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.

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! Leaf damage to pear during summer heat and wind 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! Yellowing of pair leaves is quite common in our alkaline soils, particularly if there is not enough compost added at the time of planting. 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. 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.

Q. Good morning I am writing you from Greece , more precisely from Antiparos in the Cycladic where I have recently acquired 55 acres of land on the sea side, oriented towards the west. I am reflecting on what to plant on this dry land where there is NO water. You can buy water and storage in water tanks or decide to desalinate see water. But I don’t want to have to water these trees in the future  So I am looking for plants and for fruit trees that I can plant on this land without adding any water once the plants are established. Olive trees, grapes for wine, fig trees, etc do well here without water once established. Orange lemons etc… , peaches apricots …, do well if you protect them from the wind and do provide some water during the summer.  Do you have any suggestions on what additional plants I could plant that would not need any water at all during summer once established? A. interesting project. My focus is more on the production of high quality fruit and vegetables for higher end markets. What you are asking falls more into the expertise of sustainable horticulture/agriculture, a form of permaculture. I think a lot of the techniques that you need to employ would be talked about more on permaculture Internet sites. That being said, you are on the right track. Certainly those crops you mentioned, wine grapes, olives and figs to a lesser extent might fall into that category. That kind of production is a two-edged sword; usually the visual appeal of food crops grown under restricted water is not as bountiful and it doesn’t look as good. The positive side, when you are successful these of fruits and vegetables are more concentrated in flavor and nutrition.  I worry a little bit about finding the right location to grow these things or putting the right growing strategy together to make it successful. Then there are those “tricky” crops that require more water than you think such as dates and figs. They both like a constant water source close by so they can keep their “toes wet” or they won’t bear fruit or the quality will be bad. But here is a short list of some food crops that would either grow with restricted water or with poor quality water. Wine grapes Olives Pistachios Edible cactus (Opuntia spp.) Mormon tea (Ephedris) medicinal Yucca for starch of the root and stem Pitayas such as Stenocereus Cereus sp. Parkia biglobosa Corryocactus brebistylus Goji Berry Pomegranate Tylosema esculenta Carob There are probably many more but I would need to dig. Perhaps some others might add to this list?

Q. Hi Robert, i hope you don’t mind another question, I don’t know anything about this kind of tree, but we have several of the same kind in the same condition, surrounded by a variety of others seemingly healthy…They’re fed and watered a lot, there’s lawn under them. Does it look like it’s dying? Pictures of readers ash tree yellowing A. Dennis.Thank you for the pictures. These help a lot. This is an ash tree but I am not sure which one.If you show someone the close-up of the leaves and they know it is growing in southern Nevada, they will assume it is an iron problem. This is because of the yellow leaves with the green veins in the close-up of the leaves. But I want to propose two possible other ideas.Flood the area under the tree. It could be as simple as not enough water. With limited water the tree could have yellow leaves but usually the leaves are brown or scorched around the edges. One way to find out, and it’s a simple way, is just flood the area under the tree 3 times this week and again 3 times next week. See if you see a response in the growth of the tree in about 2 or 3 weeks. This is the simplest and doesn’t cost you much money to do. Add fertilizer and iron. Another possibility is fertilizer and iron. Distribute about 3 or 4 pounds of 21-0-0 under the tree along with some EDDHA iron chelate. 2 or 3 teaspoons of iron chelate in a 5 gallon bucket of water will be enough. Another possibility is to substitute about 2 to 3 cubic feet of compost along with the iron and water it in instead of the 21 – 0 – 0. Make sure the fertilizer and iron is thoroughly washed into the soil. If this solves the problem, you should see a response in 2 or 3 weeks. Ash Decline. Is not a good one. There is a disease of ash trees called ash decline. There is nothing you can do to remedy it except to remove the tree. If you do not get a response from the increased watering and fertilizer including iron, I would conclude it is ash decline. Remove the tree and replace it with a tree that is not an ash.

