Q. I have an ornamental, purple leaf plum that’s producing fruit. My dog has been eating the fruit. Is it safe to eat? Purple leaf or flowering plum in a rock landscape A. The purple leaf plum used in landscaping was selected as a variant of a plum used in the orchard industry for many years. A similar plum that produces more fruit, Cherry Plum or Myrobalan plum, is grown for its tart fruit with a very high sugar content. Two varieties of this plum, Sprite and Delight, are personal favorites of mine. Another variant of this fruit tree is used as a rootstock for other plums. A very versatile plum! Cherry  plum or Myrobolan plum fruit tree Cherry plum fruit             The purple leaf plums (there are several different types) were selected for their leaf color and low fruit production but ornamental beauty. However, occasionally they do produce a fair amount of edible fruit. This fruit is good for making jams and jellies, adding to pies and pastries and flavoring gelato and juices but tart when eating fresh.

Q. Can you please advise me: where I can buy GOOD Roses to plant in my garden, in Las Vegas. All my roses are ab out 30 or so years old and I got them from Jackson+Perkins when they were still in Oregon! The one I bought 2 or so years ago from them, WERE DEAD ON ARRIVAL! And what I see in the nurseries her in Vegas, do not look good enough for all the work to plant them. Nevada Rose A. I know which roses are better roses and usually J&P are good ones. I like Weeks Roses but they are hard to find now I think since Plant World is no longer in business. Yes, you can have roses like this in the Mojave Desert. These are growing in Las Vegas! Maybe some Rosatians who read this post can answer. Jackson Perkins in the past had very good roses. They had award winners up until 2013 or so. They had a very good breeding program. The company has gone through several change of hands in the last decade plus so I don’t know anymore.  Please Don’t Do These Things to Roses Do more than sprinkle compost on top of rock around roses Don’t plant them surrounded by rock. Don’t prune and care for them like this. Weeks Roses Personally, I have always liked Weeks Roses. They are wholesalers so you cant buy directly from them but they sell to nurseries. They are higher priced so they are not common in the boxed stores but good nurseries that have a following from locals can afford to sell them. That group of loyal good gardeners is disappearing and the numbers dont support buying local anymore. Plant World Nursery on Charleston, used to carry them because the Las Vegas Valley Rose Society asked them to. Plant World Nursery is replaced now and that association is gone.Their website has lots of good information or general rose care. There is a list of roses they update for different climates. In the Mojave Desert we would select from the Hot and Dry List that you can find below: Click here for Weeks Roses Hot and Dry List of Roses I don’t know where to tell you to go locally. Just buy one that has good form. Watch a video I uploaded from Weeks Roses home page for those of you not terribly computer savvy. Otherwise, please visit them and browse their catalog online.  Remember, roses do well for 8 months of the year in the Mojave Desert. Be sure to plant them properly and cover the soil around them with woodchip mulch. Watch this video on Weeks Roses Home Page but for those of you not terribly computer savvy here it is. Thanks Weeks Roses! https://www.weeksroses.com/

Q. Can you help me identify what is causing Mesquite trees to stress? I have attached photos here on this email. There’s sap releasing from previous cuttings, but there has been more die back from the top (side of the south) at a faster rate, any clue what is happening? Mesquite tree dieback mentioned in the question. See how helpful good pics can be? A. Thanks for the detailed pictures. That helps. The second picture you sent clearly shows where the mesquite tree was pruned (actually it was a very bad pruning job called “topping”). The tree grew vigorously from these cuts and then this new growth died. Nothing Common Nothing I could find has been observed in mesquite like this in the past. We are going to have to start making some educated guesses. Because it is in the new growth and seems to be very closely associated with growth from previous pruning cuts, I would guess it is what we call “a vascular disease” that plugs up the water carrying vessels from the roots that travel up the trunk and through the limbs.  Maybe Unsanitized Pruning Tools My second guess is that it MIGHT have been carried to this tree through the pruning tools. This could be particularly true if the pruning tools were not sanitized before pruning. The most common reasons trees are pruned is to remove dead or dying limbs. If these limbs were infected with a disease, it is possible to take them from an infected tree and pass them off to an uninfected tree. Development of the disease takes time. But if it was an aggressive disease this could happen in a season. If not terribly aggressive, two or more seasons. This kind of problem sometimes causes sap “bubbles” to form on limbs. I call it “stress related”. What to do?  Cut the infected plant parts out of the tree using a sanitized chainsaw. Remove at least 12 inches of wood below where the infection started. Disinfect after every cut so that it is not spread to other locations. Another possibility is borer damage. Less likely but possible. If this is the case, do the same and disinfect just in case.

