Q. A few days ago I noticed that most of the leaves on my apricot tree had withered and turned brown. The same thing, to a lesser degree and later in the season, happened last year. But in the spring it brought forth an abundance of blossoms and fresh, green and healthy looking leaves and produced lots of good fruit. I checked the soil, and it is not dry, but slightly moist. I am watering daily on a drip system for 35 minutes. So, wondering if you have any idea what is causing this and if I should be concerned. This is most likely NOT borer damage. Borers typically ravage a single limb. This is over most of the tree. That most likely puts the cause in the trunk, roots or soil. A. I looked at the pictures and 3 things come to mind right away. These center around daily watering which is a no no, the rock mulch I see around the tree and the possibility that not enough water is being distributed to serve all the roots. I don’t know how much water you are giving the tree but I think the tree is running out of water before the next irrigation. I also think the rock mulch under the tree is terribly hot. First, is the rock mulch. I like rock mulch when it is used around desert plants. I don’t like rock mulch very much when it is used around non-desert plants such as fruit trees. I think you would help the tree a lot if you could rake back the rock a distance of about 3 or 4 feet from the tree and put a layer of 3 to 4 inches of wood chip mulch instead. You can get this free in North Las Vegas from the University Orchard or from Cooperative extension just south of the airport. Daily watering of trees during the summer is not a good thing. If you can apply more water to the trees and then wait one day before your next irrigation it would be helpful. Tree roots begin to suffocate when water is present in the soil all the time. Giving the soil a chance to dry and admit some air to the roots can be quite helpful to the tree. When the tree is watered, water should be applied to at least half the area under the canopy of the tree. This may require you to add more drip emitters then you have. A tree that size should have at least 5 to 6 drip emitters and would do better if there were more than that. These emitters should be placed about 2 feet apart under the canopy and about 18 inches from the trunk.  A tree that size probably requires about 15 to 20 gallons every time you water. This means if you have 6 drip emitters, they should be 3 gallon per hour emitters if you are watering for one hour. If you are watering for 30 minutes, you should use 5 gallon per hour emitters.

Q. During the past month of high heat one limb on our apricot tree appears to have died.  All the leaves on this limb dried up while the other leaves on the tree stayed green. The limb is about 1-1/2 inches in diameter near the base.  In addition to rough discolored bark there are a couple of amber-orange blobs of sap in this area of the limb (photos attached). This borer infested limb can be replaced in three years or less in our climate and in production in three to four. Any hope the limb will survive and recover next season? Should the limb be cut off now?  Could this be a disease that will spread to other limbs? A. Paul. You have described perfectly the symptoms of boring insects (borers) in fruit tree. One limb dies while the others are healthy and frequently there is sap coming from the limb in blobs or round balls. There’s the little varmint! Under the thumb. Take a sharp knife and remove the bark where you see the sap. If you are confident the limb is dead, remove all the bark down to where the limb is still alive. Cut the limb off in this area and hopefully the remaining stub will resprout with some suckers yet this year that can, eventually, replace the dead limb. With some TLC that can happen in three years or less. This winter select three or four of these suckers as possible candidates to replace the dead limb. Next growing season you will make your final selection of one or two to replace the dead one. No insecticides will do much good on these. The insect is most likely gone and the limb is dead. Cut and replace the dead limb with new growth.

