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.

Q. I applied Bonide Tree and Shrub insect control for borers and miners about six weeks ago. Now my plants are growing weird and possibly dying. Once I saw this problem, I sprayed for diseases and then today for insects. What is going on? Picture not available A. The damage to the plant was probably weed killer (herbicide) damage judging from the distorted leaves and dieback. There is not much to do at this point except spray the foliage with water, irrigate, and make sure the plants were fertilized in the spring, so they are in their best health to recover as quickly as possible. Then wait and see what happens. There is no magic cure at this point except being patient for three or four weeks.             Let’s cover some reasons why this might happen so it might be prevented in the future. The damage could have originated from you or your neighbors. This type of damage is a common occurrence during the spring and the fall months because these are the most effective times to apply weed killers. Sprayer Not Rinsed             First, never use a sprayer or spray bottle that contained weed killers to spray insects or diseases. You should have two separate sprayers or bottles; one clearly marked and used for “Weed Killers”. Weed killers are extremely difficult to clean from a sprayer or spray bottle once it’s been used for that purpose. If there is some weed killer residue that remains after washing, then voilà, you just damaged plants that you sprayed for controlling insects and diseases! Spray Drift             Secondly, you or your neighbors should never spray weed killers when there is wind. If you must use a weed killer, look at the tallest trees in the neighborhood and see if their leaves are moving. If they are, do not spray weed killers. The best time to spray weed killers is early in the morning before the wind has kicked up and it starts to get warm. Heat             The word “warm” takes me to the third rule; never spray a warm surface or when air temperatures are warm or hot. Landscape rock mulch heats up quickly as soon as the sun comes up. On a warm day, these surfaces reach 150°F or more by 9 AM on a sunny spring day. When weed killers are sprayed on hot surfaces, they volatilize and move to the neighbor’s yard with the gentlest air movement and can cause plant damage.

Q. I am growing hot peppers in big plastic pots with soil for vegetables I bought from a local nursery. The plants grow fine but the blossoms dry out and fall off without setting any peppers. They get plenty of water, not too much, and the bottom of the pots are drilled out for drainage. Soil mixes like this Rejuvenate Soil Mix should have quite a bit of compost mixed in it for growing vegetables. A. Growing plants in pots is difficult in the hot desert. The major problem is overheating of the soil. The side of the container facing the sun can reach 170° F and kill half the roots inside. Losing half the roots of a plant can be quite stressful and cause flower drop. You can kill a lot of roots with a bad soil mix, poor drainage and watering too often, but it doesn’t sound like that’s what’s happening. Five gallon nursery containers are big enough if you water early in the morning and they are on the east side.  Make sure the container is large enough. Five-gallon nursery containers are large enough if plants are watered daily, sometimes twice a day when it’s hot, and the soil stays cool. I have had luck with this size container growing vegetables and herbs if on the east side of a building so the container is shaded in the afternoons. Containers may be shaded by other containers or a vegetable bed. But larger, 15-gallon containers work better. A single cabbage growing in a five gallon nursery container             Water just before the container gets hot. Moist soil is harder to heat up than drier soil. This is because the water in the soil absorbs heat. I will usually water between 7 and 9 AM.             Double pot the container. Putting the growing container inside an outer, more decorative container shades the inside container and protects plant roots. This is called “double potting” or “pot-in-pot” container growing. If the containers are the same size and shape, put a layer of pea gravel 2 inches deep in the bottom of the outside container so they don’t lodge.             Plants grown in the double containers for more than one growing season should be twisted a half turn every month to break off roots growing through the container into the ground.

Q. I have an Ocotillo plant that is now sprouting beautiful flowers and leaves. I have been watering it with a mist spray near the top. Now that it is in full foliage can I turn of the mist and just water at the base once a week? Ocotillo and myoporum went through a rough winter in 2013. This was probably January after a good freeze. A. I have never been a big fan of misting plants like Saguaro, Joshua Tree or Ocotillo. It doesn’t hurt anything, but personally I think it’s a waste of time. The effects of misting last less than 10 minutes in the desert. Ocotillo stem cuttings will grow roots in soil that drains without any misting if they are watered regularly in the spring. Ocotillo growing in the Sonoran Desert. Although not found in the Mojave Desert, Ocotillo can be found on the edge of the Sonoran and Mojave Deserts nor far from the Colorado River.             Now that the leaves are out, turn over the watering to the roots. If it is newly planted, moisten the soil each time you water close to the trunk or stem. A basin or donut constructed around the trunk helps contain the water. Fill the level basin with 1 to 2 inches of water each time you water. Remember, these are desert plants so don’t water them as often as non-desert plants. If you do, you can kill them. A good sized Ocotillo growing at a Las Vegas residence.             In about one month, increase the size of the basin or apply the water over a larger area to encourage the roots to grow further distances from the trunk. Watch the growth of your plant. Adjust your watering intervals to encourage or discourage growth.