Xtremehorticulture

Xtremehorticulture of the Desert

Yes, Grapefruit Can Produce Fruit in Las Vegas

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

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.

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

5 Comments / community mulch pile, free mulch /

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.

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Most Desert Plants Do Not Need Sulfur Applied to the Soil

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

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.

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Grape Leaf Problems Leafhoppers and Iron

Leave a Comment / grape leaves discolored /

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.

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

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

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

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Pruning Peach Trees Now Might Lead Toward Disaster

1 Comment / summer pruning, when to prune fruit trees /

Q. Our Desert Rose peach tree is eight years old and finished harvesting for the year. We would like to know what branches, if any, we can trim now and not harm the tree or cut off all next years peaches. We have six to eight inch in length branches that come off small branches that have no leaves and appear dead, and we have other small branches that have a six to eight inch span in between leaves that we had peaches on both parts this year. We usually trim what we think is dead or excessive growth wood in January. We thinned the peaches really well, but we lost two, four to eight inch circumference branches this spring do in part to wind and the weight of the peaches. Any information you can provide is greatly appreciated.   A. I don’t know the Desert Rose peach but should be no different than the others.  Any time we are in the hot parts of the summer it is wise to be very careful when pruning.  Pruning at this time should be light at best if at all.  Right now we should be still pruning our fruit trees lightly, removing only new, young shoots that are too close together or shading the leaves too much.  We’re cutting back or removing some of this year’s growth which has been too vigorous.  Do not prune so much that you open the canopy and risk the possibility of sunburn on some of your major limbs.  However, if the canopy is too dense then you should do some thinning of the canopy to allow some light to enter.  If you need to determine if the canopy is too dense, look at the ground under the canopy.  Remove NEW shoots anywhere in the canopy that are growing straight up or straight down. Remove enough so that you see speckled light on the ground through the canopy. Then stop. Removing too much can cause damage this time of year (June/July).   The shadow of the canopy on the ground should be speckled with light.  If it is a solid shadow, then a few small branches should be removed until you see speckling in the shadow.  Only remove a few small branches to accomplish this.  No more.  Reserve the rest of your pruning for winter time when the leaves have dropped.

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Camelias Not for the Inexperienced Gardener in the Desert

Leave a Comment / desert, growing acid loving plants, Las Vegas /

Q. I wonder if you can help me diagnose a problem with my camellia, the variety is “Marie Bracey”. I had it in a container while it was young and my husband moved it for me to our back yard where it gets the morning sun and afternoon shade which is what the card read that was attached. It was growing fine but now there are about 30  leaves that have brown tips. Another question, the card says to cut back after flowering, which has not happened yet but it does not explain how to cut it and to what level. A. You are fighting an “uphill battle” growing camellias in the Las Vegas valley since they require similar conditions to azaleas and rhododendrons. Not that you can’t do  it but it will take quite a bit of care on your part. There are camellia societies, the counterparts to rose societies, on the southern east coastal areas and west coastal areas and inland in northern California. You have the Japanese camellia type. These plants are medium to large shrubs and even trees so it may take some time for it to get big enough to flower. Link to International Camelia Society Link to American Camelia Society Nice link to information and pictures of Camelias Another camellia I know you are familiar with is Chinese camellia, the plant that is used to make teas like black teas, green teas and Oolongs. So this plant does not come from the desert parts of the world. This will give you some insight as to what you will have to do; improve the soil a lot and give it some protection from the harsh desert environment. You did that by following the card attached to it. But just a warning. That card was not intended for Las Vegas but for more friendly camellia environments so you may need to take what it says a step further. Even morning sun may be too intense for it if it extends into late morning and thus contribute to the browning of the leaf edges. Other things that can contribute to leaf scorch are the poor soil conditions we have and the salty water coming from Lake Mead to our taps. Those people with well water frequently have much better water than the water coming from our taps. Another problem you will most likely have will be yellowing leaves. Camellias like the soil to be slightly acid and our soils are not. This will mean that iron will be tough for the plant to get in a form it can use. The only way to provide that kind of iron is to make the soil more acid or give it iron in a form it can use. Lots of decayed or decaying organic material will help in the soil around the roots and on the soil surface on top of the roots. Sulfur applications will also help but the sulfur should be pulverized into a powder, not like little rocks if it is to be effective. So usually the more effective way to apply iron so the plant can use it is to use chelates. Like the broken record I am, the chelate EDDHA combined with the iron is the most effective way for iron to reach the plants in our soils. Sulfur granules applied to the soil surface two years later. The granules are too large and breakdown slowly. Also these plants are on drip irrigation so the sulfur never comes in contact with water …unless it rains…in the desert? So what to do? Make sure the plant had lots of GOOD compost mixed into the soil at planting time. I would also put some sulfur with that planting soil. If you are not sure, replant it carefully this fall around the first week of October. Mulch the soil surface with organic or wood mulch. This is very important with camellia since it has a very shallow root system. Make sure the soil drains easily. Find a place that gives it early morning sun and not late morning sun, out of strong winds and not near a hot wall. Filtered light from a tree that allows scattered light on the ground with plenty of air movement (but not strong wind) would even be better but not total shade. Next spring after all danger of frost has passed (usually around the first to the middle of March) fertilize the plant with an azalea or rose fertilizer and add iron chelate as well. Expect that your camellia will not be picture perfect since it is not growing in an ideal climate and soil. Contact me next spring and let me know how it is doing and we can take it to the next step.

