Xtremehorticulture

Xtremehorticulture of the Desert

Controlling Bermudagrass Growing in…..

Leave a Comment / bermudagrass, control, devil grass, devilgrass, herbicides /

Common bermudagrass stolons creeping from the lawn over a sidewalk. Hybrid bermudagrass is much more restrained in its growth. This is a queston frequently asked, “How do I control bermudagrass in……” so let’s talk about it. The big problem is common bermudagrass. It is spread by seed, underground stems called rhizomes that can grow under the surface of the soil for many feet and re-emerge in a new location. Sort of like “Whack-A-Mole”. You pull it or spray it here only for it to popup over there. Below ground the bermudagrass cannot get the energy it needs from sunlight. It must rely on food supplies sent by the mother plant growing in sunligh OR live off of stored food in its stems. It can also spread by planting, or accidentally planting, any of its stems above or below ground. For instance you can take the above ground growth, cut it up into small pieces, throw it on the ground, water it and it will start a new plant any place these cut up pieces fall. When we WANT it to spread like this, we call are planting by stolons or “stolonizing” the area. The hybrid bermudagrasses, the kind that are nice to grow like on golf courses, is planted exactly this way. The underground stems that spread the mother plant to a new location all by growing underground are called rhizomes. The only difference between the above ground stems (stolons) and the below ground stems (rhizomes) is there location AND their propensity to either grow above or below ground. What you can do to stolons, you can do with rhizomes essentially. So if you cut up a bunch of rhizomes the same way as stolons and spread them on the soil surface, guess what will happen. You got it. You have a new lawn whether you wanted it or not. Hybrid bermudagrass stolon (left) stem and leaves (right) and rhizome (bottom) Question for YOU. What will happen if you rototill a bermudagrass weed area in the hopes of getting rid of it? Answer: You spread it. So how do you get rid of bermudagrass weeds? You exhaust it. You kill it, let it grow a bit, kill it again, let it grow, kill it again, let it grow, kill it again…… In this way you begin to exhaust its stored food supply AND by constantly killing or cutting off its access to sunlight you deny it the ability to put more stored food into its food supply. In the end you exhaust it, weaken it and it dies. You can deny it sunlight by constantly killing top growth back as soon as it gets exposed to that life-giving light a week or so. You can kill the top growth by mechanically whacking it off to soil level or below or killing it to the ground with a poison such as Roundup or even vinegar. Anything that will cause it to die to the ground and not hurt the surrounding environment. The advantage of Roundup is that it is systemic and will travel into the ground a distance and kill somewhere below ground level. To grow back requires more energy and so it will be more effective than just whacking it off or killing the tops. The disadvantage is that it is a weed killer and it may have some adverse side effects. Other chemicals to look at include Poast and Fusilade which are also systemic weed killers and are potentially less damaging to surrounding plants. Nothing wrong with a hoe, shovel and other tools that will help take it to the ground. Regardless, the secret to success will be to stay on top of it and never let it grow back more than a few inches before you knock it down again.

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Watering Citrus in Bullhead City

