Xtremehorticulture

Xtremehorticulture of the Desert

Planting Desert Spoon During the Heat

Leave a Comment / five gallon, heat, time of day /

Q. I purchased six each, 5-gallon sized desert spoons but I haven’t planted them since it’s been so hot. Should I plant them in the early morning when it’s about 90 degrees F? I have watered them three times a week. This desert spoon is in a container. The container is too small and it may not have enough soil or amended soil in it. Also it may need to be watered more often. Two headed desert spoon. The central growing point (bud) probably died and the plant suckered. A. It’s not the best time of year to plant them but yes, if you are going to plant them, plant them at a time during the day when it’s cooler and plant in wet soil. I think the major problem is the sunlight and not temperature. Never plant in a dry hole. In other words, make sure the hole has been filled with water the day before, or at least the soil is wet when it’s planted. If you elect to plant during the heat, plant as quickly as possible so the roots don’t dry out. Planting in a dry hole during the heat of the day is a common mistake made by contractors. The hole dug for this container was a bit larger than needed but you get the idea. University of Arizona recommends a planting hole three times wider than the container. So in your case three times the width of a 5 gallon container. How deep its dug is only important when the soil does not drain well. A hole filled with water should drain overnight.             The hole for planting should be dug three times the diameter of a 5-gallon container, even if it’s a “xeric” or desert plant. It’s not important to dig the hole deep unless it’s necessary. Every time you water, the water should wet all the roots to a depth of 12 to 18 inches. Root depth of plants is directly related to their height. Refer to https://wateruseitwisely.com/saving-water-outdoors/plant-watering-guide/

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Growing Blueberries in the Desert

Leave a Comment / alkalinity, container, location, pH, soil /

Q. Can we grow blueberries here? How difficult is it? Yes, these blueberries were grown in Las Vegas. But at what cost? A. It is one of those questions that “we can but with what degree of difficulty?”. I am a lazy gardener and don’t like to put a lot of effort into “out of place” plants. I have a saying, the more out of place a plant is in its needs, the more time, money, and effort we have to put into it to get it to grow or produce. Take mangoes for instance. We can grow them here but what would be our “cost” of production? Yellowing of the plant leaves is just one of the hurdles that must be overcome when growing blueberries in the desert.             We know that blueberries prefer soils that are lower in pH (about 4.5) and don’t care much for the highly alkaline soils (closer to 8.0) of the desert. That’s a 1000 percent difference! Soil pH is our first hurdle to overcome. Are we willing to monitor the soil and amend it year after year? Use very fine ground (injectable) soil sulfur, not granular or “flowers” of sulfur for lowering the soil pH. I didnt get a picture of blueberries growing in a container per se but if you look closely you can see that this blueberry is growing in a container in Las Vegas. More than a curiosity? I wouldn’t go into commercial blueberry production in the Mojave Desert. Use containers so the soil is “contained” and easier to amend. Plants need good drainage. Use pine bark for good drainage and amend it with a very small amount of sand for stability. Blueberries have shallow roots so containers should be shallow; 10 inches deep. Place plants on the east side of a building so they get shade in the afternoon.  Southern highbush blueberries can tolerate the heat but not direct sun. Blueberries need at least 6 hours of full sun every day.             If you are willing to monitor and amend the soil annually (and grow blueberries as a cuiosity) then grow at least one of the Southern Highbush blueberries such as ‘Reveill’, ‘Sharpblue’, ‘Misty’, or ‘Southmoon’. Many of the Southern Highbush blueberries are self-fruitful but you may get larger berries and increased production if they can cross pollinate. But stay away from commercial production unless you do it (and is cost effective) in a greenhouse.             Apply fertilizer once every two months when they are growing to get good crops. The biggest hurdle to overcome when grown in our climate and soil is the soil pH.

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Large Percentage of Pomegranate Fruit Comes from Older, Larger Wood

