xtremehorticulture – Page 16 – Xtremehorticulture

Chosing One Product for Pest Control

Q, If you were to buy one product for insect control on plants, what would it be? Organic castile soap for mixing in an emergency. What you shoot, is what you get when using soap and water sprays! Probably the single most important insecticide all season but it is applied in the winter as a precaution. Insurance insecticide. A. Probably soap and water sprays or an oil but not a Neem-type oil. Soap and water sprays are deadly to all insects whether the insect killed is a good guy or a bad guy. With soap and water sprays “what you spray is what you will kill”. Be careful when you use soap sprays and spray only what you intend to kill. In many ways it’s like a gun. The advantage of industrialized pesticides is that they stick around longer after you spray them. Soap and water sprays must be repeated more frequently to protect plants from undesirable insects but are perceived as more environmentally friendly. I always carry with me a bottle of soap for mixing with water in case I see an insect problem that needs my immediate attention. In a pinch you can make your own soap spray by adding about one to two tablespoons of dishwashing soap to a gallon of water. I prefer using a pure Castile soap, that I am comfortable about, to mix with water. The oils I’m talking about are the “horticultural oils” or “dormant oils” made from paraffin or mineral oil and not from the Neem plant. These types of oils have been proven to be very effective on soft bodied insects like scale, aphids, mites, and whiteflies. Follow the label directions when making an application. Don’t add soap to the concoction if it is already “homogenized” and has something in it that already mixes the oil and water together. Horticultural oils (don’t use Neem oil) comes in smaller and larger quantities.

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Bottlebrush With Open Canopy and Yellow

Leave a Comment / dwarf, flower color, forms of bottlebrush, make a tree, size, tree forms, varieties / xtremehorticulture

Q. I have a bottle brush shrub that is open and getting yellow. What to do? A. The Australian bottle brush plant is sold as a shrub but can reach heights of 25 feet so it can also qualify as a small tree as well. Bottlebrush varies from dwarf types to trees and flower color from red to white to pink. Flowers of the red bottlebrush. Later the flowers produce this which are seed capsules. Dwarf Types Just don’t use dwarf types like ‘Little John’ if you want a larger tree sized plant. In tree form it can be used on single story homes for shade. To be on the safe side plant it away from hot walls. There is a weeping form and a non-weeping form as well as dwarf varieties. Also flower color can range from yellow to red and shades of red to pink and white. One of the dwarf types, don;t know which one, with freezing damage. Yellowing Leaves It oftentimes has a problem. Yellowing of the leaves oftentimes occurs when the soil is low in nutrients as well as its organic matter content. Fix yellowing by applying a landscape fertilizer every year in the spring and combine it with an annual application of chelated iron. Enriching the soil with organic matter is done when you used small rocks by raking them back and applying a thin layer of compost to the soil, wetting it, and raking the rocks back. Large rocks may not need raking. The compost and fertilizer will just wash through it to the soil. One of the iron chelates, EDDHA. I prefer this type of iron chelate because it is stable regardless of the soil pH. Other iron chelates like EDTA and DTPA iron chelates become ineffective at soil pH above about 7.6. Apply it early in the growing season when you make a fertilizer application. Increase Density of Canopy To improve the density of its canopy, make sure it gets enough water. The plant grows best if treated as a “mesic” plant rather than a desert or xeric plant. It grows well when surrounded by lawn. Water should wet the soil about three or four feet in diameter to a depth of about 18 to 24 inches deep each time. Water it as you would any mesic plant such as ash, bottle tree, African sumac, and others. As this plant approaches ten feet tall then wet the soil about five to six feet in diameter. Another possibility might be low soil organic content. So rake the rock away and put a thin layer of compost on top of the soil, water it in and replace the rock. Pruning to Tree To get a small tree out of this, remove the lower limbs when it is 3 or 4 four feet tall so that the canopy occupies about 2/3 and the trunk is about 1/3 of its height. Plant it at least five feet away from hot walls or it will fry. Also in the desert remove lower limbs slowly as the lower limbs touch the ground. Otherwise the trunk may get sunscald.

