Xtremehorticulture

Xtremehorticulture of the Desert

Spanish Dagger (Yucca) and Curve-Leaf Yucca are Not Cacti

Leave a Comment / Spanish dagger, yucca /

Q. I have a five-foot yucca tree that I cannot get to be disease free after two years of trying.  I have tried the following chemicals; Bayer Advanced complete Insect Killer, Bonide Thuricide and Bonide Tree and Shrub Insect Control Systemic. Any suggestions on how to save it. Judging from the picture and your problems it might be Spanish Dagger, a native of the SE part of the US. Spanish Dagger, Yucca gloriosa, does not handle the heat and should not be planted in south or westerly landscapes. Not sent to me by the author. A. Judging from the picture you sent to me your yucca tree is Yucca gloriosa, a.k.a. Spanish dagger. Spanish dagger is a yucca native to the SE that gets brown spots on its leaves that resemble disease but it is either planted in the wrong location or planted incorrectly or both. This plant is both mesic (high in its water use) and not a desert yucca native. Looks like Yucca recurvifolia (aka Y. pendula) another yucca native to the southeastern and southern US that may scorch if planted in a hot location. Readers picture. Spanish dagger is an Eastern coastal native from South Carolina to Florida. If planted in our desert Southwest, this yucca will look diseased if it’s planted on the West or South sides of a home, surrounded by rock, or watered like a cactus. Because it’s a native of the southeastern United States, Spanish dagger should be planted so that it gets shade in the afternoon; on the East or north side of a home landscape in afternoon shade. Also, plant it with compost amending the soil and surrounded by other mesic plants to help moisten the soil.

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Increase Grape Berry Size by Thinning Fruit Early

Leave a Comment / berry size, grape, naturally /

Q. When do you harvest green grapes and how do you increase their individual size? ‘Italia’ seeded grape ready for harvest in North Las Vegas. A. Increasing the size of the berries (individual fruit) is a two-step process starting when the berries are very small. The correct time to begin this operation in our climate could begin as early as the end of March or the first part of April. At this time the berries have already begun to increase their size. The correct time to begin is when the berries are about the size of a young, early pea. Remove small clusters of grape berries when this size             First, leave only the large bunches and remove any small bunches. You want the average distance between bunches of about eight or 12 inches depending on how much was set. You want the remaining bunches to be big and long. Remove the bottom 1/3 of the grape cluster by pinching.             After removing the smaller bunches and getting the correct average distance apart, next reduce the size of each bunch by one third. Pinch the bottom one third of each bunch of grapes and remove it. It will decompose on the soil or mulch surface. The result is a fewer berries and fewer bunches. This results in larger fruit. 1. Keep an eye on your grapes in mid Spring. 2. When grape “berries” are young and pea-sized thin out the clusters. 3. Next pinch each remaining cluster so it is reduced by 1/3.             This is the “organic” method. There is an “inorganic” method involving spraying the bunches with hormonal sprays when they are increasing in size but the “organic” method should be adequate for most homeowners.             When to harvest is more difficult with green grapes than red grapes. Green grapes have a slight color change when they are ready to harvest. This change in color of the berries is from green to yellowish green or “bronzy” in color. To determine the harvesting date, taste a few of the berries. If the berries are to your liking, then harvest them. Birds begin their damage (pecking or stealing berries) when the sugar content rises in fruit. Seldom do they damage fruit when the sugar content is low unless they are a stupid or young and inexperienced. Whenever you start to see significant bird damage, begin harvesting ripe fruit. After the grapes are harvested there is little to no change in “sweetness”.

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Grape Berries Drying Up and Shriveling in Early Summer

Leave a Comment / berry, disease, grape, shriveling /

Q. The berries on my ‘Red Flame’ grape are shriveling and turning gray but the vine looks healthy. Do you know what the problem is? This is probably one of the bunch rot diseases, either powdery mildew or botrytis. Nothing can be done now. A. From the pictures you sent it’s one of the “bunch” diseases. The bunch diseases attack only grape bunches. At the beginning of summer is when we notice disease problems on the berries of grapes such as the so-called “bunch rots”. But that’s not the time to treat. Grape fruit (the berries) develop nicely up until that time and everything appears normal. But you can’t see the disease yet. This particular disease is either botrytis or powdery mildew of grape bunches. The cause was a fungal disease, and the grape vine needed a chemical spray for protecting the grapes in about late March or early April. There’s nothing you can do now. Fungicide sprays must be applied shortly before or right after the berries start developing.             Fungicides act differently than insecticides. Disease control using fungicides and bactericides must be applied months before the disease is seen. For homeowners, copper fungicides should be applied to these bunches (you must spray the entire vine) to protect the bunches from this disease. The exact disease name is not necessary but the fungicide is. You can apply a fungicide to your ‘Red Flame’ grapes now, but it won’t do you any good. The disease will continue and more grapes will turn “gray”.. The infection is already “inside” the berries but can’t be seen. The graying of the berries is a visual “sign” the disease is present. Using chemicals to control diseases is usually a “protective” spray. Controlling insects by applying insecticides are different. Very seldom are insecticides applied as a “protectant”; a.k.a., applied before we see the problem. Insecticides are applied usually as a “curative”; after we see they are present. How to know when to apply fungicides? Commercial growers use the weather and understand that if they don’t apply the right disease control there are risks that they could lose their fruit. If the weather is right, fungicides and bactericides may be applied to susceptible plants. Any time windy or wet weather precedes fruit development or flowering, disease control (fungicides, bactericides, viricides) are applied to highly susceptible plants.

