Q. When using soap and water for controlling insects, what do you use? A. I use an unscented organic castile soap used as a baby shampoo that has been certified organic by one of the certifying bodies for the USDA and its Certified Organic program.  This organic castile soap I use is available from Amazon It is relatively expensive compared with a liquid dish soap. I just figured if it is certified as organic and used as a baby shampoo it should be safe to use. I use three tablespoons of it mixed in a gallon of water as recommended by Clemson University.             Another good way is to use one of the commercial brands of insecticidal soap sprays for plants like Safers. These insecticidal soaps (yes, if it is used to kill insects it is technically an insecticide) are, hopefully, formulated with a decent soap or detergent that kills insects while keeping contaminants at a minimum and still safe for plants. For this reason, I use unscented soaps with no other additives like hand lotions.             Laundry detergents are a no-no. They are too harsh on most plants.             There is a misconception by some that these types of sprays are all around “safe” to use. We need to still treat these types of sprays with respect when using them. They are meant to kill any insect that is sprayed but once sprayed don’t stay long in the environment. Some soaps made from yucca extracts (Grow More’s EZ Wet for instance) and can be sprayed the same day as vegetables, herbs or flowers are harvested since it is also used to clean vegetables before they are sold.  EZ Wet is an yucca extract made for washing fruits and vegetables prior to selling (commercially) but can be used as a wetting agent or insecticidal soap. I get it from Viragrow in North Las Vegas, NV. These insecticidal soaps have no “residual” killing power like most traditional insecticides. For this reason, they must be sprayed more often.              Insecticidal soap sprays, the kind you buy or the kind you make, do affect plants. Most are harsh on plants like portulaca, gardenias and Easter lilies. Spray a little of your formulation on a few leaves of the infested plant to find out. Soap sprays remove some of the waxy layer on leaves while they also remove waxy layers from insects so they dry out faster. Sometimes it may suffocate them.             But soap sprays must be sprayed directly on insect pests to work well and these types of sprays do not kill only bad bugs. If good bugs are in the way, it will kill them as well.

Its all about WHEN to do things in growing vegetables in the Desert. Learn why.

