Xtremehorticulture

Xtremehorticulture of the Desert

Japanese Blueberry in Las Vegas Landscapes

Leave a Comment / japanese blueberry, planting recommendation /

Q. A local tree guide does not recommend planting Japanese blueberry because of “environmental challenges”. We had one at our old house and it was fine. It is the right size and shape for a spot we are considering. Young Japanese blueberry. It does not like the heat and isolation in Las Vegas landscapes. It prefers to be on the north or east sides of a home and surrounded by other plants that need water. The burlap bags on their head is to prevent them from getting sun damage. A. It gets pretty big over time. There are some things that favor it and some things that are not in favor of it. Let’s explore. Water use. In the desert this should be a concern with any plant we are thinking about. The fewer but important plants the better. It is mesic in its water use. It should be watered at the same time as other mesic plants. Try not to water xeric plants at the same time as mesic plants. Xeric (or desert) plants are watered less often than mesic (nondesert) plants. That is one of the reasons xeric plants use less water. Size. It’s slow growing but gets about the same size as European olive; 35×35. East side. It doesn’t like afternoon sun. Too hot for it on the South and West sides. Likes the east side with afternoon shade and surrounded by other plants that need watering. That and its mature size are probably the reasons it is not liked much. It is a low water using plant/shrub but not xeric. If you have the room for it and can afford the water then plant it. Put it on a water valve for mesic plants. Recommended plants for the Phoenix area.

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Wormy Apples a Problem with Honeycrisp Apples

Leave a Comment / codling moth, pheremones, spraying, trapping out, wormy apples /

Q. I have had wormy apples in our ‘Honey Crisp’ apple tree. Last year we had the same problem. I was told to spray a fungicide. I also sprayed Neem oil. I waited until the apples started to form. I still have these worms in every apple on my tree. HELP!!!  This is codling moth stuck on the sticky side of a pheremone trap. It is about 3/8 inch long and a true moth. Since the adult is a moth, the juvenile or immature form is a “worm” or larva. When populations are large they produce “wormy apples”.  A. I am guessing that you are dealing with codling moth. This is a common pest of apples and pears. They appear as “wormy apples”. They are creamy white and about 3/8 inch long when they are mature. Usually, they have a brown head. They start getting into the fruit when the fruit is small and may continue to feed as the fruit gets larger. You can read more about codling moth control by searching for “codling moth” and “IPM”.  https://ipm.ucanr.edu/PMG/PESTNOTES/pn7412.html The most reliable site is from the University of California. If this is codling moth, then picking and get rid of small fruit which is infested is the first step.  When the codling moth is flying, the moth will “sting” a small fruit causing it to drop. If it happens when the fruit is larger, it may stay on the tree. Look up for “stung” fruit or look at the ground for fallen fruit. Fruit produced later will have a larger percentage of stung fruit. Look for fruit tree species that are produced and harvested early.  Otherwise, their population continues to increase as the apple stays on the tree longer. Apples that stay on the tree longest are the most heavily infested. On the flip side, apples harvested early are the least infested. Populations of this pest increase with each generation produced. In our climate, expect codling moth to have three or four generations each year so start getting rid of infested fruit when the fruit is small. With each generation the numbers of these moths will increase and increase as the year progresses.  Start picking and getting rid of infested fruit starting about six weeks after it flowers. You can recognize infested fruit because of the brown frass coming out of it. The places where frass coming from the fruit are called “stings”. Stings are egg-laying sites by the female moth. Fruit that has frass coming from it will either fall from the tree or stay on the tree and get “wormier”. When you remove this fruit early, the population of “worms” has a better chance of staying low.  As fruit gets older, the “worms” get bigger and tunnel into the fruit deeper. They might feed on the seeds of these fruit before they pupate into a moth.  I have had good luck spraying either Bt or Spinosad several times over one season. Follow label directions. I have also had good luck if I use pheromone traps and get rid of them using these traps. I use one trap for every three or four trees.  This codling moth has already exited. Notice the “frass” left behind when it exited. Usually, pheremone traps are used for timing the application of sprays but when populations are low, I have had good luck “trapping them out”. Those traps should be put in the trees when the trees begin flowering or at least a couple weeks after they start to flower. Pheremone traps for codling moth can be bought from several places online. Look for them. The pheromone must be replaced regularly as per the instructions. Those wormy apples you got probably came from a neighbor who did not control them. This is a winged trap. More popular are the three sided “delta traps”. The winged traps, in my opinion, are better for repelling the moths. That is, better for using pheremones to keep fruit free of “worms”. The pheromones have better air circulation in those kinds of traps, the pheremones must be changed out more regularly, and the traps more concentrated. The delta traps are best for monitoring moths and telling you when to spray pesticides.