Viragrow: Better Mulch Than Woodchips around Vegetables Is A…: Q. I use woodchips around my vegetables, fruit trees and landscape plants. When I turn it over after the first freeze, what should I add …

Q. We have a serious nutgrass problem. You recommended Sledgehammer herbicide to control it. I’ve been online looking to purchase it but I keep getting directed to “Sedgehammer” products. Are they one in the same and did you just get the name wrong? This is a young not dress plant. It looks like a grass but it’s not. It’s a sedge and very difficult to control. It’s missing the nut which was dislodged in the soil when it was pulled from the ground A. Nutgrass is not really a grass at all but a sedge. Sedge usually has a way of regenerating itself when it dies and nutgrass was no exception. It’s called “nutgrass” because of the underground “nut” that remains in the soil if the top was pulled off or killed. This is nutgrass found growing in the tropics, Philippines             Hold on. I will get to your question in a second.             Killing the top of the plant is easy. It could be killed with several types of weed killers, burned off with a fire weeder or removed with a hoe. But the underground nut causes a new plant to grow in its place.             Usually not just one plant but two would regenerate from the nut to replace the one that was killed. With only those methods available, the only thing that works is to continually destroy the tops repeatedly until the nut is starved and gone. This is the nut attached to nutgrass that causes all the problems of regrowth when it is pulled from the ground orders burned back with fire or chemicals.             This works but required diligence. If you let the top grow back it would rebuild the nut and you have to start all over. But nutgrass in lawns was still a huge problem because these methods also damage lawn grasses.             I worked with a chemical weed killer found to control nutgrass in lawns, without damaging lawn grasses, during the 1990’s. This weedkiller was different than others because it killed the nut but had no effect on lawn grasses. It was given the name “Manage” by the manufacturer. The rights were later sold to a different company but the name changed to “Sledghammer”. Same product but a different name. Order it from Walmart Order it from do my own pest control             Repeat applications are needed when using Sledgehammer herbicide because not all the nuts are killed. The tops die but a few of the nuts survive and send up a new plant. Reapplication timing of the chemical is critical or the nut will re-establish.             You MUST reapply it when the new growth from nuts is young, about the four-leaf stage, or it will re-establish. If diligent, slowly you will extinguish the nuts and keep them from re-growing.             I see it is available from Walmart and Domyown Pest Control online. Try entering sledgehammer AND nutgrass AND weed killer in your online search engine.

Q. I have several heavenly bamboo that are well established in my yard. I recently noticed a lack of robust growth and signs of disease or pests or maybe both. I sent you some pictures. What do you think? Leaf discoloration, marginal burning of heavenly bamboo aka Nandina, not a true bamboo. This damage looks more like nutrient related but it could also be from water, too much or too little, or possibly salts. But this plan likes richer soils so I would dump some compost around the base of it and work it in. This is different from the other pictures. It is probably not related to plant nutrients but it looks more like damage from thrips. A. Heavenly bamboo, aka Nandina, is not a bamboo and not even closely related to it. It sort-of looks like a bamboo, hence its name. It comes from places where the soils have organics in them naturally. Not from deserts and it does not grow well in desert soils.             In warmer climates it may keep its leaves during the winter. Usually not in Las Vegas. It drops its leaves due to leaf damage from winter cold. When heavenly bamboo is surrounded by rock it usually turns yellow due to iron chlorosis. Heavenly bamboo does not come from soils like this so the problem is the rock mulch around them.             Heavenly bamboo DOES NOT like desert soils unless organics like compost is added to it and the soil kept moist. So rock mulch and planting in a desert landscape with cacti is a no-no. Might work for the first couple of years and then they slowly turn yellow, scorch, decline in health, drop their leaves and look bad.             The discoloration of the leaves, brown edges and yellowing, is probably related to the soil degrading and losing its organics over time. My guess, it has gotten progressively worse over the years. The primary problem with this Nandina is a lack of soil improvement and in proper pruning. If this plant were pruned correctly and organics were added to the soil such as compost it would not be in its current condition             Heavenly bamboo comes from Eastern Asia where soils are rich and not “deserty”. When surrounded by rock, Nandina declines in appearance and its health takes a dive over time. Nandina looks good after planting because of stored food supplies inside the plant and amendments added to the soil. But these both disappear in a few years.             There does seem to be insect damage to the leaves, possibly by thrips. Thrips are very tiny insects that can fly only well enough to travel a few inches. Flower thrips like to feed on soft flower petals and other thrips on new, emerging leaves.             Leaf damage to Nandina by thrips is a first for me in the desert so I had to do some digging in references. Fresh damage appears as “water soaked” areas. Later on these areas dry out and scarring or obvious surface damage appears as tiny brown or white spots on leaves. Western flower thrips, even though they are very tiny, cause problems like this scarring from their feeding on young nectarine fruit.             If there is rock surrounding them, rake it back and work some compost into the soil surface as deep as you can and water it in. Replace the rock on the soil surface with woodchips. Water enough in one day so you can skip at least s day in the summer and more when its cooler.             Organic sprays such as Spinosad do a good job controlling thrips. Read the label.