Italian cypress can turn brown for several reasons; how its watered, the type of soil its planted in, spider mites during summer months and borers…yes, borers. Italian cypress Italian cypress is a tree native to Mediterranean climates along the northern coastal areas of Africa, the Middle East, Greece, Turkey, Montenegro, and southern Europe. This plant grows in climates that are cool and wet in the winter and hot and dry in the summer. In the US the describes the coastal areas of southern California. It is NOT a desert plant…but it will grow there. Selections of the tree chosen for landscapes can grow to 60 feet tall and 4 to 8 feet wide. It is propagated easily from seed but varieties like ‘Glauca’ are propagated by hardwood cuttings taken in late winter or early spring. These varieties were selected for some outstanding traits that could be marketed to residential and commercial landscapes. This is a big tree. It should not be used around single story homes or commercial buildings. Its scale is for much larger residences, resorts or commercial buildings. But many homeowners select them because they are evergreen and can provide some visual privacy, not good for noise abatement. Italian cypress can turn brown. The main reasons are the watering practices and soil type, spider mite feeding damage and borers. What? Borers? You heard it here first. Soil The soil it is planted into MUST drain water or it will die. Root rot is a common problem with this tree if it is planted in soils that have lots of clay or don’t drain water. Make sure your soil drains! Irrigation and Root Rot This tree came from climates with cool wet winters and hot dry summers so don’t water too often! Put it on a valve that waters palms, fruit trees, other landscape trees and shrubs but not with lawns, flower beds or vegetable beds. It will not like it if it is watered with the same frequency as cacti and native desert trees like palo verde and mesquite unless they are watered too often! Italian cypress with drooping branches is a sign it is getting too much water. Either it is watered too often or the soil is not draining water fast enough. Enough water should be applied each time to wet the soil to at least two to two and one half feet deep. The amount to apply varies because of the soil so you will have to play around with the number and size of the emitters. But when you apply water, it should wet the area under the canopy out to the ends of the branches. Normally I will tell people AT LEAST half the area but these trees are narrow and upright so water the entire area. Spider Mites Early stages of spider mite infestation and browning. Spider mites are always there on Italian cypress. Count on it. They become a problem when it is hot, during the summer months, and the natural mites and insects that pursue and eat them are eliminated or interfered with. This can happen right a few days or weeks after an insect spray was applied or they get dusty. The insecticide kills off the good guys so spider mite populations explode in numbers.  Or dust on the leaves and branches run interference with the good guys and block them from finding the spider mites. This is like a slow leak and their numbers don’t explode like after an insecticide application but their numbers go out of control more slowly. Mite damage is not always accompanied by webbing but it can be a hint they might be there. Use the paper test to make sure. Some mites don’t spin webs.It can be an indicator they are there but don.t rely on it 100%. Use the paper test instead. Hold a white 81/2 x 11 piece of paper near the brown area and slap the browning branch against it a few times. Don’t pick a branch that’s been dead for awhile but one that is browning or recently died. Pick one with webbing in it if you want to check it. After slapping the white paper hold it still and look for little crawlies on the paper the size of this period “.” Very small. Are the small dots moving on the paper? Do they smear on the paper if you brush your fingers against the paper? If those “periods” are moving, they smear and your plant is turning brown, it has spider mites. What To Do About Spider Mites? Wash the tree from dust after dust storms. You may need a power washer. Don’t plant them near dirt roads that allow vehicles to kick up the dirt and make them dusty. This horticultural oil can be used to control spider mites when weather is cooler. Use insecticides as a last resort. Don’t apply insecticides as insurance unless there is a good reason for the application. If mites become a problem, you may need to use a miticide, not an insecticide. I use the University of California Integrated Pest Management  websites for recommendations on borer control. http://ipm.ucanr.edu/PMG/PESTNOTES/pn7405.html http://ipm.ucanr.edu/TOOLS/PNAI/pnaicompare.php?pn=7405&x=79&y=21 http://ipm.ucanr.edu/QT/spidermitescard.html Most of the insecticide recommendations are oils (e.g. Rosemary oil, Cinnamon oil, Clove oil, etc.) and should not be applied until weather cools in the fall or spring. Borers Borers were never reported to be a problem with Italian cypress. So I didn’t suspect borers until a few years ago when it was reported to me by a homeowner. I didn’t think it was true until he sent me pictures and confirmed it. They are a problem with other cypress so it makes sense. Borer damage in Italian cypress What To Do About Borers? If borers are confirmed to be a problem use the insecticide imidacloprid as the active ingredient as a soil drench. This insecticide has been implicated in colony collapse of honeybees and its use has been banned in several countries but not currently the US. Avoid

Italian cypress can turn brown in desert landscapes. Learn why and how to prevent or cure the problem.

This podcast will teach you how to correctly select, plant and care for roses in our hot Mojave Desert climate.

Listen to this podcast so you know how to protect your tender plants from freezing temps.