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When to Fertilize Cacti

Leave a Comment / cactus, fertilizer /

Q. I have some cacti in my backyard.  Should I fertilize them and when? When cacti flower they need high phosphorus fertilizer. A rose or tomato fertilizer should work. A. The standard answer is to fertilize them lightly in the spring of each year. That is the standard answer. The purpose of fertilizer is to give the plants what they need or what is lacking in the soil. Once plants have what they need, stand back, and give them a chance to grow. Giving more fertilizer than they need, and watering plants more often, does not necessarily make them grow faster. Fertilizers are not a magic “on and off” switch; you can’t force plants to get larger and bigger by giving them more fertilizer than what they need. All plants have a genetic “maximum” at which they can grow. That is why most cacti grow slowly, and other plants may or may not, depending on their “genetics”. For cacti, it depends on the fertilizer level, watering and soil mix besides their “genetics”. There is one fertilizer exception and it is a bit tricky. Nitrogen fertilizers increase the speed at which any plant, including cacti, get larger but you must be careful. There is a danger from “growing too fast” for all plants including cacti. The fancy term is “luxury consumption”. To maximize growth, apply nitrogen fertilizers no more than twice during their growing season. Be judicious when watering them and don’t let the soil stay wet. But if your cacti are growing well without it, then don’t use it.

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How Does ‘Little Miss Figgy’ Perform in Southern Nevada?

Leave a Comment / desert, Figs, Little Miss Figgy /

Q. I just purchased a dwarf fig tree (“Little Miss Figgy) at the fall plant sale at the Springs Preserve. I was planning to put it in a planter on the north side of my house which in the summer gets full sun, but which now is getting a lot of shade. Is that a dealbreaker for the fig? I have never grown Little Miss Figgy in our climate but, like most figs, it should do well. It is smaller and may be suitable for container growing. The trend now is for smaller plants and earlier production.  A. It should be fine with that amount of light on the north side of a home. All fruit trees require at least six and prefer to get a minimum of eight hours of sunlight every day when in production. That includes fig trees. It is a small tree (suitable for container production, 6 to 10 feet tall by 4 to 8 feet wide) and develops dark purple fruit with red “pulp” or interior. It was a chance mutation of ‘Violette de Bordeaux’ fig from South Carolina. I have not grown that variety, but all varieties of figs seem to do well in our climate. At that size, a 15-gallon nursery container should be adequate. Most people growing fig trees in the ground don’t water it often enough when it starts into its second batch of fruit and temperatures are higher and therefore its water use is higher as the season gets warmer. Because it’s smaller, it should use less water (but not watered less often) when planted in the ground and can rely on other sources of water that the soil might provide.

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Saving Water Through Landscape Design

