Xtremehorticulture

Xtremehorticulture of the Desert

How to Prune Arizona Rosewood Against a Wall

Leave a Comment / desert landscaping, How to prune desert trees /

Q. I planted a 5 gallon Arizona Rosewood a year ago against a wall for visual screening. How and when should I prune it? Arizona Rosewood one year after planting A. This plant can be grown as a shrub or small tree. As a shrub, led it continue to grow as it is except for any weak stems. Any weak, floppy stems should be cut back about 1/3 to half their length to encourage them to become stronger. As a tree, it can be grown with a single trunk or multiple trunks. This initial pruning to establish its architecture or form should be done during the winter or early spring. It is not too late now. If your plan is to use this as a small tree, then I would select 3 or 5 larger diameter stems (an odd number is more pleasing to the eye) coming from the ground and eliminate all other growth coming from the base. As new growth appears from the base, eliminate it at any time of the year you see it. Next, stake these stems individually in an arrangement you would like them to grow. Staking young stems for one year will encourage them to continue growing in those directions. Finally, cut any long, floppy stems back to encourage strength. Make these cuts ¼ inch above a side branch in any direction away from the wall. Remove any strong growth growing towards the wall. Here is some excellent information with more background on Arizona Rosewood by an extension agent in Arizona. http://ag.arizona.edu/yavapai/anr/hort/byg/archive/arizonarosewood.html

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Creosote Bush for Desert LandscapesIn the Mojave Desert

Leave a Comment / desert landscaping, desert plants, Mohave Desert, Mojave Desert /

Don’t overwater this plant! And it doesn’t require much in the way of fertilizers.Like any desert plant, they perform better if there is some organic matter added to the soil at the time of planting. In our Mojave desert soils there is almost 0% organic matter so a little bit will help get them established. An old stand of creosote in the background and creosote which have been cut off with a road grader and re-grew from the base.

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Parrys Agave Good Choice for Mojave Desert Landscapes

Leave a Comment / agave, desert landscaping, parrys agave, perrys agave /

Parry’s Agave Andrea Meckley, Certified Horticulturist [email protected]   Description:  Evergreen succulent Mature size: 2’x 2’ Flower:  with aged plants Water use:  low Exposure:  all day sun Origin:  Arizona, New Mexico, and Northern Mexico Parry’s Agave Hardy:  to 5 degrees F Uses:  Landscape accent plant, potted plant One of the many hardy agave species for our southwest landscapes and gardens is Parry’s agave (Agave parryii).  The grey green leaves grow slowly as a compact rosette.  Adding interest are patterns of indentations of previous leaves showing on the back of each new leaf.   In late spring to early summer old Parry’s agaves, 20 years or more, produce a twelve-foot stalk of blooms that can grow four inches a day. Hummingbirds are attracted to the flowers which begin as red or pink buds, opening to a bright yellow bouquet.  The plant dies after blooming but during its lifetime produces offsets assuring more plants will replace the original.   Planted in groups or alone this plant is attractive in the succulent garden, in pots, or in the landscape.

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Ornamental Pear in Bloom Now… A Nice Tree Where it Has Room to Grow

Leave a Comment / bradford, desert, desert landscaping, Las Vegas, Mohave Desert, Mojave Desert, nevada, pyrus, tree selection /

The good and bad about ornamental pear in the desert. I get questions very, very often about which plants I recommend. I am sorry. But I really hate that question. Half of the answer involves will it grow here and how difficult is it to grow AND the other half is the homeowners personal preference. I have no problem with the first part. It is the second part that is really difficult for me to get a handle on. Because it is a personal question. Ornamental or Callery pear. The Good. Ornamental pear, sometimes called Callery pear, has been around in several different forms for a long, long time. I have been watching them here in Las Vegas for nearly 30 years in different locations and surprising to me they really handle alot of adversity. They can handle rock landscapes, droughty conditions, poor soils, lawns and has few pest problems, unlike in some other places. It is a good choice as a street tree and parks. The Bad. I would not recommend it for home landscapes unless you have a fairly big landscape area and it is probably best if you have a two-story home, not a single-level in terms of size. It can get a bit big if well cared for, 40 feet in our desert. Although I have to admit I have not seen one get that tall here. It is not low in water use. Just like any other fruit tree its water use will be moderately high and increases proportionately as it gets bigger. It will perform better in soils improved with compost and covered in wood mulch rather than rock mulch. It can get a some fireblight (bacterial disease) some seasons if it is raining at the time of bloom (February here). It does produce fruit but it is so small it is mostly inconspicuous but can cause some litter under the tree. Winter form of ornamental pear in rock landsxcape with minimal care. In my opinion it has been limbed up too high. I would have liked to see it with more branches lower on the trunk with at least half of its height in canopy. The Ugly. Like most pears, its growth is somewhat upright and tends to get narrow crotch angles which can be improved with proper pruning and limb spreaders. I don’t care for its winter look all that much. Some will disagree with me but the trunk is not all that pretty and its form is just okay in my opinion. It can get iron chlorosis (yellowing of new growth) in some places but can be corrected using iron chelates containing EDDHA. I would recommend it but don’t put it in a small yard and be aware that this is not a low water use plant.

