dieback – Xtremehorticulture

Watering Pine Trees – Water Deep!

2 Comments / Aleppo Pine, brown needles, dieback, Pine tree / xtremehorticulture

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.

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Reasons for Palo Verde Limb Dieback

Leave a Comment / borers, die back, dieback, palo verde, sunburn / xtremehorticulture

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.

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Cause of Dieback in Newly Planted Peach or Apricot

2 Comments / dieback, new tree death / xtremehorticulture

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.

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Dieback of Mature Fan Tex Ash

Leave a Comment / dead branches, dieback / xtremehorticulture

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.

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Leaf Yellowing on Locust Possible Sunburn and Borers

Leave a Comment / black locust, dieback, Idaho locust, leaf drop, purple robe locust / xtremehorticulture

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.

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Japanese Blueberry Tops are Dying Part I.

Leave a Comment / borers, dieback, disease, Las Vegas / xtremehorticulture

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 A. I would guess that something caused a problem on the trunk or large limbs at the bottom where it has turned brown. I am guessing it might be borers or some other critter that mechanically damaged the trunk/limbs. It is possible it could be sunburn as well particularly if they were open enough to allow direct sunlight on those branches/trunk for extended periods of time. I think we can rule out diseases in our climate except for the possibility of sunburn (non pathological disease). Look at the area of trunk/large limbs just in the foot above the healthy areas and let me know if you see peeling bark, discoloration or other types of abnormalities. If it is borers (the most likely), there is nothing you can do to raise it from the dead but you can protect it with a soil drench once a year using Feri-Lome’s soil drench. It contains an insecticide that should give you about one year of control from what I am hearing.

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Sunburn on Plants a Major Desert Problem

Leave a Comment / dieback, plant damage, privet yellowing / xtremehorticulture

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. A. Thank you for the pictures. I agree with you. I do not believe it is water….directly, or can be improved by giving it more water. The problems is located on the branches or foliage showing the damage. We can eliminate an irrigation problem for exactly the reason you said and the foliage on the same side but below the damaged area is in much better condition. If the entire plant on that side had shown that kind of damage then I might be inclined to include a plugged emitter or not enough water to be a possible source of the problem. Whenever we see damage to a plant and it is localized like yours is then the usual problem is located on the branches or stems supporting the problem area OR on the foliage itself. Now, what I know because of my experience in the desert and you don’t know is that there are very few insect or disease problems on Ligustrum or privet. Most of the problems are sun related because it is not a true desert plant that can thrive in our environment easily. It does require a bit of pampering. My guess is that the stems supported the leaves or foliage has been damaged…mechanically. Mechanically just means that some outside force was at work to create the damage as opposed to a disease. Insects, such as borers, can also create mechanical damage by chewing or gnawing but I don’t think this is from insects since this plant does not have a history of that kind of problem here. That is my head knowledge telling me by deduction, not anything I can see. Here is a nice website that talks about privet problems but we currently don’t have very many of the problems listed as they do in California. http://homeguides.sfgate.com/privet-hedge-problems-43811.html The author does say this, Twig Kill Repeated shearing keeps privets neat and compact, but also forces branching until the surface of the shrub is a thick mass of branches and twigs. Sudden cold snaps in winter, dry windy weather, or drought might kill small or weak branches. If the twigs at the end of a few branches die back, the branches themselves may be lost and the resulting open spot will have to fill in with growth from other branches. Twig kill might necessitate careful hand trimming rather than shearing to ensure that new branching expands into the void. We do have one though that they don’t list…sunburn. The side damaged is toward the sun. I can’t see all of the plant but it does appear the sides away from the sun are healthier. If some over-aggressive shearing was done and opened up the top tier too much, it could open the inside branches to sunburn from our intense sunlight. That happens to a number of plants here whereas it milder climates it does not. I have seen that happen here to Podocarpus when an over aggressive gardener got carried away and pruned too much out. I will post that on my blog next week. One way to tell is to bend some of the branches on the top tier to find out if they are supple or stiff from sun damage. They might even snap if they have been damaged. Sunburn on Podocarpus after pruning and subsequent dieback. What to do? The damaged area could grow back but it will be slowly. You would live with this damage until you see some new growth “sprouts” coming from the inside branches. Many plants respond this way to damage, but not all. In the case of privet, the growth is slow, not rapid. Once this growth appears you can start to prune back the damaged stems to allow for this new growth to occur. This might take a couple of seasons. Another thing I would recommend if you don’t have it is to use several inches of wood mulch at the base of these plants. They definitely do NOT like rock mulch if that is what you have. Another less likely possibility is damage from mites to the foliage but I think this is less likely. I would say the higher probability is sunburn damage to the stems. From Reader – Thank for prompt and informative reply. Your suggestion about aggressive pruning and western sun burn might be part of the reason which I will try to correct in the future. I did add 3-4″ organic mulch at the base of the plant and I’ll do more in early spring when I begin fertilizing plants around my house. In the spring , I added iron chalets with regular shrub fertilizer, and mix some manure in the mulch. It seemed to work pretty well. Thank you again,

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Tipu Sensitive to Winter Cold in the Las Vegas Desert

1 Comment / dieback, tipu, tipuana, tree selection las vegas, winter damage, winter kill / xtremehorticulture

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.

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Privet Yellowing a Soil Problem

Leave a Comment / black spots on leaves, dieback, privet yellowing / xtremehorticulture

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.

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