Xtremehorticulture

Xtremehorticulture of the Desert

Ash Decline (Disease). Or is it?

Leave a Comment / activated carbon charcoal, ash decline, damage, dicamba, sterilant /

Q. What might be happening to our ash trees? We noticed that a couple of our ash trees are not doing well at all.  I did a quick google search yesterday and found an article you wrote about ash dieback. I’m hoping that’s not what is happening to our trees, but it does look like it. The only other thing that might have happened is that my husband put sterilant down on some rocks nearby last November. Now we are wondering if perhaps the sterilant made its way down to tree roots that may have been growing beneath the rocks?  I believe he treated the whole area with the sterilant, and you can see where the tree trunk is located in relation to the rocks.  If it is in fact a chemical injury to the trees, is there anything that can be done? Ash Decline (disease) or not?  Ash Decline looks just like the trees are not getting enough water. You wont know until you water it (give it some extra water) for a few weeks and find out. Unless you want to pay a big plant pathology bill. A. I don’t think your ash tree has this particular disease. After looking at the pictures you sent, I think it was caused by the sterilant. It’s helpful if you can tell me the name of the sterilant used. Many sterilants are taken up by plant roots. The sterilant damage usually occurs on leaves and stems. On leaves, sometimes they “scorch” (their leaf margins will burn). This is what I think I see. In many cases the leaves turn yellow or become “bleached”. This is the type of “yellowing” I’m talking about. It is not “sterilant” yellowing but this is the color I am talking about.             Tree roots watered by rainfall extend horizontally to about the length of their height. So, if you roughly (visually) lay the tree on its side and spin a circle with it, that roughly extends the length of their roots (with rainfall). Some pine trees I was given to spray with Dicamba, because we saw some dicamba issues on some pine trees when I worked for Utah State University as a Horticulturist.             In the desert tree roots follow water. Wherever water is applied, that’s where you will find its roots if this area is under its canopy. I noticed a lawn under the tree. Did you kill a part of the lawn with sterilant? Many sterilants are taken up by plant roots but this sterilant can oftentimes be seen in the leaves. Dicamba was also used as a sterilant. This is what dicamba damage looks like on pine trees. Shout out to my friends in SLC Utah.             If it is sterilant damage, you can try a couple of things. First try to wash it out. It may or may not work. Putting a lot of extra water in that area may flush the sterilant out. Just remember to give a day or so without water to give a chance for the roots to “breathe”. Roots need both air and water to survive.             There is a chance that putting activated charcoal (expensive, activated carbon its called and is specific to the sterilant) may help but it depends on the sterilant used.             When there is consistent rainfall, roots of trees extend all through the soil under its so-called “canopy”. Your ash tree grows in a lawn. Watering lawns is more even, regular, and consistent than rainfall. Ash trees do remarkably well in lawns. In my opinion that is their preferred way of getting water to the roots.             Ash trees infected with ash decline are not getting enough water to the dying limbs.  This disease plugs the water conducting vessels in tree limbs. As this disease slowly gets worse, more and more limbs begin dying because of a lack of water. The homeowner ends up removing the tree because it looks “ugly”.              To see if your tree has this disease or not, give it some extra water once a week during the summer! An extra irrigation during the week tells you if the tree has this disease or not. If the tree does not improve in a few weeks with this extra irrigation, then assume the tree has the disease.             The mistake made by most homeowners, in my opinion, is not removing the tree as soon as they decide one way or another. If you have confirmed this disease, then remove the tree as soon as possible. This tree can spread this disease to other ash trees!