Leave a Comment / green, older wood, size, split pomegranate /

Q. I need some help.  I planted a pomegranate tree about three years ago. The tree looks great and there are always lots of fruit. The problem is that by the time the fruit gets up to about 2″ in size they are splitting open.  Can’t figure out the reason and I am yet to harvest a good pomegranate.  It gets full sunshine in summer and water 3-4 times a week. Any suggestions? A. Are the arils (pulp) sweet? Maybe it is ready to harvest.             First of all, the fruit should be larger than that. The fruit should get larger as it gets older and the tree is pruned correctly. A high percentage of small fruit is produced on smaller branches.  The number of large fruit is more as the tree gets larger. A higher percentage of larger fruit will come from the larger branches. That’s the reason for getting rid of the much smaller suckers. Get rid of the suckers at the bottom of the tree and force production on to about 5 or 6 main limbs that you keep. The best and larger fruit are produced on older wood. Small fruit are produced on young and smaller wood. I think the reason why some California growers prune toward only one large central trunk is that the fruit collected from it gets larger earlier.  Pomegranate pruned into a tree shape instead of a bush.             If the fruit is green when it splits, the same is true. The tree was not getting enough water as the fruit was getting larger. The fruit starts to become red, or red or white, or red and white when it starts into its last ripening phase. Yellow pomegranate brought to me in Tajikistan.             Fruit splitting is oftentimes a harvesting problem. Taste the seeds inside (called the arils) and see if they are sweet or ‘as expected”. There is a wide variation in flavor so don’t be surprised if the fruit taste is “puckery”. If the arils are sweet or “as expected”, it might be ready to harvest. Pomegranates are ready to harvest, depending on the variety, from September (‘Utah Sweet’) until early December (‘Wonderful’). The fruit should not crack unless they are past their harvest time. Young fruit still green and developing. It is several weeks away from harvest and sweet.             If the fruit are splitting before they are ready to harvest (not sweet yet but getting there) then it is a watering issue. Just like melons, as the rind sets up for harvest (sugars are accumulating) watering becomes critical. Watering when the rind gets hard (and it doesn’t need it) will split the fruit. w Pomegranate rind split and ready for harvest. Probably ‘Wonderful’.

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Mastic Tree Problems

Leave a Comment / growth, leaf change, mastic, newly planted, pistache, Pistachio /

Q. Can you tell from the attached pictures what might be happening to our mastic tree? Mastic tree. A. My guess is that the new growth is filling a “hole” made when the plant became a shrub. Mastic is a Mediterranean tree or shrub that grows slowly and naturally as a bush, to about 20 tall by 20 feet width. It requires, at the least, annual pruning when it is young to shape it into a single or multitrunked tree. It is best used as a background tree or shrub and not a smaller version of the larger Chinese pistache. It is not as pretty. It lacks fall color, tends to be shrubby, and smaller, but does have red ornamental nuts when they are young and before they ripen around August.             If this plant were mine and I wanted a small tree instead of being shrubby, as it tends to be, I would start to prune it in the winter or late fall months. Make a decision whether you want it as a single or multi trunk tree and make the appropriate cuts.  I would expose the trunk or trunks of this tree up to my knees by starting at the bottom of the tree. I would eliminate any growth below my knees and keep any upright growth. If I saw any suckers at the base, I would eliminate them. While it’s young, I would eliminate any growth growing downward or horizontal. I would concentrate most of my pruning efforts on keeping any upright growth to make it look like a tree and give it some height.             Water it like you would an olive tree. It is mesic in its water use. It will attract the leaf footed plant bug. Shearing this tree with hedge trimmer is a mistake. Fertilize this tree once or maybe twice lightly with a standard landscape fertilizer such as 16-16-16.

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Sap Coming from Small Fruit Trees Usually Borers

Leave a Comment / fruit trees, landscape trees, newly planted, ornamentals, sun damage, sunburn /

Q. I have some newly planted peach and nectarine trees with sap coming from them. They don’t look healthy. Sap oozing from newly planted fruit trees nearly always borers. A. Borers are most likely the problem. On small, newly planted fruit trees it doesn’t take many borers to kill the trees. They usually “attack” the south or west sides of a trunk or the limb of a tree. That’s where there is sun damage. Painting these trunks and limbs with white latex paint lowers the surface temperature about 4 or 5 degrees. It may be enough in some cases. But shade is better. Borers will usually start to damage the hot side of a tree, either west or south.             The sun plays a role also. Direct sunlight on the trunk of a thin barked fruit tree can be a problem. The “smell” of sunburned and dying or dead limbs and trunks attracts female borers that are looking to lay their eggs, scientists believe. When limbs and trunks of newly planted fruit trees have sun damage, then borers are more likely to be found. This is a locust tree. Borers “smell” or find their way to the sun damaged areas of any tree. Here the top of the branches have been damaged by the sun. The bottom of branches out of sunlight are undamaged.             What to do?  Shade the young tree from Western and Southerly direct sunlight. Paint the trunk with diluted white latex paint. As a last ditch effort, drench the soil around the tree after it flowers (if possible) with a borer systemic insecticide and don’t eat the fruit for at least 12 months after the application. Which came first? Here sun damage eventually led to borer damage.

