Xtremehorticulture

Xtremehorticulture of the Desert

Rabbits a Problem? Fencing and Rabbit Resistant Plants

2 Comments / animal damage, chewing, cottontail rabbit, desert, jackrabbit, landscape plants, rabbit damage /

Q. Do you have any solutions for keeping rabbits from eating plants? I live in Sun City Anthem and they are a real problem. I just planted some lovely gerbera daisies and they’ve eaten the plants to the ground. Rabbit damage to mockorange by rabbits. They chew off plants at an angle.   Rabbits cut off plants at an angle with their teeth A. There are two solutions as far as I know. One is to put in plants resistant to rabbits or the other is to exclude them with fencing that keeps them away from the plants. If rabbits are terribly hungry, garlic or pepper sprays don’t seem to help much. Hunger overrides fear of getting caught.             Usually one inch mesh chicken wire will work as long as it is about 24 inches high and buried a few inches below the soil surface so they cannot get their nose under it or dig.             If rabbits have other food choices they may not damage your plants so much. Encourage your neighbors to plant carrots! Rabbit resistant plants University of Arizona click here

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African Sumac Limb Dieback Probably from Disease and Wet Soils

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Q. I have attached a picture of my African Sumac.  The tree showed several branches with dead leaves so we started cutting back to a point where there was moisture and some green in the bark. Should we continue cutting to make the resulting tree symmetrical or leave it alone and hope the tree recovers from our efforts? African sumac from reader A. I know there was not much you could do but the form of the tree is pretty much gone. African sumac sucker from cut shoots easily. Most of the suckering would occur within about 18 inches below the cut. You will probably also see some suckering further down on the limbs and trunk but it will not be as heavy. With the cuts made in September and October you might see some new growth over the next couple of weeks. Because the growth will be soft and succulent this time of year and perhaps not harden off very much for the winter, that growth may freeze back if we have some very low temperatures. I would not make any more cuts this time of year. You do not want to encourage that kind of growth now. However, I would suggest you consider waiting until the next spring growth and see what is alive and what is dead. When you can determine which of those large trunks are alive in the spring, go ahead and cut them back to the height where you would like to see new growth. From the look of your picture I would suggest you look at somewhere between three and 5 feet off the ground. You should start to see a lot of suckering below these cuts in the spring when there is normally no growth. Because this growth is not coming from existing buds on the tree, no growth may be delayed a few weeks compared to other plants that have not been pruned. As you see this suckering on the limbs, remove suckers that are too close together and those that are going perfectly vertical. Why did the limbs start dying? Think of any changes that were made to the landscape in the past 12 months. In my opinion, there are perhaps three possibilities. The first to involve a lack of water or too much water. Both of them can cause limb dieback. If your soil is kind of heavy and does not drain water very well it’s possible that standing water could suffocate the roots and eventually cause limbs to dieback. There is not much you can do about this if it was from those heavy rains earlier in the year or some earlier flooding event. I see you have wood mulch surrounding the base of the tree. Has that mulch been applied fairly recently? Mulches can really affect the moisture content of the soil and keep the soil moist much longer than if it is desert soil exposed to the open air. I assume you were watching your watering but if your source of water was plugged for a period of time when it was really hot, that could cause limb dieback as well from drought. African sumac does not handle a lack of water very well and it does not handle too much water very well or poor drainage. The third is possible disease problems. Again, at this stage there is probably nothing you can do about disease problems except what you are doing now and keep the tree as healthy as you can. I do not know of any specific disease or insect problems that will cause this to African sumac. I wish I could be more helpful and give you a specific answer but I can’t.

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Mushrooms Common in the Desert After Rain

Leave a Comment / mulch, mushroom is it poisonous /

Q. After the great rain last week I have large mushrooms with diameters of  8 inches in  my back yard.  One is in the middle of my Mexican Bird of Paradise.  Will it kill the plant?  My friend’s dog wants to eat the mushroom.  Is that dangerous? A. Mushrooms are common after rains in the desert and elsewhere but particularly in the desert. They feed off of decaying organic matter (organic debris like rotting wood, rotting plant life, particularly dead plants). They are a normal part of the recycling process. So when rain falls and wets dead organic matter that was previously dry due to the desert, the recycling process begins until it becomes too dry again and then stops. Just knock the tops off and destroy with a rake. Mushrooms in mulch at orchard after rain There are no guarantees the mushrooms are not poisonous so please dispose of them before the dogs eat them. The mushroom in the middle of your Mexican bird of paradise is feeding on something dead and decomposing. It will not attack something living so I would not be concerned.

