As I was walking my property, I was thinking about landscape maintenance contractors and what they should be doing when going from job to job. As I thought about it more, I realized it would be a good message to homeowners as well. Alcohol wipes are safe and easy way to sanitize pruners. Sanitize Pruning Equipment Tree and plant diseases like Sooty Canker and Fireblight and, who knows even though its not proven, Ash Decline. We know that many plant diseases are passed along from plant to plant and residence to residence by unsanitary equipment, hands and clothing. Sanitize your pruning equipment between residences. If you see a plant or tree that you are trimming and it doesn’t look right, SANITIZE any pruning equipment you use on it. Then educate your customer. Let them know you are doing it and why. Make it a difference between your company and another who doesn’t know or, worse yet, doesn’t care! BTW, most tree diseases are spread when the tree is actively growing so a good time to prune is during the winter months. ALWAYS sanitize your tools when plants are growing. Sanitize Mowers Besides lawn diseases, lawn weeds can be passed on from property to property on unclean mowers. Everyone is using a mulching mower now but they still need to be cleaned, particularly when a disease is active. Our lawn diseases are mostly “hot weather diseases” like Summer Blight. Many of our worst weeds I hear complaints about are “winter weeds” like Poa annua. Spreading lawn diseases and weeds lasts 12 months long. Ask to use your customers hose and wash mowers between jobs, Turn the mower over and spray the blade with a sanitizer before the next job. Handling Your Boss More money is a good incentive. Instead of being the “tree hugger” or “plant person” on a job, use the money angle. Charge a little more for the work you do. Or tell them it will reduce costs. It costs a bit more to sanitize your tools and equipment but your customers will pay for it. As I always tell my students, “Pursue the HIGHEST dollar you can get, not the LOWEST!” Charge for your time and let the customer know you are doing something about the spread of plant diseases and weeds.

Q. I found your blog, Xtremehorticulture of the Desert, and hoping you can tell me if my tree is a Bay Laurel or not. I looked at pictures of Carolina Cherry trees that look similar. This tree has supports which I know need to be removed at some point. The tree was planted by my builder in February of last year. Bay Laurel just after we pruned it A. Looks like Bay Laurel to me. Bay Laurel is a Mediterranean tree and more tolerant of our desert climate than Carolina Cherry Laurel. Carolina Cherry Laurel is native to the southeastern US and not tolerant of desert conditions without proper site selection, soil preparation and watering. Carolina cherry laurel is native to the SE United States so it struggles when planted in hot locations with inhospitable soil. This one is suffering from iron chlorosis.             One easy way to tell the difference is to crush the leaves and smell the herbal (Bay) aroma.  Bay Laurel leaves have a pungent aroma. When you crush the leaves of Carolina Cherry Laurel they have an aroma of maraschino cherries rather than herbal.             The second way is to look for round “glands” at the base of the Carolina CherryLaurel leaf where the leaf is attached to the petiole (leaf stem). These “glands” are characteristic of many plants in its genus (Prunus) like plums, cherry, peach, etc.             In 98% of the cases, the “supports” or stakes should be removed after one growing season. There are a few cases when the trees do not establish rapidly due to grower mismanagement or poor planting practices and need support longer than this.

Q. The bottom layer of my palm fronds turned an orange – yellow color almost overnight. Is this from too much water or not enough water? Palm fronds may turn orange before they become yellow or brown and then die. Its your signal to prune. A. Neither. The cause of these fronds turning orange or yellow is natural. These orange and yellow colors are already there, masked by the strong green color that the chlorophyll provides. We see the same color changes with “Fall color”. Canary Island Date Palm with lower fronds dying naturally.             The bottom layer of fronds die naturally. As these lower fronds approach death due to old age and shade, some of the minerals in the leaves are absorbed back into the palm, first turning the lower fronds orange or yellow and eventually brown. Sometimes these color changes occur quickly and other times more slowly. How fast depends on how hot it is. Fan palm with brown lower fronds in need of pruning and removal.             The nitrogen, phosphorus and potassium move out of the frond first followed by magnesium, chlorine, zinc and molybdenum. Lesser mobile nutrients are left behind which include sulfur, iron, boron, and copper. These mineral “remainers” dominate the content of palm fronds. This color change is your signal to cut and remove palm fronds.