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Eliminating Lawn Can Lead to Problems for Established Trees

Leave a Comment / convert from lawn to desert landscaping, desert landscape, desert landscaping, drought, retrofitting landscape, xeriscape /

Q. I have a beautiful Loquat tree where the leaves have suddenly started to turn yellow and fell off.   Most of the fruit has also fallen off. The tree was located in the middle of grass. I had the landscape converted to desert rock in September. At the same time watering schedule was changed. I suspect it is being under watered. But before I increase it I want to ask if the cold winter we had here could have caused this yellowing. A. Thanks for the pictures. It is probably not the cold. In a lawn situation the roots go everywhere and anywhere and usually spread to about 1½ to 2 times its height away from the trunk. Loquat with rock mulch applied after growing in a lawn for a few years. In many cases the drip emitters do not apply the water in the same places as lawn irrigation and the plant roots of established trees and shrubs die back. This results in leaf drop and eventual die back of the limbs of established trees and shrubs.             In drip irrigation we usually place the emitters a foot or so from the trunk. This bypasses about 80% of the root system it created when growing under a lawn.             So, yes, it probably is drought but perhaps not because you are not delivering enough water. It is more likely that most of the tree roots are not receiving water. You can place emitters over a greater area under the canopy of the tree. But I would also reduce the size of the root system.             Try root pruning the tree to reduce the size of the root system so it is closer to the emitters. Keep tree roots contained in the area directly under the canopy. Wet the soil thoroughly under the canopy and vertically slice the roots in a circle all around the tree at the edge of the canopy. This can be done with a sharpened spade. Leaf drop of established loquat due to replacement of lawn with rock mulch and drip irrigation.             At the same time, thin the canopy by removing wood. This reduces the tree’s demand for water. A tree that size will probably require 20 to 30 gallons each time you water. With the lawn now gone, the tree will actually use more water since the cooling capacity of the lawn has been removed.

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Purple Lantana Dying Out

Leave a Comment / desert landscaping, desert plants, landscape maintenance /

 yellow or gold lantana Q. Am having trouble with purple Lantana. They are dying out. The gold Lantana is still doing well. Am watering 3 days a week at 20 minutes and 4 days a week at 7 minutes. I have noticed that my neighbors are having the same type of trouble. Hope you have a solution. A. The lantanas in general flower on new wood so as they get older the flowers will get further and further from the center of the plant provided it does not freeze back. This tends to make the center kind of bare and most of the foliage and flowers at the ends. Trailing or purple lantana             If it freezes back and does not die out due to very low temperatures then the plant will stay more compact and will need to be trimmed back to a few inches each early spring. But this plant, if it is in a place where it stays warm and does not freeze back, will tend to get leggy and not have much foliage on the inside.             So make sure you cut it back to keep renewing new growth close to the center of the plant. You can do that now to some degree. Cut back one third of the stems to a couple inches in length. Stagger the cuts so that they are random on older wood through the canopy             It will require watering fairly often if the soil drains of water easily. Fertilize lightly in the spring and fall. To maintain bushiness irrigate frequently like any normal shrub. If you decide at some time to replace it make sure you add compost to the soil at the time of planting.

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Living Windbreaks Use Water – A Major Concern in the Desert

1 Comment / desert landscaping, wind control, windbreaks /

Q. We just moved from Las Vegas to Pahrump We bought a home on an acre of land – I’d send a picture but – to be honest  – its just bare high-desert land As far as we know Pahrump is considered Zone13 (Sunset). We would like your advice on trees for wind barriers. We have been told by locals that there are several pine trees that would make a good wind barrier. Judging by the look of the town, most properties have planted the pines around the perimeter of their properties. After reading SNWA desert planting ideas and other high-desert websites, we thought we would start with the pines and then layer from there (inward) For example:pines fruit or other shade trees large bushes or grasses edible and low bushes finally, low growing plants.  We want to encourage birds, hummingbirds and butterflies and we will add raised beds for veggies. Could you give us your advice on the types of pines and other trees that would grow in this area. Could you please comment on the layering plan or give us some indication which direction we should head? A. I would refer you to a fact sheet I wrote a couple of years ago which can be found at http://www.unce.unr.edu/publications/files/ho/2006/fs0688.pdf It basically says that the windbreak will affect an area downwind equal to about five times its height. Windbreaks need to be multilayered when possible with a combination of trees and shrubs. A variety of plants, not just one kind, is more desirable. The biggest mistake I see done in Pahrump is putting a big line of trees right on the border of their property. It just does not make any sense to me. If they need a fence there is a lot of things you can build that don’t require water. If it is a windbreak then it is too far from the living area to be very effective. You need to answer the questions where does the wind come from that you are trying to stop. What time of year is it a problem. Design your outside living area first. Then go ahead and place your plant materials for screening, visual barriers and windbreaks. Windbreaks integrated into your landscape can use smaller plants. Remember big plants use more water than little plants and if you put a whole bunch of trees on the perimeter of the property what good does that do except use up a bunch of water unnecessarily. Plants need to be concentrated near living areas and they need to be part of the outside living area, usually defining the “walls” and “ceilings” of these spaces. Fences on the perimeter of the property may be expensive at the beginning but they are lower maintenance and use less water than a living fence on the perimeter. In the fact sheet I purposely stay away from recommending plant materials. There are plenty of places that can recommend plants for your area including your local garden club, nursery and extension office. The extension office in Pahrump has a great little garden area that demonstrates some plants for the area. They have lists as well. Basic recommendations for trees for the desert are to keep them in scale with the house and property, and put them where they will do the most good and you can appreciate them. Every plant you put in the ground should have a good reason for being there. This is the desert and water is precious. I hope this helps a little. this is a big topic to cover.