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How to Reduce Water Use in a Condominium HOA; Part 2.

Leave a Comment / desert landscaping, landscape water use, part 2, reducing water use / xtremehorticulture

In How to Reduce Water Use in a Condominium HOA; Part 1 you determined what plant water use category you are in; Landscape water use categories 0-2 feet of water covering the irrigated landscaped area (nice job!) 3-4 feet of water covering the irrigated landscaped area (not bad) 5-6 feet of water covering the irrigated landscaped area (too much water used, scale back!) Cranking the Water Use Down If you are not happy with your landscape water use, or want to save even more water than you have, first consider eliminating trees above the roofline of the condos or at least pruning them lower. Are large trees important? Yes they are but perhaps not nearly as important as the cost of the water they need to survive. These pine trees are planted too close but the shade they produce can’t be denied. As these pine trees get larger, the cost of watering them may be worth more than the shade they produce. It will be up to you but consider removing them after replacement trees have been established. Big Trees Use More Water than Little Trees It may sound comical but people buy trees that grow 50 feet tall and only need a tree that is 15 feet tall (single story homes). Examples are pine trees. Sure pine trees may not use as much water as a mulberry but it still uses water. The bigger it grows, the more water it needs. Plant or keep trees that shade the walls and windows on the south and west sides of a building. This hot, west facing exterior wall has four small shrubs that create no shade on the wall but still require water. Their distance apart (about 10 feet) would provide the water needed to plant and locate three small trees or shrubs (ten feet tall) that would shade this hot wall. As the plants we chose to replace them got larger, more water should be added. Add one more small tree (patio tree) to provide shade for the patio area walls and door. Selecting “Backbone” Trees and Large Shrubs Selection of “backbone” trees and shrubs should be hardy, deciduous, and survive temperatures to at least 20F during the winter. What are backbone trees and shrubs? These are trees and shrubs you don’t want to lose to winter freezes. The trees and shrubs should be deciduous because we want the sun to warm this condo in mid-winter. If you want to save even more water, use small deciduous desert (xeric) trees and water them separately from the more frequently watered mesic plants. Landscape “Negative Space” The fewer plants used and the smaller they are will, for the most part, determine how much water your landscape uses. Deserts use less water by NOT growing plants. I call not planting…. “negative space”. Where are plants needed? Where are plants NOT needed? Leaves these spaces open. Creative use of negative space is challenging. In the wetter, eastern US lawns were used to occupy negative space. In the desert we must be more creative; boulders, changes in rock size (texture), changes in elevation, artwork, wall paintings…all can be important when not using water. Dry washes can use textural changes along with plants. Rocks don’t use water. Open spaces don’t use any water and the plants used were desert in origin (xeric) so they aren’t watered very often. I would substitute small trees near the windows. Textural change in the mulch and wall paintings add color and interest to an otherwise somber area and don’t use any water. What is the water use here? Planting in Desert Soil Locations of ten foot tall trees or shrubs should be 4 to 5 feet from the home. Taller trees and shrubs can be planted further away. Soil amendments should be lightly mixed with the soil at planting time along with water. Planting holes should be wide and not necessarily deep unless there is a clear drainage problem. If a slight drainage problem exists, plant on a mound of amended soil rather than digging deep. Water should be applied away from the foundation of the home. In the desert, plant roots follow where water is applied. Trees and shrubs should be fertilized once in the spring. Two times at most. Showy plants are fertilized three or four times a year and when they flower best. Trees use water. Bigger trees use more water. Lots of big trees use lots of water

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How Much Water Do Pine Trees Use?