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Century Plant (American Agave) Not Growing Well

Leave a Comment / agave weevil, damage, root rot /

Q. We have a century plant thriving over the past 10-12 years in our front yard. Towards the end of summer, we noticed lower leaves getting soft and tender, leathery even, eventually turning yellow. No new shoots are visible emerging from the core. It gets watered occasionally. Century plant or American agave. A magnet for agave weevils. A. Century plant is an agave weevil magnet! My guess is that’s the problem. The only method I know to control agave weevil is to apply an insecticide around the base of all agaves in March or April of every spring. The insecticide is used to protect the plant from spring infestations. Sprinkle a granular insecticide at the base of the plant and lightly water it. The other option is possibly to drench the soil immediately around the agave with systemic such as imidacloprid (if the label permits).  Warning sign of American agave that it might have agave weevils. Apply granular insecticide in the spring as a prophylactic treatment.             The adult weevils have wings and can fly. They can fly from a neighbor’s plants to a different neighbor’s landscape. These adult beetles lay their eggs in the crotches of the agave in the spring. They don’t use calendars but fly during the spring when it’s perfect weather. That is why the timing for an application is sometime “in the spring”. The “grubs” hatch from the eggs and tunnel inside the core of many different types of agaves and cause their tunneling damage. Sometimes the damage is so severe it kills the plants outright or it might cause a smaller problem when plants are larger. This is the type of problem agave weevil can do on established plants. Notice the base was rotten and the plant “collapsed”.             The other usual problem is watering too often. This can weaken or kill the plant. It doesn’t sound like that is your problem. I would caution you to water the plants deeply and not just a sprinkle them with a hose. Depending on the size of the agave it can take from 5 to 15 gallons of water varying from a small to a large American agave. If the American agave is large, then use three drip emitters located about 12 to 18 inches from the plant in a triangular spacing and watch for signs of stress. Apply water about three to six weeks apart during the summer.

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Wind is Damaging to Plants

Leave a Comment / damage, plants, wind /

Windy Weather Windy weather, like we had over a past weekend, is very damaging to plants. (Notice I said “is” and not “can be”?) Light winds cause very little damage. Moderate winds cause moderate amounts of damage. Strong winds cause lots of damage. Why? I can think of at least two reasons; extent of damage and water use. Shallow rooting of tree because of annual flowers planted at its base. Vegetables and Wind             Vegetables grow the best when located closest to the downwind side of a windbreak. Plants don’t care if the windbreak is living or not, they just want the wind slowed. For this reason, the best windbreaks are not solid walls (e.g., block walls) but perforated walls (e.g., chain-link fence with slats inserted in them). Solid walls cause the wind to swirl. Perforated walls cause the wind to slow. Science has shown us the best windbreaks are about 80-90% solid, not 100% solid. Windbreaks for orchard in a canyon Wind Damage and Fruit Trees             Examples of damage include leaf and flower damage with small fruit ripped from the tree with some types of fruit trees. Plants grown in windy spots are smaller than plants grown in protected areas. In strong windy locations I have seen fruit trees that lean away from the wind. Wind damage to fruit trees is the worst on trees closest to the wind. Wind damage lessens on the second and third row of fruit trees. Plant fruit trees in blocks so they give each other wind protection. Locate fruit trees that tolerate wind damage the most on the windward side of the block. Examples of wind tolerant fruit trees are pomegranates, apples, and pears. These trees will protect the less wind tolerant fruit trees. Fruit trees less tolerant of wind include citrus, plums, apricots, and peaches. Wind and Water Use             Plants during windy weather use more water. If the winds are strong and continuous, they use more water! Wind is a strong predictor of plant water use. In fact, along with how bright the sun is shining it is one of the strongest predictors of plant water use.  Pay Attention Go outside in the morning. Look at the weather. Is it bright and sunny with very few clouds in the sky? Winds is a major predictor of high-water use. Look at the trees. Are the leaves moving? Look at a flag flying on a flagpole. Is the flag barely moving? Is the flag flapping a lot? Is the flag rippling because of the wind? Those are indicators of wind strength. Bright, cloudless skies and strong winds equals high water use in our desert climate. It’s time to water during bright windy weather.