Leave a Comment / conserving water, growth, mesic, shade, xeric /

           Designing a landscape for only energy conservation (an example is lowering the cost of running the air conditioner) is quite simple. All you must do is ask yourself, “Which sides of the home are the hottest?” Create shade on the walls and windows close to the house for these hot sides. Try not using plants when you do this. Use them if you must. Creating shade that doesn’t use water requires more “brainwork” but may be necessary in the desert. Usually, the hottest areas are the exposed South and West walls and windows of a home. If you don’t know which sides are hot, use a “temperature gun” (infrared laser for measuring temperature) during the hottest times of the day. You can buy an inexpensive but accurate gun for less than $25. The hottest areas are typically handled by shading the walls and windows on these hot sides rather than shading the roof. Roofs are usually better insulated than the walls and, in particular, windows. Selecting plants to save summer electrical cost is quite simple since shading the south and west walls and windows is most important. Select plants that are “winter deciduous” so that the sun warms the house during the winter months. If water is plentiful, how much water these plants use is not important. To lower electrical costs, regardless of water, always shade the hot walls and windows of a home. Irrigation design is important. I can’t stress the importance of using “hydrozones”. Hydrozoning is when the valves control when to water plants. Xeric (desert) versus mesic (nondesert) plant water use relies on how frequently each are watered. Use mesic plants when water is provided to them at the same time. How deep plants are watered is adjustable by adding or subtracting drips. How frequently they are watered is not.  Xeric plants are not watered as often as mesic plants if you want to conserve water. This means plants are matched to a specific irrigation valve; xeric plants are put on one valve and mesic plants are put on a separate valve. This means you must know the difference between xeric (desert) and mesic (nondesert) plants. Xeric or desert plants will grow more rapidly than mesic, or non-desert plants, if they are watered like mesic plants. That’s just they way they are. Xeric plants are more “adjustable” in their growth if they are all watered at the same time, and you can adjust the frequency of watering. When mesic and xeric plants are placed on the same valve, mesic plants will signal you to water and not the other way around. When water is scarce, xeric plants (desert plants) tolerate dry soil better than mesic plants. They have capabilities of saving water through many different traits including leaf drop, changes in leaf and plant size, as well as changes to the plant at the genetic/molecular level. Xeric plants handle water shortages more efficiently than mesic plants. Being from the desert, xeric plants have evolved to soil drought. Water xeric plants less often. This means watering them with a separate irrigation valve (hydrozones). Because of this, xeric plants can get by (and often benefit) when watered less frequently than mesic plants. For instance, foothills (not Blue or ‘Desert Museum’) palo verde (Parkinsonia microphylla or Cercidium microphyllum, depending on the source of its scientific name) is a true xeric, desert, or low water use plant. It grows in flat, dry areas throughout the Sonoran Desert of the American southwest. It can survive in dry soil for long periods of time. They can’t survive without any water, but they will require watering, deeply, less often. When water is limited, xeric plant growth first begins to slow or stop. That can be hard to see. Controlling their size, controls their water use. If dry soils continue, xeric plants start dropping their leaves. That is easier to see. Fewer leaves mean there are fewer leaves present to lose water. The canopy begins “thinning out.” It’s time to water! If the soil continues to remain dry, then remaining leaves begin scorching and branches begin dying. Plants are starting to look bad. In the case of cacti, their stems may begin to shrivel. You don’t want limb dieback, or cactus shriveling, in a landscape. That’s not pretty. On the flipside, they may not look the best when that dry spell is over, but at least they have survived! In a landscape, deeply watering these plants once every 4 to 8 weeks is usually enough. Observing xeric plants regularly (once a week in the summer) will tell you if it’s time to water or hold off. Branch dieback in palo verde and other trees (mostly mesic) can be confused with the palo verde root borer. Occasionally a single, isolated branch will begin dying back to the trunk during the summer if these insects have been feeding on the roots. In cases like these, a systemic insecticide for borers might be the only solution available. As with other plants, apply this insecticide only after flowering to avoid the risk of hurting pollinators like honeybees. How much water is applied is controlled by the size of the emitters (two-, three-, four-, or 5-gallon drip emitters) or a moat surrounding trees and shrubs. For 10- to 12-foot-tall trees, flat moats about 6 feet in diameter, and 2 to 3 inches tall, will work. Figure that in most level soils, 1 inch of water will wet roots about 15 to 18 inches deep. My experience tells me that at least half the area under the tree’s canopy should receive this water. Once the roots of a tree are watered deeply enough, the only changes that need to be made to an irrigation timer are seasonal. If you try grow deep-rooted, xeric (desert) trees in a fescue lawn (called a mixed landscape which I don’t recommend), the tree frequently dies, or “wiggles” in the soil. This is because it is watered every day the

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Black Spots on Octopus Agave Leaves