            I had reports sent to me about peach trees with yellow leaves on a single branch. You might see this on other fruit trees such as apple as well. For those of you lucky enough to have this condition on your fruit tree then this may be an indicator of a borer problem that needs treatment now. Let us talk about what else to look for to confirm it and what to do. Borer problem on the limb of a three year old peach tree.             Notice I said, “yellow leaves on a single branch”. This is important because borers usually lay their eggs on a single branch, not all over the entire tree. The only exception is if your fruit tree is newly planted or less than two or maybe three years old. In this case, the borers may find the trunk of the tree enticing for egg laying and kill the entire tree outright. Usually borer damage is in full sun, on the south or west sides of the trunk. Jelly-like sap oozing from the trunk or limb of a susceptible tree after a rain is a pretty good tell-tale indicator of borers.              Look for sun or borer damage to the limb with yellow leaves on its upper surface. Borers seldom affect the shaded sides of branches or on the north or east sides. Borer damage to a newly planted tree can be lethal because the tree is so small.             What to do? Buy an insecticide that contains imidacloprid listed in the active ingredients on the label.  Follow the label directions for a “soil drench” applied around the base of the tree where water is applied. You would do this now but I would treat the tree as a non-edible for the next 12 months even if the label permits its use on fruit trees.             I have had some luck using a sharpened, sanitized knife without an applied insecticide. The knife is typically 6 to 8 inches long with a good-sized blade for removing the damaged bark. The damaged area is skinned away from the limb until fresh wood, not damaged by the borer, is seen. The damaged area cut away by the knife is only about ¼ inch deep. This cut area is not treated in any way but allowed to heal on its own. I have had some luck using a clean knife and eliminating borer neighborhoods. I have no research to back it up but it seems to work sometimes.

Q. We have three Japanese Blueberry trees in our yard: two in the back and one in the front.  All three have dead branches that snap off when you bend them.  Yet there are scattered green leaves above the dead branches and far more green leaves at the bottoms of the three plants. Is it possible this is due to lack of water?  They were all planted about 4 1/2 years ago.   Some plants will die back and regrow from its base. This can be due to a lack of water or sunburn in high light intensity environments. A. Sounds about right. Sounds like the trees went through a dry spell and then regrew. Oftentimes when trees come back from drought they sucker from the base. But some trees like oleander (grown as a tree, not a bush) will sucker from its base naturally because it wants to be a shrub. If the drought lasts quite awhile, the top can also die back. There are trees that sucker from the base naturally, but this tree shouldn’t unless it was stressed. Japanese blueberry struggling in our hot, dry desert climate.             Whatever caused the stress (you are guessing maybe a lack of water) suckers grew from the base of the tree. The top may have “fried” during the drought, and then grew leaves again, from leaf buds on the stem, when water was reapplied.             You are aware that Japanese Blueberry is not a great choice for desert climates. It is not a “desert adapted” tree. Does great in coastal California but not the desert. Make sure the trees are planted in the mildest microclimate you have (probably east or north side of your home), the soil was amended at the time of planting, water applied under the canopy 18 inches deep and the top of the soil covered with woodchips and not rock. Get free woodchips and load them in plastic bags, a car or a pickup truck. Call the Master Gardener helpline at 702-257-5555, M-F,  and see if any are available and where.

Q. How often should I water my trees and shrubs with all this heat. The weather got hot so quickly, I’m not sure when to water. I have a California Pepper Tree, two big palm trees and five Japanese boxwood shrubs. California pepper tree that was planted too close to cement and so lifted it with its roots. A. First off, don’t violate your water purveyors watering directions. These policies are in place to coordinate community water use and lower the costs of supplying water to end users like you. If you live in Las Vegas you can see it here.             All the plants you mentioned are called “mesic” plants and require more frequent irrigation compared to (xeric) desert plants. The amount of applied water depends on the size of the plant. As plants get larger, more water is applied to a larger area (even though the water wets the same depth of soil) under the plants canopy. Watering cacti too often can contribute to fast growth and so much succulence it cant stand up against its own weight.             Apply water to all the area under the plants canopy. This advice might be difficult to do with larger trees like your California Pepper, so apply water to at least half the area under a plants canopy when they are big. This way they won’t blow over as easily during a windstorm. Watering frequently near the base of a plant can cause it to lose support during a windstorm.             Lawns, annual flowerbeds and raised beds for annual vegetables require daily, or near daily, applications of water. Sometimes they need water twice a day. These plants should receive water that wets the soil to a depth of about six to 10 inches with each watering. A piece of rebar can be used to judge how many minutes to water. Rebar pushes easily into wet soil.             Shrubs and patio trees should be watered to a depth of 18 inches. Medium sized trees around 30 feet tall should receive enough water to wet the soil to a depth of 24 inches. Large trees need the soil wet to a depth of 36 inches after an irrigation.             How to know if the applied water went deep enough? Use a straight, 4-foot-long steel rebar and push it into the soil after an irrigation. It stops going deeper where the water stops.             How to water deeper with the same number of minutes? Add more drip emitters under the plant.