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Sapsucker Damage on Australian Bottle Tree

Leave a Comment / control, damage, ornamental trees, sapsucker, woodpecker /

Q. I have a 5 year old Australian bottle tree that has a large canopy.  The canopy has very yellow leaves and I have found on  the trunk  about ¼ inch holes in the trunk. There are quite a few holes but I have not counted all of them. I don’t want to lose my tree. Can you tell me what is wrong with it?  No picture was submitted of the tree damage. A. This is probably sapsucker damage. They are in the family of woodpeckers.They are migratory in the Las Vegas Valley and probably overwinter mostly in northern Mexico. So you see this kind of damage on preferred trees twice a year. https://www.uaex.edu/publications/pdf/FSA-7561.pdf Sapsucker damage on Tipu. Sapsucker damage to Southern Live Oak Sapsucker damage to blue ghost eucalyptus For more information and some suggested control measures visit my blog at these locations. http://xtremehorticulture.blogspot.com/2011/08/someones-drilling-holes-in-my-trees.html http://xtremehorticulture.blogspot.com/2015/12/holes-in-trees.html

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Leaf Yellowing of Pomegranate Could Be Weed Killer

Leave a Comment / damage, herbicide, Weed killer /

Q. Eleven of my 50 young pomegranates have leaves yellowing and dropping off. I water this area once a week by flooding. I sprayed a weed killer, 2,4-D, near the pomegranates but I protected each one with plastic to avoid damaging the trees. Where did I go wrong here? If the weed killer is the problem, is there any way to save them? It looks like the pomegranates were planted in a depression. The more I look at these pictures the more I’m concerned that it the roots may be kept too wet. The only way to know for sure is to use the soil moisture meter and measured the soil moisture just before the next irrigation. Generally speaking, pomegranates and most long grasses are not compatible. Another possible option is to plant pomegranates on a raised area of soil rather than a depression. Even though the soil is cracked on the surface it tells you nothing about how dry it is only a couple of inches below the surface. Many weed killers can travel with water. Make sure no water is added to these plants within 24 hours after we killers are sprayed on the soil. A. When I first saw your pictures I thought the soil was too wet. But I read your email that they were watered only once a week. Watering once a week in mid spring should pose no problem if the soil is not a heavy clay. If the soil is a heavy clay and remains wet a couple of days, this could cause leaf yellowing and dropping.             In the picture, I saw grass growing close to the pomegranates. If watering only once each week, I assume the grass is Bermudagrass. Tall fescue should need watering more often than this. Grass growing close to these trees will cause them to grow more slowly. Particularly Bermudagrass. So it’s always a good idea to remove grass at least 3 feet from a fruit tree.             The leaf yellowing could also come from a lack of nitrogen in the soil. However, if you are fertilizing that grass there is probably plenty of this fertilizer escaping to the pomegranates. Removing grass 3 feet from the tree will reduce competition for any fertilizers applied.             Now on to the most likely problem; weed killers. It helped that you covered each of the trees with plastic before spraying. It’s even more important if you spray this kind of weed killer when temperatures are cool and there is absolutely no wind. Hot soil surfaces cause dandelion killers like 2,4-D to volatilize (turn into a vapor) and move very easily with the very slightest air movement. This is 2,4-D damage, dandelion killer, on tomato. If the tomato plant is growing, the growth will become deformed.             Damage from 2,4-D is easy to identify when the plant is growing and producing new leaves; new leaves are deformed. If the plant is not growing and producing new leaves, leaves turn yellow and drop. The branches that supported them may or may not die as well. All you can do is wait and see what happens. This is weedkiller damage on grape. The weedkiller is unknown but the damage is unmistakable.             I am concerned with the plastic. Make sure that the same side of the plastic using contact with the plants and that you don’t accidentally wrap the plant the wrong way.             I think a better weed killer to use for your purpose might be Roundup. It does not volatilize as easily as 2,4-D. For it to work, the spray must land on green leaves or green limbs. If you prune pomegranates so their lowest foliage is about knee height from the ground, it will be less likely to be damaged.             Keeping grass 3 feet from the trunk will also help. A small plastic bucket with a hole drilled in the center of the bottom, attached to a spray wand, will help contain the spray and directed toward the weeds.