Leave a Comment / citrus, irrigation /

This is an irrigation basin around a fruit tree. The basin keeps water contained near the tree where the roots are. This basin receives its water from a bubbler (upper left inside the basin). This particular bubbler puts out two gallons per minute if the water pressure is adequate or above (it is pressure compensated which means if the pressure is higher than adequate it will still give only 2 gallons per minute) I have three trees  planted in a “L” shape with the orange and lime on the bottom of the “L” and a lemon on the top. They are about 6 years old and the trunks are about 5” in diameter. They are almost 6 ft. tall and about 7 ft. in diameter. I have the three on a separate circuit with each having a 1/2 “ p.v.c. bubbler providing water every other day at 6:30 a.m. and 8:30 p.m. for 15 minutes. this fills a water well that is about 4” deep and 4 ft. across for about 10 minutes after the water goes off. The water is then absorbed into the ground.             I have tried to let the water run longer but it seem’s to want to go outside of the well and not deeper into the well. I thought about cutting down on the flow so it would run longer and maybe soaked in to the well better but I have not tried that. I have been told to water once every 90 days and let it run for 3 hours. I would have to cut the bubblers just to a drip or it would flood the yard. I don’t know what is the best option. I get a heavy crop of limes now but just a few oranges, and they are half orange and half green. any suggestions?  Remember this is in Bullhead City and it gets very hot during june thru sept A. I forwarded your question to Terry Mikel, retired Extension Horticulturist with the University of Arizona out of the Phoenix office who knows your location very well. Here it Terry’s response: I am familiar with much of the Bullhead City soils and conditions but I have yet to hear that watering every ’90’ days  . . . I should think, or hope someone might have meant or you meant every ‘9’ days .. . That would be certainly a point of clarification . . Irrigating citrus in Hermosillo, Mexico, at USON’s research farm. This is ditch irrigation which is terribly inefficient but still more efficient than flooding the entire field. Water moves toward the roots from the ditch through the soil. The most efficient would be drip irrigation and would not need a basin or ditch but is expensive for farmers with hundreds of acres.             I personally avoid giving calendar or numerical days for watering . . There are too many factors; for example, are you near the river with a heavy clay soil or up on the higher ground where the soil drains much better? . . .             It sounds like you are careful and meticulous about watching the growth and you should check the soil in the morning hours and water when it is dry down a couple inches . .  .Remember to check in the morning not in the afternoon when the heat will dry all soils there down a couple inches . . In the morning the soil will have the cooling  of the night to percolate water up from below thus rehydrating (fancy word for wetting) the upper soil zone . . . If you want to add more water and much more efficiently then change how you add the water . . Set the repeat cycle to  whatever time it takes the initial water to move into the soil and then run the set again instead of spacing it out for hours . . This is called surge watering and it works much better than the delay . . . Maybe next summer you can try and see if you can go more days between waterings without impacting the plant . . If you have a fast draining soil it might not work; likewise, if your soil is heavier you might . . . Don’t forget that a nice thick layer of mulch on the soil surface saves a lot of water from being lost into the air through evaporation . . . There are some great Master Gardeners in your area that are both knowledgeable and grow lots of things under your conditions . . With respect to the lime’s yield vs. the orange’s yield:  My first guess is the orange is a Navel type orange . . They are notoriously sensitive to hot dry condition and their fruits drop like flies . . The plant itself does well but the fruits you get are great but the number you get is usually a disappointment . . .It’s almost a shame they are sold . . . Terry Mikel

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Praying Mantis Eggcase Confuses Reader

1 Comment / beneficial insects, egg cases, eggs, mantid, praying mantis /

Praying mantid (mantis) egg case from reader.  Q. I would like to know what this was on my Royal Blenheim apricot tree in my backyard in North Las Vegas. It appeared to be hard and had circular markings on the part attached to the tree as thought it was an egg casing. I removed it and hopefully it was not a helpful insect. You may use the picture as you wish. A. It looks like a mantid egg case to me. Please be careful. These are good guys and in the future leave the egg cases where they are or move them to a location where they will find lots of food and help you beat the bad guys. Praying mantis (mantid) released on to sweet acacia to battle cicadas.  

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Fertilizer Formula for Keeping Crepe Myrtle Healthy in Desert Landscape

Leave a Comment / crape myrtle, crepe myrtle, desert landscape, scorched leaves, yellow leaves /