Q. We recently moved into a new single-story home and want low maintenance, desert hardy plants. The plan called for 4 Japanese Privet trees and we became suspicious. My husband and I know nothing about ANYTHING that grows and so went to Springs Preserve to ask questions. The designer there assured me they would be, “Just fine”. The landscaping was completed at the end of March followed by horrific winds and the trees looked pretty battered but I figured that they would recover. But then…the heat! Fast forward to now and we have one tree completely dead, two are looking rather ghastly and one seems to be okay. We are following the watering schedule outlined by the landscape company, 7 days a week, 2 times a day for 15 minutes each.  We could use some guidance as to what happened and what my other possible plant choices could be? A. You should have trusted your instincts. You’re instinct was spot on when something didn’t seem right to you. Let’s see… You are putting in a desert landscape and using plants native to Japan… Are there deserts in Japan? Oh yes, the desert Japanese privet, I forgot about that one! Again, I have to thank Sunset magazine for letting me use these pictures that appeared in that magazine over 20 years ago. I used them many times in classes that I taught over the years.This is an example of the Prof. Jones minioasis concept of desert landscape design. It emphasizes three watering zones; high, medium and low. Of course, I’m joking with you and I hope you can appreciate a little humor at your expense. I have about 8 posts on my blog about using Japanese privet in landscapes in the Mojave Desert. About 4 or 5 of those are how they do not tolerate dry soils and they perform much better growing in lawns. You did the best you could. You checked with who you thought were knowledgeable people and they assured you everything was going to be okay. Well, they were wrong. A slide from a PowerPoint presentation I used in my classes.I am not a landscape architect nor am I landscape designer but my classes focus on water and energy conservation through exterior design. I don’t like to get involved in plant selection. It is my least favorite topic in horticulture. But the majority of these plants, and the most expensive plants on your plant palette, should come from dry climates not from places like Japan. I will forward this email to a knowledgeable person who loves this topic and she can respond to you. But I would tell you this: The first question a landscape designer should ask is what your activities are outside now and what might they be over the next 10 years. This lays the foundation for creating exterior livable spaces. Plant materials are secondary to the design and used to enhance these livable spaces. Your landscape design should include a high, water use area, a medium water use area and a low water use area. The irrigation design reflects the landscape design and helps sustain the plants growing in it. High water use areas are used to help lower energy costs such as for AC and to create pleasant environments for people to use these outside spaces. High water use areas should concentrate on plants that shade your south and west walls. You do not need trees or plants that get above 20 feet tall for a single-story home. Plants much above that height just waste water. Minioasis design concept and Hydro zoning rely on irrigation systems designed for plants having high, medium and low water requirements. Red is high, green is medium and blue is low.Again, thank you Sunset Magazine. This type of landscape design concept is Dr. Warren Jones minioasis landscape design concept developed over 40 years ago at the University of Arizona in Tucson. It is talked about in his book, “Plants for Dry Climates”. This is still a valuable resource to use when deciding on a desert landscape design and plants to grow in it. I attached some graphics for you to look at. I also included a finished desert landscape design that has a pool and lawn area. Yes, desert designs can be anything but should lower water costs, energy costs and use desert or desert adapted plant materials for the majority of its landscape.

Q. I bought this apricot tree in March and it flourished and I got lots of apricots from it within a couple months. It started to turn hot and the leaves started to turn brown I have watered it very well daily as it’s exposed to full sun and it seems like it’s withering and I can’t figure out what’s going on. Here is a few pictures of the whole tree and some of the leaves and even the bark A. Avoid watering daily. Fruit trees do not need to be watered every day even if it’s 115 F. I am watering hundreds of fruit trees that were planted in March of this year as bare root.  These trees were not in containers, and I am watering them every other day right now during this heat. But when they were planted, compost was mixed with the soil used for planting around the roots. As they were planted, water was added to the planting hole so that everything was a slurry, a muddy mess, all around the roots. Apricot leaves will scorch more if the tree is not healthy. Make sure it’s given an iron fertilizer in January or February. Water with a hose during establishment. These trees were watered with a hose 3 or 4 times in one week before the drip irrigation was turned on. A depression 3 feet wide was put around each tree so that water from the hose would collect around the tree and the soil would settle around the roots. Woodchip mulch. Finally, a 4 inch layer of wood chips surrounded each tree at least 3 feet in diameter. The woodchips were kept 6 inches away from the trunk so that water, in combination with the woodchips, did not rot the trunk where it entered the soil. These trees will not need to be fertilized for 2 years because of the compost used at planting time. You can get good compost from Viragrow in North Las Vegas. Apricot tree may scorch when surrounded by rock on the surface of the soil when it is 115° F Drainage. Take a post hole digger and create vertical holes or chimneys in the soil about 18 inches from the tree in 4 locations if drainage is a problem. These vertical holes will help drain water away from the roots and help prevent them from suffocating. Pour compost into these 4 holes and fill them. Then I would cover the soil around the tree with woodchips, not rocks, 4 inches deep. Keep the wood chips 6 inches from the trunk of the tree. Monitor soil moisture. I would buy a soil moisture meter used for houseplants that will cost you less than $10 at Lowes or Home Depot. When you take a soil moisture reading, push the tip of the meter into the soil about 4 inches deep and look at the needle. Don’t water the tree unless the needle is in the middle of the meter (5 on a 10 point scale).