Leave a Comment / landscape water use, mixed landscape, negative space, pine tree water use / xtremehorticulture

Q. We have on our street in Las Vegas pine trees that are over 20 years old and 50 feet tall. We obviously want to ensure their survival as we try to conserve water. Approximately how many gallons of water would each tree require each month? A. The exact water requirement for pine trees is going to be difficult because water use of pine trees has never been quantified in our desert climate. Even if they have, those amounts are “ballpark amounts” and close approximations. Every site is different. Every year is different. Mature pine tree about 35 to 40 feet tall and 50 to 60 feet wide. The area to water is at least 25 feet in diameter to stabilize the tree and spread the water it needs out. Can a smaller tree do the same job? It may use less water. Approximate Water Need I can approximate. We do know that as the tree gets larger it needs more water to grow healthy. Its annual water use is probably between 4 to 5 feet (48 in. to 60 in) of water applied under its canopy and surrounded by bare soil or mulch. This is approximately what it might need when its not surrounded by grass. Grass of mixed landscapes makes it cooler and it uses less water BUT not good for pine roots and its health. Increase Water Estimates: Plant Need + Salts + Water Lost When Irrigating If the tree is being watered by city water (because city water, not most well water, has salt in it) then it will need to be increased by about 20% to compensate for mixing in Colorado River water with it. Then, on top of all that, you must figure in losses due to imperfections in the irrigation system. If you are using drip irrigation, that water loss will be about another 5 to 10% beyond what it needs. Water needed by the plant + Las Vegas’ salty Colorado River water (20% more) + Water lost by the irrigation system (varies from 5 to 45%) I will just guestimate what pine trees need. Add another 25% on top of that to compensate for Colorado River salts and another 5 to 10% if using drip irrigation. The water lost each month depends on the weather so I will give you approximate values. If it is a colder than normal month, the trees use less. If it is hotter and windier than normal, the trees use more. Irrigate Following the ET Curve The water use will follow a bell-shaped curve like the one below. These amounts relate best to tall fescue lawns. Annual water use of adequately watered tall fescue in Las Vegas, Nevada. (Month 1 = January, 12 is December). Water needed by green and growing tall fescue lawns is about 1/10 of an inch of water each day in both December and January. This adds up to about 75 to 85 inches (7 to 8 feet) of water use per year. Pine trees don’t use as much water as this tall fescue lawn so its water use is about 4 to 5 feet of water (48 to 60 inches) applied under its canopy each year. Water use is in inches of water use per day when the sun is shining and very little wind. The larger the tree, progressively, more water is needed by the tree. As trees get bigger, they need more water. Monthly Water Use January tall fescue lawns in full sun use about 0.1 inch per day; so pine trees may use about 2 inches in 30 days if applied evenly under the canopy. February a tall fescue lawn uses 0.14 inch per day; so pine trees may use about 3 inches Following the same reasoning: March 0.19 inch per day; 4 inches April 0.28 inch per day; 6 inches May 0.36 inch per day; 8 inches June 0.41 inch per day; 9 inches July 0.40 inch per day; 9 inches August 0.35 inch per day; 8 inches September 0.28 inch per day; 6 inches October 0.22 inch per day; 4 inches November 0.15 inch per day; 3 inches December 0.1 inch per day; 2 inches Watering a Mixed Landscape First of all don’t. Mixed landscapes of trees and grass are difficult to water…. physically. Second, trees are better off NOT growing in grass. Their roots are better off and their roots will grow deeper. When trees are NOT in a mixed landscape, the trees can get the right amount of water and the water can be applied more easily. Trees interfere with applying water to grass as well. They get in the way. Whenever possible separate trees and lawns. Trees and lawns should be on separate valves anyway. Water in our area is just going to get saltier and saltier. Salt accumulation from the irrigation water on pine trees on this golf course slowed the growth of this tree on its lower limbs (about halfway up). The hybrid bermudagrass (growing beneath it) was fine. Mixed Landscape of Grass and Trees In a mixed landscape of grass and trees, lawns probably uses about 6 to 7 feet of water (a bit less due to shade and cooler temperatures of grass) on top of the pine water use. It depends on the temperature, sunlight, wind and humidity it receives but having two plants receiving water for the same area, although

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Privet Thin Canopy and What to Do

Leave a Comment / ligustrum, privet, thin canopy, yellow leaves / xtremehorticulture