Q. We have a crape myrtle tree in our southwest back yard. It gets plenty of water and I fertilized it last month with some Miracle Grow flowering fertilizer. At the time there were some burned edges on some of the leaves and some yellowing. Now it is really burned on the edges of all of the leaves with yellowing. HELP! Crape myrtle growing at Center for Urban Horticulture for 20 Years on Formula Mentioned Here A. A couple of things on your crape myrtle. I have kept crape myrtle growing in raw desert soil in good shape for 20 years at the Center for Urban Horticulture and Water Conservation in North Las Vegas. I used a combination of a general purpose tree and shrub fertilizer (16-16-16) plus an iron application combined with foliar sprays of Miracle Gro.             I don’t really endorse products but Miracle Gro is the one I used and have found to work just fine. You could just as easily use a different good quality foliar fertilizer for flowering woody plants. I apply the granular 16-16-16 in late January or early February using about 2 lbs. of fertilizer applied to the surface of the soil and watered into the roots without it washing against the trunk.             You can make some shallow holes in multiple places under the canopy and water it in thoroughly. At the same time, I also apply an iron chelate, iron EDDHA at the rate of a tablespoon or two scattered in the same holes and watered in so that none of it remains on the soil surface. It is light sensitive.             After about one month of new growth I then foliar fertilize the tree with a Miracle Gro spray or comparable product. I do both of these annually. You can do the same thing (except for the iron) by using a fairly large quantity of good quality compost annually. My guess is you either are missing the iron application, watering too often or not watering deeply when you do water.

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Use Distilled Water or RO Water on House Plants

Leave a Comment / disease, fungus, soil, white spots /

Q. I have a three house plants, a Christmas cactus, “Mother-in-Law’s Tongue” and an Orchid plant.  There is a white “fungus” looking on the top of their soil.  WHAT can I do to get rid of it?  Am I watering too much?  Indoors all the time.   A. It is difficult to diagnose without some pictures but this might be either a salt accumulation from using Las Vegas tap water coming from the Colorado Rivere or it could be fungus (mycelial growth) on the surface. Water taken from Lake Mead (Colorado River) at the Las Vegas location is carrying about six pounds of salt for every thousand gallons of water. Our native desert soils also contain alot of salt. I assume your houseplants were potted with some commercial potting soil so the salt load is probably relatively smaller than our native desert soils. Over time this salt can accumulate in the soil (from the tap water and soil salt) and wick back to the surface of the soil as the water in the soil evaporates. This can leave a white crust on the surface.  Salt deposited on the soil surface from the Las Vegas water coming from Lake Mead and soil salts left behind when the water evaporates. Remove the upper layer of the soil and repot the plant with fresh garden soil. Dilute your tap water with about 3/4 of the volume with distilled or RO water. I would not use pure distilled or RO water as this might cause some problems with your potting soils. Also when you water, make sure 1/5 of the water applied actually leaves the container out the bottom as drainage and discard. This helps to flush out the soil salts. If this white thing is “fuzzy”, this could be some fungal growth. Not all fungi are bad and some are decomposers and work to help break down organic materials that are already dead. Seldom do these fungi that feed on dead things attack healthy plants. Scrape off th surface, repot, keep air circulating around the plant and in sunlight when possible to help keep these fuzzies to a minimum.

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How to Get Rid of Grubs in Your Compost Pile

2 Comments / larvae, white worms /

Q. I started a Mulch bin about 10 yr. ago. It is about 4ft. by 6 ft. on the ground. Today when I went to get mulch for my vegetable garden and found a 1/2 dozen Grubs. How do I get rid of the grub and keep the worms? A. First of I would like to refer you to a pretty extensive discussion I posted on my blog regarding composts and grubs in the compost. http://xtremehorticulture.blogspot.com/2012/07/grubs-in-container-of-garden-soil.html Grubs from compost pile  Secondly, we have to remember that these grubs, like earthworms, are decomposers… they are taking raw products from your compost and helping to convert them into a soil amendment of very high quality through their gut. But we also know that these are potentially problem bugs when they mature so as you already identified it might not be a good idea to cultivate them. If it were me, the compost pile needs to be turned regularly to aerate it so it does not get anaerobic or it will get all sorts of problems. So if you are turning your compost pile then expose these grubs for the birds. Have you ever seen birds follow a tractor that is cultivating a field? the birds know that during cultivation all sorts of goodies are exposed and looking for a free lunch. The other problem you may encounter (I am not sure because it is not clear) is that your compost pile might be in some location where the birds cannot get to it such as a barrel composter or the like. One advantage that worms have over grubs is their ability to move faster than grubs can. If the soil is starting to heat up, they will go deeper quite quickly while the grubs cannot. So another alternative is to cover the compost with clear plastic and heat the upper layers of the compost but allow it to be deep enough so the worms can escape. Keep it at 165F for at least 30 minutes and let the grubs cook and then let it cool down. The earthworms will again migrate back up to the upper surfaces or through the compost. A third way is to remove the worms. Heat up the compost with solar energy (clear plastic again) and re-introduce worms after it has cooled. I hope this helps.