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Miniature Peach Poor Growth in Container Might Be Container Size

Leave a Comment / growing fruit trees in containers /

Q. I have this miniature Bonanza peach tree in a large pot for 4 years the first year several large peaches since then nothing. The second and third year flowers and fruit buds, but then they fell off and I was told by a nursery that it was because of all the high winds we had. Then this year I moved it out of the wind and same thing happened and the leaves were kind of narrow and had some tan spots on them, I sprayed it with a fungicide and it took care of the tan spots but the leaves still look anemic. Readers Bonanza peach tree with poor growth, sparse canopy and poor color.   A. You are right. The plant does look anemic. The leaves are light green at best and doesn’t really show much new growth. On peaches and nectarines the fruit is produced on one year old branches. This means that the fruit that will be produced in 2012 will appear on stems that grew in 2011. The contaimer looks small to me for a tree that old. I will bet the roots will be rootbound (circling in the container). Having a plant with rootbound roots can cause the poor growth.  Readers Bonanza peach tree in a container, closeup. If the growth of a peach or a nectarine is poor and very small then there may be little or no room on this one year old growth to produce fruit. This might be because of the soil that was used in the container. If the soil was bad to begin with then your tree will show evidence of slow decline and lack of fruit production. The poor growth could be due to several things. Make sure it is getting enough water. The volume of water that you apply needs to be enough so that water drains from the bottom of the container. Secondly, poor drainage. Water applied to the top of the soil in the container should drain easily into and through the soil. I could not tell exactly but on your picture there appears to be some flowers. That is a key question to ask yourself if your peach tree produced no fruit; “Did the tree have flowers?” If there were flowers present but no fruit then something happened after flowering that caused the fruit to drop from the tree. Nearly all peaches and nectarines are self-fertile or in other words do not need a pollinator tree. So a lack of pollination is unlikely to cause the fruit drop. Either poor drainage or not enough water could also cause fruit to drop. The question is what to do now. I would probably start over. This is a bad time of the year to try to pull this tree out of the container and try replanting it. At this point in time you could try replanting with a totally new plant. If you plan to keep it for several years I would look at a larger container. If you keep this one, rinse the inside of the container with a 5% Clorox solution and let it air dry. Make sure the container drains easily after it is full of soil. Don’t skimp on soil amendments. Use a top-quality compost amendment or good soil at the very beginning. Plant tree at the correct depth. Stake it first year of growth. Fertilize once a year in the spring and combine that with an iron chelate. Water the soil until water comes out the bottom of the container and then stop watering. I hope this helps.

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Pomegranate Fruit Failure May Be Due to Funny Looking Bug

3 Comments / control of, leaf footed plant bug, leaffooted plant bug /

Q. I wonder if you could tell me why my pomegranate tree is not letting the pomegranates ripen on the tree.  I have many but they are falling before their time. I would greatly appreciate an answer.  Leaffooted or Leaf footed plant bug on pomegranate. A. For pomegranates to fall to the ground before they are ready would be highly unusual. My guess is that your tree may have been attacked by the leaf footed plant bug. This insect is in the valley and can attack many different fruit trees but is notorious for causing early nut drop in pistachio and almond. It can also cause early fruit drop in pomegranates.             A close examination of the tree may reveal these insects in the hundreds. Look for them. I have attached a picture of them on pomegranate. If this is the case, you will require an insecticide application starting around late May or June. The preferred insecticide is probably going to be one of these synthetic pyrethroids.             This is not the name which you will see on the label. This is the active ingredient. There are many, many manufacturers of this type of insecticide so I cannot tell you the exact trade name on the label. It will vary among companies.             The label should recommend it for fruit and vegetables and the active ingredients should have some sort of pyrethroid or permethrin or something very similar to this.             I wish I could tell you exactly the name but the nurseries carry different products. The other option is to spray it with a traditional insecticide for fruit such as Sevin. Both will work.             The pyrethroids are a bit more kind to other insects and the environment. Both of these products will hurt honey bees so make sure you spray at dusk or just before sunrise when the bees have not started to look for food.

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Bitter Peaches

Leave a Comment / bad fruit, dwarf peach, miniature peach /

Q. We have two peach trees that are 7 years old.  This year the peaches on both trees taste bitter.  I don’t recall doing anything differently. One of the trees produced bitter peaches the year after we planted it. but has been fine until this year.  Do you have any thoughts on this? A. You don’t mention if the peach is a miniature or not. There is variation on the quality of fruit produced on fruit trees and much of that is surrounding the weather during the growing year. One of the genetic dwarf peaches at the UNCE Orchard in North Las Vegas with full-sized peach fruits because of thinning, pruning and proper care. For instance this year our early peaches and even our early apricots did not have the same quality in flavor due to our unusually cool spring. And they did not ripen evenly as well. Many of our fruit needs to have consistently warm or even hot temperatures during its development to develop good flavor and lots of sugar. Otherwise they can be bland or worse. I have also noticed that miniature peaches such as Bonanza produce fruit that is very variable in quality from year to year. It is nothing you did and there really is not much you can do about it. Have you heard about wines having good years and bad years? Well it is the same with most fruit. I think your fruit, and unfortunately you, had a bad year. When the weather is good during fruit development in future years the quality will be better as well.

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