July 2013 – Page 3 – Xtremehorticulture

Freeze Damage on Acacia Can Be Hard to Fix

Q. Any advice on Acacia trees would be great. These trees took a hit when the temps dropped to the 20’s in December. I see new growth, but mostly on the suckers. Should I leave the suckers there or remove them? What is the best thing to do to help these trees recover? A. This is more complicated. First you will remove any wood you know is dead. By now (June), any part of the tree which is still alive should have thrown out some growth. Remove any limbs that are dead (no growth coming from them) by cutting at point of attachment to another limb or the trunk. You should not leave any stubs when you are done. If the limb is large and heavy, you should remove it by either removing sections of the limb at a time that are manageable or use a technique that we sometimes call the 1-2-3 method. This is demonstrated pretty good on Wikihow http://www.wikihow.com/Cut-a-Limb-from-a-Tree Next, remove any broken branches. They will not repair themselves. Remove any wild or “sucker” growth. This type of growth usually has weak attachment to the trunk and not support itself in years to come. Remove any growth coming from the trunk that is not high enough in the future. This growth will not get any higher and as it gets bigger will “sag” or bend downward perhaps into places where you can bang your head. Remove these by making a “flesh cut” in other words remove it all and don’t leave a stub. Finally thin out the remaining branches so that any dead wood is removed (again by making “thinning cut” which is the same as in the third sentence, removing it at a point of attachment without leaving a stub.) Try to have the remaining branches going in different directions to help balance the crown visually. I hope this helps. By the way, I would do any major limb removal next early spring after the worst temperatures have passed. Minor cuts (with a hand shears) can be done any time.

Freeze Damage on Acacia Can Be Hard to Fix Read More »

Sago Palm All Stressed Out

1 Comment / cycas revoluta, discolor, yellowing / xtremehorticulture

Q. I have four sago palms and two are turning yellow. The two which look best were bought from a local nursery and the two which don’t were bought from a building mass marketer, They are all planted in rock mulch and watered on drip. They each get about 15 gallons each a week. They are now pushing new growth. I screened the soil they were going into when planting them and put in a lot of peat moss to amend it. They get sun all day long. I tried some local supplements but they don’t seem to be helping. Readers sago palm or cycad A. On your cycads, or sago palms, it is stress. Looks like the yellowing is from high light combined with high temperature stress. The rocks are not helping since it makes the area hotter from radiated heat. Put some shade over it but the damage is done and those fronds cannot repair themselves. You have to rely on new growth to cover the damaged growth. So it will look bad until that happens. That is my best shot at it. They will not do well with rock mulch. They don’t do well if the soil doesn’t drain easily either. They really want to have rich, organic soils, mixed with their roots, to do well. Even though they are somewhat tolerant of dry soils, they are not drought tolerant. The worst exposures for sago palm will be hot south or west facing exposures near heat reflecting walls with rock mulch at their base. The best exposures are east or even north exposures with lots of indirect light with wood mulch at their base and plenty of air movement. The best soils have been amended richly with compost and the soil covered in wood mulch (not bark mulch) that decomposes with time. Be careful of watering too often since they will get root rot if the roots stay wet for too long. In that type of environment they can handle full sun but still not the rock mulch.

Sago Palm All Stressed Out Read More »

Damage to Slik Tree (Mimosa) Looks Like Carpenter Bee

Leave a Comment / borer, large holes, tree dieback / xtremehorticulture

Q. My mother’s mimosa tree was fine May 24. Something has attacked it. I have attached photos of before and after, with closeups of a couple of damaged areas. Please advise what we should do to help the tree. Mom is heartbroken. A. I am not positive but it looks like Carpenter bee nesting damage. They usually bore holes into dead wood so I am guessing that the limb may have been under some stress and has been dead for awhile. If these were from Carpenter bees then your Mom might have seen some large bumble bee like bees in the area. These are large bees that resemble bumble bees but fly faster and more zig zaggy and as brightly colored as bumble bees. I am sorry there is not much you can do but remove the limb. With that much apparent damage I don’t think there is much you can do to save it. You can wait and see since they tunnel into dead wood but it might be severely weakened with that much damage. Mimosa is a fairly short lived tree and you were lucky to have it as long as you have. This damage did not happen overnight. It has been going on for quite some time but plants have a way of handling damage quite well for long periods before they show signs they have been weakened. This tree is in the same boat. It has been damaged for awhile but never showed any signs until recently. Carpenter Bees