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When Do You Pick Bartlett Pear?

Leave a Comment / brown rot, brown spots in flesh, corky spot, when to pick pears /

 Bartlett pear. The pear on the left is ready for picking. Notice the skin color change from green (right) to yellowish green. Notice also the seeds in the pear on the left are brown. The one on the right is still white. Q. Just this year planted a Bartlett pear, and a Comice for a pollinator. Both have pears on them now. But I thought Bartletts were supposed to ripen in August. I picked one of my four pears, chilled it in the refrigerator for a couple days, then let it sit for about three more days before slicing it. It remained hard as a golf ball and no tastier. When are they supposed to be ripe?    A. Bartletts are picked when the color of the pear turns from green to a yellowish green but still hard. Then you must put it at room temperature to continue ripening and turn soft and buttery. If you let them soften on the tree, which you did not do, the flesh will be gritty with all those stone cells in the flesh. Corky spot on Comice pear If you pick just as the outside skin turns color to light or yellowish green, the flesh has more of a buttery texture. The pear on the left is the right color for picking. Also, the seeds should be brown inside when ready to pick. We are not picking Bartlett until mid September. Just an aside, Bartlett usually does not need a pollinator in most of the Western United States. It does in other parts of the country. Also, be aware that Comice tends to get corky spot in our alkaline soils and may require foliar calcium sprays to correct that.

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There is Lots of Salt in Las Vegas Water and It Can Affect Plants

2 Comments / damage, lemon, ornamentals, pineapple guava, rose, salinity, salt /

Q. I saw that on August 12th you responded to a question regarding yellowing leaves on a Meyer lemon tree.  My tree has similar symptoms – though the yellowing is more spotty and on tips.  You advised to “give it a long deep watering about once every few weeks…to supplement the regular water to leach out the salts…” (emphasis added).             I realize that soil make-up effects watering needs, but can you give me a ballpark as to how many gallons of  “regular water” per week is needed for these trees in Las Vegas in addition to the leaching you recommended?  My tree is approximately 7 feet tall. Should I spread these gallons out over a few days a week, or is giving it these gallons slowing on a single day once a week? A. That’s actually a very interesting question and we have some research to back up the amount. There is about one ton of different kinds of salts (all of these together make up the “salt” content) in one acre foot of water that comes from the Colorado River (Lake Mead).  Rose leaf with salt damage             An acre foot of water is about 360,000 gallons. Unless you are on a well, this represents about 80% of the drinking and irrigation water provided by water purveyors (Las Vegas Valley Water District in the case of Las Vegas) in the Las Vegas Valley.             This sounds like it could be quite dilute but actually when you water to a lawn from Lake Mead it will carry 4/5 ton of salt for every 360,000 gallons that are applied. This translates to an application of 800 pounds of salt for every 1000 square feet of lawn area each year. Salt damage to pineapple guava from salt in the irrigation water             Bottom line, if this is municipal water it carries a considerable amount of salt. If you skimp on the amount of water that you apply and don’t overwater a little bit, this salt will accumulate around the roots of plants. This “little bit” of overwatering each time you water is only about 15%.             So if you apply 100 gallons you really should apply 115 gallons to help move the salts out of the root zone of plants. If it is 50 gallons, then apply an extra 7.5 gallons. Ten gallons means you should apply 11.5 gallons.             Few people are this precise when they water unless they are watering a golf course and paying $1M each year to irrigate an 18 hole golf course. So when you water you can apply a little bit extra each time you water (15%) or you can flush out the salts around the roots by adding an extra irrigation or two during the hot months to keep those salts moving out. I hope this helps.

