Bob Morris Q and A at Viragrow Monday and Friday M…: Viragrow asked Bob Morris to answer your horticulture questions at Viragrow’s office in North Las Vegas each Monday and Friday mornings. …
Bob Morris Q and A at Viragrow Read More »
Fruit Tree Pest Update 2013 Notes for the PowerPoint presentation Robert Ll. Morris University of Nevada, Emeritus Desert Green is a conference held each year in Las Vegas for landscaping industry professionals. Here is a summary of my presentation on PowerPoint and my notes for my presentation. Slide 2.The UNCE Orchard was established in 1996 in North Las Vegas at UNLV’s Center for Urban Horticulture and Water Conservation. The center is located 100 yards east of the intersection of North Decatur and Horse Drive. Visiting hours are every Tuesday and Saturday morning from 8 AM until noon. Volunteers at the Orchard are welcome. The Orchard was established as a research and demonstration facility through Cooperative Extension. Slide 3. Fruit growing can be very successful in the desert because of our isolation from commercial orchards, our low humidity which helps to suppress diseases, and our high light intensities which helps to produce high levels of sugar in the fruit. Much of our plant material comes from Dave Wilson Nursery in northern California which produces high quality fruit trees for commercial orchards and nurseries. All of the fruit trees are planted by bare root, usually in late January or early February. We produce our own compost using local horse manure and green waste. The facility is a distribution center for wood mulch which is recycled urban green waste, primarily chipped trees removed from urban landscapes diverted from being buried at our local landfills. Our principal supplier of green waste is First Choice Tree Service, a Las Vegas based company. The management of the Orchard is focused on none or reduced pesticide applications, integrated pest management and ET-based irrigations. Slide 4. Whitewash reduces borer damage. We use whitewash painted to the outside of our trees to reduce sunburn damage. Sunburn damage to the trunk and limbs can attract boring insects such as the flatheaded Apple tree borer and the Pacific flatheaded borer which are problem insects in Las Vegas landscapes. By spraying the trunk and limbs with whitewash we can reduce the surface temperature of the trunk and tree limbs by five or 6°F. Whitewash is made by diluting white latex paint, or off-white latex paint, with an equal amount of water. In some cases more water can be used but the resulting whitewash should leave the trunk and limbs white in color. The most important sides of the trunk and limbs are West and South facing as well as the top sides of limbs. These areas receive the most direct and intense sunlight and usually show the most damage from boring insects. The whitewash will need to be re-sprayed or renewed every 3 to 4 years. Slide 5. Compost at planting enhances growth. This planting is nopal cactus which is used in Mexican culture as fresh vegetable, the fruit and animal fodder (feed). Once a pad is planted in good soil, harvesting of fresh vegetable from young pads can occur the following year. In three years, cactus fruits are ready to harvest. Cactus pads were planted in 2006 on the right side of the picture using compost applied to the soil after planting. The following year, 2007, pads were planted on the left side of the picture by this time the same amount of compost was mixed with the planting soil. Irrigations were every three weeks during the summer. Fertilizer applications were identical. Cactus pads that were planted with compost mixed in the soil exceeded the growth and production of cactus planted with compost applied to the surface only. In our desert soils it is very important to properly command soil at the time of planting for good growth, even of cactus. Slide 6. Staking equals faster establishment. It is important to stake newly planted trees to immobilize the roots so the tree can become established more quickly. If trees are not staked properly and the roots are not immobilized, movement of the plant due to wind can cause slower establishment. As trees begin to leaf out in the spring their canopy acts like a sail and can catch the wind causing the trunk to bend and possibly moving the root ball. Stakes should be driven into solid soil beneath the planting hole and not just the loose soil used for backfill. Trees should be tied to the stake so that the roots are immobilized but allowing the canopy and upper trunk to move. If the stake is not driven into solid soil, the root ball can move and root damage can occur with us slowing establishment. Slide 7. Wood mulch improves tree growth and health. Applying wood mulch to the soil surface has many benefits. Mulches help to keep the soil cool, moist, suppress weeds, improve soil quality, provide nutrients as it decomposes, fosters animal decomposers such as earthworms, lower soil pH and other benefits. Many plants in the landscape prefer to grow in improved soils rather than raw desert soil. Improved soils contribute to improved plant health. The best wood mulches come from a mixture of different types of trees. Bark mulch is pretty to look at but does not break down easily and contribute to the improvement of the soil and plants. Bark mulches easily blow in light winds and move in surface water. Wood mulch that has been chipped from trees does not blow easily in the wind and interlocks because of its rough surfaces. Wood mulches should be applied to a depth of 4 to 6 inches. These mulches should be kept away from the trunks of young trees, a distance of about 12 inches, until these trees are at least five years old. Wood mulches can be created from chipped landscape trees removed from local urban landscapes. When this wood has been chipped it will not contribute any disease or insect problems to landscapes where it is applied. Slide 8. Wood mulches were applied to fruit trees immediately after planting and the growth of these trees was compared to trees that did not receive any
Desert Green Presentation on Fruit Tree Pest Update for 2013 Read More »