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Correcting Lemon Mistakes Through Proper Pruning When Young

1 Comment / citrus, lemon, pruning, sun damage /

Q. Your Xtremehorticulture blog is an awesome source of information! I live in Phoenix and question why my ‘Lisbon’ lemon tree is failing after two years. It flowers in the early spring as it should, and produces fruit, albeit, its fruit is nasty and dry. The canopy is about 10% of what it should be, and I suspect sunburn has been choking the plant. I think the tree is a goner and thinking of removing it. ‘Lisbon’ lemon tree grown in Las Vegas and sun damage to the leaves. A. Yes, I think your tree may be sunburned. Give it a chance still. At two years of age, you might be able to nurse it back to health if you follow some easy directions. You live in the northern part of the Sonoran Desert. Las Vegas is in the eastern side of the Mojave Desert. All citrus including ‘Lisbon’ lemon are subtropical; this means the tree, unlike ‘Myers’ lemon, doesn’t survive freezing temperatures very long. And in your case our very strong desert sunlight. As the canopy increases in shade and size, giving more shade to the fruit and the tree itself, the fruit will improve. Guaranteed. Don’t let the fruit overripen before you pick it. That’s a no-no. This citrus tree was limbed up too soon and the trunk may develop sunburn in hot locations. You might be able to get away “limbing it up” like in the seaside and Mediterranean area of Portugal, where ‘Lisbon’ lemon probably originated, but it won’t work in the desert Southwest. Leave the tree shrub-like the first few years until it gets established and then slowly limb it up, making sure the trunk and limbs stay shaded, as it gets older. Citrus with a full canopy but exposed fruit still developed sunburn in Arizona. Make sure the soil has been amended at the time of planting. This is a subtropical fruit tree and requires more organic matter in the soil than we have in most of our desert soils. I would not surround this tree with rock or rock mulch on the surface of the soil. Instead, use a layer of 3 to 4 inches of wood chips keeping the wood chips away from the trunk the first few years of its life. As the wood chips on the soil surface decompose or rot in the presence of water, it will slowly add “organics” back to the soil. Rock doesn’t do that. The last thing to consider is planting the tree on the north or east side of your landscape, or at least 3 or 4 feet away from a hot west facing or South facing wall. It may or may not need it but it can help the tree. All fruit trees need about eight hours of sunlight each day, but subtropical trees can do without the 120°F heat common in Phoenix. If they are in good health, they will withstand the desert heat.

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A Black Fig is a … Black Fig

Leave a Comment / fig, fruit, growing, propagating /

Q. A friend gave my husband some fig fruits. This friend said the fig tree is just so full of fruits enough for all his friends and birds. They’re so sweet, very deep (almost black) purple, and small; about an inch around. Can you identify this fig please? Unknown “black fig” from homeowner.  A. There are many different black or dark purple fig fruit varieties. All the fig varieties do well in Las Vegas if there given enough water. I need more to go on than just the size and the color of the fruit. Varieties of black or purple figs include ‘Black Mission’, ‘Blackjack’, ‘LSU Purple’, ‘Violet de Bordeaux’. Celeste and others. From your description my guess would be ‘Black Mission’ but it’s just a guess. ‘Celeste’ fig ripe. Next March try rooting about ten stem cuttings from the tree if you want to preserve the fruit. You will have to label in “Unknown” unless you can discover the variety. Use a rooting hormone like Hormex #16 when you do it just to improve your chances of success. These are grape cuttings but it gives you the approximate size of stem cuttings. Dip the cut ends in rooting hormone to improve your chances of success. Birds can be a big problem since this fruit is ready to harvest the same day birds like them. Unlike some other fruit, figs are what we call “non-climacteric” which means they must be left on the tree until they are ripe and ready to be harvested. Other non-climacteric fruit include grapes, apples, pomegranates, and a few others. Bird pecked fig fruit.

