Xtremehorticulture

Xtremehorticulture of the Desert

Ash Roots Can Be Removed with Care

Leave a Comment / how to cut roots, How to remove Ash roots /

Q. I have a 15-year-old ash tree in my backyard and roots are pushing up the brick walkway. Would it hurt the tree if I took up the brick and cut the roots off before they grow under the brick? The walkway is about six feet from the tree. A. It shouldn’t be a problem that far from the tree but let me tell you how I make that determination. I look at where water is being applied to the tree. Tree roots will grow toward water. They will grow more aggressively where there is more water and fertilizer. They grow less aggressively in and toward dry areas. Roots of fan tex ash At a distance of 6 feet away from the trunk there should be no problem at all unless it is getting all of its water mostly from the area where roots are being cut. If tree roots are getting water from multiple locations then there should be no problem at all if you remove these roots. Roots of ash surfacing in a lawn Cut the roots in that area which are growing to a depth of 12 inches. After cutting them, sanitize the cut ends of any large roots that have been cut with soap and water. Let the cut ends of the roots dry and heal for a couple of days before putting soil back around them. There are some plant diseases present in soils that can enter the tree through open wounds. Sanitizing the cut ends and letting them heal first helps prevent these diseases from entering the tree. Backfilling around the cut ends of roots while cuts are still fresh can increase the likelihood of disease problems.

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Brown Center of Pampas Grass Common

Leave a Comment / pampas grass, pruning /

Q. A few weeks ago I cut my ornamental pampas grass down, removing all last year’s dead growth. As the new growth is starting, I noticed a peculiar brown, circular pattern in the center that hasn’t happened in the past. The new growth is coming along fine; nice and green, and a couple inches taller. Just nothing in the center. Brown Center of pruned pampas grass A. This brown center is common to many ornamental grasses as they get older. When the plant is very young and juvenile the entire plant is green, even the center. As these plants get larger, they grow from outside shoots, or tillers, that make the plant larger in diameter. Each year this clump of grass gets larger and larger with the brown interior getting larger as well. When these ornamental grasses get larger, the entire clump is dug up and divided into several smaller clumps. This propagation technique is called “division”. The brown portion of the plant is removed and the smaller plants are replanted or containerized and sold as a juvenile plants. However, the new growth of your plant will cover up the dead interior and I don’t think you will notice it anymore until you cut back again. 

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Whitewash Not Meant for Stopping Rabbits

Leave a Comment / how to make whitewash, the purpose of whitewash, Whitewashing fruit trees /

Q. I planted a couple of fruit trees and a visitor started chewing on it a bit, possibly a baby rabbit.  What should I treat it with or should I just paint it now with whitewash such as a 50/50 mixture of latex paint and water? I read this mixture stops rabbits from chewing on them. A. I would strongly suggest you protect these trees from rabbits by putting a 2 foot tall cylinder of 1 inch hexagonal chicken wire around the outside of the tree. This excludes rabbits from chewing on the trunks. A cylinder of 1 inch hexagon all chicken wire surrounding a new fruit tree to protect it from rabbit damage Once the trunks get about 3 inches in diameter rabbits will no longer bother them and it can be removed. Be sure to bury the bottom edge of this cylinder one or 2 inches into the soil. I don’t know if whitewash will prevent rabbit damage. The major reason for applying whitewash is to help prevent sunburn to the trunk and limbs of young, and even older fruit trees susceptible to sunburn. Fruit trees particularly susceptible are peach and nectarine. Whitewashing the trunk and large limbs of an older fruit tree  Whitewash years ago was made from a mixture of lime and water. Now most commercial whitewash is made from diluted white latex paint. I recently purchased some commercial, ready to use whitewash and I still found it needed more diluting with water. You want a mixture of water and latex paint that changes the color of the bark from brown to a very light color. This better reflects sunlight and reduces damage from sunburn. I have never heard of it used to deter rabbits so in my opinion it is strictly folklore unless it can be validated by others. There is a lot of anecdotal information floating around out there that is not very accurate but simply passed on without any proof.

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Spraying Oil on New Fruit Trees Not a Bad Idea

Leave a Comment / Horticultural oil, new fruit trees, new planting /

Q. Should you spray fruit trees with horticultural oil if you are planting them for the first time? New bare root fruit tree ready for planting A. Horticultural oils are made from refined mineral oil and used during cooler times of the year to smother insects that might cause problems to a number of different plants. Even though horticultural oils are “natural” they are considered an insecticide since they kill insects by “smothering” them. They are most effective on aphids, scale insects, whiteflies and spider mites. Horticultural oils are indiscriminate killers of insects, similar in that regard to soaps used as insecticides. They are indiscriminate because they kill any insect, bad or good, that is sprayed. But these types of sprays are safer to apply and for the environment than most conventional insecticides. Aphids causing leaf curling and stickiness on Plum No, you don’t need to spray newly planted trees with horticultural oil when planting them unless you think they were infested when you bought them. However, it is not a bad idea and probably a good safety precaution since these trees are coming from places where there are usually a lot of new insects that can be brought into your garden.

