Watering Pine Trees – Water Deep!

Q. I recently moved into a condo that has pine trees on the property. Some of them look like they aren’t growing much but those still in grassy areas look much better. Some other pines have branches that are dying back. Do I need to supply water to these trees?

The very new growth in the spring of pine trees are called "candles" because they look like candles. All the new growth for that pine tree is contained in that candle. If water is available to the tree, candles will stretch and get big. If water is limited, the candles will not stretch and the new growth will stay small.Notice the buds at the base of the candle. I will talk about these buds in the next picture.

A. All of this is not simply a water issue. There is probably a disease problem going on as well. But first things first. Pine tree branch growth, and how dense the tree is, has a lot to do with how much water it receives in the spring and early summer months. Just as important is how deep the water drains in the soil, to encourage deep root growth, after it’s applied.

Branches of pine trees are in the whorls along the trunk. In the picture above, you can see the buds at the base of a candle. Those buds will grow into limbs that are in whorls around the trunk.

            Most native pine trees grow along canyons or stream banks where water is plentiful in the spring months and less available later in the season. Water availability coincides with spring growth which in turn increases the tree density.

            Water pine trees deeply, particularly in the spring months. How deep? Water should drain 24 to 36 inches into the soil each time it’s watered. To make sure it’s deep enough, measure this depth with a long thin metal rod like a piece of rebar. Plenty of water this time of year helps push new growth. This new growth supports the needles responsible for a dense tree canopy. Deep irrigations are important later in the year, but less often, to maintain this density.

This blow over can happen to trees when they receive shallow irrigations and shallow applications of water. This is a mesquite but it can happen to pine trees, and does. Water large trees deeply to avoid blow over during strong winds. With deep irrigations, roots will grow deeply.

            Lawn watering only applies water about eight or 10 inches deep. This is not deep enough for large pine trees as they get bigger. Watering lawns with shallow irrigation may keep the trees denser but it doesn’t encourage the deep roots needed during strong windstorms. Besides the lawn water, large pine trees should get periodic deep watering as well. Pine trees in lawns may look full but they usually will blow over during windstorms as they get bigger.

Aleppo Pine Blight is classified as a disease but there is no known pathogen or living disease agent associated with it. In extreme cases it can cause entire branches to die. But the tree with this problem should be and Aleppo Pine, not a different type of pine.

            Branch dieback of pine trees is usually a physiological disease that cannot be cured called Aleppo Pine Blight. In most cases, new pine needles in the spring replace the dead needles lost during the winter months.

Reasons for Palo Verde Limb Dieback

Q. The palo verde tree in our daughter’s yard looks like it has damage. The top has some dead branches in it. We have had to remove some limbs because of this problem. Can it be saved?

A. There are several different kinds of Palo Verde used primarily in desert landscaping. All have tender new growth that can be severely damaged when exposed to intense sunlight. It is important these trees are pruned throughout their lives so that the tree’s canopy shades the trunk and limbs.

If desert adapted trees have limbs removed that expose the trunk or large limbs to direct sunlight and sunburn, borers can be a problem in these trees such as Palo Verde and acacia

            Pruning them in a fashion that exposes limbs and the trunk to intense sunlight causes damage that causes limb death that becomes visible a few years later. It’s a progression that usually starts with bad pruning practices. This progression begins when too much is removed from these trees. When too much is removed, the limbs and trunk are exposed to high intensity desert sunlight.

Exposing the trunk and lower limbs to direct sunlight and sunburn can create future problems to trees like the Palo Verde.

            Intense, direct sunlight on young limbs first causes a discoloration due to intense sunlight. As this direct sunlight repeats day after day, exposed areas of limbs and trunk facing the sun die. Water can’t through dead areas of the trunk and limbs.

            Unless this sunburn causes severe damage, the top of the tree probably looks fine. The tree can still move water around the damaged area from roots to tree branches. The damage could be as much is 50% of the limb and trunk area and the tree looks fine.

This is not Palo Verde but when the trunk and limbs are exposed to intense sunlight for a long period of time, year after year, the intense sunlight can damage or even kill the living part of the tree under the sunburned area. The beginning of this damage can be very attractive to some wood boring insects which can make the damage worse.