Q. I have a fruit tree with leaves that are brown on the edges and a dust that covers the leaves. Some of the leaves are turning gray green on branches and the tree does not look healthy. Spider mites our famous for causing damage to Italian cypress. They cause Browning and branch death, usually there is webbing seen as well. That’s why these critters are called “spider” mites. But they are more closely related to spiders than they are insects.It’s always a good idea to wash off Italian cypress with a hose when they get dusty. A. Most likely the tree damage was caused by spider mites. Spider mites are a summer pest problem during hot, dry weather.             Another telltale sign that you mentioned is the “dusty” appearance of the leaves. This “dust” results from dead spider mites left behind as the population grows.             Look for feeding damage to the leaves caused by spider mites. This feeding damage causes tiny yellow dots scattered all over the surface of the leaf and accompanied by tiny black dots the size of this period. By the way, the tiny black dots is mite “poop”. Even though mites feed on leaf bottoms, the yellow dots can be seen on the top of leaves.             A common misconception is that webbing must be present if mites are the problem. Spider mites leave behind “webbing”, like the weak form of a spider’s web. But not all mites that cause plant damage spin webs. Leaf damage and webbing scene on tomatoes caused by spider mites.             So, finding webs when there is damage is not a “dead giveaway” that the damage is from mites. It could be one indicator, though. There are real spiders who are “good guys” that spin webs and hang out in plants. These spiders can be beneficial.             Mite attacks to plants may come after the application of a hard pesticide. Bad mites are always present on plants but their numbers are controlled by predatory insects and even “good mites”. So, applying a hard pesticide to control borers, for instance, could lead to an outbreak of spider mites because the predatory “good guys” were killed.             What can you do? Confirm that spider mites are the problem. Use a white paper test. Shake or slap an infested branch on a white piece of paper or paper plate. Closely look at the white surface for tiny dots, the size of a period, crawling along the paper.             Smear them with your fingers if you aren’t sure. If you see lots of them, along with plant damage that I described, you have confirmed mite damage.             Multiple applications of soap and water sprays do a good job getting small outbreaks under control. Hosing the leaves of plants monthly, or after a dust storm, removes dust from the leaf surface which can increase spider mite populations.             Severe infestations of spider mites may require a pesticide application. Whenever spider mites were problem during the year, be sure to apply two dormant oil sprays during the winter months.

