Xtremehorticulture

Xtremehorticulture of the Desert

Shoestring Acacia Losing Lots of Leaves

9 Comments / acacia stenophylla, irrigation problem, phyllodes /

Freeze damage to shoestring acacia Q. I had three shoestring acacia trees planted 5 years ago and right now they are losing a tremendous amount of leaves. They are on high flow emitters that are adjustable and putting out a large amount of water. They get watered every other day for 15 minutes. The trees are approximately 20 feet tall.             Is there any reason why they would lose so many leaves?  My understanding with these trees is they produce very little litter but that is not the case. I would appreciate any help you could give me on this. Also there are 4 emitters for each tree about eight to ten feet from the trunk. A. Shoestring Acacias (Acacia stenophylla) has a long record of success in desert regions of the west.  This good history of success is often the result its adaptability and letting the soil dry between waterings.  Flowers of shoestring acacia             Your comment that the ‘leaves’ are falling (Oddity fact: The long thin ‘leaves’ are in fact phyllodes and not true leaves but do the photosynthesis) leads me to think the very frequent watering has set up conditions not conducive for a maturing tree.             After 5 years in the ground I would think your watering cycle could be as much an issue as anything.  Unless you live on some of the very sandy, stable dune soils of Palm Springs or in southern California/southwestern Arizona (Yuma mesa area) trees in the ground for 5 years would be better watered much less frequently with a larger volume at each watering.  This would also include having the source of the water being moved out away from the trunk targeting the water out closer to the drip line of the tree.              Whether there might be a disease involved and complicating the situation is nearly secondary.  The watering regime you described could easily have set up the conditions for the fungus to get started and any treatment would include a change in watering schedule to allow drying between waterings.             Please feel free to respond if you have any questions or other things that might have ‘hit’ the tree. Things like: root damage from digging, severe wind that may have damaged the trunk, certain herbicide (weed killer) usage, pool back flushing, inadvertent chemicals spilled in the area, compaction from parking vehicles in the tree’s shade, etc.              I would be interested if you live in a marginal cold area.  This tree begins to suffer if the temperatures drop to the high ‘teens. Terry Mikel

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Leaves of Shrubs Dry, Burnt and Falling Off Could Be Several Reasons

Leave a Comment / Uncategorized /

Leaf scorch on Cherry Laurel Q. I now water once a week but my shrubs are looking like they might in the hottest part of the summer. Leaves look dry, burnt and falling off. My average shrub is about 3’x3′ and receives 3-4 gallons per week week based on my emitters and time on. Did I cut back too much ? What should I do to try to revive them ? A. Your watering sounds very appropriate and probably what I would have scheduled as well. You have to make sure, however, that the water which is scheduled to be delivered to your plants is actually getting there. Make sure you check for plugged emitters when the system is on. You should have a filter on your drip system even if you are on city water. Leaf scorch on mockorange due to chlorosis and inadequate plant nutrition              It could be several possibilities. I have to walk through them with you because I don’t know much about their previous history. For me, it looks like possibly watering, possibly collar rot at the base of the trunk where the rock mulch sits against the stem, it could be very low temperature damage as possibilities. If there were some very low temperatures just prior to that than this could be just that. If there were no low temperatures than most likely it is not. Then we have to look at watering issues including the rock against the trunk. First determine whether the plant is dead or not. Bend some branches and see if they snap. If they are still supple and just have damaged leaves then it is a temporary setback and they will regrow and set new leaves in the spring. If they snap when you bend them, it may be dead. You will have to pull it anyway so start bending the branches and see how much of the plant is dead. If the amount is sizable, remove it. When you remove it look at the trunk where the rock mulch was resting against it. Planting so shallow that the container mix from the nursery is exposed to the open air and wicks water from the rootball Use a knife or your thumbnail and scrape the bark away from the trunk starting about an inch above where the rock mulch sat and down along the stem to the roots. Look to see if there appears to be a dark area or rotten area in the trunk or bark around the rock mulch line. If there is, then it is collar rot. Make sure on any new shrubs that rock mulch does not lay against the trunk or, in some cases, the plant was not planted too deeply. It should have been planted the same depth as it was growing in the nursery container. Nurseries don’t have many plants this time of year because they are trying to reduce their inventories. You can look for a replacement plant but chances are you may not find one that you like until next spring when it gets warm. I hope this helps.