            This damage from sunburn attracts insects such as borers that feed on living parts of the tree close to the damaged area. This feeding by borers causes even more damage that reduces water movement to the limbs. Perhaps the first year or two, trunk and limb damage goes unnoticed because the canopy looks fine.

The first sign of sunburn is a discoloration or off-color to the trunk, limbs or even fruit on fruit trees.

            But at some point, damage becomes severe enough that water movement from roots to the canopy is reduced.  Limbs start dying back because the tree can’t get enough water past the damage. This usually happens during the heat of the summer when demand for water is highest.

            The homeowner now notices the limb death in the canopy. The homeowner removes dead limbs. This exposes the tree to more intense sunlight and further damage. Tree damage is so severe and unsightly the homeowner considers removing it. This is the tree “death spiral”.

            What to do? Damage to the tree may be already extensive. Decide whether you can live with this damage or not. If not, have the tree removed. If you decide to keep the tree, then encourage it to heal as quickly as possible. Contribute to this healing by giving it enough water on a regular basis and apply fertilizer in early spring.

Cause of Dieback in Newly Planted Peach or Apricot

Q. Dying leaves on peach or apricot?

These fruit trees recently planted, whitewashed and the tops cut off. New growth occurred below the cut but it proceeded to die.

A. Not much information to go on with this question so I will give a broad response. From batch breaks pictures sent with this message, the fruit trees appear to be newly planted, whitewashed and the central stem pruned at about waist height.

Bareroot trees must be handled carefully

            If this tree was newly planted and bareroot (no container), it must be staked firmly in place, so roots do not move during the first few months of growth. Securing the tree solidly, in one place, encourages strong, future rooting.

            I assume the soil was amended with compost at the time of planting for better rooting and drainage. Build a donut or moat around the tree, 2 to 3 feet in diameter, to contain water from a hose. Water the tree with a hose once a day for three days in a row to settle the soil around the roots and remove air pockets.

How to water

            When that is finished, water every other day during warm times of the year. Make sure to skip at least one day before watering so that roots can "breathe". Watering every day for a month could suffocate roots and kill the tree or at least cause it to be sickly.

            Bareroot tree roots dry and die quickly. These important roots provide water and nutrients from the soil and are very small. Not large. These tiny roots dry out and die in seconds. Excessive drying of these roots causes “transplant shock” resulting in slow growth after planting.

Protect the tiniest of roots from drying out

            Bareroot trees can be finicky. You don’t see bareroot trees sold much anymore to homeowners. Only experienced gardeners should buy them. The roots of these trees must be kept moist from the time they leave the nursery until they are planted.

How to identify overly dried roots

The feeder roots of plants, responsible for the majority of water and nutrient uptake by plants, is even smaller than these small white roots of Myers lemon growing in a container.

            A common symptom of bareroot trees that have excessively dry roots is a short, flush of new growth after planting followed by their death. The death of new growth looks like a lack of water. And in reality, it is. Roots have died and can no longer supply water to new growth.

            If you think this might be the case, wait and see what happens after planting. In about two months, if you do not see new growth then the tree is dead and should be replaced.

Dieback of Mature Fan Tex Ash

Q. I was cleaning up the leaves from my Fan-Tex Ash tree and noticed that there was sap leaking from 4 different limbs of the tree.  Attached are some pictures.  The tree is about 18 years old.  Although the first picture shows a small number of leaves remaining, the tree has always has had a nice canopy of leaves including this past year.   The tree is in rock much, but it receives nutrients (24-8-16) from an in-line liquid fertilization system.

Readers Fan Tex ash tree

I did some on-line research and the sap could be caused by stress (not enough water) or some type of borer.  The tree receives about 30 gallons of water each time it is watered.  In the winter it is watered once a week, spring and fall twice a week, and in the summer 3 times a week.  Is it common for this tree to have borers or is this problem likely caused by insufficient water?

A. The amount of water it is receiving sounds about right or possibly a little bit on the light side. It is definitely not being over watered. Your frequency of application also sounds about right seasonally. If this tree is surrounded by rock mulch then the amount of water applied may not be enough.