Q. I recently harvested my garlic crop, wrapped it in burlap, and hung it up to dry.  How long should I let it dry in the Vegas heat? Last year I let it go for over a month and the bulbs got mushy. Freshly harvested garlic. A. If the bulbs got mushy then it was harvested too early or the bulbs stayed too wet. In our climate, don’t wrap garlic in burlap but dry it in the shade instead. I never had problems drying garlic. I leave the tops attached, bunch them together and hang them in the shade. Chesnok Red garlic hanging in the shade to finish drying.             To me, this seems a bit early to harvest garlic. My garlic was harvested in late May or June when the tops had dried back about 1/3 in the field. It is hard to tell without seeing them, but the bulbs should be fully developed when harvesting. Browning of the tops is a way to know if they are starting to mature or not. If you let the tops all turn brown then the “paper” wrapping around the bulbs will get damaged. Polish White garlic growing in North Las Vegas.             Garlic is planted in the Fall and harvested in early to mid-summer after the bulbs have formed. Shake the soil from the plants when you harvest, don’t wash them. I grew about 25 varieties of garlic and they all did well here. This is a good climate for garlic. So, keep an eye on the plants and harvest them when they are fully formed on their own and dry them in the shade.

Q. I have a 2-year old Flavor Supreme pluot and a four-year old Flavor King pluot. Recently my Santa Rosa plum (their pollinator) died from borers. The Flavor Supreme had only a few fruit while the Flavor King was loaded. Do I need to plant a plum tree to pollinate the Flavor Supreme? Or does it have a small number of fruit because it is only 2 years old?  Ripe Santa Rosa plum ready for picking. A. Flavor Supreme pluot has wonderful fruit but its production is sketchy because of spring freezes. So most likely the tree was thinned of some fruit by some late spring freezes. Plus, its only two years old! Some years Flavor Supreme may get no fruit even though it flowers because of a freeze. This is less likely to happen with Flavor King. Flavor King pluot. Has a lot of plum in its genetics.             Santa Rosa plum produces good soft fruit in our climate and is a good pollinator for most pluots. Flavor Supreme is a pollinator for Flavor King pluot as well. Throw Dapple Dandy pluot in that group as well. But pluots will still produce fruit without a Santa Rosa plum or pluot in your yard. Just possibly a lighter crop. If a neighbor has a Santa Rosa plum or Dapple Dandy pluot then it is to your benefit. Flavor Supreme pluot

            I am getting quite a few emails about cacti dying, particularly agave. Some are guessing the culprits are ants, diseases and other readers appear to be stumped. American Agave can die in about May of any year. Agave Weevil             The culprit is the agave weevil that lays its eggs at the base of agave leaves. As their young-uns hatch from the eggs, they burrow into the stem of the agave and all through it including the roots. The plant rots and dies from all the damage done usually in late April or May. We are seeing it now. A pesticide applied around its base in March, and lightly watered in, usually prevents the damage from getting worse. The other option is not to grow agave. Agave weevils can decimate agaves in May if left unchecked Drainage a Must             If you’ve never grown any cacti before, make sure the soil drains easily of water and that don’t water these plants too often. I have found a deep watering every three weeks is frequent enough to push new growth and get the plants larger. Know the Origin of Your Cactus  Some cacti are not meant for very hot locations because they come from milder climates. Photo taken at the LV Sorings Preserve. Some beautiful cacti and other succulents come from the hot, dry deserts of Central and North America. Make sure they are placed in full sun. Other cacti may come from milder, coastal or high-altitude desert climates and need protection from the intense Mojave Desert sun. Knowing where cacti come from empowers you and its landscape placement.

Q. I have a Mexican Bird of Paradise and ‘Sun Trumpet’ Tacoma plant growing close together. Both have deformed, dwarfed growth, and damaged leaves. The Bird of Paradise feels sticky as well. I tried sprays for insects, including Neem oil, and cut the plants down completely to have them grow back with the same issue. Other plants in the yard are doing fine. Any help is appreciated. Herbicides applied to the soil or on a hot windy day can result in damage to the leaves and stems of plants. Sometimes plant death. A. I don’t think these plants are facing a disease or insect problem.  Soil Contamination Possibly It is hard to say without guessing, but from your description it sounds like a soil contamination issue. Plant an ornamental grass and broadleaf plant in that area and see if you get the same response. If it were a cooler time of the year, I would tell you to germinate a seed mix with grasses and wildflowers in it. Brush Killer or Soil Sterilant             There may be a weed killer applied to this area and responsible for this problem. Some weed killers like dicamba, if applied at a heavy dose or used as a “brush killer”, can damage broadleaf plants like your Bird of Paradise and Tacoma and not hurt grasses. The high rate of this type of herbicide is why some weed killers are labeled as a “Brush Killer”. There are other weed killers sold as “Soil Sterilant” that can persist for years and kill most plants grown in that soil. Replace Soil or Change Plants             Some weed killers are difficult to remove by leaching with water. If the ornamental grass isn’t damaged but the broadleaf plants are, then either replace the soil in that area to a depth of about 12 inches deep or only grow ornamental grasses in that spot.