Damage to Slik Tree (Mimosa) Looks Like Carpenter Bee Read More »

Preventing Summer Lawn Disease on Tall Fescue

1 Comment / brown patch, dead grass / xtremehorticulture

During the heat of the summer your tall fescue lawn will be stressed. It does not like 117F heat during the day or at any time for that matter. When under stress, fescues will be prone to attack by lawn diseases. Makes sense, doesnt it? We are more prone to getting sick when we are under stress too. This can become a big problem if the lawn is already stressed by a weak irrigation system, mowing the grass too short and even applying too much nitrogen 3 to 4 weeks before the onset of heavy stress. Lawns in parts of the yard where there is poor air movement are more prone to getting disease than those where air can move across its surface easily. Most plant diseases like it best when the humidity rises and there is poor air movement which fails to dry out the grass. To help prevent disease in your lawn make sure the lawn is mowed at its proper height for fescue; no shorter than 1 1/2 inches. No taller than 2 1/2 inches this time of year keep mowers that were on diseased lawns from cutting your lawn or at least make sure the mower is clean when you start mowing don’t apply nitrogen for at least four weeks prior to the onset of high temperatures; low nitrogen and high potassium fertilizers would be a better choice or using more expensive slow release fertilizers or manure-based fertilizers if your lawn is prone to disease in the past, apply a fungicide to your lawn now irrigate ONLY in the early moring hours just before sunrise. Never water in the beginning or middle of the night.

Preventing Summer Lawn Disease on Tall Fescue Read More »

Yes, Remove Citrus Suckers

Leave a Comment / grapefruit, lemon, lime, orange, rootstock, watersprout / xtremehorticulture

Q. The low temps this winter affected my citrus trees. Most of my new growth is on the suckers. Should I remove them? Or just let the tree be. A. If you look at the trunk of the tree you should see a bend in the trunk or “dogleg” where the top was budded or grafted on to the rootstock. I doubt if it is on its own roots which would mean you would see no bend or dogleg. Graft or bud union creates a “dogleg” on the trunk. Anything coming from or below this bend should be removed and kept off. Whenever you see any type of growth at all from these spots it should be removed. If you let this growth develop it will rob growth from the part of the tree you want to keep and eventually dwarf or kill the good part of the tree. Next you want to allow the lowest branches to develop from the trunk at a height you want these branches to remain. The distance these lowest branches are now will be the height they will be in ten years from now. If these are too low then move up the trunk to a place where you want the lowest limbs to develop. Remove any of these unwanted lower limbs completely from the trunk by cutting them as close to the trunk as possible. You can do this now if you want or you can wait until next January or February if there is fruit on them. I am not sure which citrus you have but if it is lemon they should probably be harvested in December. Birdseye view of limbs radiating from the trunk of a young fruit tree to provide balance. Try to find limbs to keep which are coming from the trunk going in different directions. Hopefully you will find one limb going north, one south, one east and one west (I think you get what I mean by going in different directions as this will give the tree “balance” and reduce shading of itself). On the limbs coming from the trunk, remove shoots going straight up or straight down. This leaves shoots that spread out in a fan (horizontally or laterally) but remove shoots that are growing up or down. This allows for better light penetration inside the tree and helps distribute fruit production throughout the canopy rather than just on the perimeter. I hope this helps.