Q. What is wrong with this bush or tree? What can I do to make it look healthy? Not the tree reader is talking about but it does have a “thin” canopy. It is not dense. How to thicken it? More water and applied to a wider area and add fertilizer once a year. If it is yellow like this, add chelated iron (I prefer iron EDDHA) to the fertilizer in very early spring. It may need compost added to the soil top as well. A. What I am seeing is a thin canopy and some leaves that have brown tips (leaf scorch). I think this is a ligustrum or privet. When I see a thin canopy, it usually means the soil has “run out’ of organics. Rake the rock on top of the soil back about two feet in all directions and apply a thin layer of compost. This compost will “dissolve” into the soil with water and increase the “organics”. Japanese privet in particular has a difficult time holding leaves when grass is removed. Leaf scorch or tip burn revealing the plant is not getting enough water, it is planted in a place that is too hot, or plant nutrition is bad. Increase the water to the plant, consider moving it to a new spot, or improve its nutrition with fertilizers or compost or both. This time of year (beginning of October) we are transitioning from watering three times a week to two times a week. Each application should be about 5 to ten gallons of water applied to this area via three to four emitters. This can be calculated with the number of minutes you are applying water combined with the size and number of drip emitters. To change the amount of water, do not alter the minutes but instead increase the size of the emitters, or increase number of drip emitters. The other option is to replace the surface rock with a layer of fine woodchips over this same area. For faster results apply a thin layer of compost to the soil surface and water it in. Then cover this area with woodchips.

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‘Bonita’ Ash and Ash Decline Disease

Leave a Comment / ash death, ash decline, dying / xtremehorticulture

Q. I planted a very large ‘Bonita’ ash tree this year and was worried about ash decline disease. This last May we noticed there were not as many leaves growing as we expected and many of the ones that were growing scorched and fell off. After 4 months of very good care to water, fertilize, and condition as told, the ‘Bonita’ ash tree does not look as we were told when we bought it. While it has grown taller, it had not filled in much. ‘Bonita’ Ash Tree recently planted. A. Ash Decline disease can be confused with a lack of water. It may also be confused with poor planting practices and leaving the ash out too long before planting. Possible ash decline disease. The only real way to say it is ash decline is to send a sample to a plant pathologist familiar with the disease. Nearly all ash trees are susceptible to ash decline disease, particularly if it has Arizona ash genetics in it. ‘Bonita’ ash does. So do ‘Modesto’, ‘Raywood’, ‘Rio Grande’, and other ash trees commonly sold in nurseries. That being said, this disease is usually not a problem on young ash trees as long as they are not stressed and there are no diseases present that might cause it to spread. Young ash trees are normally very strong and healthy. Disease Pressure The keys to resistance are “disease pressure”; how much of this disease is present on ash trees in your neighborhood and the “health” of your trees. The disease agent that causes ash decline is not terribly virulent. It is not like a disease such as fireblight which can be terribly destructive under the right conditions. If the ash trees in your nearby neighborhood don’t show any symptoms (branch or limb dieback) and kept healthy, then most likely the tree you planted will live disease free for many years to come. Give Them Water and Fertilizer and See if they Recover Make sure your tree are not water and fertilizer stressed. All ash trees are “mesic” in their water needs. Even desert ash trees, such as Arizona ash, grows near waterways. Like mulberry, all ash trees are dioecious; there are male trees and female trees. There is little difference in the health of a male vs. female ash tree. Ash tree surrounded by lawn and well fertilized and watered. They are mesic and can withstand a lawn. Ash trees can get big. Make sure they get enough water as they get bigger. Getting enough water is one key to having a thick and broad canopy and staying healthy. The irrigation under the tree should be enlarged every two to five years to compensate for their increase in size. Keep Ash Trees in Good Health The other important ingredient regarding canopy density and health are annual fertilizer applications. At least once a year and its canopy density, apply a fertilizer high in nitrogen, the first number on the fertilizer bag. Examples might include 16-6-8 or 16-16-16. Ash tree about 3/4 mature and surrounded by grass. They can get big. Their need for water is not as much as mulberry but close. Ash trees don’t care much for rock on top of the soil unless their roots are growing in a rich soil underneath it. Periodically rake any rock away from the trunk of the tree, enlarge the irrigation system, apply compost to the soil surface and fertilizer. The rock can be raked back the same day you are finished.