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Can I Use Compost With Worms in It?

5 Comments / armyworm, compost, cutworm, damage, decomposers, Miller moth, pupae /

Q. I have been collecting vegetables scraps for the last 6 months for composting but did not have a cover on my bin.  I have found the compost loaded with this bug or worm.  Can I use this compost? There are too many to pick out.  I’m afraid if put in soil they will kill plants but my compost is really good!! A. This is pretty common in compost. This question is one of the most common questions asked about composting on my blog.             Many of these types of insects feed on decaying foods and composts that are not quite finished composting. Once the compost is finished they are seldom a problem.             I don’t know how much compost you are talking about but if it is possible to layer out the compost the birds will come in and gobble them up.             You can cook them in the sun and they will decompose in your compost. To do it correctly the compost must be “fluffy” or loose enough to allow the heat to spread through it evenly.             Spread the compost in a layer several inches thick. It should be slightly moist but not wet. Cover it with a clear plastic drop cloth and hold it in place with some nails or staples. The edges of the plastic must be sealed so no heat escapes.             Hold it in place with some rocks, blocks or bricks so it does not blow away. Leave it in direct sunlight for about two weeks. The temperature will get hot enough to kill most of the insects. Maybe pupa of cutworm or armyworm? Pupa is the transitional stage between larva or worm and the adult. In these cases moths. The adults are moths that you will see flying around your porch light at night. As a kid we used to call them “Miller moths”. Kind of dusty, maybe an inch across. They used to fly right into the light and sometimes get “fried”. When you see these moths, the eggs they laid will hatch in a few days and it is time to put down some Bt sprays or dusts on your vegetable garden.

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There is Lots of Salt in Las Vegas Water and It Can Affect Plants

2 Comments / damage, lemon, ornamentals, pineapple guava, rose, salinity, salt /

Q. I saw that on August 12th you responded to a question regarding yellowing leaves on a Meyer lemon tree.  My tree has similar symptoms – though the yellowing is more spotty and on tips.  You advised to “give it a long deep watering about once every few weeks…to supplement the regular water to leach out the salts…” (emphasis added).             I realize that soil make-up effects watering needs, but can you give me a ballpark as to how many gallons of  “regular water” per week is needed for these trees in Las Vegas in addition to the leaching you recommended?  My tree is approximately 7 feet tall. Should I spread these gallons out over a few days a week, or is giving it these gallons slowing on a single day once a week? A. That’s actually a very interesting question and we have some research to back up the amount. There is about one ton of different kinds of salts (all of these together make up the “salt” content) in one acre foot of water that comes from the Colorado River (Lake Mead).  Rose leaf with salt damage             An acre foot of water is about 360,000 gallons. Unless you are on a well, this represents about 80% of the drinking and irrigation water provided by water purveyors (Las Vegas Valley Water District in the case of Las Vegas) in the Las Vegas Valley.             This sounds like it could be quite dilute but actually when you water to a lawn from Lake Mead it will carry 4/5 ton of salt for every 360,000 gallons that are applied. This translates to an application of 800 pounds of salt for every 1000 square feet of lawn area each year. Salt damage to pineapple guava from salt in the irrigation water             Bottom line, if this is municipal water it carries a considerable amount of salt. If you skimp on the amount of water that you apply and don’t overwater a little bit, this salt will accumulate around the roots of plants. This “little bit” of overwatering each time you water is only about 15%.             So if you apply 100 gallons you really should apply 115 gallons to help move the salts out of the root zone of plants. If it is 50 gallons, then apply an extra 7.5 gallons. Ten gallons means you should apply 11.5 gallons.             Few people are this precise when they water unless they are watering a golf course and paying $1M each year to irrigate an 18 hole golf course. So when you water you can apply a little bit extra each time you water (15%) or you can flush out the salts around the roots by adding an extra irrigation or two during the hot months to keep those salts moving out. I hope this helps.