Q. Not sure of what to do with this plant, Any suggestions? A. Aloe doesn’t like it in the same spot you might plant a cactus. It likes a little bit more protection from the sun and it also likes improved soils. I would plant it on the east side of a building or the south side if it’s getting some filtered light. Northside is possible but there needs to be lots of reflected light. You can plant it in a desert landscape surrounded by rock but in a few years it might not grow very well, turn yellow and begin to dieback to the ground. It’s a succulent so you have to plant it and water it differently from a cactus. It will like more soil amendment such as compost mixed with the soil around its roots at the time of planting. You will have to water it about like a shrub growing in your yard, maybe twice a week or when you see it begin to shrivel. Water and fertilizer. Because it is not a cactus, it should be watered and fertilized more often. I would fertilize it once or twice a year in the spring and early summer. It will respond very nicely to compost applied to the soil within 6 to 10 inches of the plant, no closer. Then water it in. Water it about every two weeks or when you see it start to shrivel. Your Aloe vera can be propagated very easily by removing the soil around its roots and cutting off any new “starts” or pups with a sharp knife or pruning shears. If you don’t do this every couple of years they will get overgrown. They make good container plants but like I said you will have to take it out of the container every few years when it starts to get overgrown and divide it, cut off the pups for replanting. If you cut off the pups and lift them from the soil right away, put them in the shade for a day so the cut end has a chance to heal over. Don’t plant it with a fresh cut. You can also take a long sharp knife and cut the soil between the mother plant and the pup. Cutting through the soil will also cut the attachment to the mother plant. Do not lift it but leave it in the soil next to the mother plant for a few weeks. This will give the pup a chance to grow more of its own roots. Then go ahead and lift the pup with a long knife, pushing it up through the soil beneath from beneath it rather than only pulling it from the soil by its leaves. You can replant it in a container or new spot immediately. As far as the health/medical benefits of aloe, It has a lot of uses. I think you will get a lot of comments from this post so stay tuned.

Q. A long time ago I asked you for any details you might have for this somewhat gawky, but pretty plant, with its small red flowers come spring and summer.  Hummingbirds love them. The botanical name is: Pedilanthus macrocarpus. I am interested in trimming, feeding and any other details particularly to encourage more large blooms of the red flowers. We have two of these plants facing Southwest, and one is about 5 feet high and straggly. A. I don’t really know much about this plant. When I start investigating a plant, any plant whether I know it or not, I start digging for information usually from University documents and reliable nurseries. This plant has been given is “Lady’s Slipper”And it is a perennial succulent. From Mountain States Nursery From Arizona State University From the University of Arizona This plant is from Baja and the Sonoran Desert. That tells me a lot. Yes it can tolerate desert soils and desert conditions but it does like to have a drink of water periodically. I also suspect this plant will grow better with a little bit of organics mixed in the soil at the time of planting. Or some organics added to the surface of the soil where there is water and let it decompose around the plant. It might also like to be misted periodically since it’s from Baja. It seems to be tender to freezing temperatures below 30° F. It may not handle intense desert sunlight so it’s best growing under trees in those exposures or on the east side of the building. I couldn’t find information on what triggers the flowering of this plant but information from Arizona State University says this plant blooms more profusely during the winter months. It remarks that summer flowers are not as striking. Flowering might be triggered by temperatures, daylength or rainfall. So let’s talk about how to get more flowers, and larger flowers, on this plant. More flowers. The more growing points this plant has, the more flowers it will produce. Generally, pruning this plant to improve flower production should be done at its base; removing entire stems from deep down inside the plant rather than any kind of shearing or cutting off the terminal ends of the branches.  Some of the longer stems can be cut back so that they will grow more stems to produce flowers. These are called “heading cuts”. One heading cut will produce 3 to 4 new stems that can produce flowers. Fertilizer. I believe in the use of compost for soil improvement and adding nutrients, fertilizer, for the plant growing in desert soils. Apply perhaps one quarter cubic foot of compost to the soil at the base of this plant in early spring. Try supplementing this plant with a high phosphorus mineral fertilizer such as triple super phosphate or bonemeal.  Apply all fertilizers containing nitrogen in half rates the label states. Begin applying phosphorus fertilizers about two weeks before it is known to bloom. Do not apply any nitrogen fertilizers or compost after August 1 through November. Sunlight. Make sure it has at least 8 hours of sunlight. Keep it out of spots where it has intense sunlight such as your walls facing West or South. Water. Water it sparingly as you would a desert plant, but deeply when you do. Try watering once every 2 to 3 weeks. Use its growth as an indicator whether to water again. If it’s not pushing a lot of new growth, water it more often. Apply water a distance from the plant equal to up to at least half of its height. Drainage. This plant must have good drainage or it will die or fall over.