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If Fruit Trees are Planted Correctly They Can Take the Heat

Leave a Comment / borers, newly planted, planting, sun damage /

 Dig the hole three times WIDER than needed. Plant in a wet hole. Amend or mix that soil or bring in different soil. The planting hole is dug three times wider than you need it. Amend or mix the soil with about 20 to 30% of a very good compost. Mix in a good compost when planting. Stake all fruit trees. Make sure the trunk cant move when you are finished. Stake fruit trees, all of them, so the trunk can’t move. Protect the fruit trees from rabbits with chicken wire for the first three to four years if you live near a golf course or an open desert. Put at least two inches of mulch (wood chips that rot) on top of the soil. Three inches is better. Keep it 6 to 12 inches away from the trunk until the tree is six years old. These are wood chips from whole entire trees, not bags of wood bark. Water every other day or every third day, wide and deep.

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Fruit Trees Like Hot Weather if Prepared for It

Leave a Comment / fruit trees, hot weather, soil preparation, watering /

Q. Now that it has gotten hot, my fruit trees (some new, some established) don’t look so good. When fruit trees are fist planted, if they are not planted right they will look a bit rough. Their looks will improve with time if these deficiencies are corrected. If their size (and increased water use) and soil improvement is accounted for when watering they will look better and better. A. When fruit trees are first planted, they may look good. That is because they are watered correctly for the first three or four years. After that fruit trees get bigger, and need more water applied wider and to the same depth. This means more water! Don’t change how often they are watered. When they are watered, they need to be watered to the same depth, to a wider area (which means more water) and with an increasing amount of water each time they are watered. This is because they are bigger, and water should be applied to a wider area. When fruit trees are first planted (when the weather is cooler) they need water every other day, improved soil and soil put in a flat and level moat around the tree to capture it.             What I find to be effective is to apply water to the area under a mature fruit tree (seven years in the ground and longer) that is about six to seven feet wide. Much of the area watered depends on the soil you have but most soils are (even though they are hard when dry) a sandy loam when irrigated. I prune fruit trees (in the winter) at seven feet and let them grow during the year to close to 8 or 9 feet tall, not their full size. This pruning allows for ladder-less fruit harvesting. When the fruit tree is three or four years in the ground the tree is pruned to establish the major fruit bearing limbs             To do this I water the fruit trees to about 18-24 inches deep in the soil. The area I want to apply water is about half the area under the fruit trees. This usually requires about 8 drip emitters (or two concentric rings of drip tubing with emitters placed 18 inches apart) when the fruit trees have been in the ground 5 to 6 years. The rings are spaced18 inches apart, too! The fruit trees are planted about ten feet apart in all directions. I prune them so they fit into this area, and you can walk around them to harvest, fertilize, and prune. Limbs are only removed at the bottom if they touch the ground. Otherwise picking fruit starts at the lowest limb!!!!             Figs are good to have in the orchard because, in my experience, they grow but will not fruit if they come up short on water. Fruit is the first to go, not growth. If you have fruit on your fig trees in July and August, then the other trees are getting the right amount of water too. Figs are a “water indicator” fruit tree for me. Fig trees, as all fruit trees, are big solar collectors. If you cant reach the fruit it is wasted. If the fruit is too low it is wasted. If the fruit is too close together it is wasted.

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Low Water Use Plants Need Water in the Desert

Leave a Comment / desert plants, irrigation needs, water /

Q. Over a year ago our city planned a new extension to a community Park and put in a dirt trail surrounded by “native plants”. They dug wells and put in an assortment of plants and trees with no water source. The first month they used a fire hose from the hydrant to water the plants. Since then, nothing. I counted over 185 dead plants this morning. My question to you is there certain plants for that zone or location that will be able to survive without any water? Cleveland sage is best planted on the east and north sides of a building. It comes from the Baja and coastal California where it grows best in a Mediterranean climate.  Water to get it established and then not more often than about every two or three weeks. A. Not really, no. Even cacti occasionally need water to get established and grow after planting. Cold hardy desert plants are best planted in the fall; winter tender plants in the spring. In very dry summers, desert plants will need supplemental water once a month or more during the summer to look good and survive. Cities and homeowners are not Mother Nature. Even so-called desert plants need water occasionally (and usually some soil improvement) periodically/regularly/deeply to look their best. Homeowners won’t tolerate plants that look bad. Opuntia, or bunny ears cactus, are native to all over the desert southwest including the Mojave desert. To get growth water them about every three weeks in the summer.             For each plant that makes it in the desert after a rain, thousands of plants don’t. The advantage of desert plants is their ability to survive periods of time without water. To think we can guess where plants will survive after planting is pure arrogance. Desert plants respond to water. They respond best when the water is applied to the same spot. They respond by growing. Texas sage or ranger (the barometer plant) hates, hates, hates to be trimmed by a hedge shears unless its growing as a hedge. This is what happens. Water it about once every two or three weeks or when the leaves start to drop.             Some, like Texas ranger (the barometer plant of the Chihuahuan desert) produce flowers on new growth after a rain. As these desert plants get drier, they first drop their leaves (if they have any). Even cacti will put on some new growth after a rain and may even flower!