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Desert Problems with Star Jasmine

Leave a Comment / chlorotic, leaf burn, leaves yellow, scorch, Star Jasmine /

Q. I have a Jasmine plant and it was flowering but not it’s not and not looking good. What is your call on it? A. Most times when people say they have a “Jasmine” plant they mean star jasmine. Star jasmine is not a true Jasmine, but the fragrance can be delectable which is true of most in that plant family. Star Jasmine, a vine or groundcover from warm areas of China, may develop iron chlorosis when grown in a rock mulch.             Star jasmine comes originally from China so it will like improved soils and dislike rock mulch. Whenever a plant comes from a non-desert area then try to plant it on the East side of your landscape. This area receives shade in the afternoon and is more hospitable to plants that are not from the desert. It can be grown as a groundcover or as a vine, but it must be tied to a trellis to get it to perform as a vine. Star jasmine grown near a door or window will provide a great fragrance to a home. Star jasmine needs an organic soil with woodchips covering it to look its best.             Most star jasmine in poor health are surrounded with rock mulch. If your star jasmine is in poor health, then surround it with wood chip mulch rather than rock mulch. When it’s planted, make sure the soil is amended with compost. Dig the hole three times wider than the container or its root system and add the amended soil to this planting hole. If it’s a 5 gallon or larger plant, then stake it. The wood stake that comes with many local nursery plants is adequate for smaller plants as long as it is pounded into the solid soil beneath it and retied with nursery tape. Most plants require only one season of staking and then it’s removed.             The only way to re-green yellow leaves is by spraying it with an iron solution. Early next spring, apply any iron chelate to the soil. For difficult yellow plants to “green-up”, use the EDDHA iron chelate applied to the soil in early spring.

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Weed Control Around Saguaro

Leave a Comment / desert, Weeds /

Q. I have a 25-foot Saguaro cactus with at least 7 arms in my Palm Springs landscape. My gardener just put Roundup around it to control weeds. We had this done a few years ago, and since then the Saguaro leans dramatically.  I didn’t want him to put it there. Saguaro cactus in a Sonoran landscape in Parker, Az. A. I wouldn’t spray Roundup close to it unless you protect the Saguaro. It says on the label to protect anything green because it is a general killer. It was developed originally is a grass killer but it will kill nearly everything if you apply the right concentration. The base of Saguaro will develop tough brown “bark” areas as it gets older. Even though it might be there, protect the base with cardboard when spraying systemic weed killers like Roundup.             An older Saguaro like yours should be developing some woody brown areas towards the base as parts of it remain green but that’s not enough. Anything you don’t want damaged or killed, protect it. An easy way to do that is a cardboard barrier to protect the Saguaro. After you’re finished spraying you can either remove it or just use it as a shield when you’re spraying Roundup close to it.

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Peaches Produce Fruit at Different Times With Different Flavors, Aroma and Flesh Color

Leave a Comment / flavor, location, peaches, terroir /

Q. Several years ago at the University orchard on Horse Drive you gave us a list of five different peach trees to plant, each ripening at different times. We’ve enjoyed peaches from May through September ever since. Thanks. ‘Earlitreat’ peaches on May 24, 2005, at the University orchard in North Las Vegas. Other good early peaches include ‘FlordaPrince’. ‘FlordaKing’, and ‘Earligrande’. A. I prefer to plant entire fruit trees, rather than a single tree with several varieties (think “fruit cocktail” trees). that ripen at different times of the year for many different reasons. Let’s talk about one of them. Peaches like this Early Elberta (‘July’ or ‘Kim’) make the next round along with ‘June Pride’, and ‘Snow Beauty’. Generally, the varieties of fruit trees that flower earliest produce the earliest fruit. In our climate peach varieties start flowering the first week of February and other later producing varieties of peach may start flowering as late as the as the end of April. Later flowering varieties frequently produce fruit later as well. Dont forget the flat peaches like ‘Donut’ and ‘Galaxy’. They produce fruit also around July. As examples, the peach variety named ‘Earlitreat’ begins flowering the first week of February. Other early producing peaches like ‘FlordaPrince’ and ‘FlordaKing’ start flowering about a week after ‘Earlitreat’.  If there is a frost while the flowers are open, think early spring through early summer, it produces less fruit or maybe no fruit at all! These varieties of peaches will produce fruit (if frost permits) in mid to late May until early June. Peach varieties like ‘Indian Blood’ may be worth the October wait due to its very special aroma and flesh color. The variety of peach called ‘Red Baron’ produces fruit around July but doesn’t begin flowering nearly a whole month later than ‘Earlitreat’; early March! By selecting varieties that flower early or later usually will affect when the fruit is produced. The missing information are the varieties that taste the best! Each peach variety is different, performs differently in the desert and tastes different. If a light frost occurs anytime between February 1 and the middle of March (estimated date for our last frost can be as late as March 15!) then we will be guaranteed fruit if we are growing several varieties of peach trees in the same location.

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