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. I’m curious if there is any other reason other than drought or overwatering that would cause my donut peach growing in a container to wilt within 24 hours? I pruned the dead branches off and touched very little of the live wood. Donut peach wilting A. Donut peach, sometimes called bagel peach, Saturn peach, pan tao peach, and a bunch of other names, are a good choice for our climate and soils. They are a novelty but deliver very sweet fruit great for eating fresh and birds love too! A problem that I have mentioned in the past as well as how to avoid it. Stark Saturn Donut peach             Thanks for the pictures and I will post them here and on my blog. I understand it is still in the container and you will plant it soon.             For leaf wilting to occur, something is stopping the water from reaching the leaves. This could be a soil problem, root damage, stem damage or direct damage to the leaves. Obviously, a lack of water or watering too often so the roots suffocate can cause wilting.             A common problem this time of years is applying fertilizer or strong compost too close to the trunk. This can cause the leaves to wilt because of the high nutrient content (salts) in fertilizers and many rich composts. If applied next to the trunk or against it, it can cause plant wilting followed by death.             Apply fertilizers and compost no closer than 12 inches from the trunk. If the container is smaller than this, then use a very small amount and apply it more often. Stark Saturn Donut peach with bird damage             Check for borer damage on the trunk. I had trees coming from the nursery, both container and bare root, with borers already in the trunk. If your tree had borers in it the same season you bought it, the borer came with the tree when it was bought. No extra charge!             Spray the trunk with water from a spray bottle several times until the stem is soaked. If the borer is active, you will see globs of brown or dark red sap coming from the stem. Sometimes I can squeeze the stem with my first two fingers and I can feel “sponginess” where the borer is feeding just under the bark. Dig it out with a sanitized, sharp knife and let it heal.             It is possible that spray drift from weed killers could do it but I may be grasping for straws with that one.  When using compost as a fertilizer for fruit trees keep the compost away from the tree trunk.

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.

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. You emphasized it’s better to water longer rather than more often. But what if that’s not possible? Our small condo community has an old irrigation system with everything watered from the same lines. We irrigate for nearly 24 hours. Less than that and small plants really struggle. Is there anything we can do?  This picture says it all. This is an example of the Mini-oasis landscape design pioneered by the late Dr. Warren Jones (University of Arizona). He and Mary Rose Duffield published a book called “Trees for Dry Climates” in the 1980’s that talked about this water saving design technique now renamed hydrozoning. I “borrowed” this picture from Sunset Magazine many years ago. Thanks Sunset! A. Telling you to water longer rather than more often, I am telling you what to strive for, what’s best for the plants, your condo community and your landscape. There is no “quick fix” to use when irrigating that solves this problem without making major changes to the landscape and irrigation system. This is a “birds-eye view” of the same landscape in Tucson. Thanks again, Sunset!             I am very confident your condo community could have an eye appealing landscape that could save water and energy while not using more than about 2 to 3 feet of water applied to your landscape per year. Lawns use between 6 and 8 feet of water per year, 200 to 400% more. This shows an irrigation layout for a minioasis design. The valves are isolated to three different watering zones; high, medium and low. This is how water is conserved while still making life comfortable in our hot desert climate. I am indebted to you, Sunset!             Landscape water use should aim for between 650,000 to 975,000 gallons per acre per year. Some areas of the landscape, where people are active, are more intensively planted and use more water while other areas use less but the average should fall between these numbers.             If you are currently using an amount of water that is close to this and happy with how your landscape looks and performs, then do nothing. You are doing a very good job in managing exterior water use.             But if landscape water usage is considerably higher than this, then consider re-landscaping the common areas. This can be done in stages so the upfront cost is manageable.              Most likely the irrigation strategy used now in your condo community is giving landscape plants many small “sips” of water rather than large gulps. It is not ideal but if it’s working for you, and not cost-effective to make changes, then keep everything the same.             Plant replacements should be planted during the coolest times of the year and not during the heat. Designate someone to water these plants with a hose about every 3 days after they are planted. After new growth has begun, they can be turned over to the irrigation system.             Seldom are there noticeable problems from watering plants with too much water unless the applications are excessive. Excessive watering causes plans to yellow and died during the heat.             However, problems you MIGHT see irrigating daily with tiny sips of water include plant leaves scorching, plants dying back, large trees that blow over in strong winds and excessively high water bills.

