems. Unfortunately, this pesticide is extremely good at what it does and fills a pest control niche that few other pesticides, if any, currently can fill.

We need other choices. The niche that it fills is a very effective borer killer that is systemic and for the most part gives you season-long control. Some of the same reasons it is so good may make it also dangerous to use. Even though the label allows for its use on fruit trees for example, I discourage people from applying it to those trees because it is systemic. I believe that any systemic insecticide has the potential to enter the food that we eat.

Method of application protects bees. Methods of application have a lot to do with exposure to bees. Those pesticides which are applied as a liquid or as a foliar application to the leaves and stems of plants have a higher probability of coming in contact with bees than the same pesticide applied as a soil drench. Soil drenches are liquids applied to the soil and rarely come in contact with bees.

Common products containing Imidicloprid.
Be careful of plants treated. However, this particular insecticide is systemic and can be transported from the roots of plants to the flowers that bees may visit. So in the case of this particular insecticide applying it as a soil drench may still be a problem for bees that visit flowers of plants that were treated with a soil drench. The larval form of many butterflies and moths rely on the leaves of some plants as a food source. Systemic insecticides applied as a soil drench may also be a problem for these insects.

Best use for this pesticide? If we are to continue to use this insecticide perhaps its best use might be as a soil drench on trees and shrubs that are nonflowering and are not used as a food source by anything that we value.

Alternatives? As for alternatives, I do not know one that is this effective for borer control. If we are talking about borer control then prevention is the key. This means preventing sunburn to these plants and keeping them actively growing and healthy is a partial solution.

As for other insect pests that it controls you have many alternatives. However, these alternatives will probably not be as persistent so you will have to apply them more often.

Whenever your focus is on protecting bees you must consider how toxic the chemical is toward these critters, avoiding applications when plants are in flower, applying foliar pesticides at very early morning hours or at dusk when bees have gone home, using pesticides which have a very short life after they are applied and are not persistent in the environment. And even more importantly we must begin to think about the use of pesticides as a last resort, not a first choice when there is a problem.

Pruning Japanese Blueberry to Encourage Growth

Q. I have 13 Japanese blueberry's they have been planted for quite a few years. They have grown tall but only one filled out from the bottom to top because of some shading. This shading is now gone. What can I do and when to stimulate the growth and hopefully have them fill out all over. 

Japanese blueberry picture from another reader.
 A. Severe shading can cause branch or limb dieback. Reduced light to branches can also cause leaf drop and poor growth on living wood.


What to do? Determine if these branches are alive or dead. If they are dead then all you can do is remove them back to the trunk or back far enough to healthy wood. Grasp these branches and bend them. Dead branches will snap like a dry or dead twig. Living branches will bend and not break as easily. If you bend a living branch back far enough of course it too will break so you have to be careful when bending them.

Wait and hope.If they are dead and you have pruned them back, all you can do is wait and hope that light reaching inside the plants will “sprout” new growth and fill in over time. If they are alive then do not prune them all the way back but cut off just a few inches of the ends just far enough to cut into living wood.

Dead branch of Japanese blueberry from another reader.
This might be one or two inches or six or more inches depending on where living wood is located. These types of cuts are called “heading cuts” and remove the terminal buds and will stimulate the plant to fill in bare areas.

When to do this? Do this in about early to mid-February next spring. Fertilize the plants at that time with a tree and shrub fertilizer or even a lawn fertilizer and give the plants a two or three deep waterings with a hose a few days apart. The water from the irrigation system will move the fertilizer into the root area. The fertilizer should be a high nitrogen fertilizer. It would be helpful to give them some iron applied to the soil as well at the same time.

Again More Rabbit Damage!

Rabbit damage to chard. Picture courtesy of another reader.
Q. We live in Sun city Summerlin the rabbits are eating our plants Star jasmine, silver spoon yuccas, and even canary island date palms lower leaves. We have tried Shake-Away Fox and Coyote Urine Granules and scaring them but nothing has worked. Any suggestions or tips would be helpful.

A. These kinds of products are deterrents. Once they are hungry those will not stop them and they will eat even less desirable plants. The only real way to get a handle on them is exclusion (fencing)
which can look horrible. Planting less desirable plants (Arizona fact sheet found on the link below) will help push them to more desirable plants they can find in the neighbors yards.

Rabbit resistant plants Arizona


Fire Barrel Cactus Adds Interest to Desert Landscapes




Care and Pruning of Pyracantha and Honeysuckle

Q. I am writing and enclosing photos of my pyracantha and honeysuckle. I cannot find info on the issue/treatment. A friend suggested I email you after reading the LVRJ column.

A. Thanks for the pictures but they were not very helpful without more information. Let me tell you what I know about these plants and maybe that can help.

Both of these plants grow well in our climate in a mixed, non-desert landscape. They are not desert adapted or desert plants so they will not perform well with rock mulch.

Over time, they will perform better using wood mulch on the surface of the soil.

They should be irrigated at the same time as other non-desert plants. They should be on an irrigation valve that provides water as frequently as other nondesert trees and shrubs.

Most landscape plants require at least one fertilizer application each year in the spring or late winter. You can apply these spring fertilizers into March. Any general landscape, tree and shrub fertilizer will be good.

Pyracantha occasionally develops yellowing due to iron chlorosis so an application of EDDHA iron chelate to the soil at the same time as the fertilizer would be advised. Apply both within a
foot of drip emitters on top of the soil. The iron chelate needs to be covered with mulch.

Pyracantha has a history of borer problems, particularly if it is planted in a southern or westerly exposure in rock mulch with lots of heat and intense sunlight. Borers can be active in the plants and the plant can still appear healthy for one or two seasons.

After a season or two of borer attacks branches turn brown and begin to die back. They normally die back to where the borer damage while the rest of the undamaged plant below this remains green. Prune these dead branches out and let the plant regrow from these areas.

Pictures from reader
Because of the dead branches, the interior wood and trunk will receive intense sunlight. This intense sunlight increases the chance of sunburn to larger limbs and the trunk. This sunburn damage attracts boring insects (borers) to those locations.
Borer damage in purple leaf plum


For this reason, shade from the canopy on the interior wood of the plant is extremely important. Many woody plants in the rose family, which includes Pyracantha, are subject to damage from intense sunlight due to their thin outer bark.

Most of our fruit trees are also in the rose family and are subject to sun damage and borer
problems. Pruning should be pruned to maintain a moderately dense canopy. A canopy which is not so open provides filtered sunlight to the interior of the plant and reduces sun damage. You don't want it pitch black inside the canopy but you do want filtered light, not intense sunlight, for any length of time.

Honeysuckle is a good vine to use here. However, it tends to get woody at the bottom as it gets older. This woodiness at the base can be managed by pruning it correctly. Woodiness at the base is promoted when the vine is pruned only at the top. Several years of pruning the top results in an unattractive plant that is mostly wood without much foliage.

When pruning this plant this winter, instead focus pruning efforts on the area close to the soil surface. Find large stems originating from this area and remove one third of this older wood close to the ground. This removes a lot of plant material from the vine but promotes new growth from the pruned stems.

Limb dieback of peach due to borers

These types of pruning cuts encourage new growth from the base of the plant. Next winter remove one third more at the same location and you should be back on track and reversing the aging of this plant, making it more juvenile. Focus your pruning efforts closer to the ground.