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Grape Bunch Disease Need Applications of Fungicides in the Spring

Leave a Comment / botrytis, bunch rot, control, grapes, mildew /

Q. I am a big fan of your RJ newspaper column, but I haven’t seen any answers about what’s happening to my grapes. Please advise. This the stuff isn’t on all my grapes. I have four plants and maybe 10-15% have this white stuff on certain bunches. This is from the reader and I would call it a “bunch rot” a bunch disease that must be controlled in the spring, according to the fungicide label. Most homeowners use a “copper based fungicide for control. A. It’s a disease of the bunches; a “bunch disease”. I thought this might happen mostly because of our wet spring. Bayer tells us, when treating for grape bunch diseases, that about half of the improvement is due to better air circulation and the other half using a copper-based fungicide. They are right! Collectively, both downy and powdery mildew are called “bunch diseases”. The fungicide must be applied right after a rain or during high humidity days just after it flowers. Grapes flower in mid March in Las Vegas. One of the bunch diseases later in the summer (about May) from about three or four years prior. To late for the first application of most fungicides but give it a try.             This looks like one of the grape diseases, probably grape downy mildew. Try removing bunches and leaves so that you have one bunch every foot. If it is tight with leaves, remove some of the leaves as well to improve air circulation. Don’t remove too many leaves so that you get direct sunlight on the grapes or limbs. You want to improve the air circulation around the bunches and the berries but without putting the bunches (and limbs) in direct strong sunlight for any length of time in the desert. One of the grape bunch diseases from a few years ago in Las Vegas.             You can apply a spray mixture of a copper-based fungicide according to the label. Liqui-Cop and Bordeaux sprays come to mind, but any copper-based fungicide (a fungicide that includes copper in the ingredients) should work. You may have to repeat the application. Read the label.  Warning. Grapes must be on the label of a fungicide because of testing and recommendations concerning the rate of application. One of the many copper-based fungicides. Check the label to make sure your crop and rates are mentioned.             Remember fungicides help prevent plant diseases but do not “cure” the plant of a particular disease. You are spraying early to prevent the spread of a bunch disease. There is some evidence that Neem oil has given some protection, but copper-based fungicides are better. Grape leaf removal around grape bunches to improve the air circulation.             You may be too late with a spray of any kind, but it is worth a try. Do it very soon and follow label directions for controlling these “bunch diseases” on grapes. Next time apply your favorite spray earlier in the season, right after rain or during high humidity, to prevent the spread of “bunch diseases”.

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Wittwer Vegetable Primer Available

Leave a Comment / Mojave Desert, raised bed garden, vegetable garden /

Q. I received the Wittwer vegetable “bible” but I must admit, I’m a little confused by the title, as It seems to be pertaining to Moapa and Virgin Valleys and not the Las Vegas Valley.  As longtime residents of the Las Vegas Valley, don’t those valleys have a different climate than the Las Vegas Valley? Dr. Sylvan Wittwer’s vegetable garden in Logandale, Nevada, eastern Clark County in southern Nevada. Vegetable growing conditions are similar to Las Vegas. A. Yes, they do. It is slightly different, a bit warmer to be exact. The climates between the two valleys are very similar. Both valleys are in the Eastern Mojave Desert. It’s hard to find information from a source like Dr. Sylvan Wittwer for the Las Vegas Valley. Dr. Sylvan Wittwer was the past extension vegetable specialist for Michigan State University but originally from Hurricane, in southern Utah in Washington County.             Dr. Wittwer was the retired Vegetable Specialist from Michigan State University when he moved to our eastern Mojave Desert climate. He grew vegetables in this climate for eight years before he moved back to Utah. It’s difficult to find reliable information in the Las Vegas Valley from such a notable source. If you want, contact me at [email protected] and I will email you the entire pdf copy.

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