Xtremehorticulture

Xtremehorticulture of the Desert

Argentine Cactus is Yellowing

Leave a Comment / shading cactus, sun damage to cactus, why is my cactus yellow /

Q. I have two quite large Argentine Giant cactus, each with many pups they’ve offset from their base. They are both located on a West facing patio, one is in a large pot and the other is planted in native soil. The one in the pot always turns yellow on its south side this time each year. The one in the ground does not. The potted one has been in that pot for about seven years, and I generally give it fertilizer a couple times a year.  I think I’ve even tried a bit of iron, though I don’t really think that is the problem. A. The usual reason for this cactus becoming a yellowish in color is sun damage, particularly if it only on the side facing the sun. Other possibilities could be the buildup of salts in the soil, lack of nutrients, root damage and cold damage. But the bottom line is stress. Because the cactus has a restricted root system and has no ability to take water from deeper or surrounding soils, the plant may be more stressed in a container than the one planted in the ground. That’s how I would view it. The yellowing is resulting from stress. I think the plant in the container will stress more easily than the one in the ground. This cactus will turn yellow (side facing the sun) in a stressful microclimate when planted in the ground. You should consider all of these as possibilities but I think it is most likely sun damage or bleaching of the plant tissue by intense sunlight. They will do a little bit better without so much intense sunlight, particularly the one in the container. All that being said, make sure that the soil has adequate drainage and you are not watering too often so that you can eliminate root damage because of the soil kept too wet. Choose a good fertilizer for it. I like Cactus Juice as a fertilizer for cacti and succulents. I’ve had a lot of good reports from people using this fertilizer on them. When you water it next time make sure you add enough water so that a good 20% of the water applied comes out the bottom holes or moves past the roots to keep the salts flushed.

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Cactus Baby Separation From Mother is Easy

Leave a Comment / how to propagate cactus, how to separate pups from mother cactus /

Q. Is there any way to separate the babies from the mother cactus when they are joined along the stem or do you just let them grow? A. Yes, you can separate the baby cacti, or the pups, from the mother cactus even if they are growing along its trunk. However, I would let them grow. They are quite interesting in a landscape when they are allowed to grow more naturally.             The easiest cacti and succulents to separate are those which produce what we call “offsets” or sometimes we call them “pups”. Offsets are pups that are produced separately from the mother plant, usually on short rhizomes. The rhizome is cut which separates the pup from the mother cactus. The pup then is totally on its own and will send down its own roots and establish itself.             Pups are any “baby cactus” or succulent whether it is an offset or attached directly at the stem. When pups are attached directly to the stem they can be separated from the mother plant with a sharp, sterilized knife. The pup is allowed to “heal”for several days in a warm environment without any direct sunlight. This healing produces callus tissue which protects both plants from dehydration and diseases. Once the healing has finished, the pup is placed on top of soil with extremely good drainage where it can root. The soil is moistened about every three weeks during this time. No rooting hormone is necessary. This may not be the same cactus, but you can get an idea of what it might do. http://www.delange.org/CactusArgentineGiant/CactusArgentineGiant.htm it can add a very interesting element to your landscape if left alone.

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Pecan Black Bitter Nut Damage Due to Leaf Footed Plant Bug?

Leave a Comment / bitter taste of pecan, black spots on pecan meat, insect damage to pecan nuts, pecan kernal, pecan nut /

Q. I have several pecan tree and some of the nuts I cracked this year have black spots on the nut and others have a soft brown film on part of the back of the nuts. What caused these problems and what can I do to prevent it.? The pecans have been producing for 30 years and  I have never had the problem until last year. A. I am guessing that these black spots are on the meat or seed that you normally eat. I am also guessing that when you eat this pecan meat that it is bitter. If you are moving your head up and down in agreement then this is insect feeding damage by one of the stink bugs. Visit this page to see black spots on the meat We do have stink bugs in Las Vegas but one particular type of stink bug or a close relative is the leaf footed plant bug which also damages pomegranates, pistachios and almonds. Closeup of leaffooted plant bug. Photo contributed by Bill Stillman. This feeding damage can cause the entire nut to drop off the tree or can cause these black spots to appear on the meat. To eliminate this kind of damage you would have to spray the entire tree with an appropriate insecticide. You would have to start early because they will begin building their population on the tree as early as April. These insects also feed on tree leaves, vegetables and all of our major fruit trees. They overwinter on ornamental plants that remain evergreen in our landscapes. The adults have wings so they can fly from neighbor to neighbor. Soap and water sprays will kill these insects if they are sprayed directly with this concoction. Soap and water sprays have no residual so no poison remains when it dries. This can be an advantage and disadvantage. Other sprays are fruit and nut sprays that contain synthetic pyrethrins or pyrethroids. These will also work but the main problem you will have is getting the spray to cover the large tree from head to toe. These black spots can be broken off of the nuts and the nuts can be eaten with no problem.