Prescription Fertilizers for Trees and Shrubs Notes to the PowerPoint Presentation Desert Green 2013 Robert Ll. Morris, Emeritus University of Nevada [email protected] Desert Green is a conference held annually in Las Vegas for landscape professionals. This is a copy of my presentation on PowerPoint and my notes for the presentation. Slide 1. Title slide with contact information. Slide 2. Characteristics of desert soils. Desert soils contain very little organic matter and they are chemically and physically undeveloped. Because they contain so little organic matter in them, they have very little structure or are structureless. For this reason they sometimes tend to drain poorly. Their alkalinity or pH is normally high. Frequently they contain high levels of salt of all different types. If these soils have never been developed, they can change rapidly both physically and chemically when water is applied to them. Slide 3. There are 16 or 17 nutrients that are essential to plants. Several of these are needed in large amounts and we call these major elements or macronutrients. The rest of the nutrients are needed in a much smaller amounts, still just as essential. These are referred to as minor or micronutrients. All of these nutrients are essential to plant life and if any one of them is missing, the plant will die. If any of these are insufficient for the plant, it can display visual symptoms, poor health and subject to increased disease and insect problems. Bags of fertilizer traditionally contain nitrogen, phosphorus and potassium if they are a complete fertilizer. These three nutrients are called NPK and their relative amounts determine the fertilizer ratio. Carbon, hydrogen and oxygen the plant obtains from air and water. Most desert soils contain adequate amounts of calcium, magnesium and sulfur. Of the minor elements, iron, manganese and zinc can be in short supply to plants because of the soil’s alkalinity or high pH. In most desert soils were landscape plants are being grown, nitrogen is most commonly found in the greatest need by plants. Second to nitrogen is probably available iron. Slide 4. The three numbers on the fertilizer bag give an indicator of the amount of nitrogen, phosphorus and potassium contained in the bag, in that order. Sometimes there is a fourth number present. Although not legally required it usually represents the amount of sulfur contained in the fertilizer. The fertilizer ratio tells us the relative amounts of NPK. For instance, if the fertilizer has a ratio of NPK of 3:1:2 then fertilizers such as 12-4-8 and 21-7-14 would represent this ratio. Slide 5. Although all nutrients are needed for a plant to live, nitrogen represents the one nutrient that is universally in short supply. Nitrogen helps to drive plant growth and causes increases in size. It stimulates increased leaf and stem growth, causes a darkening of leaf color, hastens plant growth after winter dormancy and helps to increase the amount of food manufactured by the plant. If applied too late in the year, it will decrease a plant’s hardiness to freezing temperatures. Most nitrogen fertilizers are pure white in color. Most nitrogen fertilizers dissolve easily in water and moves readily through the soil with irrigation water. Slide 6. Lack of nitrogen shows up in plants as slow growth, foliage with a light green color and a lack of density in the canopy. Slide 7. In pine trees a lack of nitrogen shows up in the same way. This translates to a canopy which is not full, small candles and needles occupying the ends of branches while most of the branch is without needles. Slide 8. If too much nitrogen is applied, plants might grow rapidly with an extremely dense canopy and very dark color. When nitrogen is applied in large amounts it can cause scorching to occur on leaves and tip dieback on needles. In some cases it may cause plant death. Applying too much nitrogen is a waste of money and causes environmental problems as well. Slide 9. Adequate amounts of phosphorus is most closely related to good root growth and plant establishment, flowering and fruit production, seed and oil production. When soils are cold and wet this can lead to a lack of phosphorus taken up by plant roots. There is a quick recovery by plants as soon as the soils begin to warm. Phosphorus fertilizers are typically dark in color, usually dark gray or brown. Slide 10. Unlike nitrogen, phosphorus can stay present in the soil for long periods of time, does not dissolve easily in water and does not move through the soil unless the soil is very sandy. Phosphorus levels can build in the soil with repeated applications of high levels. In some cases phosphorus can build to toxic levels with repeated applications. Phosphorus can interfere with other nutrients, iron in particular. Over application is a waste of money and can lead to environmental pollution. Slide 11. Deficiency of phosphorus can sometimes lead to purple discoloration of the plant which disappears when phosphorus becomes available again. This is very common to many plants in cold, wet soils. Slide 12. Potassium is sometimes underappreciated in fertilizer applications. Deficiencies are hard to see since a deficient plant gives no outward symptoms. Potassium chloride, a common potassium fertilizer used in mixing fertilizers together, as a reddish-brown color. Slide 13. Over applying potassium usually will not harm anything and it does not build up in the soil like phosphorus does. Deficiencies of potassium can lead to a plant’s decreased tolerance to stresses such as heat, cold, freezing, disease and others. Slide 14. Nutrients needed in smaller amounts. Of the seven nutrients needed in much smaller amounts, iron, manganese and zinc are the ones most likely to be in short supply for plants growing in alkaline soils. Of the three, iron is by far the one found most efficient in plants. This is odd because iron is one of the most abundant minerals on earth. The key to its limited availability to plants is the pH
Desert Green Presentation on Fertilizing Woody Plants with Notes Read More »