Look at New Growth

Look at how much new growth occurs every year. At eighteen years of age the tree is in youthful maturity. The tree should be growing at least 8 to 12 inches minimum every year of new growth. If new growth is less than 8 inches every year then there is a problem.

You are right in several things. It could be damage from borers. It could also be from stress such as a lack of water.

Ash Decline Disease

Fan Tex ash is an Arizona ash. Arizona ash has a problem with ash decline disease. For this reason, I no longer recommend planting any of the Arizona ash trees including Fan Tex. The tops of the trees could have developed ash decline even though this look is not typical of ash decline. 

Ash decline usually hits one or two branches at a time and causes dieback and slow growth and leaves scorching. It is also possible it has sooty canker disease. Borers are usually associated with sunburn of limbs lower in the canopy. If this tree were topped with a chainsaw it is possible that any of these three possibilities could be a problem.

Dieback of ash due to Ash Decline

A severe case of ash decline on Modesto ash

If this is ash decline disease, the tree is a goner and it will continue to slowly decline in coming years. I would recommend that it would be removed. If this is borers or sooty canker disease then some pruning might help it recover. If you decide to keep this tree, I would have a qualified arborist selectively remove the damaged parts of this tree. Certified arborists know how to prune trees and improve their ornamental value.

Fertilizer Injector

It is nice to know that these trees are getting part of what they need through an injection system that deliverables mineral fertilizers.

Rock Mulch

This is only a partial solution to successfully growing ornamental trees in desert soils. If these soils are covered in rock mulch then the soil is probably low in organic content. The organic content can be very important to ornamental trees growing in desert soils. Rock mulch causes desert soils to slowly become less and less organic over the years. Mineral fertilizers will not solve this problem. Either covering the soil with woodchip mulch that decomposes or continually adding compost to the soil will work. As this soil becomes more “mineralized” over time the tree may continually decline.

If the soil is covered in rock mulch, add compost to the top of the soil and water it in. You would do this once a year for the next three or four years but it is a slow soil improvement process. This is all hinged on whether you have rock mulch or not. The faster option is to make vertical holes with post hole diggers throughout the root area of the tree and backfill these vertical holes with compost. This gets the compost mixed into the soil much faster and produces faster results.

If this turns out to be borers than applications of systemic insecticides may be her only solution to the problem. In any case, someone needs to make a decision about what the problem is which determines the course of action.

More Problems Growing Japanese Blueberry in the Desert

Q. We planted two Japanese blueberry trees in March of 2011 and have fertilized and watered them according to instructions. This summer they both are losing leaves and have white tips on the edge of the leaves. Another name beside Japanese Blueberry is Elaeocarpus Decipiens. Do you have any information or advise on these trees?

A. Questions about Japanese blueberry have been popular because people have not had much luck with them in desert landscapes. They are not really intended for desert landscapes even though they will grow in the desert if planted and managed with care. So I have linked you with a few of my responses regarding this tree from my blog.

http://xtremehorticulture.blogspot.com/2014/05/japanese-blueberry-tops-are-dying.html

http://xtremehorticulture.blogspot.com/2014/05/japanese-blueberry-top-dieback-followup.html

http://xtremehorticulture.blogspot.com/2014/04/japanese-blueberry-orange-leaves.html

http://xtremehorticulture.blogspot.com/2015/01/pruning-japanese-blueberry-to-encourage.html

http://xtremehorticulture.blogspot.com/2012/08/japanese-blueberry-leaves-falling-and.html

I hope this helps.

Leaf Yellowing on Locust Possible Sunburn and Borers

Q. Do you have idea why some many of the leaves on my locust tree are turning yellow?

A. The most frequent problem with locust trees, Idaho or black locust, is borers in the trunks. This will cause exactly what you're talking about, yellowing of leaves and leaf drop.

            This is followed by branch dieback. Dieback of limbs may take a couple of seasons after the initial borer attack but if you are not looking for borer damage early, you will see leaf drop a couple of years into the attack.

            Borers entered the trees usually where the tre is sunburned. This is normally on the west and south facing sides of the trunk or limbs. Horizontal limbs may be damaged on the upper surfaces as well.