Yes, Remove Citrus Suckers Read More »

Yes, Grapefruit Can Produce Fruit in Las Vegas

Leave a Comment / can you grow citrus in las vegas / xtremehorticulture

Q. I have a dwarf Rio Red Grapefruit tree and a dwarf Valencia Orange tree both from Durling Nursery in my back yard in Mesquite, Nevada . They are 2 years old (planted in May 2011) and about 3 feet tall. The grapefruit produced 1 grapefruit in December 2011 and 2 grapefruit in December 2012. The fruit was great. The orange has not produced so far. This winter I thought I lost both due to the cold but they came back strong and look wonderful except some yellowish leaves. The problem is they are very bushy and crowded with some branches touching the ground. I feel they need pruned. I found a lot of information on how to prune the trees but the when to prune is conflicting. I have been told do it in the spring, the summer, the fall and not to do it in summer, etc.. Can you please help me with this? Thanks for your time. Grapefruit produced in Las Vegas back in about 1986 by Hobby St. Denis. A. In the desert it is a bit more tricky because of our high light intensity and potential for sunburn if we prune too much at the wrong time. But the bottom line is this. You can do SOME pruning any time of the year. BUT only do aggressive pruning during the winter months OR if you have fruit on the tree wait until after harvest and prune then. On citrus you want to prune before it flowers again. The other thing about citrus is that it can be damaged by winter cold as you know. It is best if you can wait until you are pretty sure most of the cold has passed and then prune it. This way if there is some cold damage you can remove it at the same time as you prune. Or prune and protect it from any cold damage. I hope this helps.

Yes, Grapefruit Can Produce Fruit in Las Vegas Read More »

Come and Get Your Mulch at the UNCE Orchard. Free!!

5 Comments / community mulch pile, free mulch / xtremehorticulture

Q. I am interested in opting your community mulch. I want to cover my backyard with mulch instead of rocks or other decorative elements. How do I figure out how much I would need? Also, what is your delivery fee? A. This is a mulch program aimed at keeping some of the wood taken from trees in the valley and using it in our landscapes rather than put into landfills. Our desert soils are nearly void of organic matter yet we dump all this organic “waste” into our landfills. How crazy is that? Mulch pile at the UNCE Orchard in North Las Vegas All of the mulch is available for pickup only at the UNCE Orchard in North Las Vegas. The orchard acts as a reservoir for holding wood mulch until arrangements can be made to pick it up. We participate with First Choice Tree Service in this program. Without this option it is taken to a landfill where it is buried. Another option you have it to call a trucking firm and arrange for them to pick it up and deliver it for you. Another option is to have a landscape contractor do the footwork for you. A further option is to contact the arborist companywho deliver it at the orchard and see if they will deliver it to you instead. You would need 12.3 cubic yards per 1000 square feet. There is a calculator for this found at Mulch Calculator For directions to get to the Orchard call the Master Gardener Help Line at 702-257-5555. The Orchard is open for mulch pickup any Tuesday or Saturday morning if it is not a holiday.

Come and Get Your Mulch at the UNCE Orchard. Free!! Read More »

Most Desert Plants Do Not Need Sulfur Applied to the Soil

Leave a Comment / lower alkalinity, lower pH, make acidic, sulfuric acid / xtremehorticulture