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Where to Get Pheremone Traps

Leave a Comment / fruit trees, insect trapping, organic pest control, phermone traps /

Delta trap with pheremone inside Q. Do you know where I can get pheromone traps for insects that cause damage in our area and also for thrips that damage nectarines? A. Try Peaceful Valley at http://www.groworganic.com/weed-pest-control/organic-pest-control/insect-lure.html             Pheremone traps can be used to identify what insect problems you have in your backyard orchard and when to spray. Commonly we use them for peaches, nectarines, apples and pears. You will want a trap for each insect and about three or four lures for each trap since they have to be replaced regularly. You will replace the lures about every 4 to 5 weeks until harvest then you can stop. Wing trap with pheremone inside             There are no traps for thrips. For thrips you will need Spinosad biological insecticide which you can get from local nurseries. The label may not say spinosad but may say something like borer, bagworm control. You may have to look at the ingredients to see the spinosad.

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Must Cut the Roots of Italian Cypress to Put in a Block Wall

Leave a Comment / cutting tree roots /

Q. We are thinking of taking out our wooden fence and replacing it with cinder-block wall.  The Italian cypress trees grow along 2 sections of the fence and are about 20 years old.  The new block fence will go on the other side of the wooden fence but there’s the footing to consider which will cut into the root system.  My question to you is, what are the chances of these trees surviving since we won’t know how much of the root will be cut into?  I can send pictures of the base of the tree with the irrigation and the existing fence post to give you a better picture of the area or I can send measurements of what I am planning.  Not sure if the pictures will give you enough detail to make an informed prediction.  This is a picture of the soil around some oleanders after a block wall had been removed and was being replaced. This is not the readers but a friends. The oleanders were being watered in a shrub bed with bubblers. Notice that there is not alot of root development next to the wall. As you know the trimming of these trees are time consuming and/or expensive to hire out.  We wonder if the block wall will bring more heat to the yard and could the heat from the wall burn the tree?   The reason we are considering this project is that with our dogs we are simply worried that if a plank snaps that our dogs will get out and possibly hurt.  We like to rustic look of the wooden fence but we wonder if the block wall might be a better choice for security.  Any thoughts on your part would be appreciated.   A. Let me talk about things I know something about, the damage to the trees if you decide to move ahead with a block wall, replacing a wooden fence.     In the desert, plants grow where there is adequate water. If a good supply of water is on your side of the fence, the roots will tend to grow more in that direction. If there is lots of water on the other side of the fence, they may tend to grow in that direction.  Notice the difference between the shallow fleshy roots of the palm tree (left) and the oleanders on the right. Palm roots grow where there is more air, near the wall.     So try to picture that your tree’s roots will grow more in the presence of water. Would this be on your side of the wall or your neighbor’s side? So if a cinder block wall is constucted, a trench will be dug and a footer laid to support this very heavy wall. You are right, this will definitely eliminate a portion of their root system.    If these tree’s roots are growing toward your neighbor mostly, then these trees will suffer significant damage. If your landscape is dry and the neighbor’s is wet, this might cause severe damage to your trees.     If their water is coming mostly from your yard and your neighbor’s is dry, hen cutting the roots on the side toward your neighbor will probably have a more minimal effect. This picture from Washington State University shows how some plant roots will grow toward a good balance of air and water such as close to the container wall.     Likewise if their water is coming from a water source in small amounts from drip irrigation close to the trunk adn the resest of the yard is dry then the impact will probably  be minimal. In other words,if you are trenching in soil that stays dry for most of the year you will probably be okay.     Another word of caution. The week before they put in the footer water the trees very well. Then let the soil dry out until they dig. Encourage them to dig, put the footer in and backfill the soil as soon as possible to minimize damage to the trees. As soon as possible, irrigate the trees again.

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