Xtremehorticulture

Xtremehorticulture of the Desert

How to Reduce Water Use in a Condominium HOA; Part 2.

Leave a Comment / desert landscaping, landscape water use, part 2, reducing water use /

 In How to Reduce Water Use in a Condominium HOA; Part 1 you determined what plant water use category you are in;  Landscape water use categories 0-2 feet of water covering the irrigated landscaped area (nice job!) 3-4 feet of water covering the irrigated landscaped area (not bad) 5-6 feet of water covering the irrigated landscaped area (too much water used, scale back!) Cranking the Water Use Down If you are not happy with your landscape water use, or want to save even more water than you have, first consider eliminating trees above the roofline of the condos or at least pruning them lower. Are large trees important? Yes they are but perhaps not nearly as important as the cost of the water they need to survive. These pine trees are planted too close but the shade they produce can’t be denied. As these pine trees get larger, the cost of watering them may be worth more than the shade they produce. It will be up to you but consider removing them after replacement trees have been established. Big Trees Use More Water than Little Trees It may sound comical but people buy trees that grow 50 feet tall and only need a tree that is 15 feet tall (single story homes). Examples are pine trees. Sure pine trees may not use as much water as a mulberry but it still uses water. The bigger it grows, the more water it needs. Plant or keep trees that shade the walls and windows on the south and west sides of a building. This hot, west facing exterior wall has four small shrubs that create no shade on the wall but still require water. Their distance apart (about 10 feet) would provide the water needed to plant and locate three small trees or shrubs (ten feet tall) that would shade this hot wall. As the plants we chose to replace them got larger, more water should be added. Add one more small tree (patio tree) to provide shade for the patio area walls and door. Selecting “Backbone” Trees and Large Shrubs Selection of “backbone” trees and shrubs should be hardy, deciduous, and survive temperatures to at least 20F during the winter. What are backbone trees and shrubs? These are trees and shrubs you don’t want to lose to winter freezes. The trees and shrubs should be deciduous because we want the sun to warm this condo in mid-winter. If you want to save even more water, use small deciduous desert (xeric) trees and water them separately from the more frequently watered mesic plants.  Landscape “Negative Space” The fewer plants used and the smaller they are will, for the most part, determine how much water your landscape uses. Deserts use less water by NOT growing plants. I call not planting…. “negative space”. Where are plants needed? Where are plants NOT needed? Leaves these spaces open. Creative use of negative space is challenging. In the wetter, eastern US lawns were used to occupy negative space. In the desert we must be more creative; boulders, changes in rock size (texture), changes in elevation, artwork, wall paintings…all can be important when not using water. Dry washes can use textural changes along with plants. Rocks don’t use water. Open spaces don’t use any water and the plants used were desert in origin (xeric) so they aren’t watered very often. I would substitute small trees near the windows. Textural change in the mulch and wall paintings add color and interest to an otherwise somber area and don’t use any water. What is the water use here? Planting in Desert Soil Locations of ten foot tall trees or shrubs should be 4 to 5 feet from the home. Taller trees and shrubs can be planted further away.  Soil amendments should be lightly mixed with the soil at planting time along with water.  Planting holes should be wide and not necessarily deep unless there is a clear drainage problem. If a slight drainage problem exists, plant on a mound of amended soil rather than digging deep. Water should be applied away from the foundation of the home. In the desert, plant roots follow where water is applied. Trees and shrubs should be fertilized once in the spring. Two times at most. Showy plants are fertilized three or four times a year and when they flower best. Trees use water. Bigger trees use more water. Lots of big trees use lots of water

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Changing from Lawn to Desert Landscape