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Why Carolina Cherry Laurel Struggles in the Desert

Leave a Comment / carolina cherry, carolina laurel, why is my cherry laurel dying /

Picture sent by reader of  the Carolina Cherry Laurel Q. One of my Carolina cherry trees has some branches with brown leaves and the branches were easily broken off.  I have attached a picture of one of the branches.  There is an area of the main trunk, about halfway up the tree, which is very black. A. I receive a number of questions regarding damage to Carolina cherry or that they don’t look very good. The majority of the reasons why this plant struggles here is because it is native to the southeastern United States where the soils are rich and moist. They will struggle here if they do not receive TLC. The other problem may be where they are planted. Closeup of the trunk. This is usually due to sunburn on the trunk due to planting in very hot locations in the yard and leaf loss that allows direct sunlight to damage the trunk. Leaf drop of Carolina Cherry Laurel. In this case the cement and bricks surrounding the plant could poise some problems.             Your Carolina cherry laurel most likely has been damaged by the intense sunlight of our desert Southwest. When damaged by strong sunlight, we see limb and branch dieback accompanied by leaf drop. Often times this damage is black with brittle limbs and bark that peels. Frequently the tops of these trees will die as well. They tend to look very sparse in our climate and soils.             Because this plant is not a southwestern US native, we have to be careful with it here. When planting it, the soil must be enriched with compost at the time of planting and the surface of the soil should be covered with wood mulch, not rock mulch.             They struggle in very hot locations. This includes the south and west exposures of the landscape particularly close to the very hot walls. They perform better if clustered with other plants with similar soil and water requirements. Same CCL as above but showing one is performing better than the other when growing under similar circumstances. It is possible the one on the left will do the same thing over time. It is also possible there could be some root disease problems due to the cement and possible overwatering and/or collar rot disease.             They may develop yellow leaves which would be corrected by applying an appropriate iron fertilizer. The one I always recommend is the iron chelate EDDHA. It is stable when applied to the soil regardless of the alkalinity. This is not true of other iron fertilizers.

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Growing Tropical Hibiscus in the Desert is Not Easy

Leave a Comment / how to grow hibiscus, roselle hibiscus, why did my hibiscus die /

Tropical hibiscus growing in Las Vegas Nevada in the Mojave Desert. Q. I’m forwarding pictures of my existing hibiscus that turned brown this past winter.  It actually looks like there’s some growth on two of them but the others look pretty grim.  Should I give them a chance to grow or start again?  Also, if I do attempt to let these live should I trim them to the ground? A. It looks like your hibiscus really got hammered this past winter. And this winter was not really that cold. These are most likely tropical hibiscus. Hibiscus is a common name for a number of different plants with different attributes. These range from the tropical hibiscus to plants that we call hibiscus but are winter hardy in our climate. Roselle hibiscus growing on MoCa Farm in the Philippines. Your hibiscus was probably one of the tropical or subtropical types. Judging from your picture, the soil looks like it was hardly improved at all and rocks are strewn along the surface. These issues must be addressed if you expect these plants to do well at all in the future. They need a lot of soil amendment added at the time of planting. Even though they can handle a lot of heat, they cannot handle the extreme heat and low humidity of unshaded south and western microclimates of the Mojave Desert. They will look best protected from late afternoon sun and the soil covered with organic mulch. They will also do better if surrounded with plants that need moist, organic soils as well. I would cut them to the ground in the spring, fertilize and water them and see if they will come back. Pull the rock away from them and put down a layer of compost about one inch thick followed by three inches of wood mulch on the surface. Keep the wood mulch away from the stems of the plants by about 12 inches. In the future you will treat them like herbaceous perennials; let them grow during the warm and hot months and cut them to the ground after they freeze back. Pile mulch around their base that is three to four inches deep. This may be enough to minimize winter cold damage. Here is an article we (MoCa Farm) wrote for Food Tank on the growing and culinary use of Roselle hibiscus in the Philippines. http://foodtank.com/news/2014/02/a-love-affair-with-roselle 

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Vegetables and Herbs Presentation for Arizona Master Gardeners

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This is the Presentation I made to the Arizona Master Gardeners in March, 2015, on vegetable and herb growing in the Mojave Desert. I intended it as a beginning primer for newcomers to gardening in the desert. If there is a problem downloading this document, email me at [email protected] and I will send it to you.

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What Vegetables Can I Plant in March?

2 Comments / What vegetables can I plant in March /

Here is a list of vegetables you can plant in March in the Las Vegas Valley. The Las Vegas Valley is around 2000 foot elevation (650 meters). Lower elevations can start earlier than this. Higher elevations can delay planting a bit. March Bush beans (s), broccoli (s,T), brussels sprouts (T), cabbage (T), carrots (s), sweet corn (s), eggplant late in the month (T), green beans (s), pole beans (s), kale (s), kohlrabi (s), lettuce (s), onion sets, onions (T), peppers late in the month (T), potatoes, radishes (s), spinach (s), Swiss chard (s), tomato late in the month (T), turnip (s) T= tramsplants are best s= cam be started by seed

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You Can Still Prune after New Growth Starts