            Check the bark on the trunk or limbs see if it is loose. It may easily pull away from the trunk particularly on the south and west sides. Damage is usually on larger diameter parts of the tree.

            Remove bark away from damage to areas and clean the damage down to fresh wood. You don't need to paint it but if you want it painted, paint it.

            Use a liquid insecticide soil drench to help protect the tree and give it a chance to recover during early stages of an attack.

Japanese Blueberry Tops are Dying Part I.

Q. I’m having a problem with my Japanese blueberries. Some are fine and the two on the end appear to be drying out but only towards the top? Do you have any idea what’s causing this? The soil is not dry and they all get the same amount of irrigation.

Japanese blueberries tops dying back

Sunburn on Plants a Major Desert Problem

Q. I have three 3-tier privets in the front of my house. One of them, showing in the two attached pictures, seems to have trouble at the top tier, which grew yellowish and small leafs, while the bottom two tiers grow normally. The top part of the trunk close to the sickly tier shows darker color.  Nursery people told me that the troubled shrub got too much sun and needs more water. But I have watered the shrubs (all three of them next to each other) with the same amount and same frequency. To tell me just the top tier of one shrub needs more water does not make much sense to me, right?

My question is: why only the top tier turn sickly yellow while others are growing normally? and what can I do to protect it from dying?  Thanks.

Tipu Sensitive to Winter Cold in the Las Vegas Desert

Q. We purchased 11 Tipu trees in March of 2012.  We purchased these trees because they were recommended as fast growing trees for our property. Three of the 11 trees we planted died during the winter of 2012-13 and only growing “suckers” around the base of the trunks.  An arborist told us the trees were “toast” and recommended we might leave the suckers to regrow into a tree rather than remove them. Is there anything else we can do to help these trees or do you think they are a lost cause? 

Tipu showing regrowth from the base after winter kill due to low temperatures.

A. As you have already found out, this tree will freeze in our climate. This is what I believe killed the tops of your trees this past winter. According to Arizona State University it is hardy down to about 25°F. Temperatures below this cause winter leaf drop first followed by branch and trunk death as temperatures drop further.

            What you are seeing now is resprouting of the tree from the base which was protected from freezing temperatures by the soil. If the temperature had dropped even further you might have lost the entire tree with no regrowth from suckers.

            The arborist was right. You could select one of the stronger suckers and remove the rest. If you want a multi-trunked tree then leave three to five. These nurtured suckers will grow up to be a new tree that will promptly freeze to the ground again when temperatures drop to that 20ish F range.

            I am not in favor of growing this tree here and I will tell you why. This tree is originally from South America where it can reach heights of 100 feet with a 60 foot spread. In our harsh, desert climate it won’t get that tall but might reach 40 feet or so.

            In the wetter parts of California it has been used in water conservation landscapes. It is not a desert plant and should not be considered low water use and in the same category as acacias for instance. These trees should be considered moderate in their water use, similar to ash of a similar size.

            In some places they are considered invasive and their root systems destructive. This should not be the case here if you plant them several feet from walls, sidewalks, driveways and foundations. Plus, you should water them infrequently, not with shallow frequent irrigations and irrigate on sides away from structures to less damaging root growth.

            A lot of people in the warmer Phoenix area like this tree. There are a few who don't like the litter it produces and fear it's destructive potential. In a nutshell, because of its lack of cold hardiness, I do not believe it is suitable for the cooler climate of the Las Vegas Valley.

Privet Yellowing a Soil Problem

Q. My Japanese privet was doing great. I gave it your EDDHA iron chelate elixir 6 months ago. I was watering three times a week and have now cut back to once a week. The leaves are now yellowing with brown spots, the same as it did last year. So, what should I do to the green back?

Privet with leaf yellowing

A. We see this yellowing of the leaves quite a bit in Ligustrum or privet. They prefer moist and enriched soils so I think this is a combination of both a lack of fertilizer and poor soil conditions.

They are not a very good desert plant and don’t really like desert landscapes very much.  The yellowing is most likely a combination of high light intensity along with a general decline in health which makes them more reactive to these tough conditions. 
 

Black spots developing on leaves weakened due to poor health. Perhaps anthracnose but should disappear if plant becomes healthy again.