October 29 There are some freezing temperatures projected by the National Weather Service for the Las Vegas Valley over the next few nights. Temperatures may drop as low as 28F in some lower parts of the valley. What makes this worse is that landscape plants are not prepared for freezing temps. They need time to prepare and progressively lower temps help them to do this. Sudden freezes are the worst and cause the most damage! Where are the Possible Problem Areas? Any lower parts of the valley where cold air has no where to drain or if it does drain, it drains slowly. Think of water. Cold air settles into low spots or pockets. But we really dont know how cold it will get. The NWS is telling you this so you have time to prepare and they usually are very cautious in their predictions. This bougainvillea froze back at the peak of its beauty Wind Makes it Worse If this cold air is combined with wind in your spot it will make it worse. Wind can channel between buildings and picks up speed in those spots. Wind removes any heat that might linger around and helps drop temperatures to freezing. Skies with good cloud cover and no wind usually don’t allow freezing temps if there is a threat. Look at the sky and cloud cover before you go to bed. Cloud filled skies mean warmer temps on the ground. Cloudless skies mean a greater chance of freezing. Plants and Plant Parts That Might Freeze Bougainvillea, a tropical plant that loves the heat of the desert, will freeze at 32F. It just does. Other tropical plants that freeze like this are tomatoes, peppers, eggplant and most of the hot weather vegetables. Plants that still have flower buds may lose them. Flower buds are very sensitive to freezing temps. They are more susceptible to freezing temps as they get closer to opening. If you have plants like Camelias that are loaded with flower buds, they may drop. Citrus too. Make a mental note which plants have flower buds. Flower bud drop due to a light freeze and damage to the edges of new leaves are signs of a light freeze. Summer Fertilizing and Freezes Never, never, never apply nitrogen fertilizers to plants that are tender after August 1. Nitrogen fertilizers push tender new growth that is more susceptible to freezes than phosphorus and potassium. This includes compost! No compost applied to freeze tender plants after July 1. The fertilizers contained in compost are slow release and last longer so stop applying them earlier in the year to tender plants. Fertilizers with anything in the first number, nitrogen, should not be applied after August 1 to winter tender perennial plants. Vegetables are fine because you will pull those to plant Fall vegetables. Protect Tender Plants Covering the plants with a freeze blanket or crop cover gives you about 5 degrees of protection. Thats all. Temperatures may get as low as 28F so freeze blankets or crop covers will work provided cold air does not get inside. So fasten them to the ground tightly to prevent wind and cold air from entering the inside. Apply them  to plants when the ground is still warm in late afternoon. Don’t wait until night because you are relying on heat from the ground to get captured under the frost blanket. Crop covers or frost blankets give you about five degrees of protection.

Q. I really didn’t understand the “soil” here, did not dig large enough holes and didn’t amend the dirt when I planted my oleanders. It’s been 5 years and I’ve tried to correct their scrawny growth by adding plenty of mulch and fertilizing regularly but the growth continues to be weak.  Any suggestions how to encourage stronger growth? Its like backpedaling when you try to amend the soil after planting. Do it at the beginning and save yourself some grief and hard work. A. As a friend of mine would say, “Pay me now or pay me later.” At some point you will pay the price for good plant growth and modify the soil at planting time or later when it is more difficult. Amend Soil at Planting Time             Whether it is raw desert soil or imported “soil” brought into the development by the developer, soils in developments are typically horrible in the Las Vegas valley. Constructing planting holes at the very beginning and using amendments are extremely important for good plant growth. Its cheap insurance. Look at the size hole this guy dug for a 5 gallon mesquite tree. The brownish soil tells me it probably has 2% organic matter already but this mesquite tree will LOVE it. Just remember to mix the amended soil with native soil at the perimeter so there is no “hard edge” for roots to grow through. Oleanders like Wet Winters and Hot Dry Summers             Oleanders are Mediterranean plants. They grow well in a Mediterranean climate and soils but need some help when grown in the desert. The help is in the form of constructing a decent planting hole, using soil amendments that encourage good growth when the plant is young, and adding supplemental water. They love the heat and low humidity of our desert environment. Oleander is tough. If given enough water they can survive just about anywhere.             Now you have the job of amending the soil after it has been planted. Hopefully, your oleanders were planted with at least six hours of full sun every day. If not, prune any interfering trees so that they receive enough sunlight. Fixing Trees After Planting             Auger holes 12 inches deep around these plants so the holes occupy about half of the surface area. Fill these holes with a rich compost or make a rich compost by mixing a granular fertilizer like 16-16-16 with standard compost at the rate of two Grande coffee cups full for each cubic foot of compost.             Construct a donut around the plant for containing the irrigation water and hand irrigate for about two weeks filling the donut each time. After that, let your irrigation system take over. Prune it after about three to four years of growth and fertilize lightly each spring.