Hello Robert (a.k.a. Xtremehort) I’ve recently moved from the cool, humid gardening of Scotland to the arid, sun-scorched earth of southern Nevada. What an adventure – complete opposites in the gardening world. I discovered your blog while searching for help with plants and I’m enjoying reading your posts and learning a lot about gardening issues here in the desert.  And I spotted your older post on snail problems and thought your readers might like to know what I tried.   Vacant snail shells picture from the reader I discovered hostas one day, while exploring a big gardening exhibition, and decided I had to have these fabulous plants in my garden.  So I bought several varieties, took them home and had fun planting them out.   Readers Hostas Big mistake. It was like putting up a neon sign saying, “Free Caviar Here Guys” as snails descended on my garden. Now I should add that I hadn’t seen many snails up to this point.  So how the heck did they know I had planted hostas?  Overnight they stripped a few of my young plants to almost bare stalks so war was declared. As we had a variety of pets at that time, and a resident hedgehog under the shed, I wanted to avoid using anything that could be toxic.  I had tried several of the suggestions you mention in your blog, but without much success.  I also tried using: crushed egg shells and coffee grounds mix – limited success. crushed garlic and coffee grounds – again limited success.  (But this works well around the base of roses and keeps the bug population down) chunks of orange and lemon peel pieces of slightly crushed-up aluminum foil around the plant cocoa bark mulch But none of these proved to be good long-term solutions.  Scottish recommendation By adding hostas I was obviously offering 4-star Michelin cuisine, and my garden was rapidly being overtaken by snails and their extended slug families. So I decided to dig up all my hostas and put them in large clay pots.  That solved the problem for a short time.  Then I discovered the perfect answer, after chatting to friends who were gardeners.   Vehicle grease. It worked 100%. I smeared Castrol multi-purpose chassis grease, about 2 inches up from the base of each pot. They couldn’t go through it.  And if you apply a thick layer, it lasts for ages.  For added protection, I also sat the pots on sharp gravel. At last my hostas started to thrive and look beautiful.  Until one day I noticed familiar munching marks on a few leaves.  That’s when I discovered that snails are clever little blighters.  And not easily deterred.  They were dropping onto the hostas from overhanging plants. After a bit of relocation and plant pot checking to catch the ones that were hiding, I solved that problem too.  I’d finally won the war. I hope this might help some of your readers with their snail problems.  Happy gardening and thanks for all your grand advice. 

Q. Can you use lava rock as a groundcover around any shrubs? I am thinking particularly of Japanese boxwood. A. Lava rock was used extensively in Las Vegas landscapes as a surface covering before desert landscaping became popular. Desert landscaping uses specialty rock mulch of different colors and sizes and its use has pushed lava rock out of this niche. Lava rock has some interesting qualities, different from the rock we have available to us today. It can be a good alternative to rock mulch we have available to us today.             Lava rock, or any rock mulch for that matter, would not be a good choice around Japanese boxwood. Japanese boxwood grows better in soils amended with compost and the soil covered in organic wood mulch, not rock mulch or lava rock.             Using rock mulch or not depends on the plants. I am frequently asked which plants can tolerate rock mulch and which ones cannot. That’s difficult to explain unless you know where the plant originated. Plants that originate from desert climates can generally handle rock mulch better than those which don’t. Sometimes that information is difficult to find.             Boxwoods come from non-desert environments. They don’t come from the “deserts of Japan”. They come from wetter and cooler climates than ours. This suggests to avoid placing them in West and South exposures, but amend the soil at the time of planting with compost and cover the soil with something that decays such as wood chip mulch, which adds organics back to the soil.             Lava rock falls into the category of a rock mulch. It does break down over time adding minerals to the soil but adds no “organics”. The same problem occurs with other rock mulches. Over a few years, the compost added during planting is gone, replaced by the minerals without organics. These soils may be rich in minerals but lack the physical properties needed for good drainage, root growth and the chemistry required for nondesert plants to thrive.

Q. I have 4 Bottle trees in my Phoenix-area yard facing south. The largest looked fine 2 days ago with new leaf growth starting.  Today all the leaves  on it have turned completely crispy.  Is it likely to recover or has it just died?  Makes me worried about the other 3 Bottle trees. Trees were planted June 2015. Bottle tree picture with similar problem from a previous question A. There was a piece of information I was looking for but I didn’t see it. It’s pretty critical. If these are older trees, then it is most likely something that recently happened like recent strong winds or a spike in the temperature and they will recover just fine. As long as there is good drainage these trees can survive and thrive in a lawn!               If these are newly planted trees then I am a little more concerned. My concern is about watering. Bottle trees are notorious for having roots that are sensitive to too much water remaining in the soil. This can be from watering too often or poor drainage or both. Hopefully, these are older trees that have been in the ground for a few years and they suddenly had leaf scorch and/or leaf drop and they will recover just fine maintaining normal irrigation for this time of year.               If these are newly planted trees and you are watering them frequently as they are getting established then I’m a little worried. If they are recently planted and you are watering frequently, this can cause roots to die from suffocation, keeping the soil to wet.               Make sure the trees have good soil and water drainage around the roots. Water them thoroughly once a week this time of year. Give them a good rest without any water between irrigations.               Big trees use and require more water than smaller trees so make sure that the largest tree has been getting enough water each time you irrigate. The largest tree should be getting more water than the smaller ones. If it doesn’t have more emitters, you should consider adding more so that it gets more water.               My sense is that these are older and established trees and they will come back just fine if you water them deeply but infrequently.