Q. I have a Kieffer pear tree that is newly planted about 4 months. It’s located along a wall that runs north-south and gets full sunlight. For the past few weeks I’ve noticed that dark splotches are beginning to appear in some of the leaves. It usually starts along the tips or edges. Recently, the tree is beginning to show yellowing on all the leaves on the edges. I have a picture attached. I’d be very grateful for any help! A.  Leaf browning along the edges of the leaves on pear is quite common during the heat and strong winds of summer. The temptation is to give it more water which can actually damage the tree and might even kill it. Some of this damage to leaves is common during the heat and winds of summer. In pear trees oftentimes leave damage becomes black and can look like a disease. Don’t panic! Browning or blackening of pear leaves is quite common when they are damaged. What to do?   Make sure the tree is staked during its first year of growth. Staking a tree is supposed to force the roots not to move in the soil during the tree/s establishment. It is not supposed to immobilize the tree above ground. The tree above ground should move and sway with the wind but the roots should have no movement. Water the tree frequently during the first month of establishment and then try to “wean it” off of frequent watering when you start to see new growth. All trees and shrubs go through a stage in their establishment from container to the ground where new roots grow into the surrounding soil. Once roots have begun to grow and the tree becomes established, there will be a flush of new growth from the tree. Remove the stake after the first growing season.Try not to water more than every other day when temperatures are near 110° F. Give the soil a chance to drain before you water again. Pear leaves can yellow and have brown spots when needing iron. Add compost and iron. Sometimes these trees just do not have enough nutrients in the soil to get them through the summer. For a young pear tree like yours, add about one half cubic foot of compost in a circle around the tree without touching the trunk. Like a donut. Before applying the compost to the soil surface, put a couple teaspoons of iron chelate beneath it and water everything in to the soil with a hose. The most effective iron applications this time of year are sprayed on the leaves but it is a little hot to do that now. Cover the soil at the base of the tree with wood chip mulch. This is particularly true of fruit trees. Fruit trees preferred to grow in soils that have organics in them. The decaying of woodchip mulch on the soil surface in the presence of water adds organics to the soil. Covering the surface of the soil with rock does not. Keep the wood chip mulch away from the trunk the first few years.

Q. I have a problem with my Muscogee crepe myrtle here in north Florida. I planted it last year and it had nice, healthy purple flowers. Then I pruned it, added some iron chelate and epsom salts to the soil and these little warts sprouted all over the tree. I cut them all off and they are growing back. Will this tree do anything this year or should I replace it? A. The iron was a good idea, not sure about the Epsom salts, but be careful when you prune crape myrtle. Some of these warts, as you call them, probably resulted from your pruning. Pruning the wrong way can cut off all of the future flowers for a while.             I posted some tips on handling crape myrtle but it was in the desert. Maybe some of these tips can help. http://xtremehorticulture.blogspot.com/2014/06/reviving-crepe-myrtle-after-neglect.html http://xtremehorticulture.blogspot.com/2014/01/pruning-crepe-myrtle-correctly.html http://xtremehorticulture.blogspot.com/2014/09/leaves-of-crepe-myrtle-yellowing.html  Spread 4 to 6 inches of woodchip mulch beneath the tree where it’s irrigated.That will help build the sand and return nutrients.             Iron should be applied to the soil in early spring. Later than this might not help much. The best iron chelate contains EDDHA as the chelating agent. Apply it in January. Apply a Rose type fertilizer at the same time. Crape myrtle in sandy soil. It can be good for it provided you add nutrients to the soil, organics, iron and fertilize once or twice a year.             One application of fertilizer per year is normally all that you need when growing it on most soils. On your sandy soils, I would split the fertilizer application in two; apply half in the spring and the other half late summer or early fall. Crepe myrtle sets up its flower buds in the late summer and fall for next years blooms. Don’t cut them off.             These growths along the trunk and limbs look like the tree is trying to send out lots of new suckers to perhaps compensate for the pruning you did. Allow them to grow only where you want new growth. Otherwise, remove them as soon as you see them. Crape myrtle can look like this growing in sandy soil if it gets the right nutrients and organics.             Flowers grow from the ends of the branches. So if you removed all of the ends of the branches, it will not flower that year. It has a good chance of flowering next year and years after provided you did not make the same mistake pruning.             The best time to prune this tree is immediately after all the flowering has finished. When pruning, do not shear off all of the ends of the branches. No, no, no. This removes all of the flowers for next year. Remove entire branches. This type of pruning is called “thinning”.             If branches are healthy, do not prune them back at all unless they are too long.