4 Comments / desert landscaping, desert plants, shade /

Q. After 6 years of trying to have a beautiful lawn in Las Vegas, I finally give up. The water company has offered me $3/foot to convert to water smart landscaping. What should I do? Do I add more rocks and plants? Artificial turf? What trees should I use, if any? A. If you do nothing else after removing the lawn, plant some trees or large shrubs that shade to the West and South exterior walls and windows of your home. This will help reduce air conditioning costs during the summer. These plants should be deciduous, in other words drop their leaves for the winter. Shade South and West Walls             Select trees that grow to about the same height as your home. Avoid trees that grow huge. They use more water and don’t really provide any extra savings in air-conditioning costs. A two-story house can handle bigger trees so in your case these should be deciduous trees so they drop their leaves in the winter and allows sunlight to warm the house. I will get back to you with some recommendations on some plants. Sometimes just a vine on a trellis is enough to shade a wall or entrance from the hot sun. Choose Desert Trees I would steer you towards trees that are adapted to desert environments, in other words, “desert trees”.Regardless of the trees you select, plant them a distance from your home no closer than half of their mature height. Plant them no closer together than this either. Dig the holes for the trees at least 3 times the width of their container and no deeper. Smaller trees establish more quickly and grow more rapidly in the beginning than larger trees. Irrigate the soil around plant roots no closer than 3 foot away from the foundation of the home. Many desert trees have excellent form and good looks like this Mesquite in this desert landscape. Fake Grass Has Pluses and Minuses             Personally, I don’t care for artificial grass unless it’s used for a specific purpose other than just covering the ground. It gets terribly hot during the summer if it’s in the sun and requires upkeep. If you go in that direction, start asking some questions because it is not maintenance-free. I wouldn’t use artificial turf unless you have a reason to put it in. Aesthetics, or just looking at it, is not a good reason to install it. It’s in the sunlight it gets exceedingly hot during the months of about April through September. It starts cooling down sometime in mid-to-late October for the fall months. If the air temperature is about 105° F, and the sun is shining directly on it, the surface temperature of your artificial grass will be about 165° F. I know because I’ve measured it. Some artificial lawns look very realistic but they will be also more expensive. Suggestions Start appreciating open spaces. That’s what concerns water deserts is open areas. Don’t fill the entire landscape area with plants. Learn to appreciate what is called “negative space”. Shade the walls and windows of your home on the south and west sides. With a two-story home this requires trees 25 to 40 feet tall. Don’t plant anything closer to the house than 3 feet from it. Apply the irrigation on the side of the plants away from the house or any cement surface such as patios, driveways, sidewalks, etc. Think of your landscape plants in multiple layers; the tall ones, the medium-sized once, small ones and groundcovers and vines. Odd numbers of plants are usually more appealing to the eye than even numbers up to about 7 plants. Above that number, the eye doesn’t seem to notice the difference. Repeat plants through your landscape to provide some continuity and rhythm. There is no need for every plant to be different from each other. Repetition or repeating plants is a good thing and landscape design.

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Privet Tree Leaves Black Spots are Disease? No.

Leave a Comment / desert landscaping, leaf disease, leaf drop, leaf spots, Ligustrum japonicum, rock mulch /

Q. I’m sending you a photo of a leaf from my privet tree that has some kind of fungus. Can you suggest some fungicide for me to use? Spotting on privet leaves. It could be a disease problem but it would most likely not be there if the tree was getting proper care. A. I think it is just a lack of good nutrition and perhaps a lack of adequate watering rather than a disease caused by a pathogen like a fungus. Even if it were a fungus disease, it is more susceptible to disease if it is in poor health. However, too much irrigation water applied too often can look similar to this.             Not enough water usually results in leaf drop in the early stages of stress with this tree. I will post your picture on my blog for readers to see your particular problem.             Japanese privet does much better in mixed landscapes rather than alone in rock mulch, if you have it in rock mulch. They do not like soils that develop in a rock environment and have trouble picking up the right nutrients from these types of soils to stay healthy. Please be aware that this tree is not a desert plant so it will require more care to keep it looking good. EDDHA found in the ingredients of an iron chelate fertilizer             Without soil improvement you might try giving it a better fertilizer product. Fertilizers for trees and shrubs from manufacturers such as Miracle Gro, Peters, Jobe’s fertilizer spikes and others will provide better nutrition for the plant than using an inexpensive agricultural fertilizer. Add to this an iron product that contains the EDDHA chelate (look at the ingredients).             Specialty fertilizers like these are not inexpensive. However you can save some money by not using it each time you fertilize. You can make an application and then boost plant performance by using just a little bit of nitrogen fertilizer when the plant needs it.             But if the plant is in rock landscape you will need at least one expensive fertilizer treatment annually to improve your plant performance under the poor soil conditions of rock mulch landscapes.

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Landscape Committee Wants Evergreen Shade Trees

Leave a Comment / desert landscaping, desert plant selection, homeowner Association, replacement trees /