This may be too much for you but if you want to reinvigorate them I would go back in with some decent fertilizer such as Miracle Gro or Peters and either or both spray it on the foliage along with a teaspoon of Ivory liquid in each gallon of water. Then I would also follow up with some compost at the base of the plants and wood mulch to a depth of 4 inches or so. 

You will probably not see much reaction this time of year since it is going into “hibernation” but should see a difference next spring. Keep the soil moist but the mulch will help to enrich the soil and keep the soil more moist than before. 

Make sure it is getting adequate water. I would estimate about ten gallons per each application for that size of plant. That would be a minimum. You could do a bit more even like 15 gallons. They would like to be treated more like a rose bush than a cactus and would, in fact, like lawn watering schedules over tree and shrub watering. They do better in lawns is what I am saying. Don’t forget a fertilizer application along with your iron next February.

Watch Out for Deadly Fireblight on European Pear, Asian Pear and Quince

Frequently I see this problem pop up on fruit trees in May or June.

Readers pear tree

Q. I have a pear tree which is about 10 years old.  Up until this year, it has been pretty healthy.  This spring it got a disease. I am hoping you can identify it for me from these pictures and tell me what I can do to treat it so that it won’t be a problem in the future.

            I thought at first it might be fireblight but it is not with the new growth.  It seems to have attacked all the places where there would have been fruit. I have inserted pictures for you and hope that these are helpful. It is not receiving any overhead spray.  It is watered with a drip system.   

A. This is fire blight. This is a bacterial disease which is more rare than fungal diseases on plants. One way it is spread is through the flowers either by blowing wind during rainy weather or by pollinators such as honey bees.

            Flowers of apple and pear come from spurs which are short shoots on older wood. If the disease enters through the flower then it will spread through the older growth and into the new growth if it is present. It does not necessarily have to attack new growth.

Fireblight in pear

            It can be seen on older growth as well. On new growth if it is present it will show the textbook picture of shepherds hook which I posted on my blog. If new growth was not present then it will simply die back and demonstrate a blackened, scorched, fire appearance.

            This disease is extremely virulent and must remove as soon as possible from the tree and the growing area. Cut out the infected limb to 12 inches below the visible infection. Sterilize pruning instruments with a dilution of bleach and water both before and after the cut has been made.

            Put the cut limb into a plastic bag, tie the bag and immediately put it into the trash. Do not try to mulch or compost this infected limb. Oil your pruning tools after you disinfect them with bleach so they don’t rust.

Classic fireblight shepardshook and black
scorched fire symptoms

            Wash your hands after you have finished pruning. This disease is fairly rare here due to our isolation from orchards and low humidity. It attacks European pears like Bartlett, all Asian pears and Quince but does not damage Keifer pear. I hope this helps.

Rosemary Bush Very Susceptible to Dieback if Overwatered

Rosemary dieback from reader

Q. Can you diagnose what is wrong with my rosemary bush?  We have two rosemary bushes which are less than three-feet apart.  One is beautiful; the other has die-back in the center.  The one that has the die-back was replaced last year because the previous one had the same problem.      Both of these plants receive the same water and the same fertilizer.  When I replaced the rosemary plant last year, I did a 50/50 mix of compost and native soil.  I don’t see any pests on either of the plants.  Any suggestions?

A. I looked at the pictures. There are no specific pests that would cause this type of damage on rosemary. The most likely culprits would be physical damage to the stems (broken stems) or root rot or collar rot from either planting it too deeply or keeping the soil around the one with dieback too wet.

Healthy rosemary of reader

            If the soil was heavily amended with mulch or compost and it was planted in this then it is possible it could have been planted too deeply while the other one was not. Sometimes plants will sink in the planting hole if the soil is too "fluffy" at the time of planting.

            This sinking and soil consequently coming in contact with the stem due to follow-up waterings, can cause the main stem or side stems to decay and then entire stems can dieback.

            I would carefully lift the plant out with a shovel and examine the main stem or trunk and side stems and see if they were planted too deeply. Rosemary is very susceptible to collar rot or keeping the soil too wet. If the stems are rotten, dispose and replant in a new location.