Leave a Comment / agave, black spots on leaves, disease, leaves /

Q. Is there something we need to do for these spots on the leaves of my octopus agave? A. I think this is a fungal disease that favors a higher humidity than we normally have in the desert. The disease was caused and spread by the rain and wind that we had earlier. You don’t want any fungal disease spreading to the mainstem. To prevent that, you can apply a common landscape fungicide to the cactus after you have a repeat of the rain and wind event. Watch your weather app. If your weather app says the rain is returning, apply the landscape fungicide the day after it occurs. Broad-based landscape fungicides are meant to prevent the spread of many different types of disease. Fruit and vegetable growers use copper-based fungicides as a protectant for many different kinds of foliar diseases. To be used effectively, and like most fungicides, they must be applied before the presence of disease. Organic fungicides are the only organic option worthwhile against diseases such as late blight and downy mildew. Think tomatoes, peppers, eggplant, and potatoes. These diseases have the ability to kill plants. Copper is also an essential nutrient for plants but use it sparingly. Copper fungicides, like this one from Bonide, help prevent widespread infections of many more diseases when they are caught early enough. When used occasionally, copper is also an essential minor element for plants. In the meantime, prune out any black “spots” or lesions that you see in the stems. I think these are fungal lesions with dormant fungi waiting for the next rain event to make it active again. Sanitize between any cuts to eliminate re-infecting the plant. Use 70% ethyl alcohol to sanitize a knife or pruning shears. Using both the fungicide after wet weather and cutting out the black spots helps eliminate future problems. Make sure you’re not overwatering it and improve soil drainage around its roots. Octopus agave originates in the Sonoran Desert of Mexico therefore it doesn’t like getting watered too often. For instance, it will not survive in a lawn. Take it off the irrigation controller and hand water with a hose. Watering these plants once with a hose only gets the water 3 or 4 inches deep. Water these plants five times a year; only three or four times during the summer and once during the winter. The soil must be dry between waterings!

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Fertilizing in the Fall?

Leave a Comment / fall, fertilizer, iron, nitrogen /

Q. Is it too early to fertilize now my oleanders, lantana, rosemary, and chase tree? This could be temperature, nitrogen or iron. Try different fertilizers. If you find the right fertilizer it will become darker and greener. That’s how you know its a fertilizer problem. A. You can fertilize now (October) and skip the spring application. Woody plants put nitrogen fertilizer (whatever is “left over”) into “storage” until spring. The only plants you want to skip are the so-called “winter tender” plants which you don’t list (except the tops of lantana which are damaged at 32F). Those are the plants which are sensitive to winter cold damage and include most of our citrus and freeze tender plants like bougainvillea. You don’t want to stimulate new growth that could be damaged by freezing temperatures. This might include the more tender dwarf salmon colored flowered oleanders (5 foot and tender at 20F) but not the traditionally big ones like the reds and white flowered types (18 foot) which are cold hardy to about 10F.             Skip fall soil applications of iron fertilizers and wait to correct yellowing due to iron in early spring. Plants will respond to soil applied iron fertilizers best in the early spring. Fall applications of iron fertilizers are best when sprayed on the leaves. Use liquid detergent like dishwashing soap or (best) use a spray surfactant such as a wetting agent when you spray. Also it is best to use distilled water so the pH is not alkaline or acid. Better for iron uptake by the plant through its leaves. Makes more iron available.

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Different Types of Sago Palm (Cycad)

Leave a Comment / cycad, sago palm, species /

Q. Have you ever seen a sago palm that has different types of leaves and fronds? I can’t find any pictures of a sago that look like this.  Also, mine grew extremely fast, in a matter of weeks. I purchased the sago with the original fronds that are dark colored.  The tree had been living about 6 feet from a windmill palm tree.  Do you think it could have crossed? Even if sago palm (cycad is a better term, Cycas revoluta) is located on the north side of a home it still has a browning on the leaflet tips because of our low humidity. This sago palm can handle colder temperatures than other types. A. First of all, the sago palm is not a palm at all. It is just called a type of palm which its not. Each sago palm has evolved different strategies to handle where they are from. There are different types or species and even genera of sago palms. These are based upon their appearance, how big they grow and where they are available. Most are classified as the King sago palm, Queen sago, Queen sago palm and (a totally different genus and species) and the true sago palm to name just a few. The king sago palm, or Cycas revoluta, is the most widely grown type and most commonly available. The king sago palm is quite small, growing only to about 8 feet tall and 8 feet wide, making them small enough to qualify as an “indoor plant”. This is a queen sago palm (Cycas circinalis) is from a large nursery in central India. It is native to southern India and grows about 12 feet tall and 12 feet wide in hot, humid climates.   https://www.naturenursery.in/product/queen-sago-palm/             Sago palms come from a variety of climates but mostly tropical or semi tropical. Lots of different kinds to pick from if you can search online or buy them from out-of-the-way places. I occasionally look at Lowe’s and Home Depot’s garden centers for occasional “deals” but you have to know what you’re buying or at least willing to take a loss if you don’t. Rare sago palms can also be purchased from nurseries online as well as eBay.             All the information is the same regarding the fast-growing sago palms. They prefer to grow on the east side away from direct sunlight or at least in what we call “filtered” or speckled light. They also prefer to grow in amended soils and not in rock mulch. Some of them like warmer climates than others. Each one has evolved differently.             Be careful of fast-growing sago palms or cycads. It usually means they become larger than most others. Most sago palms are characterized as “slow growers”. I don’t know which type you have but some are meant for interiors and not the winter cold outdoors. Be careful unless you know what you are looking for. Use the scientific or Latin name when possible. Sometimes nurseries will confuse them and sell you one that you are not expecting. Even the pros get it wrong sometimes.