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Flies A Big Problem in Parts of the Las Vegas Valley

10 Comments / flies, pests /

Q. My husband and I spend four months away from the Valley during the summer. When we returned in late September we could not believe the number of flies in our yard…..and because we are used to leaving our doors open….in our house. We have always bragged to those less fortunate than we are and live elsewhere in the country, mainly in the East, how we have virtually no flying insects in Las Vegas. I’ve had to eat my words this fall….along with some flies. I have not been able to even sit outside and read without being bombarded in the face with these nasty insects. We live in Sun City Anthem….the far southern end of the valley. Is there something blooming/growing in my yard that flies really like? Has anyone else noticed this proliferation? A. Yours is the first report I have seen about an increase in flies this year. I do not know the products that are used for flight control, which is not an area of expertise for me. I would suggest however that somewhere, someone may be using a source of compost or manure products that are attracting flies. The best advice I can give in the safest is to find out what is attracting them and where and address the problem there. If you do not do it this way and simply spray to control flies or use some sort of sticky trap you will not solve the problem but just work on the symptoms of a problem. I hope this helps. PS. Since this was printed in the newspaper several people wrote to me and said they had the same problem. I lived in the valley at the time and I didn’t really notice it. Anyone else have any suggestions?

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White Fluffy Stuff on Cactus Can Be Removed Easily

Leave a Comment / cactus, cochineal scale, red dye, white fluffy /

Cochineal scale on Opuntia or beavertail cactus Q. My wife and I read your interesting article regarding white spots on cactus. Yes, we have them and didn’t know what to do about it. Now we do. I zapped the beavertail with a solid water stream and within seconds the spots were gone and the beavertail looked as good as ever. Many thanks for the simple solution to an otherwise difficult problem. Using a hose and sweep nozzle to wash off cochineal scale A.This is cochineal scale. A very similar cousin to this one was used for making a beautiful red dye. Remember that this does not get rid of them permanently. They will come back relatively soon and you will have to repeat spraying with your hose. If this becomes bothersome then you will have to rely on a pesticide such as Sevin after you hose them off. Make sure you read the pesticide label before applying it.

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Blue Point Juniper Unique to the Las Vegas Area and Probably Has Mites

Leave a Comment / juniper, mite control, mite damage, spider mites /

Q. My 9-foot tall cone-shaped blue point juniper has a huge area that is turning brown. What can I do to restore the burnt-like brown to a normal green? I looked at the brown area closely and found whitish cobwebs with little white dots on the area.  What mites are inhibiting the juniper and what is the best way to get rid of them? Click here to see a Blue Point Juniper A. Junipers are notorious for two things and uprights possibly a third; spider mites which are frequently associated with webbing, root rot when they are planted in heavy soil or if they are watered too frequently or both and possibly borer damage. Damage from overwatering usually appears at first as single branch dieback.             Blue Point Juniper is a small to medium sized upright very small tree or shrub that is cone shaped with a bluish green color. This is a very pretty plant in the right landscape. I have not seen very many of them growing here in our landscapes. Webbing from spider mites             Spider mite damage can cause browning but normally the surrounding foliage of the juniper appears to be dusty looking. Most of this dustiness appears, to me, to be dead mites. Spider mites are extremely small, about the size of the period at the end of this sentence.             The webbing may not mean anything. Just because there is webbing does not mean it has a problem with spider mites. Spider mites can be of a type that creates webbing or it may be of a type which does not. Secondly, there are good mites and bad mites. The good mites help to control the bad mites so spraying a chemical aimed at controlling mites may just backfire.             The best way to determine if spider mites are an issue is the paper test. Take a white sheet of paper and a branch of the juniper and slap the branch or foliage against the white paper. Hold the white paper still and look at the dust or debris on the paper. If spider mites are present you will see a number of tiny dots the size of a period moving on the paper.             Usually spider mite problems begin developing during the heat of the summer, not when it is cool. Soap and water sprays once a month during the summer is a common way to try and keep spider mites from becoming a problem. If the problem is severe than that may require a miticide or insecticide for controlling mites. Scanning electromicrograph of spider mite the size of a pencil dot.             Since you have had this juniper for quite a while it is probably not root rot due to overwatering unless you have recently changed the irrigation pattern or if there has been a release of water near the plant in the past few months. This might be from a leaky irrigation valve or broken pipe.             Borers in major limbs or branches are a problem on some upright junipers such as the Hollywood twisted juniper. It might be on this plant as well. Boring insects that tunnel into these branches cause these limbs to die while the surrounding area stays green. Pull the canopy of this juniper apart and look at the limbs inside of it to see if there is sap coming from a limb or limbs. The damaged limb is pruned out just below the sappy area.             Once a branch is damaged and it has turned brown it is difficult to get it to come back to green again. If the damage is not severe it might come back over time if the problem that caused the browning is corrected. If the damage is severe it may be permanent like the toothless gap of a smile and never repair itself.             The nurseries to carry a green paint that can be used to help the plant cosmetically. This is a problem with plants that grow beautiful, perfect cones of canopy. Response Thank your very much for your detailed response.  My two blue point junipers are doing quite well now after I sprayed them with insecticide.  I live in Sun City Anthem and you are right–nobody else has these trees.  Mine are now six years old, eight feet tall and trimmed to a conical shape.