Leave a Comment / How late can I prune fruit trees, when to prune fruit trees /

Q. Took your recommendation and planted a Dapple Dandy pluot and Santa Rosa plum in the same hole about 18 inches apart. New growth has already started to appear. What I’d like to do now is cut and lower the height of the Santa Rosa plum to the same height as the pluot. Is it too late to do that? Pluot and plum planted in the same hole. Santa Rosa plum is one of the best pollinators for Pluots. The fruit trees are whitewashed to help prevent sunburn. A. No, it is not too late to prune. People are mistaken when they think the only time to prune is during the winter months and when new growth appears, it is no longer permitted. This is a not correct.             One of my professors used to say, “The best time to prune is when the pruners are sharp.” I still agree with him. However I would alter that by adding, “as long as it is a hand pruners.” If you are removing large diameter wood using a saw or loppers timing is more critical.             In short, go ahead and lower the height of that pluot. Make sure you whitewash the upper surfaces of any exposed limbs to reduce sunburn unexposed branches. I will talk about summer pruning next month. I will post more about this topic on my blog.

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Be Careful with Fertilizers for Tomatoes

Leave a Comment / How to fertilize tomatoes, what fertilizer is best for tomatoes, what should I use to fertilize tomatoes /

Q. I was reading an older article from Linn Mills about foliar fertilizing tomatoes. Linn was saying to spray tomato plants with phosphorous. I read an organic article in which they use fish-seaweed extract in your opinion which is better to use? High phosphorus fertilizers do not cause all vine and no fruit A. Great advice from Linn! You want to give tomatoes a complete fertilizer at the time of planting. You can use organic sources or conventional fertilizers. It will not make much difference to the plant. These can be applied to the soil or to the plant leaves if they are a liquid. After an initial application of a fertilizer, phosphorus should be in abundance, not nitrogen, with further applications. The problem with organic sources like compost added to the soil at the time of planting is that the fertilizers or nutrients they contain last so long. This is because the nitrogen in the compost is released slowly over a period of several months. This is not true of organic foliar sprays like seaweed extracts. An overabundance of compost added to the soil will cause tomatoes to produce a lot of vine and delay flowering. This is not necessarily true of their close cousins, peppers and eggplant. If flowering is delayed in tomato and begins during the heat of the summer, it can result in little to no fruit production. Example of a high phosphorus foliar fertilizer to stimulate flowers and fruit Inexpensive conventional fertilizers (farm fertilizers) release its nutrients quickly. One big shot is released during the first few irrigations and the amount of fertilizer available to the plant diminishes quickly after that. These quick release or conventional fertilizers, at least the nitrogen component, lasts four to six weeks and 80% of it is gone. Quick release fertilizers, applied at planting time, are perfect for tomato growth and fruit production. Foliar fertilizers, fertilizers applied as a liquid to the leaves and stems, act very similarly to quick release fertilizers applied to the soil. Liquid fertilizers applied to leaves last a very short time; 2 to 3 weeks. Foliar fertilizers need to be applied more often than fertilizers applied to the soils. Foliar fertilizers should always contain a wetting agent to help that fertilizer gain entry inside the plant. We want tomato plants to gain size quickly for about four weeks before they set fruit. If nitrogen is released in large amounts after that time, it will likely cause a delay in flowering and put on leaf and stem growth instead. Example of a 1:1:1 fertilizer If you are foliar feeding, you should have at least two different types of foliar fertilizers, maybe even three. The two which are most important are a high nitrogen content (highest first number) fertilizer and the second is a foliar fertilizer with high phosphorus content (highest second number). If you get a third one then make it a fertilizer in a 1:1:1 ratio of nitrogen, phosphorus and potassium. Whenever possible make sure the third number, potassium, is also high in all three fertilizers or make sure it is applied to the soil and available to plants.

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Help Save My Photinia from Dying

Leave a Comment / iron chlorosis, leaf scorch, leaf yellowing /

Q. Our red tip photinia appears to be dying. It is 8 years old and receives full sun. The leaves are turning brown and dry.  Is there a disease causing this or is it the very hot weather we have experienced this summer?  We fertilize and  apply iron regularly. Photinia with iron problems and soils with lack of organic matter A. The usual problem with Photinia occurs when their planted in desert landscaping with rock mulch covering the surface of the soil. They are planted with some soil amendment in the planting hole which disappears in two or three years. Sometime during the fourth and fifth year Photinia begins to develop yellow leaves. Photinia with the beginning of the decline These yellow leaves become a brighter yellow and begin to scorch around the edges. If this problem is not fixed, Photinia gets worse and we see die back of the stems and the canopy of the plant opens up and looks very sparse. The problem is the rock mulch for this plant. They do not like it. They like organic soils, not soils covered in rock. You have two options. Pull the rock mulch back and add compost to the soil around each of the Photinia about an inch deep and scratch it into the surface. Next cover the area with wood mulch, not rock mulch. Add iron fertilizer and a regular fertilizer to the plants. Water them in thoroughly with a hose. Cut the Photinia back close to the ground and let it regrow. Hopefully this will get them off to a good start this spring. Continual additions of compost every two years will help this plant stay healthy. The second option is to dig and remove these plants and start all over. Make sure the soil they are planted in as 50% compost mixed with it. Cover the soil with wood mulch and grow them out. Fertilize once a year in January with the commercial fertilizer for trees and shrubs and make sure you add an iron fertilizer at the same time.

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