Q. My peach tree produces copious amounts of fruit but they have a bitter taste year after year. What can be done to sweeten the fruit? Genetic dwarf or “Miniature” peach. These are NOT called semi-dwarf but are true genetic dwarf. They stay very small and commercial growers thought genetic dwarf trees would revolutionize the peach industry. They didn’t. The fruit quality was not nearly as good as they hoped. They are popular in home landscapes due to their size. A. This is a problem with the variety of peach you selected. Variety names are names like ‘Bonanza’ dwarf peach, ‘Elberta’ peach, ‘FlordaPrince’ peach or ‘MidPride’ peach. There is nothing you can do to the tree or the soil to improve fruit quality. If you are not happy with the quality of the fruit after 3 or 4 seasons, replace the tree. One of the Elberta type peaches. Popular in the desert as well as the humid eastern states.             If yours is a miniature peach, like ‘Bonanza’, a genetic dwarf tree, then this could be the root of the problem. Genetic dwarf or miniature peaches were never accepted by the commercial peach industry because of fruit quality. Donut peaches like this ‘Stark Saturn’ are a novelty peach in both yellow and subacide white flesh and very high sugar content when allowed to ripen on the tree. Performs very well in the desert with high sugar content.             Some years the quality of the fruit produced is better than other years but generally the fruit quality is subpar when compared to varieties of fruit grown on standard-sized trees such as ‘Elberta’ or ‘MidPride’. A favorite peach of mine because of its shocking red flowers in the spring and very good fruit flavor in the desert.             Choose a peach by its varietal name and find out what varieties are good ones for our desert climate. The variety of the peach is extremely important for good fruit quality. Some of these varieties are marketed as “semi-dwarf” because of their grafted rootstock. The quality of the fruit is still good regardless of the rootstock but stick with a reliable varietal name. Another personal favorite, an old timer, Indian Blood peach. A subacid peach with wonderful floral qualities, delicious fruit and shocking red flesh when left on the tree to ripen.             Fruit quality varies with variety and climate where it’s grown. Fruit tree varieties that taste delicious in Georgia may not have the same quality when grown in the Mojave Desert. This is also true vice versa. Another favorite and not because of its flavor but because it is so early. Hard to find a peach producing fruit in May, even before most apricots. But ‘Earlitreat’ variety does. Along with FlordaPrince and FlordaKing. Solid early producers for the desert with good flavor.             In hot climates, the usual problem is a lack of flavor because of low acidity even though the sugar content can be very high. Sugar only tastes sweet. The balance of different acids is what gives a peach flavor. I would replace this tree with a variety that has a history of good flavor in our climate. See my list of fruit trees for the Mojave Desert

Q. I have a hybrid Bermudagrass lawn with weed problems of clover, crabgrass and chickweed.  I sprayed the lawn in spring with a liquid weed killer using garden hose. Weeds loved it. I bought a spreadable product which can’t be applied during temperatures above the 80’s.  Is there anything that I can do before the fall?     Most high end golf courses like this one in the hot Mojave Desert climate uses hybrid bermudagrass as its base and overseeds with perennial ryegrass in the fall if the price of water permits it. Hybrid bermuda has been the grass of choice in hot climates because of its beauty and resilience. A. Hybrid Bermudagrass, if managed correctly, will have very few weeds as a residential lawn if mowed, fertilized and watered correctly. Mowing frequently at the proper height, applying high nitrogen fertilizers every 6 to 8 weeks and watering to keep it “perky” keeps most weeds at bay. Hybrid bermudagrass must be mowed frequently to encourage horizontal growth which is important for keeping weeds at bay. Frequent mowing creates shade on the soil which discourages weed growth. This is a Toro reel-type mower for mowing golf course fairways, greens and tees.             Mowing height depends on the variety of hybrid Bermudagrass. All of them should be mowed below one inch and a few of them grow best when cut at ½ inch or less. Frequent mowing at these heights encourages a thick, horizontal mat of grass that prevents these weeds.             Apply high nitrogen fertilizers every 6 to 8 weeks during its growing season, particularly in the summer months. Reduce the amount of fertilizer applied to the grass to between ½ to 3/4 of the recommended rate on the bag. Fertilizing with high nitrogen fertilizers and mowing frequently work well together to prevent weed growth. Ammonium sulfate is a conventional mineral fertilizer high in nitrogen which promotes leaf, stem growth and dark green color.             Irrigate during the early morning hours before sunup. Make sure to apply enough water to penetrate the soil 12 inches deep. You will be surprised at how many of these weeds will be eliminated through proper mowing, fertilizing and irrigation.             Weed control in Bermudagrass is more effective in the spring and fall when temperatures are cooler. Weeds are more resistant to weed killers when stressed by the heat. Weeds are more susceptible to weed killers during cooler months. Goosegrass looks very similar to crabgrass except for white radiating from the center when it is mowed. Pre-emergent weed killers must be applied about two months later to control goosegrass compared to crabgrass.             Make sure it is crabgrass and not goosegrass. They look very similar. Crabgrass control begins mid to the latter part of January. Goosegrass control begins 2 months later. Pre-emergent weed killers are applied to the lawn to kill seed as it germinates so these weed killers must be applied before the seed germinates or you’ll get no control. Follow label directions. Crabgrass doesn’t have this white center like goosegrass and it appears much earlier in the season. Weed control for crabgrass happens very early in the spring.             To control clover and chickweed use a liquid weed killer containing either MCPP, 2,4-D and dicamba OR MCPA, 2,4-D and triclopyr listed as ingredients on the label. Apply it either in combination with a fertilizer and applied with the drop spreader or liquid applied with a compressed air sprayer. Hoes-end applicators, in my opinion, do not do a very good job.             Do not apply water for 24 hours after an application. Mix a wetting agent with the spray to help it get inside the leaves. Read and follow label directions.