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What are Those White Fuzzies on My Plants?

3 Comments / white egg cases, white fuzzy disease /

 White fuzzies on bell pepper. Q. I have one coreopsis among many that also is showing the white fuzzy on the stem. In addition there are black specks on the leaves. Same thing, two different stages, or two different problems? The coreopsis in general is sickly, and I see that something is eating the leaves. Planted around the edge of the watering basin (5′ in diameter) of an old peach tree. Watered by filling the tree basin twice a week. I have not sprayed with anything. A. Those are the egg casings of a couple different critters .  One can be one of the Sharp Shooters (not the ones that vector Oleander Leaf Scorch/or on grapes Pierce’s Disease – Same bacterium different stains but all carried by the Glassy Wing-, Smoke Tree-, and Emerald- Sharp Shooters)  . . . These Sharp Shooters are kind of cool when if standing under a tree with the sun on the other side of the tree i.e. back lighted you can see the raining of fluid from the Sharp Shooters . . Sometimes if you stand under a tree you can feel the moisture raining down . . Just try and remember it’s bug pee . . Another critter with similar egg cluster is a close relative that passes through our lives nearly non-detected except for the egg casing . . White fuzzies on Coreopsis They tend to show up on just a few plant stems and a few more plants on their petioles .  . Most think it’s a fungal infection . . The Sharp Shooter impact to plants is negligible so in this case the education value far outweighs any possible impact to plants . . -Terry Mikel

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Reader Had No Luck Using Spinosad and Soap and Water on Leafhoppers on Grapes

Leave a Comment / kaolin clay, leafhoppers, sunburn, surround /

My picture of grape leaf with leafhopper poopoo (the black specks) This came in from a reader regarding his lack of luck using Spinosad or soap and water sprays for leafhopper control in grapes. I want to share my experience using the diluted spray of a wettable clay compound to prevent leaf hopper damage to our grapevines. Last year our grapevines were greatly infested with leaf-hoppers. Repeated applications of insecticidal soap and spinosad could not make a dent in the insect damage. This year, we began early, when there were about 10 leaves on each arm of the vine, trying a natural wettable clay powder called Surround, that leaves a white coating of clay on wherever sprayed. We flocked the leaves both sides as best we could in a manner reminiscent of Christmas tree flocking, and left a white residue on both sides of the leaves that was intended to make leaf hoppers unable to damage the leaves through the clay barrier. The reapplication of spray becomes more difficult as the season proceeds and requires a definite commitment of the gardener to persist. Surround application to pear, turns the foliage white from the clay We can now say that for all our efforts, leaf hopper damage is much the same as last year. But there are two positives. First, the grape skeletonizer eggs don’t have a chance as they are dead abornin’. Second, the birds who are inclined to peck every last one of our figs, do not peck the whitened figs. So at last we can have some tree-ripened fruit. -Harrison Thanks Harrison. I would like to post your observations. On the other hand I have had luck with Spinosad on leafhoppers on grapes for several years in a row. It does not totally wipe them out but it did reduce the numbers considerably over previous years. And we never really saw damage to the berries themselves with the leafhoppers they were just a nuisance. As far as Surround goes I have used it at the orchard for a couple of years to reduce sunburn on apples and never really got it to work well and it was a pain to apply so gave up with about half of a 50 lb bag left.

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Queen Palms Must Be Treated Like Queens If They Are to Survive in the Desert

Leave a Comment / irrigation of palms, palms, queen palm /

Queen palms planted in front of a casino dead after winter freeze in Las Vegas Q. Hi, I’m a follower of your blog and I have two questions if you don’t mind answering them.  First, what is your overall opinion of queen palms in the Las Vegas climate?  It seems like every winter they struggle but eventually come back in the late spring, early summer.  My second question is, what is the best water requirement for a 15 gallon queen?  Is it best to have a few 4 gallon emitters over an hour time or many 1 gallon emitters over a few hours?  I’m just curious what is the best way to water them.  Also do I water every other day or 3 days a week in the summer months?  I would greatly appreciate a response!  Thanks in advance A. Queen palm is not the best choice in palm trees for our climate in general. This is a harsh environment for them particularly our very low winter temperatures, our lack of humidity, strong dry winds and poor soils. Once we recognize this then we can begin to address the situation and determine if a queen palm is a good choice for us and what we will have to do to get it to work here. The absolute worst thing you can do with a queen palm is put it directly into a very our harsh climate, fully exposed to the elements and not amend the soil or amend it very little.             If you were to plant it in our desert environment then you would try to find a place for it out of strong winds, protected from extreme winter low temperatures and amend the soil adequately at planting time and use organic surface mulches that break down and improve the soil over time. This is hard to find here in Las Vegas so planting them here will have poor results unless you can find this ideal micro environment; not impossible but hard to find. Queen palm planted in rock/desert landscape and yellowing or chlorotic due to poor soil conditions             Palms are high water users in the small space that they occupy. So water does not have to be applied over a large area but should be applied in an area equal to at least half of the spread of their canopy. The water should be applied so that it soaks the soil down to about 24 inches each time you water.             The soil should never go totally dry and surface mulches will help in this. Also planting understory plants that require more frequent watering will also help. How many gallons does a 15 gallon palm require? About 7 to 10 gallons each time you water or about half to 2/3 of the volume of the container (even though a 15 gallon container does not hold 15 gallons).             Four emitters would be good in a square pattern about a foot from the trunk. How many minutes (or hours) should you run it? I don’t know. Depends on your emitters. If these are 2 gallon per hour emitters then 60 to 75 minutes.             The other question to answer in watering is how often. You are asking about a one day difference in your watering. I really cant tell you that without knowing more about your soil and how much water it holds. If it drains freely and doesn’t hold much water then every other day now. If this is a soil that can hold a bit more then every third day would be good.             Why don’t you try using a houseplant soil moisture meter to help determine the how wet the soil is before you irrigate. Once you do this a couple of times it will become more intuitive about how often to water.