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Do Pine Needles Make a Good Compost?

Leave a Comment / compost, pine needle, pine needles, soil amendment /

Q. Should I leave the pine needles around the basin of the trees, or should I rake them out and pick them up? I feel that cleaning them from under the trees helps the water penetrate into the soil quicker and not sit on top of the needles.  My part-time gardener says I should keep them around the trees so that they act as a mulch.  Which is correct? In the desert, pine needles mixed with other ingredients for compost, add nutrients to the soil.  A. Your gardener is correct but in a reverse sense you are too! If you can stand leaving the pine needles in place, (they do not make the soil more acidic, and if they did, what’s wrong with that?) they will decompose (provided the soil is kept moist) more slowly than fine woodchips. But they will decompose. These decomposing pine needles add to the soil nutrition and soil organic content. If there is enough of them (2-3 inches deep) they conserve soil moisture, add organics to the soil as they rot, keep the soil cooler and help prevent annual weeds. Pine needles make a good compost even if they don’t rot as easily as some other ingredients and, in desert soil where a lack of acidity is a problem, can maybe help to pH lower! A common problem reported has been that they create acidity when they rot. In the desert, who cares? Our soil needs it.             Rake the pine needles so they are 2 -3 inches deep under at least half of the canopy of the pine tree. If the trees are not yet ten years old (or bark has not started to develop on the trunk) then keep them away from the trunk 6 to 12 inches (keep that soil uncovered and dry).

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Explosion of Caterpillars in the Desert

Leave a Comment / caterpillar, hummingbird moth, larva, sphinx moth /

Q. This is a photo of a caterpillar that is on most of the plants in our neighborhood. Do you know what it is and what we can use to get rid of them? Caterpillar explosion in the desert after a rain. This probably the caterpillar or larva form of a sphinx moth. A. A caterpillar explosion, just like in the picture, has occurred all through Las Vegas and Arizona where it’s been raining and, because of the water, food supply is abundant. Caterpillars like these can be a common sight where there are so-called “summer monsoons” and rains such as found in central and southern Arizona and this year as far north as Las Vegas. Southern Arizona (Sonoran desert) gets more than double the water than the Mojave desert so there is a lot more food to sustain “caterpillars”. https://dbg.org/yellow-hornworms-invade-phoenix/ https://www.usatoday.com/story/news/nation/2014/09/24/monsoon-season-leaves-arizona-crawling-with-caterpillars/16186181/             They should be easy to control with soap and water sprays, Neem oil as well as any commercial pesticide available such as Sevin. It’s important to follow any label directions present for the right dosage and spray these immature insects. After they die from any kind of pesticide, then there’s always the cleanup.             However, this year’s “hatch” has been particularly large in southern Nevada compared with previous years. Two years ago in Tucson, Arizona, the hatch was a large one due to summer monsoons like we had in Las Vegas. The conditions must be perfect; several large rains following each other which cause plants to grow and provide food and coverage. Sometimes this food might be our vegetables, landscape plants, and fruit trees. Sometimes this food is found only in the desert.             These caterpillars are usually the white-lined sphinx moth (hummingbird moth) painted in a lime green or yellow with black longitudinal stripes, with or without a spine on the end. These insects sometimes act as pollinators just like butterflies, flies and other flower loving insects. After they have gained the right size, they drop to the ground and develop into the sphinx moth in moist soil. On the negative side we might see a burst of pest problems in our tomatoes and grapes due to their munching. So be prepared!

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