Q. I am on our landscape committee for A Henderson HOA. We are going to remove many dead and diseases trees in our small community. Mostly privets that through the years have died after we converted to desert landscape from grass. Others are mainly ash trees that are diseased and or have dead limbs and with pruning look terrible. Most of our yards face either East or West. We have been advised to replace the trees with fruitless olives or living oak. All yards are small and have rock mulch. As many other communities we are cash poor and need to make a wise decision because it will be expensive. We are looking for evergreen, shade trees if possible. I forwarded this question to Andrea Meckley, a Certified Horticulturist working in the Las Vegas area since 1992. A.  I understand your situation with the privet trees doing poorly.  Since you are going through the expense of replacement I realize you want to make good choices.  Below are a few thoughts: 1. Fruitless Olives:                   Pros:  evergreen, little leave drop                   Cons:  slow grower, sometimes they will fruit even though they are not supposed to.  If this happens you can apply a solution to stop them from fruiting if it concerns you 2.  Southern Live Oak:                   Pros:   evergreen                  Cons:  slow grower, debris from leaves and acorns Between the two above I would choose the Olive.   Young European olive Young Live Oak Since you have existing sycamore and desert willow trees that are deciduous, I would also consider the following medium size evergreen and semi-evergreen trees:  Xylosma tree (Xylosma congestum), Holly Oak (Quertcus ilex), Blue Palo Verde (Parkinsonia florida), Desert Museum Palo Verde (Parkinsonia ‘Desert Museum’), Bay Laurel standard trunk tree (Laurus nobilis), and Shoestring Acacia (Acacia stenophylla) which may be a little messy.  Palo Verde in Bloom Young shoestring Acacia One good source for good pictures and more information can be seen at Southern Nevada Water Authority website.  Please contact me if you wish to discuss further. Andrea Meckley Certified Horticulturist American Society for Horticultural Science [email protected]

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HOA Replacement Trees for Privets, Ash and Sycamore

1 Comment / desert landscaping, HOA, homeowner Association /

Q. I am on our landscape committee for a Henderson, Nevada, HOA. Needing professional advice, I thought of you immediately, as a longtime resident I read your weekly column and read your blog.  This fall we are going to remove many dead and diseases trees in our small community. Mostly privets that thru the years have died after we converted to desert landscape from grass. Others are mainly Russell Ashes that are diseased and or have dead limbs and with pruning look terrible, lopsided, etc. I am without hope that with the pruning done they will ever pull out of it. The various landscapers thru the years used the ashes as replacements and as I have read in your column are no longer considered a good choice. Most of all our yards in our small community face either East or West. We have been advised to replace the trees with Fruitless Olives or Living Oak. All yards are small and have rock mulch. As many other communities we are cash poor and need to make a wise decision, because it will be expensive. We will be replacing approximately 25-30 trees. The other mature 15 yr. old trees in our landscape are sycamore and for the most part doing well, along with a few other Desert Willows,etc.  We are looking for evergreen, shade trees if possible. Thank you so much, I forwarded this email to a certified horticulturist working here in southern Nevada. She has worked with plant selection for a number of years and enjoys answering this type of question.I do want to mention that sycamores are a poor choice as a landscape tree for single-story or even two-story residences. They just get too tall, they consume a lot of water and require a lot of maintenance because they are out of their climate zone. In my opinion they should not be planted in hot desert climates and desert soils. They are a larger scale tree and require big properties to look good. They do well in arid climates provided there is enough water for them. Certainly they should not be planted in large quantities. Bob Morris Sycamore near south facing wall with heat damage to the leaves facing the wall A. Bob Morris forwarded your email to me.  I am Andrea Meckley, a certified horticulturist working here in the Las Vegas area since 1992.  I understand your situation with the privet trees doing poorly.  Since you are going through the expense of replacement I realize you want to make good choices.  Below are a few thoughts: 1. Fruitless Olives:                   Pros:  evergreen,  little leave drop                    Cons:  slow grower,  sometimes they will fruit even though they are not supposed to.  If this happens you can apply a solution to stop them from fruiting if it concerns you. 2.  Southern Live Oak:                    Pros:   evergreen                  Cons:  slow grower, debris from leaves and acorns Between the two above I would choose the Olive.   Since you have existing Sycamore and Desert Willow trees that are deciduous, I would also consider the following medium size evergreen and semi-evergreen trees:  Xylosma tree (Xylosma congestum), Holly Oak (Quertcus ilex), Blue Palo Verde (Parkinsonia florida) , Desert Museum Palo Verde (Parkinsonia ‘Desert Museum’), Bay Laurel standard trunk tree (Laurus nobilis), and Shoestring Acacia (Acacia stenophylla) which may be a little messy.  One good source for good pictures and more information can be seen at snwa.com under ‘landscapes’ and then under ‘plant search’.  Please contact me if you wish to discuss further. Hope this helps.  Andrea Meckley, CH [email protected] 

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Preserving Large Trees When Converting to Desert Landscaping