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Good Apples for Mojave Desert

Leave a Comment / anna apple, apple selection, golden dorsett, Mojave Desert, pink lady apple /

Q. I live in Summerlin and have a Bartlett pear tree in the ground. I wish to plant an apple with a harvest time as far as possible from the Bartlett pear, so as not to have too much harvested fruit on hand at any one time. Can you inform me of one or two apple varieties with a harvest time as far apart as possible from my Bartlett pear’s harvest time? I have received conflicting information from three, rather authoritative, local sources. Pink Lady apples picked November 15 2008 at UNCE orchard A. You can go either later in harvest which would be late November and early December or you can go earlier. If you go later, Pink Lady apple should be about a month after Bartlett pear. If you go earlier you could plant Anna or Golden Dorsett as a good early Apple. I tend toward Golden Dorsett myself based on taste. Both are yellow apples but both are good apples, not great but good. Pink Lady is a great Apple in our climate.

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Elberta Peach Fruit Problems is in Management

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Q. Thank you so much for the recommended fruit tree list.  When we were out at the orchard, we talked to one of the grape pruners who liked the O’Henry peach.  It seems to be quite high in chill hours.  Does it do well here?  We have an Elberta, which harvests in August, and the fruit is always small and on the mushy side.  Other than that question, I think we have our list picked out. Early Elberta peach at UNCE orchard in north las vegas A. You may be doing something wrong with the Elberta peach. Our July Elbertas, Early Elbertas and Lemon Elbertas all do well. About a 4.0 on a 5.0 scale. O’Henry has only been in a few years and it is a bit early to tell yet. I would focus on an early peach and get it off the tree, a mid season and then you have your late season. But all our Elbertas are good peaches and not small if you thin them and not mushy if you get them off the tree when you should. Get an early one. O’Henry is not early and near the same time as Elberta. http://www.davewilson.com/home-gardens/growing-fruits-and-nuts/selecting-varieties-and-rootstocks/fruit-and-nut-harvest-chart

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Aerate Soil Around Trees by Coring not Punching Holes

Leave a Comment / aerating tree roots, aeration, drainage /

Q. You mentioned drainage could be a problem for my trees.  When I water with the drip process the water does pool but eventually drains. I have not dug up the ground to see if the roots are wet and lying in water, but I did take a 2 foot spike (1/2 inch diameter) and drove it into the ground around the tree. Seemed like a good way to help drainage. Is it? A. For now, yes, you could punch some holes in the soil down to a depth of 18 inches but taking soil cores out (e.g., post hole digger) is much more effective than punching holes into the ground with a solid piece of metal that compacts the soil on the inside of the hole. The best way to get some drainage over the long haul is to cover the soil with organic mulch rather than rock mulches. As the organic mulch dissolves or breaks down and improves the soil then water will drain better. Increase the time between irrigations when you use mulches of any kind. Mulches will keep the soil wet, longer.

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Will Green Light Chelate Cure Iron Chlorosis in Highly Alkaline Soils

1 Comment / acidify soil, EDDHA, hi pH, iron chelate, iron fertilizer, vinegar /

Q. I used a product called Green Light. It contains chelated iron, copper and zinc for correcting plants that are yellow. Is this similar to the chelate you talk about for our soils? A. I know the Green Light chelate product and it will not be very effective in our tap water which is alkaline or our well water. It will also not work in most of our soils because they are also too alkaline. This product will work if you adjust the water with some acid and use it as a spray on the leaves of the plant. If you have a gallon of water you can put a small amount of vinegar or pool acid used to adjust alkalinity of pool water. Test the water with some pool pH strips or a kit if you are using pool acid. If you are using vinegar, two or three tablespoons of vinegar in a gallon of water should be enough. After adding the acid and mixing the water you can add chelates to the spray solution. Follow the label directions and then add two more things to your mix. First, add a small amount of liquid fertilizer or a powdered fertilizer that dissolves in the water. Secondly, add about a teaspoon of liquid detergent to the finished spray mix. Make sure everything is dissolved and thoroughly mixed. This spray solution must be used very soon after it is prepared. Use it all up and don’t save any of it. It will probably not last. Use this mixture any time temperatures are cool. Only spray long enough until you begin seeing this liquid spray run off of the leaf surface. Spray both sides of the leaves; once over the tops of the leaves and a second time with the spray pointing up so the undersides of the leaves are sprayed as well. The addition of a liquid detergent to the mix will help move the solution inside the leaf. The small amount of fertilizer will make the chelate more effective. If leaves have already become quite yellow, spray them once every few days for about four or five applications.