Q. I have a Chitalpa tree that faces west with lots of direct sunlight. The tree bark has separated from the trunk leaving the inner portion of the tree exposed. There are very few leaves on the tree. Help! Not the treaders tree but if chitalpa like this is put in a part of the landscape without enough water applied over a wide enough area under the canopy then the tree can struggle. A. The tree trunk has sun damage. Probably because the tree’s lower limbs were removed too soon. This sun damage has caused the bark to be easily lifted from the damaged part of the trunk. Sunburn has cooked the living part of the tree that faces West while the side facing East may still be alive. This is sunburn on a locust tree. This side is facing the sun, probably the south or west side. The tree is surrounded by rock and t his can reflect alot of heat and light back at the trunk and cause greater damage. Paricularly if the tree was limbed too high at the start.             Sunburn of the trunk can leave it exposed to other problems like wood boring insects (borers) and diseases like sooty canker. Let’s hope it is just sunburn on the trunk causing the poor growth. Locust tree has sunburn on the upper surface of its limbs.             My concern is that the tree might be surrounded by rock. Reflected heat from the rock can damage the trunk if the tree was pruned so the lowest branches are removed. Not a good idea when the tree is young and the trunk susceptible to sun damage.             When trees are young, leave the lowest branches attached to the trunk to help shade it from sun damage, particularly from the West side. Remove lower branches when the trunk gets older and develops a thicker bark layer that insulate it from direct sunlight. Tree wounds like this large one can heal by the cambium layer “rolling over” the damaged area and eventually burying it.             If there are no insect and disease problems, the tree will heal itself by “rolling over” its new growth on top of the damaged area. The tree just needs adequate water and fertilizer to do this.             Apply water to a large area under the canopy. This area should be at least half the area under the canopy. Apply enough gallonage so the applied water wets the soil to 18 inches deep. Although this tree can handle a rock landscape, water it as frequently as fruit trees and other non-desert landscape trees.

Q. I cut back my roses last mid-winter and they grew back just fine this summer. Later, all the leaves discolored, blotchy yellow. Any advice how to correct this and prevent it from happening next year? A. I would like to see some pictures showing me what you mean. But before I get into this, if you want roses in the desert I would go to the Rose Show on November 9. Rosarians are experts on growing roses in the desert. Some of them have 300 or 400 roses growing in their yards! They know roses. Come talk to them on November 9. When it’s hot, the roses use more water. When temperatures cool off, they need less water. If the soil stays soggy when temperatures begin cooling, the newest leaves begin to yellow. It’s an iron problem called chlorosis caused by suffocation of the roots.             I have seen this too many times! Rock placed on top of the soil contribute to a soil problem while woodchips won’t. Spraying the plants with iron fertilizer may be a temporary fix but not a long term one. Rocks covering the soil around roses eventually cause browning of leaves and dieback.             Roses like soils that allow water to drain from around the roots. To get this kind of soil there must be organics in the soil. Organics come from things that rot, not rock. Putting rock on top of the soil causes the soil to lose its organic content over time. But the slow digestion or rotting of organics like woodchips keeps the level of organics in the soil high over time. Expect your roses to look like this in a couple of years if you use rock.             The rotting of organics is caused by moist soil, plant nutrients in the soil like nitrogen, and warm soil temperatures. Rich compost has lots of plant nutrients like nitrogen and organics all bundled together. This bundle of organics and nutrients all rotting together helps keep a healthy balance of good chemistry that benefit the plant nutritionally and environmentally. Roses that grow this well will require compost and iron applications at a minimum.             To correct this yellowing problem requires some expense and work on your part. When temperatures start to cool off this fall, remove whatever is covering the surface of the soil. Mix iron chelate called EDDHA with some rich compost at a rate of about 2 ounces per cubic foot of compost. You can have roses in bare soil but amend this soil and improve it before planting. Notice the color. This color indicates it has at least 2% organics in it. Add EDDHA iron in January and a fertilizer.             Auger holes around the roses to about 12 inches deep and pour this compost and iron mix in the holes and irrigate the plants. Replace the surface cover with woodchips to a depth of 2 to 3 inches. Spray the leaves with a liquid iron fertilizer three times, three to four days apart.             In the early spring each year mix one ounce of EDDHA iron chelate in a bucket of water and pour it around your roses along with your favorite rose fertilizer. This should prevent leaf yellowing of roses in the future.