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Established Trees and New Artificial Grass

Leave a Comment / artificial grass, established tree, landscape, tree dying / xtremehorticulture

Q. I have a small tree planted in 1998 that has roots growing under some artificial grass. It was put down many years ago. I have a tree that is sending big roots underneath this grass for probably 10 feet or so. This mound is probably 6 inches or more in height. I need to know if I pull this artificial grass back and cut that root if it would kill the tree. Tree roots under artificial grass may be dead and can be removed. A. Sounds like maybe the small tree was planted 23 years ago before the artificial grass was installed. If the tree was planted before the artificial grass then probably the tree roots got no water. If they got no water then the roots are dead and cutting them is no problem. Ash tree roots grow where there is a steady supply of water, air and fertilizer. In the desert, ash trees need water and air first and fertilizer second. In lawns ash tree roots will grow near the surface of the soil because that is where the best balance of water and air can be found easiest. And when the lawn is fertilized, the tree loves it! Will the Tree Fall Over? So maybe the tree will fall over and maybe not. It would be difficult to say without looking and making some guesses. Tree roots provide anchorage for the tree as well as take up water. If the soil is dry under the artificial grass, then no roots are sent out by the tree or they die if there is none. Trees do not send roots out into dry soil, and they do not get larger unless they have access to water. Larger still if the get water AND air. So possibly that root is still alive. Find out for sure. We don.t know but it looks like this tree will not get water from neighboring plants. Trees can “steal” water from neighboring landscapes, other plants, lawns and other places. As this tree gets larger it will need more water. It can get more water by adding emitters. Trees send roots out in one or more directions in the presence of water. Tree roots don’t respect property lines and walls. In sandy soil, moist soil can be found about 0 to 18 inches from a source of water. In a heavier loamy soil, moist soil will be further; maybe 18 to 36 inches from its water source. If roots find a preferred mix of water and air, they proliferate. If the soil stays dry, then they don’t. Tree roots, like us, are lazy. When we hand water mature trees we have to guess where the roots are. If water has been there over and over, then its a good guess roots are their too. If we continuously wet the soil in the same spot and its close to plants, roots will multiply. Make an Educated Guess What to do? Look at the area and find the possible permanant sources of water where tree roots might grow. Those spots might have the greatest chances of tree roots. If there are plenty of places where water was applied, cut the offending root back in increments until the offending root is not a problem. Leave as much there as you can. Stake the Tree Stake the tree for one to two seasons of growth and apply water to the same areas over and over that were not root pruned. Soon after the root was cut, prune the tree and remove one quarter to one third of its canopy. Check for reestablishment of the roots after the second year of growth. The first couple of years the tree will grow slowly. Generally, if tree roots growing from the trunk are evenly balanced, about half of all existing living roots can be removed without damaging the tree if they have balanced growth from the beginning.

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Succulents for Las Vegas Gardens

Leave a Comment / dying, phytophthora, root rot, seed, stem cutting / xtremehorticulture

Q. I have a succulent garden which is under our patio cover. Periodically a plant that seems to being doing well suddenly goes sour. I use a moisture meter and try not to overwater. When propagating plants from seed or cuttings sanitation is very very important. These are babies just getting started!!! A. All cacti are classified as succulents but not all succulents are classified as cacti. What we consider succulents from our deserts usually require more care than cacti from our deserts. This means they usually need more protection from the sun, wind and a bit more water. Sanitation I am a firm believer in keeping everything as clean as possible. First is the potting soil. When potting soil is reused, sanitize it or get new potting soil. Do this easily by putting the moist soil, or the entire container a few days after an irrigation, in a clear plastic bag in full sun during the summer. Make sure there are no air leaks. Let it sit like this for about three days. Heating up everything to about 160F. for at least 30 minutes sanitizes it. This method is called solarization. Sanitize or sterilize all of the equipment with 70% ethyl alcohol: particularly anything with a blade. Sometimes the plant part (seeds or cuttings) were not healthy or strong enough until they grew roots. Some older fungicides, namely Captan, Thiram, Zineb (dust, powder or wettable powder), were available to protect the roots until the plant got established in the ground. We would put a small amount on the flat end of a wooden toothpick in a seed packet and shake it (seed treatment) or dip cuttings to protect the roots until the plants were established.