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Potatoes Look Dead and Never Bloomed

Leave a Comment / potatoes dead, what killed my potatoes /

Q. Thank you for all your help! New problem: my potatoes are all about dead. They looked great in the Spring, but they never even bloomed. Is there any hope? Why did they die? I have them in a raised bed. Potato tuber forming from underground shoot (stem) coming from the potato plant stem A. It is really hard to say what is going on without more information but let me run down the ideal situation for you and maybe you can figure it out. If I were to take a guess, I would guess it may have to do with your soil or watering or both. The ideal soil is a sandy soil and not a heavy clay type of soil. Sandy soils allow for good tuber production, easy harvesting, fewer disease problems which attack the roots and irrigations that are easier to manage. Potatoes growing with drip irrigation Potato plants can be started by quartering your favorite potato tuber with a clean knife and letting the cut tubers heal for 48 hours inside the house or in a cool area. You can also dust the tubers with a fungicide if you like. The other way, a preferred way, is to buy potato “seed” (which is really small potato tubers or tubers that have been cut and allowed to heal) that have been officially “certified” to be free of diseases and viruses. Of course this is more expensive but reduces the chances of disease in your potato plants. Potatoes plants (and tubers for that matter) are sensitive to freezing temperatures. For this reason we plant potato “seed” very soon after we are fairly certain spring freezing weather has passed. This can be any time from early to the end of March in our climate. Planting later than March will probably not result in very good production. Potato seed is planted about two to three inches below the soil and about twele to 18 inches apart. If the variety of potato is a real vigorous grower then space them further apart (18 inches). A better way is to sprout the seed before planting. This helps to get them off to a good start. You would sprout the seed in a shallow box in the house in a room that is warm and has plenty of light. Once the seed sends up sprouts that are a few inches long, plant them carefully in the prepared soil about two inches deep and about twelve plus inches apart. Water them in thoroughly. Make sure you have put a good high phosphorus fertilizer in the prepared bed and the soil has been composted well. Once the potatoes have shown some good growth to maybe 12 inches in height, pull the composted soil around the plants so that only a few inches of potato plant is peeking above the soil. This is called hilling and is needed so that the potato stems send out side shoots where the potatoes will form. If you don’t do this you probably won’t have very many potatoes.  Keep hilling around the potatoes every couple of weeks as they keep growing above this soil that has been pulled around the stems. Keep the soil moist or mulch the potatoes so they don’t get knobby. I hope this helps. You can harvest any time tubers have formed. Just carefully dig down around the stems and feel around for tubers, cut and remove.

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Something’s Eating My Basil and It’s Not Me!

Leave a Comment / eating basil, pesticide /

Q. Sir ,this picture shows my  chewed “genovese ” basil ,if you enlarge the picture you will see small insects resembling those who ate the leaves of the vine . What can I do without poisoning my basil? Thanks for your answer. Luciano’s Genovese basil with damage Regards ,Luciano A. I enlarged the picture gradually up to 800% but still could not make it out. The feeding looks more like a larger pest such as root weevils or caterpillar (larvae of moth) to me. Smaller insects would be more likely holes throughout the leaf rather than on the edges of the leaves.  Soap and water sprays have to come in contact with the insect.             Organic types like Bt (Dipel or Thuricide) or Spinosad will focus a lot on the caterpillar types and give you some overnight protection if done at dusk and would be a good first effort. Follow label directions. If this does not work then I would move toward one of the pyrethrum or pyrethroid products with vegetables or herbs on the label. Check the ingredients for these products.             Sevin might also work but apply only at dusk since it is lethal to bees which will be visiting basil a lot unless you keep the flowers clipped off. Spinosad also is tough on bees so use it only at dusk.

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