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Young Apricot Leaves Drying Up and Liquid Oozing

Leave a Comment / damage, dogleg, rootstock, sap oozing, scion, young tree leaves drying /

Q. I planted a Blenheim Apricot in March.   At first it did not seem to take but within four weeks it began showing growth whereas all the other fruit trees took almost immediately.  Its been doing fine until just recently when I noticed some of the leaves on the main truck were drying up.   I check the moister level regularly.   Looking closer at the graft there seems to be some liquid oozing out.   Enclosed are some photos of the liquid, drying leaves, and tips of higher leaves.   Any thoughts on what I’m up against.   Rootstock is Citation Hybrid if that helps. All my other fruit trees planted in the same general area are doing just great. Iron chlorosis, inter veinal chlorosis, or yellowing between the veins typical of new growth when iron chlorosis is present A. Some great shots and I would like to post them on my blog. Your photos tell a nice story I dont get to tell very often. But first lets look at the obvious and the is the discoloration of the leaves. The yellowing between the veins is called “interveinal chlorosis”. Chlorosis just means “yellowing” so it is yellowing between the veins. The most common reason for this in our alkaline soils is nutritional and frequently it is a lack of iron. Other nutrient deficiences that can cause similar types of chlorosis can include manganese and zinc deficiencies. I would guess this is an iron problem. The picture of the sap at the place where the rootstock (in this case Citation) meets what we call the scion (in this case yours is Blenheim apricot) we see some damage. It is very close to the bud union or dogleg (where the two meet). Bud union or dogleg. Where the Blenheim apricot was budded or “grafted” on to Citation rootstock and sap The damage may have started at the time of planting and is most likely from sun damage or sunburn. This area should have been painted with whitewash or any diluted white latex paint. Dilute 1:1 with water. Or you can put anything in front of that area that would give it some shade until the tree puts on some canopy and shades itself. You can use wooden shingles, cardboard, anything to cast a shade on the trunk. Usually, if the trunk gets sunburn then it is highly likely it will also draw borers to the damage and you will get borer damage there. It is very likely this is what you are seeing. YOu can find out easily by bending the canopy of the tree over. If the trunk breaks, it will break at the borer damage and you will most likely see them there. If it does not break when you bend it, it may just be sunburn. If the sunburn is not extensive, it is posssible it could heal itself but rather unlikely. You may have lost the tree. Interestingly, this dunburn and damage at the dogleg can also lead to the chlorosis or yellowing of the leaves as well. The sunburn damage can interrupt the flow of nutrients including iron up the tree and the interruption may be enough to limit the supply of available iron and lead toward iron chlorosis. However, some iron chelate sprays on the leaves a few times, along with a teaspoon of Ivory liquid per gallon of spray, may be enough to green the leaves up. I would guess 4 to 6 applications made in the wee hours of the morning when it is cool. Next time whitewash the trunk at the time of planting or provide some shade on the trunk until the canopy gives enough shade to protect itself.

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Tree Damage from Dormant Oil?

Leave a Comment / damage, dormant oil, evergreen trees, fir tree, spruce tree /

Q. I need some help. About a month ago I was advised by a gardener that two ornamental fir trees needed to be sprayed. He suggested I use Ortho Volck and I did this at the prescribed dilution rate. Now both trees seem to be in trouble as shown in the attached photographs. Did I spray too heavily? What can I do to try to save these firs? “Fir” damage from oil A. Dormant or summer oils are not supposed to be applied to Douglas Fir, Spruces such as birds nest, many juniper and cedars. I assume Volck oil says this on the label. It may cause defoliation or needle drop. In some cases you might have some branch dieback, perhaps enough to ruin its looks. It is safe on pines if you follow the rate of application. You mention that you have fir trees which is unusual in the Las Vegas valley but if these are in any of these categories you could have spray damage. If the damage is not too severe I think they will drop damaged needles and show some new growth from terminal buds and buds inside the canopy (branches). Hopefully they will recover.

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