1 Comment / desert landscaping, irrigating large trees /

Q. We are planning on removing our lawn and changing over to desert landscaping but after reading your blog I am wondering how the old, large Modesto Ash trees will fare from this change? Do you think it would be an issue? I tried to find out about their root system, it seems like it is shallow, but won’t that be an issue as the roots will be damaged and then covered with hot rocks? See this posting on my blog: http://xtremehorticulture.blogspot.com/2015/08/converting-to-desert-landscapes-can.html Large tree suffering die back due to drought after conversion to desert landscaping A. I am not telling you not to convert to desert landscaping but be cognizant that established trees can get hurt in the process and many landscapers do not know how to convert from lawns to desert landscaping with existing large trees.  If you have large trees in an established landscape you have some options.  1. Leave the lawn surrounding the big trees and remove lawn where there are no big trees.  2. Remove lawn and spiral in-line drip tubing around the existing trees out to a distance of their drip line (spread). However, if you do this you should put this drip tubing on a separate valve and run it longer and less often than drip going to other plants.  3. Put LOTS of plants beneath these large trees and drip irrigate them to assist the existing trees with enough water. This is above and beyond having emitters for the large trees, too.  4. Use a lawn irrigation valve to feed bubblers to existing trees and form a basin around the trees to capture water from the bubblers. This is called basin/bubbler irrigation and is a form of flood or border irrigation. The basins must be level and flat and be three to four inches thick.

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Converting to Desert Landscapes Can Damage Existing Trees

2 Comments / desert landscaping, irrigation of trees and shrubs, retrofitting landscape, rock mulch, xeriscape /

Q. We removed half of our lawn with a 15 year old Chilean Mesquite in the middle which has done very well up to this point. Besides water from the lawn it had its own water supply located near the trunk. During grass removal, roots were chopped and six small plants with drip emitters in the rock mulch surrounding the tree. Will the tree be okay now that the front half sits in rock with only the plant emitters providing water. A. The short answer is it will not. You need to supply more water to this tree or it will begin to drop its leaves and the branches will begin to die back. Mesquite roots growing deep for water.             Now the long answer. Chilean Mesquite is among a group of plants, called phreatophytes, which have the potential to develop a very deep root system when growing in the wild along arroyos. In the case of mesquite, 200 feet or more. This is if the tree is in the right location together with deep, infrequent rains that help establish roots to that depth. Arroyos, or desert gullies, concentrate rainwater in one location pushing water to great depths with the roots of these plants not far behind.             Phreatophytes like mesquite when grown with water that is applied frequently grow rapidly, vigorously with a very dense canopy. In many home situations, trees do not develop deep roots because the water supplied to them, such as your lawn, is applied only to the surface few inches.             During 15 years of growth, the vast majority of roots will grow in a “mesh” 12 to 18 inches just below the lawn. The six irrigated plants planted under the canopy will help somewhat but not enough. Removal of tree roots also reduces generally speaking, most trees can lose as much as 50% of their roots and still recover provided they get adequate amounts of water.             My hunch is your mesquite will start dropping leaves at the onset of hot weather and you will see limb death in the canopy. The roots will try to reestablish themselves wherever they can find water but the canopy will die back because of root loss and inadequate amounts of water. Tree dieback after converting from lawn to desert or rock landscape.             What should you do? During this hot weather you should put a hose out there and irrigate the rock beneath the tree about once a week during hot weather. This is a stopgap measure.             You might consider installing a “bubbler and basin” around the tree in the future to provide more water. Use an irrigation valve previously for the lawn for the water source to bubblers. An irrigation bubbler is installed 2 feet from the trunk. If this basin is quite large, two bubblers located in this basin might be needed to fill it. Each time you irrigate, fill the basin. Mesquite blown over because shallow rooted due to lawn and flower bed             It is important that the basin constructed is level and wide enough to lie on top of about half of the area under the canopy of the tree. A level basin, or berm, is built around the trunk approximately 3 to 4 inches high of the tree with the trunk at its center.             The bubbler is a type of emitter that pushes out usually 1 to 2 gallons a minute. Drip emitters emit gallons in hours, not minutes, so this is a large amount of water applied in one spot in a very short. Of time. This is why the basin or berm is needed.             If the tree is on a slope, then install the basin around the trees so that it is level. The water from the bubbler must flood the basin and be contained by the basin for it to work well. This may take 10 to 15 minutes with bubblers and anywhere from 20 to 30 gallons every time the tree is watered.             In midsummer when it’s hot this, watering might be once a week to every 10 days or so for desert trees like mesquite. Adjusting how often you water and how much is applied each time will determine how fast the tree grows and how dense the canopy is.             If you begin to irrigate less often, but apply more water each time, you will slowly encourage the roots of desert trees like mesquite to grow deeper.

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