Q. Do desert-adapted shrubs like Texas Rangers, Cassias etc benefit from adding sulfur soil? Will they perform better in a pH around 7.5 as opposed to 8.0? I know it’s probably not necessary but I’m just wondering if the add’l sulfur in the soil will help them thrive better or if it’s overkill. A. We have to remember that the pH scale is exponential – like the scale used to measure earthquakes. So changing the pH from 8 to 7.5 is huge. Our soils are chocked full of calcium carbonate or lime which wants to force the soil to a pH around 8.2. Because there is so much lime in our soils, lowering the soil pH is always just a temporary solution to the problem. Yes, sulfur in moist, warm soils will slowly bring the soil pH down from 8 to some lower value. So will decomposing organic matter. Mineral sulfur (not sulfates) will produce acidity as the sulfur changes to the sulfate form. Sulfur granules When most of the sulfur has been converted to sulfate the pH will begin to rise again rather rather quickly. Then you apply more sulfur and it will work again in the same manner. Two years after spreading granular sulfur in a desert landscape. It still has not broken down. When organic matter is mixed in the soil and is decomposing, the micoorganisms responsible for breaking down this organic matter release carbon dioxide. This carbon dioxide mixes with soil water and produces carbonic acid which also lowers the soil pH. However, it also only works only in warm, moist soils. The question becomes is it really necessary? In some cases probably not. The pH of the water conducted from the roots to the leaves of most plants is about 6.8. So any time you can keep the soil close to pH 6.8 you are better off. Some plants are more fussy about soil pH than others and demonstrate this fussiness through problems such as the leaf yellowing due to iron chlorosis. These fussy plants need the soil modified with sulfur or organic matter or the additions of iron in a form that works at a higher pH. At a pH of 8 the only chelate applied to the soil that really works is EDDHA. This is the reason I mention it so often. pH stability diagram for different iron chelats. Note that EDDHA chelate remains stable as the pH increases. Borrowed from this website Many desert plants would also prefer to have their roots surrounded by a soil at a pH of 6.8 but can tolerate soils much higher than this. Plants not from desert soils, like photinia and Indian hawthorn apparently do not handle soils with a high pH very well. What can you do? The plants you mention are tolerant of desert soils and so probably not have problems. Watch your plants. If they demonstrate they are having some problems (yellowing of leaves, unhealthy weak growth) and you have planted them correctly, watering and fertilizing them, then apply some sulfur or wood mulch at the surface that will decompose and let the soil slowly adjust its pH during the warm months. If they are doing well without it then don’t bother. If yellowing leaves are the problem then apply the iron chelate, iron EDDHA, to help get iron inside the plant in a form it can use. I would do it case-by-case.

Most Desert Plants Do Not Need Sulfur Applied to the Soil Read More »

Grape Leaf Problems Leafhoppers and Iron

Leave a Comment / grape leaves discolored / xtremehorticulture

Q. I have been growing grapes for 7 years. Last year and also this year, I have had problems with the leaves. I have attached 2 photos. Can you please tell me what is wrong with my vines? They are still producing grapes. Thank you! Readers grape leaves A. The pictures were a bit hard to see. I think I am seeing two things. One is some strong discoloration between the veins, almost white. The other are some speckling of the leaves all over the leaves. If I am seeing this correctly I think you have some leafhopper damage (speckling) which would be tiny bugs that are jumping all over the place when you are handling the leaves and the other I think is an iron problem. Grape leaf. Speckling is feeding damage from leafhoppers. With the jumping bugs you could have sprayed Spinosad in about May when they were young and you could have knocked the population back. That would have been the same time for controlling skeletonizer and hornworms so you would have hit three pests with an application of this product about one week apart in May. One example of a spinosad spray at a local nursery. The other would be controlled with an iron chelate application to the base of the grape plant in about March, just before new growth. It would be watered in after you applied it. The iron chelate to use would be EDDHA.

Grape Leaf Problems Leafhoppers and Iron Read More »

Should We Be Rethinking the “Ant Problem” in Fruit Trees?