Q. Not Sure the type of Cactus but it does well in my yard.  I  do not understand what happens to the top of one and the other produces flowers? Readers pictures of his cacti with and without fasciation.  A. Technically called fasciation but commonly called cresting in cactus. Sometimes cresting can add lots of value to some cacti. It is more of a curiosity than anything else. The usual method for getting rid of it is to cut it out and it seldom comes back. Read more about fasciation and cresting on Wikipedia.  It can happen to other plants as well from my collection. Fasciation on asparagus Fasciation on European pear. Fasciation on rose. Fasciation on ash tree Fasciation on boxwood.

MoCa Family Farm Is our farm in the Philippines. It is certified for agritourism and we are certified to teach many classes in tropical horticulture and farming through RLearniong Center. I would invite all of our friends to visit our Facebook page and become our Friends! We grow many different tropical fruits, vegetables, herbs and spices on our farm. Q. What are the main challenges in growing tropical fruits in the desert?  Fruits like mangos, lychee, longan, jackfruit. It seems like Las Vegas has all the same conditions as Southeast Asia, except the humidity, but my understanding is that humidity is good for preventing disease. Are the  colder temperatures in winter the only impediment to growing these fruits? A.  Having a small-scale family farm in the Philippines and growing a wide variety of different fruits, herbs, spices and vegetables I can tell you the challenges can be many trying to grow these in the desert. There are some things we can grow quite easily while there are others that pose a lot of challenges. But I encourage people to try. Many of our annual vegetables in the desert are perennial in the tropics. Take for instance tomato, peppers and the like. Pruning guyabana (soursop) at MoCa Family Farm RLearning Center. We emphasize keeping our fruit trees small so they are easier to harvest. But I think you are talking mostly about tropical plants such as banana, mango, papaya, perhaps tea, coffee. Each tropical plant presents its own set of problems. But as I tell many of my students, when you grow plants, the further these plants are from originating in the desert or desert adapted, the more time, energy and money it will take growing them. Avocados at MoCa Family Farm Here is a partial list of things to consider. Temperature. Many tropical plants can handle desert heat but they cannot handle cold in any way, shape or form. Damage to tropical plants can start when temperatures drop below 50° F. Some tropical plants experience chilling injury at refrigeration temperatures. Think of putting a banana or tomato in the fridge. And of course freezing damage. When temperatures drop below freezing, most tropical plants cannot handle it. If you’re growing a tropical plant that experiences these types of damage and of course you have to protect them from it. This might mean a greenhouse, hoophouse are wrapping these plants for thermal protection. Immature rambutan growing in the Philippines Light intensity. Sunlight is more intense in the desert and there is more of it than in most tropical climates. Planting tropical plants on the east or north side of a structure may be enough to protect them. Planting and filtered light such as from an open tree canopy or shade cloth may be enough. Sunburn on Apple fruit growing in the Mojave Desert Humidity. Some tropical plants and even temperate plants grow best with some humidity. In the Mojave Desert it is common to experience relative humidity at 30% or below for many days of the year. This can pose problems for some tropical and even temperate plants in flowering and fruit set. We experience fewer plant diseases in the desert because of low humidity. Very poor fruit set on Bing cherry growing in the Mojave Desert with 12 other varieties of sweet cherry. I speculated it was because of low humidity and poor fruit set. Flowering was fantastic. Soils. Surprisingly, tropical soils can have very low organic content and still be dark to black. Desert soils where rainfall is under 10 inches per year have unacceptable organic content even for cactus! Our soils organic content is far below 1%. The soil chemistry is usually unacceptable for many tropical plants with too much alkalinity and salts. Desert soils need organic content of 2 to 3% for lawns, palm trees, many of our trees and shrubs. 5% organics would be nice to have for fruit trees and 10% for growing vegetables. Even in the tropics, the addition of compost to the soil to grow vegetables is a very good idea if the soil has never been farmed. Typical Mohave Desert soil in the Las Vegas Valley. Extremely low organic content. Daylength. The amount of darkness a plant receives can act as a “trigger” for flowering in some plants. In the tropics daylength is not such a big deal since there is not much variation during the year. Instead, the alternation of wet and dry seasons can trigger flowering in some tropical plants. I hope you can see that growing tropical plants in a hot/cold desert climate can be very tricky. How that plant is managed in our temperate, desert climate depends on which plant you want to grow. But in the very least you have to address soil barriers with compost and surface mulch, avoid planting in South or West facing exposures, keep them from freezing or possibly chilling injury and be aware of problems that might be associated with humidity. This is the bare minimum that you must think about if you plan on growing tropical plants in the desert.