Q. I have two Mexican fan palms in my backyard that are 16-18 feet tall. One is 3 feet from a retaining wall and 6 feet from a pool. Another is 3 feet from the corner of my house which is on a slab. Do I need to worry about the roots damaging the wall, pool or slab? Way too close for palms to be planted to a wall. A. The short answer is you should be concerned anytime something that can get large is growing close to anything that can be damaged. The good news is that palm roots don’t typically damage walls, swimming pools and concrete slabs as much as other types of tree roots. But they can cause damage.             Palms in general are not a good choice around pools but Mexican fan palms get huge and should never be planted close to structures. Smaller palms, such as windmill and Mediterranean fan palm, would be a better choice. The closest large fan palms should be planted to walls, swimming pools and house slabs are perhaps 10 feet away. Palms look beautiful near a pool but they can cause problems and very messy when they drop seed.             There are a couple of options if you don’t want to remove these palms. One is installing a root barrier so that palm roots are deflected away from structures that could be damaged. Root barriers are installed and extend about 30 inches deep or more and reside slightly above soil level.             The second option is to use water for directing root growth. In deserts soils are normally dry due to a lack of rain. Tree roots grow where water is available. By placing irrigation water away from walls, cool decking or a house foundation we can direct tree root growth away from these potential problem areas.             Water does not need to be applied evenly under plant canopies. I recommend keeping water 2 – 3 feet away from these potential problem areas.

Q. My Italian cypress started to lose their color and then die. Upon inspection of the trunk, I saw borers in them. Borers seemed to take place within two months or so and killed a few mature trees. I treated them with Bayer Tree and Shrub Insect Control but wanted to know if there is anything else I can do to help save them. Borer damage found in Italian cypress trunk Bora damage found in another Italian cypress trunk Suspected board damage found in Italian Cypress A. Damage from borers or boring insects is typically a slower progression than a couple of months unless the plants are small. You are right, the progression in many plants is a change in color from a vibrant green to a dull, gray green color as the limb and leaves are dying from a lack of water.             My guess is borer damage to your trees started before this year. Internal damage to the trunk from borers can be present for several years before enough damage has accumulated to result in the death of older trees. If trees are growing vigorously, they can recover from light borer damage on an annual basis.             This color change due to damage starts in midsummer when air temperatures begin to heat up and plants require more water. Damage from boring insects begins in mid-spring (March) but get progressively more intense as these insects become larger and more voracious feeders.  By midsummer (June and later) internal damage to limbs and the trunk can be extensive, unrecoverable by the plant, and the supply of water from the roots is cut off. Homeowners have this product available for borer control containing Imidacloprid in the active ingredients. It comes in other names as well. It is always best to check the active ingredients to make sure. Apply it late spring after any flowering has occured to avaid possible problems with honeybees. This chemical has been implicated, not proven, in colony collapse of honeybees. The safest way to apply it in our environment is a soil drench. Always read the label before applying any chemical.             You chose the correct insecticide to use but it was probably applied too late. The best time to control boring insects with these types of insecticides is in mid spring when they first become active.             Consider using pesticides as a last resort because they can be a bit like “whack-a-mole” and contribute to other pest problems. Death of boring insects can happen in a few days when systemic insecticides are applied as a liquid drench to the soil.

Q. I have a ‘Green Gage’ plum tree that is 18 years old and produces plenty of plums each year. In August I saw sap coming out of one branch and along the trunk in several places.  Last week the bark started to separate and it looks like the trunk is starting to split. The leaves on that limb are starting to die. This side of the tree receives the west sun. All the other branches on the tree appear to be fine. A. Green Gauge is a good plum for our desert climate and 18 is not old for a plum tree. Plums can be “sappy” compared to other fruit trees but from your description it sure sounds like borers. You won’t hurt anything, but I would take a very sharp knife that has been sanitized and start actively looking for borers.             It is possible to remove the outer layer of bark covering the trunk and limbs and reveal the immature form of this insect, called the larva, causing the damage. Once exposed like this, it will die.             Expose all the damage caused by borers down to healthy wood. Leave this exposed area open for healing.  I would say that about 80% of the time this is an effective way to remove the borer and allow the limb to recover. What I Would Do I would first remove some bark on top of the area where I think borers might be residing. Hold the sharp knife nearly flat and push the blade away from you to remove the bark. After removal, inspect the wood to see if it is alive or dead. If it is alive, stop and don’t do anything more. If it is dead, remove all of this dead bark until you see bark that is alive. If you find evidence of borers, try to find them in this dead area and remove them. If the borer damage is extensive it might require removal of the limb or branch. Do not paint this area but let it heal in the open air. Using a sharp, sanitized knife to remove the bark that surrounds a borer infested limb. Removal of the dead wood caused by borers Successful removal of borers the previous year and the tree showing signs of healing.