Leave a Comment / how to control ants in fruit trees / xtremehorticulture

I get alot of questions on how to control ants in fruit trees. Is it really necessary? Are we doing the right thing when we eradicte them? (Posted originally at Washington State University’s Orchard Pest Management online and can be found at http://jenny.tfrec.wsu.edu/opm/displayspecies.php?pn=890 ) Ants — Greg Paulson and Everett C. Burts (originally published 1993) Ants are the most efficient and numerous of all predaceous insects. Some ants, such as certain species of Formica, can be used in orchards to help control pests and reduce reliance on pesticides. Hosts Ants can prey on a wide variety of insects. Their primary role in orchards is as predators of pear psylla on pear. Life stages Egg: The egg is white and oval. Larva: The larva is shiny white and elongated. Pupa: The pupa is a dull white or tan. Adult: Adults range in size from about 1/12 inch (2 mm) to 1/2 inch (12 mm). Many are black, but there are also red, brown and yellow species. The head is large with long, elbowed antennae and is joined to the thorax by a thin neck. The thorax is connected to the abdomen by a narrow, flexible waist, or petiole. In some species, the petiole is just one segment, while in others it is two segments. The swollen part of the abdomen behind the petiole is known as the gaster. During part of their life cycle, when they mate and disperse, the reproductive ants have wings. Life history A typical ant colony consists of sterile female workers and soldier ants governed by one or more queens. The queen lays eggs. Worker ants forage for food, maintain the nest and care for the queen and her developing brood. Soldiers defend the colony and its resources from enemies. Ants overwinter as adults in a colony. In the spring, the queen resumes egg laying. A queen can lay thousands of eggs each year. Workers carry the eggs to nursery chambers in the nest. Larvae are fed and cared for by workers. After several weeks, the larvae develop into pupae from which worker and soldier ants later emerge. Once or twice a year, usually in the late spring and early fall, a special brood of eggs develops into winged male and female reproductive ants. Swarms of these ants leave the nest to mate and disperse. After mating, new queens either move away to establish new colonies or, in species that have more than one queen per colony, they may stay in the nest. Once established in a nest, the queen sheds her wings. Males die or are killed soon after mating. Queens usually mate only once and use stored sperm to fertilize eggs for the rest of their lives. Management Ants as biological control agents Over the centuries, predaceous ants have been exploited in countries around the world to control a variety of pests. Ants can be used in orchards to help control pests such as pear psylla and reduce reliance on pesticides. Ants eat psylla nymphs and young adults and also remove honeydew, reducing fruit russet. Some ant species will farm, or tend, other plant-damaging insects. For example, the ants may feed on sugar produced by aphids and protect the aphids from predators and parasites in return. But some researchers believe that honeydew-producing insects such as aphids help scatter the ants throughout the tree, enabling them to protect the plant better from other, more damaging pests. If undisturbed, ants will establish permanent colonies and build up to large numbers. Introducing ant colonies In most orchards, ants have been eradicated by pesticides. However, ant colonies can be collected and reintroduced. If the mosaic can be preserved in an orchard, predatory ants can contribute significantly to pest control within two years of introduction. Formica neoclara and Formica podzolica are appropriate species to use in orchards. Both are indigenous to Washington’s pear growing regions. They have more than one queen, which greatly increases the reproductive capacity of the colonies and lessens the risk of a colony failing to become established if a queen dies. They are not aggressive, do not sting, and seldom tend aphids. Both species nest in the soil, forming low mounds that are easy to excavate and do not interfere with orchard equipment. Other closely related species, such as Formica montane, could also be used. Protecting ant colonies After ant colonies have been introduced, they must be protected and allowed to spread throughout the orchard. The two greatest threats to ant colonies, particularly new ones, are pesticides and physical damage to the nests. Most orchard practices do not harm ant colonies, with the exception of disk tillage to control weeds, which destroys nests. Other weed controls, such as herbicides, should be used if ants are in the orchard. It is relatively easy to conserve ant populations in organic orchards because pesticides such as Bacillus thuringiensis (Bt), granulosis virus, rotenone and other products certified for use in organic orchards are not toxic to ants. In conventional orchards, apply pesticides when ants are least active and use compounds that are the least toxic to ants. Ants are not yet active when dormant sprays are applied. Later in the season, ants are least active between about 10 p.m. and 4 a.m. They are also relatively inactive from about 11 a.m. to 4 p.m., particularly on hot days. Organophosphate and carbamate insecticides are highly toxic to ants, and their residual effect can last for up to two weeks. Synthetic pyrethroids also are toxic to ants, but they are effective for only about a week. The best compounds to use with ants for pear psylla control would be insect growth regulators, which have little effect on foraging ants. Good dormant control of pear psylla is essential where ants are used as biological control agents. Pear psylla begin to reproduce at least a month before ants become active in the spring. Early season chemical control is needed to keep psylla populations below damaging levels until the ants begin foraging. Note: so

Should We Be Rethinking the “Ant Problem” in Fruit Trees? Read More »