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Branch Dieback in Citrus (Orange)

Leave a Comment / branches dying, citrus / xtremehorticulture

Q. I have a ‘Eureka’ lemon tree with a branch or two that are dying. Is this borers? Lemon tree with single branch dying back. A. Probably not borers but a disease. Look for sap near the location where the branch died. Single Branch Dieback of Lemon Most Likely Shoot and Twig Dieback Disease Branch dieback in citrus, particularly lemon, is very confusing. It is not likely to be a borer problem. Most likely it is a disease issue called “shoot and twig dieback” of citrus. A lot of federal funding went to California to answer a branch dieback disease questions for homeowners and commercial growers, with lemon branch dieback found to be quite common. If it were me, I would cut the dead branches back and eliminate the dead branch to a place where it was healthy and growing in the direction I wanted. As a precaution, I would sanitize the pruning shears with undiluted 70-90% ethyl alcohol before and after each branch removal. Treat the fresh cuts with copper sulfate (Bordeaux mix) as a precaution.

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Tree Planting Requires Proper Hole Preparation in the Desert

Leave a Comment / boxed, how to, mastic, planting trees / xtremehorticulture

Q. I had a boxed mastic tree planted recently. I didn’t like how it was planted. It was planted with the trunk not straight, the top of the roots exposed, the soil in the hole was dry, and I had them remove the bottom of the box. They were going to plant it with the bottom of the box still under the root ball. Mastic tree planted too shallow. Also the area is very small for such a large tree. A. I looked at the pictures you sent to me, and I agree it was not planted well. Sloppy planting. The hole was dug too small, and it was not planted deep enough. About 30% of the soil should be amended for drainage and moisture retention. Out of sight, out of mind. The soil surrounding your tree may or may not have enough amendments added. Watch this video on planting trees in Arizona that I thought was pretty good. Mastic (Pistacia lentiscus) trunk was planted with the trunk at an angle which is less of a problem than the exposed rootball (above). Mastic is related to pistache (Pistacia lentiscus). Like all pistache trees, it is mesic in its need for water. This tree is Mediterranean in origin rather than western Chinese or Central Asian. Water requirements for both are similar and both develop red fall color. It grows well in a lawn where it gets plenty of water or surrounded by other mesic shrubs for the same reason. When planting on a slope, the lowest side of the hole should be used for judging the hole depth. Add water at the top and sides of the hole, not the bottom. This tree is fine growing in soil covered in rock. If this tree shows signs of poor growth in a few years, add a layer of compost on top of the soil and water it in. Water should be applied on the “uphill” side of the tree but three feet at least from the foundation of the house. Dry Hole Problems The problem planting in a “dry hole” is removal of air pockets. Dry soil pushed into the rootball (and using the butt end of a shovel to shove it further) may or may not remove them. Usually not. When planting in a slurry of soil the air pockets are removed at planting time (look for the bubbles), less “transplant shock”, and less concern about tree stability (staking) after planting. Air pockets in the soil will not do that. Wet the Soil Making a slurry is easy to do. Just use a hose during planting. Sometimes a dry soil can be compensated in the first few months by circling a moist rootball with a “moat” or donut on top of the rootball when planting and wetting the soil after planting. Either that or apply water slowly or several times to get it to soak in. This tree grows about 25 feet tall with about the same spread when fully mature. Pay attention to branch direction and the house when planting. Dig the planting hole at least three times the width of the plant container. Amend the soil removed from the planting hole with “organics” of some sort to keep the soil loose, friable, and well drained after planting. How Close to the Home? I wouldn’t plant it any closer than 8 to 10 feet from a house to accommodate the watering and branch growth. Trees should be planted as close to vertical as possible. When trees are planted from a wooden box, usually the bottom of the box is removed first, and the sides are removed after lowering it into the hole. Fill the hole half full and then ADD water to make a slurry. Never add dry or hot soil to a planting hole.

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