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Bottle Tree Losing Leaves

Leave a Comment / brachychiton populneus, death, dying, irrigation problem, limb dieback, overwatering, root rot /

Q. I have bottle trees planted next to the house and for some reason the one in the middle is losing leaves on the bottom branches. The trees are getting watered two times each week for 40 minutes. I cleared out the rock mulch and replaced it with cedar mulch around the base of the tree. I lost a bottle tree last year so I’m trying to figure out why. A. Bottle trees represent about 15 or 20 different types. All of them have a swollen trunk which, some people speculate, they use for storing some water during dry periods. We typically use only one type of bottle tree in the valley.             The cedar mulch won’t add any nutrients to the soil but it will slow evaporation of water from the soil surface. Bend side branches without leaves to see if they are dead. If they are still flexible and don’t snap, they may come back when it cools.             Remove any branches that are growing toward the house. Planting those trees in that location was not the best idea.             I remember these trees being brought into the valley as early as the late 1980s during our first push on desert landscaping. They were brought in by landscape contractors and architects because they were being used primarily in Southern California.             The first problem I remember was irrigation. People did not know that these trees required watering less often. They were watering them much like any other landscape plant. These trees are very susceptible to over irrigating.             Although not a desert tree like the Acacia, it does handle arid climates and infrequent waterings. These waterings, when they do occur, should flood the entire root system about 2 to 3 times a month during the summer. The next irrigation should not occur until the soil is dry or you run the chance of getting root rot and the tree may suddenly die during the summer heat.             The next problem was how they were being used. The tree needs to be in full sun. They should not be planted against hot South or West facing wall. Very young, green trunks of this tree can get severe sunscald in these locations followed by limb and branch death.

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Insecticides Applied to Soil Not Good Idea Around Food Plants

Leave a Comment / bugs, control insects, fruit trees, lemon tree, systemic insecticides, whats eating leaves /

Q. Something is eating the leaves on my lemon tree. What can I use to prevent this? I found a product at the nursery and it says you can apply it to the soil to control bugs. A. If something is eating the leaves I would not be too concerned unless it is really eating a lot of leaves. We really have to be careful when we apply these types of poisons on the soil and around the food we eat.             If this insecticide is taken up through the roots and spread through the plant to kill a bug, we might also have small amounts in the fruit as well. The insecticide dissolves in water and moves down through the soil where it is absorbed by the roots. Once absorbed, it moves up through the plant providing protection from insects.             These types of products are called systemic insecticides and move into new growth after the application. The insecticide stays inside the plant and gives it protection from bugs. Rain or water cannot wash off this internal protection and you cannot wash it off by scrubbing the fruit.             There is an old saying, “The dose makes the poison.”  Insects, because they are small, require less of a poison to kill them than larger animals.  Even though insecticides have a label to tell you what you can or cannot apply it on, it does not mean that the product is entirely safe.             If you have to use an insecticide to control damaging insects, then I would recommend something that you spray on the outside of the plant rather than something which is taken up by the plants through its roots. In many cases, these insecticides which are sprayed on the plant will wash off or degrade in the environment.             It is up to you as the consumer whether you want to purchase this product and use it. As for me, I would not eat the fruit from a tree where an insecticide was applied to the soil and taken up by plant roots.

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Sap Oozing from Apricot May or May Not Be Borers

Leave a Comment / borers in apricot, what is causing sap from my apricot, why is sap oozing from apricot /

Q. Can you tell me what happened to the apricot tree? A. Boy that does not look good. The first assumption people make is borers. This can be true but there are other things that can cause sap to ooze for limbs and the trunk. Stress is one of them particularly in plum. Another is overwatering or rotting of the trunk. So the first thing I would do is pull that mulch away from the trunk and inspect it. Sap oozing from limb You may have to take a sharp, sterilized knife and cut into the area just an inch below the level of the mulch or soil directly below the sappy area. The wood should be cream colored. The cut does not have to be big, just a knick is enough. Just enough to see the color of the wood or actually just below the bark, the cambium layer. If the wood has good color then remove a couple of globs of sap and cut the same way just below the sap. This will be a bigger cut, enough to see the wood. Look for any signs of sawdust or sappy sawdust just under the sap. If you see traces of tunneling just below the bark and in this cambium layer then you can conclude it is borer damage. During winter, cut into the limb and reveal the borer, removing all loose bark or remove the limb if it is bad enough. Lastly watering too often, keeping the soil moist without letting it dry out can also cause sap to bubble to the surface which is really due to stress again most likely. Pull the mulch away and let it dry out if you think that might be the problem. If borers are the problem, dig them out with a sterile knife and let the tree heal afterwards.

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