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Ornamental Pear a Good Choice But Needs Special Soil Preparation at Planting

Leave a Comment / Bradford pear, desert landscaping, ornamental pear /

Q. We recently planted a fruitless Bradford Pear tree in the place of a tree that was dead. It is in good soil which I mixed with planting dirt from Star Nursery, where we purchased the tree. It was in a 15 gallon pot and is about 10 feet tall in the ground, so I would think it is possibly two to three years old. I realise this is not the best time of year to put a tree in the  ground, but hope that it’s maturity will give it a good start. We had a number of these trees in our yard from new when we lived in Texas and they did very well in the heat there. So I wonder if you have any advice or tips for us now we have one here in Nevada. We did do the ‘call before you dig’. Any advice etc will be really appreciated A. Ornamental pear varieties like Bradford, Chanticleer and others perform reasonably well in our desert keeping in mind they are not desert plants. I have watched them growing for many years along Maryland Parkway in front of the Boulevard Mall and across the street from it.             They have beautiful blooms in the spring and a nice round, dense canopy provided they are planted and maintained properly. They probably should not go into the hottest part of the landscape with a lot of reflected heat.             With this in mind they will never perform well for any length of time in a rock mulch landscape. They may do okay growing in rock mulch for a few years but after about five years the leaves will begin to yellow and scorch, the canopy will thin, and branches will die back.             When this happens, it will be open to borer attacks, the same kind that attack other fruit trees. These trees should be planted in an organic mulch such as wood chips which decompose and add valuable organic material back to the soil.         Ornamental pears should be planted with lots of organic material in the planting hole, they need to be staked solidly for the first growing season. After the first growing season they should be firmly established in the soil.             Fertilize them once a year just like you would any other fruit tree. Use a well balanced fertilizer with the three numbers the same such as 8-8-8, 10-10-10, etc or fertilizers sprayed on the foliage 3 to 4 times after the leaves emerge before it gets hot. They will benefit from periodic applications of iron because they will get yellowing from iron chlorosis.             I like to divide our landscapes into three water use zones; high water use, moderate water use and low water use. These water use zones represent the total amount and frequency of water applied.             These trees could easily go into the high or moderate water use zones but never the low water use zone. The watering frequency would be the same as other large trees and shrubs as you would apply water under the canopy so that at least half the area under the canopy is wetted to a depth of 18 inches.

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Branches Dying in Elm Probably Not Dutch Elm Disease

2 Comments / branch dieback, desert landscaping, lm leaf beetle, sap oozing, Siberian elm, slime flux, wetwood /

Elm leaf beetle damage Q. I have about 10 elm trees and my neighbor has 4 or 5. The branches seem like they just die. This pass year I lost 2 complete trees. I have been told there is a elm airborn disease. Can you please tell if that is true and what can I do about it? A. There is no airborne disease of elms that you have to worry about. I think there is some confusion about Dutch Elm Disease and these trees. Siberian elms are not as susceptible to DED as some other elms which are not planted here anyway.             Most of the elms here are Siberian elms, an inferior elm for landscape purposes. By the way, one of my favorite large trees is Chinese or Evergreen elm, a very nice tree that grows well in our climate with very few problems.              The usual disease problem we see on Siberian elm is a relatively harmless disease called slime flux. This is a bacterial disease which invades the wood and causes basically fermentation inside the trunk and large limbs. ooze from the bacteria is pushed out of the trunk or limbs and weeps down the side of the tree frequently from a pruning cut. If you get close to this ooze it will smell like fermentation or yeasty. Wetwood or slime flux comig from pruning cut             This smell frequently attracts flies to the ooze. It is thought that the flies can pick up this bacterial contamination and spread it to new wounds on several trees besides Siberian elm. If we see this particular disease on the tree we usually ignore it since it really does not cause any long term ill effects.             As far as insects go the worst problem is elm leaf beetle which skeletonizes the leaf. We usually ignore this too since it usually does not cause severe damage to the tree but does cause the leaves to become unsightly. These trees are tall/large with the leaves very high in the air so damage to them is usually ignored. It would be very costly to spray these trees to control this problem.             The last problem we have had with Siberian elm is when older landscapes with these elms growing in lawns is converted to rock landscapes. Frequently there is not enough water applied for these trees to continue to be healthy and the branches die back due to lack of water and a poorly designed irrigation system for the elm to survive.

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