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Heavenly Bamboo/Nandina Yellowing and What to Do

Leave a Comment / Correcting iron chlorosis yellowing late in the season, heavenly bamboo, iron chlorosis, Nandina /

Q. I noticed all my Nandinas, also called heavenly bamboo, are turning bright yellow. Is this a fungal disease problem? I’m worried that whatever this is will spread to all the other plants. A. No, it is not caused by a disease organism. This is severe iron chlorosis and fairly common to heavenly bamboo growing in alkaline and desert soils. Leaf yellowing happens frequently because of a lack in organic matter in the soil, increasing alkalinity or soil pH. I see heavenly bamboo planted with rock mulch and this yellowing frequently becomes a problem in a few years after planting in these situations. Heavenly bamboo and rock mulch and yellowing Start a program of soil enrichment and add a good quality iron product to the soil now as new growth is appearing. If there is rock mulch present, remember this type of mulch is probably adding to the problem. Plants like Nandina do not like rock mulch but grow healthier in a wood mulch environment. Personally, I prefer iron EDDHA chelate as the source of iron to apply to the soil. It is a dry powder and must be watered into the soil accompanied by a good quality fertilizer. Iron does not move from the soil into leaves that are already yellow. Iron applied to the soil only affects new growth and new leaves. The only way to improve the green color of existing yellow foliage is to apply iron fertilizers as a foliar spray. Use any of the iron foliar fertilizers (liquids or powders that are mixed with water to make a liquid) and sprayed on the leaves. Sometimes it can take three or four applications, a week apart, to get them to green up adequately. Some plants green up with a single application. The water used when spraying liquid iron should be distilled water. If using tap water, adjust the pH of the water to 7.0. When making applications to leaves always use a wetting agent such as EZ Wet. You can also improve the new foliage to dark green by pruning them back, close to the ground, and letting them regrow after you apply iron EDDHA, compost, water and a fertilizer.

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Queen Palm Not A Good Choice in Desert Climates and Soils

Leave a Comment / queen palm, queen palm brown, Why is my queen palm yellow /

Q. Our backyard is in full sun, gets very windy, and has very poor soil. We are landscaping around a new pool and would like a tropical look. We would love to put in a queen palm but we read they may not do well here. Any suggestions for a different palm like Kentia or Foxtail? A. The queen palm won’t work in your situation. It does not like poor soils, heat, lack of humidity and wind. It is not a good choice for our hot desert climate in general. Queen palm tends to look “ratty” in our desert climate and soils. Be careful planting palms near a pool. Most people do not like the seeds dropping and the mess it makes. The only palm which stays small and hearty for our area is the windmill palm. The pygmy date palm is a possibility but it is sensitive to our winter temperatures and may suffer from winter freezing. The Mediterranean fan palm stays short but can get quite large in diameter. Both Kentia and Foxtail palms are not meant for our climate. Kentia palm is considered a “tropical” palm and intended for interior use in desert climates. There are plenty of plants that give a tropical look to a landscape that are desert adapted and tolerant of our soils. Mesquite, desert bird of paradise, flax, ornamental grasses, canna lilies, rose of Sharon, crape myrtle, Gold dust plant (shade), papyrus, nandina, mock orange, cats claw vine, can be used to mention a few. Tropical looking landscapes should be densely planted and designated as a high water use area. Use compost and wood chip surface mulches that won’t blow easily to improve our soils and their growth. 

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Citrus Seldom Needs Fruit Thinning

Leave a Comment / citrus fruit thinning, Meyer lemon /

Q. We have a two-foot tall, two-year old Meyer’s lemon with 40-50 young blossoms.  Shouldn’t some clusters be thinned and if so how? Lemon tree planted with mulch. Keep the mulch away from the trunk for the first couple of years. A. Don’t thin them. In most cases citrus does not need to be thinned. The plant will drop the fruit it cannot support. It is not like a peach, apple, plum where small fruit must be removed to make way for larger fruit. Just let it be and see how well is sets this year. My guess is that it will drop most of the blossoms or fruit that it cannot support. It may drop all of them if the tree is too young to support fruit growth and branch growth at the same time. Lemon with a good fruit set             That being said, sometimes citrus does have too much fruit on a limb. Leaving too much fruit on a limb can break the limb. If the fruit is closer than the diameter of a large fruit, start removing some when they are the size of a quarter. 

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Leaf Browning Due to Insecticide

Leave a Comment / accidental insecticide spray, concentrated spray, leaf death /

Q. I am hoping you can advise me on how to save my rose bushes I planted last spring. I sprayed my them accidentally with a concentrated insecticide, not diluted. The next morning the leaves looked like wilted spinach and I cried. Will the bushes die?  A friend told me I should have applied it to the soil. Rose leaf scorch and death due to concentrated insecticide application. They will grow back. A. They will come back. You burned the leaves with the concentrated insecticide. You should see new leaves and growth popping out in a week or so. During this time be careful not to overwater. Water them normally or even less often if they do not have leaves. Always follow the label directions when applying and don’t listen to friends. Application depends on the insecticide. Some insecticides are root systemic and applied on the soil around the roots and watered in. Others are foliar and applied to the leaves. You do not know which is which unless you read the label. The label will tell you how to apply it, when to apply and the application rate.

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Multiple Trees Together Better Choice Than Multi-Budded Trees

Leave a Comment / multiple budded tree, multiple fruit on a single tree, multiple trees in a single hole, planting trees /

Q. I lost two fruit trees this winter because of an irrigation problem. I would like to replace them with 4-in-1 pluot and plum tree. I’m hoping it’s not too late to plant. Two-in-one hole fruit trees…one Santa Rosa plum and pluot by reader.  A. It is not too late to plant fruit trees in containers but it is too late to plant them bare root or sold in packages. I am not a big fan of fruit trees that have more than one variety on the same tree. In a few years the more aggressive varieties dominate and kill the weaker varieties. In a very short time the tree is dominated by one or two varieties instead of four. I prefer separate trees planted very close to each other and managed as one tree. I would plant these trees about 12 to 18 inches apart; one on the east side of a large hole and the other on the west. In the case of pluots and plum, the plum tree should be a Santa Rosa which is a good pollinator for pluots. Pluots are self-pollinating in our climate but having a Santa Rosa plum tree close may help with fruit set and increase yield. Two rules should be followed when planting trees close together; never let them grow back into each other and keep them both pruned and trained to the same size.

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